Heterodiazocines: Synthesis and Photochromic Properties, Trans to Cis Switching within the Bio-optical Window.

Science.gov (United States)

Hammerich, Melanie; Schütt, Christian; Stähler, Cosima; Lentes, Pascal; Röhricht, Fynn; Höppner, Ronja; Herges, Rainer

2016-10-04

Diazocines, bridged azobenzenes, exhibit superior photophysical properties compared to parent azobenzenes such as high switching efficiencies, quantum yields, and particularly switching wavelengths in the visible range. Synthesis, however, proceeds with low yields, and derivatives are difficult to prepare. We now present two heterodiazocines which are easier to synthesize, and the general procedures should also provide facile access to derivatives. Moreover, both compounds can be switched with light in the far-red (650 nm). Accessibility and photophysical properties make them ideal candidates for applications such as photoswitchable drugs and functional materials.

Naphthalene-based fluorophores: Synthesis characterization, and photophysical properties

International Nuclear Information System (INIS)

Feng Jinwu; Chen Xiaopeng; Han Qingchuan; Wang Hongbo; Lu Ping; Wang Yanguang

2011-01-01

U-type, 1,8-diarylnaphthalenes and 1,8-diarylethynylnaphthalenes were synthesized and their structures were characterized by spectroscopic methods. Emission performance of these compounds with donor and acceptor was largely depended upon the solvent polarity and environmental acidity, which implied that they might be used as solvent polarity sensors or pH sensors as well. Moreover, some 1,8-diarylnaphthalenes exhibited aggregation-induced emission enhancement (AIEE) based on their photophysical investigation and might be used as light emitting materials for optoelectronic applications. - Highlights: → 1,8-Diarylnaphthalenes and 1,8-diarylethynylnaphthalenes were synthesized. → Emission of these compounds depended on solvent polarity and environmental acidity. → Some 1,8-diarylnaphthalenes exhibited aggregation-induced emission enhancement.

Synthesis of novel styryl derivatives from 4-chloro-2-(morpholin-4-yl)-1,3-thiazole-5-carbaldehyde, study of their photophysical properties and TD-DFT computations

International Nuclear Information System (INIS)

Sekar, Nagaiyan; Umape, Prashant G.; Padalkar, Vikas S.; Tayade, Rajratna P.; Ramasami, Ponnadurai

2014-01-01

Novel fluorescent styryl push–pull compounds having electron donating thiazole unit were synthesized by condensing 4-chloro-2-(morpholin-4-yl)-1,3-thiazole-5-carbaldehyde with active methylene compounds via classical Knoevenagel condensation. The synthesized styryl molecules were characterized by spectral analysis. Photophysical properties of these styryl derivatives were analyzed and the effect of change in solvent polarity and viscosity on their absorptive and emissive properties has been investigated. Density functional theory (DFT) and time dependent-density functional theory (TD-DFT) computations have been used to understand the structural, molecular, electronic and photophysical parameters of push–pull dyes. Bakhshiev and Kawski–Chamma–Viallet correlations were used to calculate the ratio of ground to excited state dipole moment of the synthesized novel styryl compounds. -- Highlights: •Novel styryl derivatives are synthesized from thiazole aldehyde. •Photophysical properties of styryl derivatives were evaluated and supported by TD-DFT computations. •Experimental photophysical results are in good agreement with the theoretical results obtained by TD-DFT computations. •Compounds show fluorescence in solid state as well as in solvents of different polarities

Synthesis and optical properties of water-soluble biperylene-based dendrimers.

Science.gov (United States)

Shao, Pin; Jia, Ningyang; Zhang, Shaojuan; Bai, Mingfeng

2014-05-30

We report the synthesis and photophysical properties of three biperylene-based dendrimers, which show red fluorescence in water. A fluorescence microscopy study demonstrated uptake of biperylene-based dendrimers in living cells. Our results indicate that these biperylene-based dendrimers are promising candidates in fluorescence imaging applications with the potential as therapeutic carriers.

The photophysical and photochemical properties of new unmetallated and metallated phthalocyanines bearing four 5-chloroquinolin-8-yloxy substituents on peripheral sites

Energy Technology Data Exchange (ETDEWEB)

Nas, Asiye; Demirbaş, Ümit [Department of Chemistry, Karadeniz Technical University, 61080 Trabzon (Turkey); Pişkin, Mehmet [Marmara University, Faculty of Art and Science, Department of Chemistry, 34722 Kadıkoy-Istanbul (Turkey); Durmuş, Mahmut [Gebze Institute of Technology, Department of Chemistry, PO Box 141, Gebze, 41400 Kocaeli (Turkey); Kantekin, Halit, E-mail: halit@ktu.edu.tr [Department of Chemistry, Karadeniz Technical University, 61080 Trabzon (Turkey)

2014-01-15

The synthesis and characterization of novel peripherally tetrakis-(5-chloroquinolin-8-yloxy) substituted metal-free (4), zinc(II) (5), lead(II) (6), cobalt(II) (7), copper(II) (8) and nickel(II) (9) phthalocyanines are described for the first time in this study. The spectroscopic, photophysical (fluorescence quantum yields and lifetimes) and photochemical properties (singlet oxygen production and photodegradation under light irradiation) of metal-free (4), zinc(II) (5) and lead(II) (6) phthalocyanines are investigated in N,N-dimetilformamid (DMF). The newly synthesized cobalt(II) (7), copper(II) (8) and nickel(II) (9) phthalocyanine compounds were not evaluated for this purpose due to open shell nature of these central metals in the phthalocyanine cavity. The influence of various the nature of the central metal ion (zinc, lead or without metal) on these properties has also been investigated and compared. -- Highlights: • The synthesis and characterization of novel peripherally tetrakis-(5-chloroquinolin-8-yloxy) substituted metal-free (4), zinc(II) (5), lead(II) (6), cobalt(II) (7), copper(II) (8) and nickel(II) (9) phthalocyanines. • The spectroscopic, photophysical (fluorescence quantum yields and lifetimes) and photochemical properties of metal-free (4), zinc(II) (5) and lead(II) (6)phthalocyanines in N, N-dimetilformamid (DMF). • The influence of various the nature of the central metal ion (zinc, lead or without metal) on these properties.

Pyridine-Based Conjugated Polymers: Photophysical Properties and Light- Emitting Diodes

National Research Council Canada - National Science Library

Epstein, A

1997-01-01

We study the photophysical properties of the pyridine-based polymers poly (p-pyridyl vinylene) (PPyV) and poly (p-pyridine) (PPy). The primary photoexcitations in the pyridine-based polymers are singlet excitons...

Novel nonplanar triphenylamine-centered oligofluorenes: Synthesis, thermal, photophysical and electrochemical properties

International Nuclear Information System (INIS)

Zhang Yujian; Ouyang Mi; Yu Chunhui; Hu Bin; Lou Qianping; Zhang Cheng

2011-01-01

A series of fluorene derivatives containing a triphenylamine (TPA) derivative core and two oligofluorene peripheries was effectively synthesized. These compounds are fluorescent and emission color ranges from blue to red. The spiro-skeleton molecular structure leads to excellent glass transition temperatures and weak intermolecular interactions. Simultaneously, novel nonplanar triphenylamine-centered oligofluorenes solve the spectral stability problem and hole-injection issue for fluorene-based materials. The photophysical properties of 6 and 7 are investigated in solvents with different polarities, which reveal the existence of the Charge Transfer (CT) excited-state in these molecules. - Highlights: → Novel nonplanar oligofluorenes consisting of triphenylamine (TPA) derivatives as the core and oligofluorenes as the peripheries were facilely prepared via CF 3 SO 3 H-promoted Friedel-Crafts and Suzuki cross-coupling reactions. → These as-prepared compounds effectively solve the spectral stability problem and hole-injection issue for fluorene-based materials. → The ability of hole-injection and emission color could be fine tuned by R substituent at the C4 position of TPA.

N-2-Aryl-1,2,3-Triazoles: A novel class of blue–green emitting fluorophores-synthesis, photophysical properties study and dft computations

Energy Technology Data Exchange (ETDEWEB)

Padalkar, Vikas S.; Chemate, Santosh B.; Lanke, Sandip K.; Sekar, Nagaiyan, E-mail: n.sekar@ictmumbai.edu.in

2015-12-15

Three novel 2-{2-[4-(N,N-diethylamino)–2–hydroxyphenyl]–1H–benzo[d]imidazol–6–yl} –2H–naphtho [1,2-d] [1,2,3] fluorescent triazole derivatives were synthesized from 2-(5-amino-1H-benzimidazol-2-yl)-5-(N,N-diethylamino)phenol and amino substituted naphthylsulphonic acids. The absorption, emission, quantum yields and dipole moments of these compounds were evaluated in methanol, acetonitrile, N,N-dimethylformamide and dimethylsulfoxide. The compounds 8a and 8c absorb in the near visible region, while compound 8b shows two absorption peaks, short wavelength peak is in the near visible region and long wavelength absorption in the visible region. Compounds are fluorescent in solution and emit in blue and green region. The photophysical properties of the 8a–8c were compared with structural analogs reported till date. The experimental absorption and emission properties were compared with the theoretical data obtained by DFT and TD-DFT computations with TD–B3LYP and CAM–B3LYP functional with 6–31G (d) and 6–311G (d) basis sets. Theoretical results obtained by TD-B3LYP functional are well in line with the experimental results. The compounds are thermally stable up to 300 °C. New compounds were characterized by spectral techniques. - Highlights: • First unique study of blue-emitting ESIPT triazoles. • Improved photophysical properties compared to similar analogues. • Experimental and TDDFT data on photophysical properties. • Dipole moments from solvatochromic data.

Type II photoinitiator substituted zinc phthalocyanine: Synthesis, photophysical and photopolymerization studies

Energy Technology Data Exchange (ETDEWEB)

Korkut, Sibel Eken [Department of Chemistry, Yıldız Technical University, 34210 Davutpaşa, İstanbul (Turkey); Temel, Gokhan [Department of Polymer Engineering, Yalova University, 77100 Yalova (Turkey); Balta, Demet Karaca [Department of Chemistry, Yıldız Technical University, 34210 Davutpaşa, İstanbul (Turkey); Arsu, Nergis, E-mail: narsu@yildiz.edu.tr [Department of Chemistry, Yıldız Technical University, 34210 Davutpaşa, İstanbul (Turkey); Şener, M. Kasım, E-mail: mkasimsener@gmail.com [Department of Chemistry, Yıldız Technical University, 34210 Davutpaşa, İstanbul (Turkey)

2013-04-15

The novel 4-(9-oxo-9 H-thioxanthen-2yloxy) phthalonitrile (TX-Pht) and its peripherally tetra substituted zinc phthalocyanine complex (TX-ZnPc) have been prepared and characterized by spectroscopic and elemental analysis techniques. Photoinitiated polymerization of methyl methacrylate (MMA) with TX-ZnPc has been investigated in the presence and absence of a co-initiator. Fluorescence and phosphorescence measurements have been also performed to determine the photophysical properties. Low fluorescence quantum yield (Φ{sub F}=0.08) compared to the unsubstituted ZnPc has been found. This allows initiator to undergo intersystem crossing into the triplet state and the lowest triplet state possesses π-π{sup ⁎} configuration. Highlights: ► Zinc phthalocyanine (ZnPc), peripherally functionalized with photoactive thioxanthone (TX) groups was synthesized. ► The photophysical and photochemical properties of resulting photoinitiator were studied in DMF. ► Photoinitiated polymerization of MMA with TX-ZnPc was investigated in the presence and absence of co-initiator.

Copolymers containing meta-pyridylvinylene and para-arylenevinylene fragments: synthesis, quaternization reaction, and photophysical properties

Science.gov (United States)

Barashkov, Nikolay N.; Olivos, Hernando J.; Ferraris, John P.

1997-12-01

We report the Wittig reaction of the diphosphonium salt of 2,6-bis(chloromethyl)pyridine with terephthaldehyde, 2.5- dioctyloxyterephthaldehyde, or 9,10-anthracenedicarbaldehyde to form conjugated copolymers with fragments of 2,6 - pyridylene and para-arylenevinylene. The protonation reaction of poly(para-arylenevinylene)-co-(meta- pyridylvinylene) with hydrochloric acid and the quaternization reaction of poly(2,5-dioctyloxy-1,4- phenylenevinylene)-co-(2,6-pyridylvinylene) with methyl triflate have been investigated by spectrophotometric and fluorescent methods. The absorption, excitation and fluorescence spectra of these copolymers as well as their corresponding model compounds were studied and compared. The photophysical properties of the investigated polymers suggest that these materials could be good candidates for the fabrication of efficient blue and green light-emitting diodes.

Synthesis, characterization and photophysical properties of ESIPT reactive triazine derivatives

International Nuclear Information System (INIS)

Kuplich, Marcelo D.; Grasel, Fabio S.; Campo, Leandra F.; Rodembusch, Fabiano S.; Stefani, Valter

2012-01-01

Four new reactive fluorescent triazine derivatives were obtained from nucleophilic aromatic substitution of cyanuric chloride. The compounds were characterized by infrared spectroscopy (IR), nuclear magnetic resonance ( 13 C and 1 H NMR) and high resolution mass spectrometry (HRMS MALDI). UV-Vis and steady-state fluorescence (in solution and in solid state) spectroscopies were also applied to characterize the photophysical behavior. The dyes are fluorescent by an intramolecular proton transfer mechanism (ESIPT) in the blue-orange region, with a large Stokes shift between 6365-10290 cm-1. The fluorescent cyanuric derivatives could successfully react with cellulose fibers to give new fluorescent cellulosic materials. (author)

Unprecedented Hexanuclear Cobalt(II Nonsymmetrical Salamo-Based Coordination Compound: Synthesis, Crystal Structure, and Photophysical Properties

Directory of Open Access Journals (Sweden)

Zong-Li Ren

2018-03-01

Full Text Available A novel hexanuclear Co(II coordination compound with a nonsymmetrical Salamo-type bisoxime ligandH4L, namely [{Co3(HL(MeO(MeOH2(OAc2}2]·2MeOH, was prepared and characterized by elemental analyses, UV–vis, IR and fluorescence spectra, and X-ray single-crystal diffraction analysis. Each Co(II is hexacoordinated, and possesses a distorted CoO6 or CoO4N2 octahedrons. The Co(II coordination compound possesses a self-assembled infinite 2D supramolecular structure with the help of the intermolecular C–H···O interactions. Meanwhile, the photophysical properties of the Co(II coordination compound were studied.

Analysis of the photophysical properties of zearalenone using density functional theory

Science.gov (United States)

The intrinsic photophysical properties of the resorcylic acid moiety of zearalenone offer a convenient label free method to determine zearalenone levels in contaminated agricultural products. Density functional theory and steady-state fluorescence methods were applied to investigate the role of stru...

6-Aminocoumarin-naphthoquinone conjugates: design, synthesis, photophysical and electrochemical properties and DFT calculations

Energy Technology Data Exchange (ETDEWEB)

Miranda, Fabio S.; Ronconi, Celia M.; Sousa, Mikaelly O.B.; Silveira, Gleiciani Q.; Vargas, Maria D., E-mail: miranda@vm.uff.br, E-mail: mdvargascp@gmail.com [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Inst. de Quimica

2014-01-15

Four novel 6-aminocoumarin-naphthoquinone conjugates were synthesized and their photophysical and electrochemical properties, investigated. 2-Chloro-3-(2-oxo-2H-chromen-6- ylamino)-1,4-naphthoquinone 1 did not present appreciable fluorescence in solution in comparison with 6-aminocoumarin, 6-AC. In order to understand the reasons for the fluorescence quenching in this compound, two strategies were attempted. Firstly, compound 1 was N-methylated to remove the intramolecular N-H...O=C electrostatic interaction that maintained the two units fixed, but the emission properties of the product 2 were not significantly different from those of 1. Time-dependent density functional theory (TD-DFT) calculations of compounds 1 and 2 indicate that the fluorescence quenching is related to the electron acceptor character of the naphthoquinone ring. The second strategy, therefore, involved the substitution of the chlorine atom in position 2 of the naphthoquinone nucleus for different electron donor groups (compounds 3-5), but again the emission properties did not change significantly. To explain these experimental findings, TD-DFT calculations of the ground (S{sub 0}) and excited (S{sub 1}) states of all molecules in solution were carried out. The results suggest that the energy states in these conjugates are such that the fluorescent group (6-AC) donates electrons to the naphthoquinone LUMO resulting in an oxidative photoinduced electron transfer (oxidative-PET). (author)

η6-Cycloparaphenylene transition metal complexes: synthesis, structure, photophysical properties, and application to the selective monofunctionalization of cycloparaphenylenes.

Science.gov (United States)

Kubota, Natsumi; Segawa, Yasutomo; Itami, Kenichiro

2015-01-28

The synthesis, structure, photophysical properties, and reactivity of cycloparaphenylenes (CPPs) coordinated to group 6 transition metal fragments are described. The η(6)-coordination of [9]CPP or [12]CPP with M(CO)6 (M = Cr, Mo, W) afforded the corresponding [n]CPP-M(CO)3 complexes (n = 9, 12; M = Cr, Mo, W). In the (1)H NMR spectra of these complexes, characteristic upfield-shifted singlet signals corresponding to the four hydrogen atoms attached to the coordinated C6H4 ring of the CPPs were observed at 5.4-5.9 ppm. The complex [9]CPP-Cr(CO)3 could be successfully isolated in spite of its instability. X-ray crystallographic analysis and computational studies of [9]CPP-Cr(CO)3 revealed that chromium-CPP coordination occurs at the convex surface of [9]CPP both in the solid state and in solution. TD-DFT calculations suggested that the emerging high-wavenumber absorption peak upon coordination of [9]CPP to Cr(CO)3 should be assigned to a weak HOMO-LUMO transition. Moreover, by using the complex [9]CPP-Cr(CO)3, a rapid and highly monoselective CPP functionalization has been achieved. The established one-pot method, consisting of complexation, deprotonation, nucleophilic substitution, and decomplexation steps, yielded silyl-, boryl-, and methoxycarbonyl-substituted CPPs in up to 93% yield relative to reacted starting material.

Synthesis and photo-physical properties of fluorescent 1,3,5-triazine styryl derivatives

Directory of Open Access Journals (Sweden)

Padalkar Vikas S

2011-12-01

Full Text Available Abstract Background Organic fluorophore contains well-defined D-π-A (Donor-π system-Acceptor push-pull system have wide application in the field of NLO, OLED and high tech application. Electron donor diphenyl, triphenyl and carbazole conjugated with electron acceptor terminal through π-system were reported recently for high-tech applications. N,N-Dialkyl substituted 1,3,5-triazine also acts as donor keeping this idea in mind we developed D-π-A styryl dyes. Results Novel "Y"-shaped acceptor-π-donor-π-acceptor type of compounds were synthesized from 4,4'-((6-(4-(diethylaminophenyl-1,3,5-triazine-2,4diylbis(oxy dibenzaldehyde (DIPOD as electron donors and different active methylene compounds as electron acceptors by conventional Knoevenagel condensation reaction. Their photophysical and thermal properties were investigated. Conclusion It was found that the strong electron acceptor-donor chromophoric system of these compounds showed high Stoke's shift and excellent thermal stability. Compounds showed positive solvatofluorism behavior from nonpolar to polar solvent. All compounds have good thermal stability.

Photophysical and photochemical properties of novel metallophthalocyanines bearing 7-oxy-3-(m-methoxyphenyl)coumarin groups

International Nuclear Information System (INIS)

Taştemel, Ayşegül; Karaca, Birsen Yılmaz; Durmuş, Mahmut; Bulut, Mustafa

2015-01-01

Tetra-peripherally and non-peripherally 7-oxy-3-(m-methoxyphenyl)coumarin-substituted zinc(II) (4a and 5a), indium(III)acetate (4b and 5b) and magnesium(II) (4c and 5c) phthalocyanines were synthesized for the first time. These phthalocyanines were characterized by elemental analysis, FT-IR, 1 H NMR, UV–vis spectroscopy and mass spectra. The novel phthalocyanines showed excellent solubility in general organic solvents, such as dichloromethane, chloroform, tetrahydrofuran (THF), N,N-dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The photophysical and photochemical properties of these phthalocyanines were investigated in DMF. The effects of the central metal ions (Zn 2+ , Mg 2+ , In +3 ) and the position (peripheral or non-peripheral) of the substituents on the photophysical and photochemical parameters were reported for comparison. The singlet oxygen quantum yield values of novel phthalocyanines ranged from 0.29 to 0.82 in DMF. In this study, the fluorescence quenching behavior of the studied zinc(II) and magnesium(II) phthalocyanine complexes was also described by the addition of 1,4-benzoquinone. - Highlights: • 7-oxy-3-(m-methoxyphenyl)coumarin-substituted Zn, In(III)OAc and Mg phthalocyanines. • Investigation of their photophysical and photochemical properties in DMF. • The effects of metal types and position of the substituents on these properties.

Polar red-emitting rhodamine dyes with reactive groups: synthesis, photophysical properties, and two-color STED nanoscopy applications.

Science.gov (United States)

Kolmakov, Kirill; Wurm, Christian A; Meineke, Dirk N H; Göttfert, Fabian; Boyarskiy, Vadim P; Belov, Vladimir N; Hell, Stefan W

2014-01-03

The synthesis, reactivity, and photophysical properties of new rhodamines with intense red fluorescence, two polar residues (hydroxyls, primary phosphates, or sulfonic acid groups), and improved hydrolytic stability of the amino-reactive sites (NHS esters or mixed N-succinimidyl carbonates) are reported. All fluorophores contain an N-alkyl-1,2-dihydro-2,2,4-trimethylquinoline fragment, and most of them bear a fully substituted tetrafluoro phenyl ring with a secondary carboxamide group. The absorption and emission maxima in water are in the range of 635-639 and 655-659 nm, respectively. A vastly simplified approach to red-emitting rhodamines with two phosphate groups that are compatible with diverse functional linkers was developed. As an example, a phosphorylated dye with an azide residue was prepared and was used in a click reaction with a strained alkyne bearing an N-hydroxysuccinimid (NHS) ester group. This method bypasses the undesired activation of phosphate groups, and gives an amphiphilic amino-reactive dye, the solubility and distribution of which between aqueous and organic phases can be controlled by varying the pH. The presence of two hydroxyl groups and a phenyl ring with two carboxyl residues in the dyes with another substitution pattern is sufficient for providing the hydrophilic properties. Selective formation of a mono-N-hydroxysuccinimidyl ester from 5-carboxy isomer of this rhodamine is reported. The fluorescence quantum yields varied from 58 to 92% for free fluorophores, and amounted to 18-64% for antibody conjugates in aqueous buffers. The brightness and photostability of these fluorophores facilitated two-color stimulated emission depletion (STED) fluorescence nanoscopy of biological samples with high contrast and minimal background. Selecting a pair of fluorophores with absorption/emission bands at 579/609 and 635/655 nm enabled two-color channels with low cross-talk and negligible background at approximately 40 nm resolution. Copyright �

Synthesis, photophysical and electrochemical characterization of terpyridine-functionalized dendritic oligothiophenes and their Ru(II complexes

Directory of Open Access Journals (Sweden)

Amaresh Mishra

2013-05-01

Full Text Available Pd-catalyzed Sonogashira cross-coupling reactions were used to synthesize novel π-conjugated oligothienylene-ethynylene dendrons and their corresponding terpyridine-based ligands. Their complexation with Ru(II led to interesting novel metallodendrimers with rich spectroscopic properties. All new compounds were fully characterized by 1H and 13C NMR, as well as MALDI–TOF mass spectra. Density functional theory (DFT calculations performed on these complexes gave more insight into the molecular orbital distributions. Photophysical and electrochemical studies were carried out in order to elucidate structure–property relationships and the effect of the dendritic structure on the metal complexes. Photophysical studies of the complexes revealed broad absorption spectra covering from 250 to 600 nm and high molar extinction coefficients. The MLCT emission of these complexes were significantly red-shifted (up to 115 nm compared to the parent [Ru(tpy2]2+ complex.

Effect of diblock copolymer properties on the photophysical properties of dendrimer silicon phthalocyanine nanoconjugates

Science.gov (United States)

Chen, Kuizhi; Pan, Sujuan; Zhuang, Xuemei; Lv, Hafei; Que, Shoulin; Xie, Shusen; Yang, Hongqin; Peng, Yiru

2016-07-01

1-2 generation poly(benzyl aryl ether) dendrimer silicon phthalocyanines with axially disubstituted cyano terminal functionalities (G n -DSiPc(CN)4 n , (G n = n-generation dendrimer, n = 1-2)) were synthesized. Their structures were characterized by elemental analysis, IR, 1H NMR, and ESI-MS. Polymeric nanoparticles (G n -DSiPc(CN)4 n /m) were formed through encapsulating G n -DSiPc(CN)4 n into three monomethoxyl poly(ethylene glycol)-poly(ɛ-caprolactone) diblock copolymers (MPEG-PCL) with different hydrophilic/hydrophobic proportion, respectively. The effect of dendritic generation and the hydrophilic/hydrophobic proportion of diblock copolymers on the UV/Vis and fluorescence spectra of G n -DSiPc(CN)4 n and G n -DSiPc(CN)4 n /m were studied. The photophysical properties of polymeric nanoparticles exhibited dendritic generation and hydrophilic/hydrophobic proportion dependence. The fluorescence intensities and lifetimes of G n -DSiPc(CN)4 n /m were lower than the corresponding free dendrimer phthalocyanines. G n -DSiPc(CN)4 n encapsulated into MPEG-PCL with hydrophilic/hydrophobic molecular weight ratio 2000:4000 exhibited excellent photophysical property. The mean diameter of MPEG2000-PCL2000 micelles was about 70 nm, which decreased when loaded with G n -DSiPc(CN)4 n .

Self-organization, interfacial interaction and photophysical properties of gold nanoparticle complexes derived from resilin-mimetic fluorescent protein rec1-resilin.

Science.gov (United States)

Mayavan, Sundar; Dutta, Naba K; Choudhury, Namita R; Kim, Misook; Elvin, Christopher M; Hill, Anita J

2011-04-01

In this investigation we report the synthesis of optically coupled hybrid architectures based on a new biomimetic fluorescent protein rec1-resilin and nanometer-scale gold nanoparticles (AuNPs) in a one-step method using a non-covalent mode of binding protocol. The presence of uniformly distributed fluorophore sequences, -Ser(Thr)-Tyr-Gly- along the molecular structure of rec1-resilin provides significant opportunity to synthesize fluorophore-modified AuNPs bioconjugates with unique photophysical properties. The detailed analyses of the AuNP-bioconjugates, synthesized under different experimental conditions using spectroscopic, microscopic and scattering techniques demonstrate the organizational pathways and the electronic and photophysical properties of the developed AuNP-rec1-resilin bioconjugates. The calculation of the bimolecular quenching constant using the Stern-Volmer equation confirms that the dominant mechanism involved in quenching of fluorescence of rec1-resilin in the presence of AuNP is static. Photoacoustic infrared spectroscopy was employed to understand the nature of the interfacial interaction between the AuNP and rec1-resilin and its evolution with pH. In such bioconjugates the quenched emission of fluorescence by AuNP on the fluorophore moiety of rec1-resilin in the immediate vicinity of the AuNP has significant potential for fluorescence-based detection schemes, sensors and also can be incorporated into nanoparticle-based devices. Copyright © 2011 Elsevier Ltd. All rights reserved.

Photophysical and photochemical properties of novel metallophthalocyanines bearing 7-oxy-3-(m-methoxyphenyl)coumarin groups

Energy Technology Data Exchange (ETDEWEB)

Taştemel, Ayşegül; Karaca, Birsen Yılmaz [Marmara University, Faculty of Art and Science, Department of Chemistry, 34722 Kadıkoy-Istanbul (Turkey); Durmuş, Mahmut [Gebze Technical University, Department of Chemistry, P.O. Box 141, Gebze 41400, Kocaeli (Turkey); Bulut, Mustafa, E-mail: mbulut@marmara.edu.tr [Marmara University, Faculty of Art and Science, Department of Chemistry, 34722 Kadıkoy-Istanbul (Turkey)

2015-12-15

Tetra-peripherally and non-peripherally 7-oxy-3-(m-methoxyphenyl)coumarin-substituted zinc(II) (4a and 5a), indium(III)acetate (4b and 5b) and magnesium(II) (4c and 5c) phthalocyanines were synthesized for the first time. These phthalocyanines were characterized by elemental analysis, FT-IR, {sup 1}H NMR, UV–vis spectroscopy and mass spectra. The novel phthalocyanines showed excellent solubility in general organic solvents, such as dichloromethane, chloroform, tetrahydrofuran (THF), N,N-dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The photophysical and photochemical properties of these phthalocyanines were investigated in DMF. The effects of the central metal ions (Zn{sup 2+}, Mg{sup 2+}, In{sup +3}) and the position (peripheral or non-peripheral) of the substituents on the photophysical and photochemical parameters were reported for comparison. The singlet oxygen quantum yield values of novel phthalocyanines ranged from 0.29 to 0.82 in DMF. In this study, the fluorescence quenching behavior of the studied zinc(II) and magnesium(II) phthalocyanine complexes was also described by the addition of 1,4-benzoquinone. - Highlights: • 7-oxy-3-(m-methoxyphenyl)coumarin-substituted Zn, In(III)OAc and Mg phthalocyanines. • Investigation of their photophysical and photochemical properties in DMF. • The effects of metal types and position of the substituents on these properties.

Photophysical properties of coumarin-120: Unusual behavior in nonpolar solvents

International Nuclear Information System (INIS)

Pal, Haridas; Nad, Sanjukta; Kumbhakar, Manoj

2003-01-01

Photophysical properties of coumarin-120 (C120; 7-amino-4-methyl-1,2-benzopyrone) dye have been investigated in different solvents using steady-state and time-resolved fluorescence and picosecond laser flash photolysis (LFP) and nanosecond pulse radiolysis (PR) techniques. C120 shows unusual photophysical properties in nonpolar solvents compared to those in other solvents of moderate to higher polarities. Where the Stokes shifts (Δν-bar=ν-bar abs -ν-bar fl ), fluorescence quantum yields (Φ f ), and fluorescence lifetimes (τ f ) show more or less linear correlation with the solvent polarity function Δf={(ε-1)/(2ε+1)-(n 2 -1)/(2n 2 +1)}, all these parameters are unusually lower in nonpolar solvents. Unlike in other solvents, both Φ f and τ f in nonpolar solvents are also strongly temperature dependent. It is indicated that the excited singlet (S 1 ) state of C120 undergoes a fast activation-controlled nonradiative deexcitation in nonpolar solvents, which is absent in all other solvents. LFP and PR studies indicate that the intersystem crossing process is negligible for the present dye in all the solvents studied. Photophysical behavior of C120 in nonpolar solvent has been rationalized assuming that in these solvents the dye exists in a nonpolar structure, with its 7-NH 2 group in a pyramidal configuration. In this structure, since the 7-NH 2 group is bonded to the 1,2-benzopyrone moiety by a single bond, the former group can undergo a fast flip-flop motion, which in effect causes the fast nonradiative deexcitation of the dye excited state. In moderate to higher polarity solvents, it is indicated that the dye exists in an intramolecular charge-transfer structure, where the bond between 7-NH 2 group and the 1,2-benzopyrone moiety attains substantial double bond character. In this structure, the flip-flop motion of the 7-NH 2 group is highly restricted and thus there is no fast nonradiative deexcitation process for the excited dye

Photophysical properties and energy transfer mechanism of PFO/Fluorol 7GA hybrid thin films

Energy Technology Data Exchange (ETDEWEB)

Al-Asbahi, Bandar Ali, E-mail: alasbahibandar@gmail.com [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Department of Physics, Faculty of Science, Sana' a University (Yemen); Jumali, Mohammad Hafizuddin Haji, E-mail: hafizhj@ukm.my [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Yap, Chi Chin; Flaifel, Moayad Husein [School of Applied Physics, Faculty of Science and Technology, Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia); Salleh, Muhamad Mat [Institute of Microengineering and Nanoelectronics (IMEN), Universiti Kebangsaan Malaysia (UKM), 43600 Bangi, Selangor (Malaysia)

2013-10-15

Photophysical properties of poly (9,9′-di-n-octylfluorenyl-2.7-diyl) (PFO)/2-butyl-6- (butylamino)benzo [de] isoquinoline-1,3-dione (Fluorol 7GA) and energy transfer between them have been investigated. In this work, both PFO and Fluorol 7GA act as donor and acceptor, respectively. Based on the absorption and luminescence measurements, the photophysical and energy transfer properties such as fluorescence quantum yield (Φ{sub f}), fluorescence lifetime (τ), radiative rate constant (k{sub r}), non-radiative rate constant (k{sub nr}), quenching rate constant (k{sub SV}), energy transfer rate constant (k{sub ET}), energy transfer probability (P{sub DA}), energy transfer efficiency (η), critical concentration of acceptor (C{sub o}), energy transfer time (τ{sub ET}) and critical distance of energy transfer (R{sub o}) were calculated. Large values of k{sub SV}, k{sub ET} and R{sub o} suggested that Förster-type energy transfer was the dominant mechanism for the energy transfer between the excited donor and ground state acceptor molecules. It was observed that the Förster energy transfer together with the trapping process are crucial for performance improvement in ITO/(PFO/Fluorol7GA)/Al device. -- Highlights: • The efficient of energy transfer from PFO to Fluorol 7GA was evidenced. • The resonance energy transfer (Förster type) is the dominant mechanism. • Hsu et al. model was used to calculate Φ{sub f}, τ, k{sub r} and k{sub nr} of PFO thin film. • Several of the photophysical and energy transfer properties were calculated. • Trapping process and Förster energy transfer led to improve the device performance.

Multifunctional material based on ionic transition metal complexes and gold-silica nanoparticles: synthesis and photophysical characterization for application in imaging and therapy.

Science.gov (United States)

Ricciardi, Loredana; Martini, Matteo; Tillement, Olivier; Sancey, Lucie; Perriat, Pascal; Ghedini, Mauro; Szerb, Elisabeta I; Yadav, Yogesh J; La Deda, Massimo

2014-11-01

A new combination of luminescent ionic transition-metal complexes (M = Ru(II) or Ir(III)) with gold silica-based nanoparticles (GSNPs) gives a promising nanomaterial for application in biomedical fields. Herein we report the synthesis and the photophysical properties of Ru(II) and Ir(III) complexes doped gold core-polysiloxane shell particles prepared by microemulsion method and characterized by Transmission Electron Microscopy, Dynamic Light Scattering and UV-Vis spectroscopy. The cytotoxicity and photodynamic activity of the obtained 50 nm-diameter nanoparticles were evaluated in vitro, providing noteworthy results. Furthermore, their intrinsic phosphorescence allows the localization of the photosensitizing nanoparticles into the cytosol of tumor cells by fluorescence confocal microscope. These valuable features designate them as multifunctional nanoplatforms for theranostic purposes.

Controlling photophysical properties of ultrasmall conjugated polymer nanoparticles through polymer chain packing

KAUST Repository

Piwonski, Hubert Marek

2017-05-16

Applications of conjugated polymer nanoparticles (Pdots) for imaging and sensing depend on their size, fluorescence brightness and intraparticle energy transfer. The molecular design of conjugated polymers (CPs) has been the main focus of the development of Pdots. Here we demonstrate that proper control of the physical interactions between the chains is as critical as the molecular design. The unique design of twisted CPs and fine-tuning of the reprecipitation conditions allow us to fabricate ultrasmall (3.0–4.5 nm) Pdots with excellent photostability. Extensive photophysical and structural characterization reveals the essential role played by the packing of the polymer chains in the particles in the intraparticle spatial alignment of the emitting sites, which regulate the fluorescence brightness and the intraparticle energy migration efficiency. Our findings enhance understanding of the relationship between chain interactions and the photophysical properties of CP nanomaterials, providing a framework for designing and fabricating functional Pdots for imaging applications.

Effect of diblock copolymer properties on the photophysical properties of dendrimer silicon phthalocyanine nanoconjugates

Energy Technology Data Exchange (ETDEWEB)

Chen, Kuizhi [Fujian Normal University, College of Materials Science & Engineering, Fujian Provincial Key Laboratory of Polymer Materials (China); Pan, Sujuan [Fujian Normal University, College of Chemistry & Engineering (China); Zhuang, Xuemei [Fuzhou No.2 Hospital (China); Lv, Hafei; Que, Shoulin [Fujian Normal University, College of Chemistry & Engineering (China); Xie, Shusen; Yang, Hongqin, E-mail: hqyang@fjnu.edu.cn [Fujian Normal University, Key Laboratory of Optoelectronic Science and Technology for Medicine of Ministry of Education (China); Peng, Yiru, E-mail: yirupeng@fjnu.edu.cn [Fujian Normal University, College of Chemistry & Engineering (China)

2016-07-15

1–2 generation poly(benzyl aryl ether) dendrimer silicon phthalocyanines with axially disubstituted cyano terminal functionalities (G{sub n}-DSiPc(CN){sub 4n}, (G{sub n} = n-generation dendrimer, n = 1–2)) were synthesized. Their structures were characterized by elemental analysis, IR, {sup 1}H NMR, and ESI-MS. Polymeric nanoparticles (G{sub n}-DSiPc(CN){sub 4n}/m) were formed through encapsulating G{sub n}-DSiPc(CN){sub 4n} into three monomethoxyl poly(ethylene glycol)-poly(ε-caprolactone) diblock copolymers (MPEG–PCL) with different hydrophilic/hydrophobic proportion, respectively. The effect of dendritic generation and the hydrophilic/hydrophobic proportion of diblock copolymers on the UV/Vis and fluorescence spectra of G{sub n}-DSiPc(CN){sub 4n} and G{sub n}-DSiPc(CN){sub 4n}/m were studied. The photophysical properties of polymeric nanoparticles exhibited dendritic generation and hydrophilic/hydrophobic proportion dependence. The fluorescence intensities and lifetimes of G{sub n}-DSiPc(CN){sub 4n}/m were lower than the corresponding free dendrimer phthalocyanines. G{sub n}-DSiPc(CN){sub 4n} encapsulated into MPEG–PCL with hydrophilic/hydrophobic molecular weight ratio 2000:4000 exhibited excellent photophysical property. The mean diameter of MPEG{sub 2000}–PCL{sub 2000} micelles was about 70 nm, which decreased when loaded with G{sub n}-DSiPc(CN){sub 4n}.Graphical abstract .

Selective synthesis and characterization of chlorins as sensitizers for photodynamic therapy

Science.gov (United States)

Montforts, Franz-Peter; Kusch, Dirk; Hoper, Frank; Braun, Stefan; Gerlach, Benjamin; Brauer, Hans-Dieter; Schermann, Guido; Moser, Joerg G.

1996-04-01

Chlorin type sensitizers have ideal photophysical properties for an application in PDT. The basic chlorin framework of these sensitizers has to be modified by attachment of lipophilic and hydrophilic residues to achieve a good cell uptake and tumor enrichment. In the present study we describe the selective synthesis of amphiphilic chlorins starting from the readily accessible red blood pigment heme. The photophysical properties of the well defined synthetic chlorins are characterized by photophysical investigations. The kinetic of cell uptake, the localization in the cell and the photodynamic behavior of the amphiphilic sensitizers are demonstrated by incubation of A 375 cancer cell lines with structurally different chlorins.

Design, synthesis and photochemical properties of the first examples of iminosugar clusters based on fluorescent cores

Directory of Open Access Journals (Sweden)

Mathieu L. Lepage

2015-05-01

Full Text Available The synthesis and photophysical properties of the first examples of iminosugar clusters based on a BODIPY or a pyrene core are reported. The tri- and tetravalent systems designed as molecular probes and synthesized by way of Cu(I-catalysed azide–alkyne cycloadditions are fluorescent analogues of potent pharmacological chaperones/correctors recently reported in the field of Gaucher disease and cystic fibrosis, two rare genetic diseases caused by protein misfolding.

Novel asymmetrical pyrene derivatives as light emitting materials: Synthesis and photophysics

International Nuclear Information System (INIS)

Li Yang; Wang Dong; Wang Lei; Li Zhengqiang; Cui Qing; Zhang Haiquan; Yang Huai

2012-01-01

A series of novel substituted pyrene derivatives with asymmetrical groups have been successfully synthesized in excellent yield. Structures of the asymmetrical compound were fully characterized by 1 H-NMR, IR spectroscopy and mass spectrometry. By introducing ethynyl functions to pyrene, we obtained highly efficient blue and green light emitting materials. It has been demonstrated that the emission characteristics of pyrene derivatives have been bathochromatically tuned in the visible region by extending the π-conjugation. The photophysical properties of these compounds were carefully examined in different organic solvents and different concentrations. The electrochemical properties and geometrical electronic structures of the new pyrene derivatives have been investigated by cyclic voltammograms and density functional theory (DFT) calculations. - Highlights: ► It is the first research about asymmetrial pyrene derivatives as highly efficient light emitting materials. ► The solvatochromism and concentration effect of the new compounds have been discussed. ► Furthermore, the electrochemical properties and geometrical electronic structures were also investigated in this paper.

Photochemistry and photophysics concepts, research, applications

CERN Document Server

Balzani , Vincenzo; Juris, Alberto

2014-01-01

This textbook covers the spectrum from basic concepts of photochemistry and photophysics to selected examples of current applications and research.Clearly structured, the first part of the text discusses the formation, properties and reactivity of excited states of inorganic and organic molecules and supramolecular species, as well as experimental techniques. The second part focuses on the photochemical and photophysical processes in nature and artificial systems, using a wealth of examples taken from applications in nature, industry and current research fields, ranging from natural photosynth

Photophysical properties of chirality: Experimental and theoretical studies of (R)- and (S)-binaphthol derivatives as a prototype case

International Nuclear Information System (INIS)

Tsuboi, Taiju; An, Zhong-fu; Nakai, Yosuke; Yin, Jun; Chen, Run-feng; Shi, Hui-fang; Huang, Wei

2013-01-01

Highlights: ► The effect of chirality on photophysical properties was investigated. ► The same photophysics of enantiomers was observed in solutions. ► But different photoluminescent efficiency and lifetime were found in neat film. ► The different symmetry and formation probability of dimmers may be the main reason. ► The joint experimental and theoretical study explains these differences well. - Abstract: The key monomers of binaphthol-based chiral materials, (R)- and (S)- 6,6′-dibromo-2,2′-bis(octyloxy)- 1,1′-binaphthyl (R–M and S–M, respectively), were synthesized and characterized by UV–vis absorption spectra, circular dichroism (CD) spectra, photoluminescence (PL) lifetime, PL quantum efficiency at room temperature, together with PL spectra at various temperatures between 12 K and 296 K in both film and solution. The photophysical properties of R–M and S–M were investigated in detail with a joint experimental and theoretical study, in order to reveal the effects of chirality on the π-conjugated chiral systems. Higher photoluminescent quantum efficiency and better PL spectra purity in solid film of R–M were observed and discussed

Photophysical properties of hexyl diethylaminohydroxybenzoylbenzoate (Uvinul A Plus), a UV-A absorber.

Science.gov (United States)

Shamoto, Yuta; Yagi, Mikio; Oguchi-Fujiyama, Nozomi; Miyazawa, Kazuyuki; Kikuchi, Azusa

2017-09-13

Hexyl diethylaminohydroxybenzoylbenzoate (DHHB, Uvinul A Plus) is a photostable UV-A absorber. The photophysical properties of DHHB have been studied by obtaining the transient absorption, total emission, phosphorescence and electron paramagnetic resonance spectra. DHHB exhibits an intense phosphorescence in a hydrogen-bonding solvent (e.g., ethanol) at 77 K, whereas it is weakly phosphorescent in a non-hydrogen-bonding solvent (e.g., 3-methylpentane). The triplet-triplet absorption and EPR spectra for the lowest excited triplet state of DHHB were observed in ethanol, while they were not observed in 3-methylpentane. These results are explained by the proposal that in the benzophenone derivatives possessing an intramolecular hydrogen bond, intramolecular proton transfer is an efficient mechanism of the very fast radiationless decay from the excited singlet state. The energy level of the lowest excited triplet state of DHHB is higher than those of the most widely used UV-B absorbers, octyl methoxycinnamate (OMC) and octocrylene (OCR). DHHB may act as a triplet energy donor for OMC and OCR in the mixtures of UV-A and UV-B absorbers. The bimolecular rate constant for the quenching of singlet oxygen by DHHB was determined by measuring the near-IR phosphorescence of singlet oxygen. The photophysical properties of diethylaminohydroxybenzoylbenzoic acid (DHBA) have been studied for comparison. It is a closely related building block to assist in interpreting the observed data.

Photophysical and adsorption properties of pyronin B in natural bentonite clay dispersion

Energy Technology Data Exchange (ETDEWEB)

Rostami, Mohammad Reza [Department of Chemistry, Faculty of Sciences, Atatürk University, 25240, Erzurum (Turkey); Kaya, Mehmet [Recep Tayyip Erdoğan University, Faculty of Arts and Sciences, 53100 Rize (Turkey); Gür, Bahri; Onganer, Yavuz [Department of Chemistry, Faculty of Sciences, Atatürk University, 25240, Erzurum (Turkey); Meral, Kadem, E-mail: kademm@atauni.edu.tr [Department of Chemistry, Faculty of Sciences, Atatürk University, 25240, Erzurum (Turkey)

2015-12-30

Graphical abstract: The molecular aggregation of PyB in bentonite aqueous dispersion is observed by using molecular absorption spectrum. - Highlights: • Molecular behavior of PyB adsorbed on bentonite was spectroscopically followed. • H-aggregates of PyB in bentonite aqueous dispersion were formed. • The adsorption characteristics of PyB on bentonite particles were determined. - Abstract: The present study focused on the adsorption and photophysical properties of pyronin B (PyB) in bentonite aqueous dispersion. The photophysical properties of PyB in the aqueous dispersion were studied by using UV–vis absorption, steady-state and time-resolved fluorescence spectroscopy techniques. In this concept, the interaction of the dye with bentonite particles in the aqueous dispersion was spectroscopically followed depending on certain parameters such as interaction time, pH and the dye concentration. Obtained spectral data revealed that the aggregate structures (H-type) of PyB in the aqueous dispersion were formed in the dye concentration range studied. The non-fluorescence nature of H-aggregates and the clay minerals governed the fluorescence property of PyB. The mentioned non-radiative processes caused the fluorescence lifetime of the dye to decrease compared to that in water. The adsorption process of PyB on bentonite was examined depending on contact time and initial adsorbate concentration. An adsorption isotherm was good-fitted by the Freundlich model with a linear regression correlation value of 0.999. The adsorption of PyB on bentonite particles was in agreement with pseudo second-order kinetics.

Aggregation and Photophysical Properties of Water-Soluble Sapphyrins

Czech Academy of Sciences Publication Activity Database

Kubát, Pavel; Lang, Kamil; Zelinger, Zdeněk; Král, V.

2004-01-01

Roč. 395, - (2004), s. 82-86 ISSN 0009-2614 R&D Projects: GA AV ČR KSK4040110 Keywords : water-soluble * sapphyrins * photophysical Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.438, year: 2004

NLOphoric and solid state emissive BODIPY dyes containing N-phenylcarbazole core at meso position – Synthesis, photophysical properties of and DFT studies

Energy Technology Data Exchange (ETDEWEB)

Telore, Rahul D.; Jadhav, Amol G.; Sekar, Nagaiyan, E-mail: n.sekar@ictmumbai.edu.in

2016-11-15

Two boron-dipyrromethene dyes with N-phenylcarbazole core at meso position were prepared and characterized. They show small Stokes shifts (15–20 nm), high molar extinction coefficient and high quantum yield. Their photophysical properties were compared with the known meso aryl, 4-aminophenyl, N,N-dimethylaniline and N-butylcarbzole boron-dipyrromethene dyes. The bulky nature of N-phenylcarbazole leads to an increase in molar absorptivity and quantum yield. The Catalan solvent parameters are found to be the suitable for defining the solvatochromic absorption and emission properties. Confocal laser scanning microscopy showed solid-state fluorescence. Density Functional Theory is used to determine the static first hyperpolarizability (β{sub ο}) and its components (μ, α{sub 0}, Δα, and γ) using B3LYP/6-31G(d) at ground state and excited state in different polarity solvent. The geometries of the dyes were optimized by using B3LYP/6-31G(d) and their electronic excitation properties were estimated using time dependent density functional theory.

Protonated serotonin: Geometry, electronic structures and photophysical properties

Science.gov (United States)

Omidyan, Reza; Amanollahi, Zohreh; Azimi, Gholamhassan

2017-07-01

The geometry and electronic structures of protonated serotonin have been investigated by the aim of MP2 and CC2 methods. The relative stabilities, transition energies and geometry of sixteen different protonated isomers of serotonin have been presented. It has been predicted that protonation does not exhibit essential alteration on the S1 ← S0 electronic transition energy of serotonin. Instead, more complicated photophysical nature in respect to its neutral analogue is suggested for protonated system owing to radiative and non-radiative deactivation pathways. In addition to hydrogen detachment (HD), hydrogen/proton transfer (H/PT) processes from ammonium to indole ring along the NH+⋯ π hydrogen bond have been predicted as the most important photophysical consequences of SERH+ at S1 excited state. The PT processes is suggested to be responsible for fluorescence of SERH+ while the HD driving coordinate is proposed for elucidation of its nonradiative deactivation mechanism.

Photophysical, Photochemical, and BQ Quenching Properties of Zinc Phthalocyanines with Fused or Interrupted Extended Conjugation

Directory of Open Access Journals (Sweden)

Gülşah Gümrükçü

2014-01-01

Full Text Available The effects of substituents and solvents on the photophysical and photochemical parameters of zinc(II phthalocyanines containing four Schiff’s base substituents attached directly and through phenyleneoxy-bridges on peripheral positions are reported. The group effects on peripheral position and the continual and intermittent conjugation of the phthalocyanine molecules on the photophysical and photochemical properties are also investigated. General trends are described for photodegradation, singlet oxygen, and fluorescence quantum yields of these compounds in dimethylsulfoxide (DMSO, dimethylformamide (DMF, and tetrahydrofurane (THF. Among the different substituents, phthalocyanines with cinnamaldimine moieties (1c and 2c have the highest singlet oxygen quantum yields (ΦΔ and those with nitro groups (1a and 2a have the highest fluorescence quantum yields in all the solvents used. The fluorescence of the substituted zinc(II phthalocyanine complexes is effectively quenched by 1,4-benzoquinone (BQ in these solvents.

Synthesis, structure, electrochemistry, and photophysics of methyl-substituted phenylpyridine ortho-metalated iridium(III) complexes

International Nuclear Information System (INIS)

Garces, F.O.; King, K.A.; Watts, R.J.

1988-01-01

Synthetic, structural, photophysical, and electrochemical characterizations of ortho-metalated [Ir(NC) 2 Cl] 2 dimeric and [Ir(NC) 2 NN]Cl monomeric complexes, where NC = 2(p-tolyl)pyridine (ptpy) or 3-methyl-2-phenylpyridine (mppy) and NN = 2,2'-bipyridine (bpy) are described. Structural characterizations by 1 H and 13 C nuclear magnetic resonance (NMR) indicate the presence of symmetry elements in these complexes. The ultraviolet-visible absorption properties of these complexes are reported. The results of voltametric measurements of these complexes are included. 55 references, 10 figures, 6 tables

Rationalizing substituent effects in 1-azathioxanthone photophysics

Science.gov (United States)

Junker, Anne Kathrine R.; Just Sørensen, Thomas

2018-01-01

The influence of an electron donating substituent on the photophysical properties of 1-azathioxanthone dyes has been investigated using optical spectroscopy and theoretical models. The motivation behind the study is based on the fact that thioxanthones are efficient triplet sensitizers, and thus promising sensitizers for lanthanide centered emission. By adding an aza group to one of the phenyl ring systems, direct coordination to a lanthanide center becomes possible, which makes azathoixanthones great candidates as antenna chromophores in lanthanide(III) based dyes. Here, three 1-azathioxanthone derivatives have been synthesized targeting efficient triplet formation following absorption in the visible range of the spectrum. This is achieved by adding methoxy groups to the 1-azathioxanthone core. The derivatives were characterized using absorption, emission, and time-gated emission spectroscopy, where fluorescent quantum yields, singlet and triplet excited states lifetimes were determined. The experimentally determined photophysical properties of the three 1-azathioxanthone compounds are contrasted to those of the parent thioxanthone and is rationalized using the Strickler-Berg equation, Hückel MO theory, and Dewar’s rules in combination with computational chemistry. We find that the transition energies follow predictions, but that the overall photophysical properties are determined by the relative energies as well as the nature of the involved states in both the singlet and the triplet excited state manifolds.

A High Molar Extinction Coefficient Mono-Anthracenyl Bipyridyl Heteroleptic Ruthenium(II Complex: Synthesis, Photophysical and Electrochemical Properties

Directory of Open Access Journals (Sweden)

Peter A. Ajibade

2011-06-01

Full Text Available In our quest to develop good materials as photosensitizers for photovoltaic dye-sensitized solar cells (DSSCs, cis-dithiocyanato-4-(2,3-dimethylacrylic acid-2,2'-bipyridyl-4-(9-anthracenyl-(2,3-dimethylacrylic-2,2'-bipyridyl ruthenium(II complex, a high molar extinction coefficient charge transfer sensitizer, was designed, synthesized and characterized by spectroscopy and electrochemical techniques. Earlier studies on heteroleptic ruthenium(II complex analogues containing functionalized oligo-anthracenyl phenanthroline ligands have been reported and documented. Based on a general linear correlation between increase in the length of π-conjugation bond and the molar extinction coefficients, herein, we report the photophysical and electrochemical properties of a Ru(II bipyridyl complex analogue with a single functionalized anthracenyl unit. Interestingly, the complex shows better broad and intense metal-to ligand charge transfer (MLCT band absorption with higher molar extinction coefficient (λmax = 518 nm, e = 44900 M−1cm−1, and appreciable photoluminescence spanning the visible region than those containing higher anthracenyl units. It was shown that molar absorption coefficient of the complexes may not be solely depended on the extended π-conjugation but are reduced by molecular aggregation in the molecules.

Photophysical properties of novel Porphyrin-Flavin Dyads

International Nuclear Information System (INIS)

Stark, S.

2001-10-01

Photosynthesis belongs to the fundamentals of life on earth, therefore it is an important matter in natural sciences. The basic principle of photosynthesis is the transformation of solar light into chemical energy. The starting steps of photosynthesis are light-induced energy- and electron-transfer-steps with singular efficiency. One attempt to enlighten the molecular processes involved is to synthesize simpler model systems with similar properties. Important research goals are the dependencies of light-induced processes on distance and orientation of donor and acceptor. A second aim next to the clarification of the molecular conditions of photosynthesis is to create molecular light-driven machines. The most simple so-called biomimetic model system consists of an electron-donor connected to an electron-acceptor via a spacer-group. This simplest form is also referred to as dyad. Beyond dyads far more complicated compounds have been introduced consisting of several donors and/or acceptors, so-called triads, tetrads, pentads etc. Usually porphyrin serves as electron-donor. Next to chinones several other electron-acceptors are used, e.g. anthracene, pyromellitimide and fullerene. Artificial photosynthetic centers are often more stable and/or the excited states are easier to detect compared to the natural photosynthetic center. The photophysical characteristics of four dyads are reported in this work. The dyads consist of porphyrin (either free-base or zinc-metallated) and flavin, connected by different spacers. These dyads reveal photo-induced electron transfer from porphyrin to flavin and energy-transfer in the reversed direction with different efficiencies. The object of the study is the dependency of these processes on the structural features. The spacer of the dyads 1a-1c is an aromatic bridge which leads to well defined donor-acceptor distances. Because of this structure conjugation through the spacer is increased, whereas the absorption in the visible and near UV

Bibliographic study of photophysical and photochemical properties of laser dyes

International Nuclear Information System (INIS)

Doizi, D.

1986-06-01

Laser isotope separation of uranium requires high power and precise wave length. This report is a bibliographic and experimental study of the photophysical and photochemical properties of seven commercial laser dyes which have an emission wavelength in the range 5500-6500 A: Rhodamine 110 or 560, rhodamine 6G or 590, rhodamine B or 610, rhodamine 101 or 640, sulforhodamine B or kiton red 620, sulforhodamine 101 or 640 and DCM or LC 6500. Absorption and emission cross section values, fluorescence lifetimes and quantum yields in various solvents are indicated. For each dye, a non exhaustive list of laboratory experiments made with two types of pump sources: Nd YAG (532) and copper vapor laser is given. When it is known, the toxicity of the dyes is mentioned [fr

Imaging, photophysical properties and DFT calculations of manganese blue (barium manganate(VI) sulphate)--a modern pigment.

Science.gov (United States)

Accorsi, Gianluca; Verri, Giovanni; Acocella, Angela; Zerbetto, Francesco; Lerario, Giovanni; Gigli, Giuseppe; Saunders, David; Billinge, Rachel

2014-12-18

Manganese blue is a synthetic barium manganate(VI) sulphate compound that was produced from 1935 to the 1990s and was used both as a blue pigment in works of art and by conservators in the restoration of paintings. The photophysical properties of the compound are described as well as the setup needed to record the spatial distribution of the pigment in works of art.

Photophysical properties of some xanthylium salts performances under CVL pumping

International Nuclear Information System (INIS)

Doizi, D.; Lompre, L.A.; Gazeau, M.C.

1995-01-01

We report the photochemical and photophysical performances of some new dyes belonging to the xanthylium salts family. Performances under Copper Vapor Laser (CVL) pumping are described and compared to those of Rhodamine 6G. (author)

Physicochemical/photophysical characterization and angiogenic properties of Curcuma longa essential oil

Directory of Open Access Journals (Sweden)

LILHIAN A. ARAÚJO

Full Text Available ABSTRACT This study analyzed the physicochemical and photophysical properties of essential oil of Curcuma longa and its angiogenic potential. The results showed that curcumin is the main fluorescent component present in the oil, although the amount is relatively small. The experimental chorioallantoic membrane model was used to evaluate angiogenic activity, showing a significant increase in the vascular network of Curcuma longa and positive control groups when compared to the neutral and inhibitor controls (P 0.05. Histological analysis showed extensive neovascularization, hyperemia and inflammation in the positive control group and Curcuma longa when compared to other controls (P <0.05, characteristic factors of the angiogenesis process. In conclusion, Curcuma longa oil showed considerable proangiogenic activity and could be a potential compound in medical applications.

Physicochemical/photophysical characterization and angiogenic properties of Curcuma longa essential oil.

Science.gov (United States)

Araújo, Lilhian A; Araújo, Rafael G M; Gomes, Flávia O; Lemes, Susy R; Almeida, Luciane M; Maia, Lauro J Q; Gonçalves, Pablo J; Mrué, Fátima; Silva-Junior, Nelson J; Melo-Reis, Paulo R DE

2016-01-01

This study analyzed the physicochemical and photophysical properties of essential oil of Curcuma longa and its angiogenic potential. The results showed that curcumin is the main fluorescent component present in the oil, although the amount is relatively small. The experimental chorioallantoic membrane model was used to evaluate angiogenic activity, showing a significant increase in the vascular network of Curcuma longa and positive control groups when compared to the neutral and inhibitor controls (P Curcuma longa essential oil and the positive control (P >0.05). Histological analysis showed extensive neovascularization, hyperemia and inflammation in the positive control group and Curcuma longa when compared to other controls (P Curcuma longa oil showed considerable proangiogenic activity and could be a potential compound in medical applications.

Synthesis, dynamics and photophysics of nanoscale systems

Science.gov (United States)

Mirkovic, Tihana

The emerging field of nanotechnology, which spans diverse areas such as nanoelectronics, medicine, chemical and pharmaceutical industries, biotechnology and computation, focuses on the development of devices whose improved performance is based on the utilization of self-assembled nanoscale components exhibiting unique properties owing to their miniaturized dimensions. The first phase in the conception of such multifunctional devices based on integrated technologies requires the study of basic principles behind the functional mechanism of nanoscale components, which could originate from individual nanoobjects or result as a collective behaviour of miniaturized unit structures. The comprehensive studies presented in this thesis encompass the mechanical, dynamical and photophysical aspects of three nanoscale systems. A newly developed europium sulfide nanocrystalline material is introduced. Advances in synthetic methods allowed for shape control of surface-functionalized EuS nanocrystals and the fabrication of multifunctional EuS-CdSe hybrid particles, whose unique structural and optical properties hold promise as useful attributes of integrated materials in developing technologies. A comprehensive study based on a new class of multifunctional nanomaterials, derived from the basic unit of barcoded metal nanorods is presented. Their chemical composition affords them the ability to undergo autonomous motion in the presence of a suitable fuel. The nature of their chemically powered self-propulsion locomotion was investigated, and plausible mechanisms for various motility modes were presented. Furthermore functionalization of striped metallic nanorods has been realized through the incorporation of chemically controlled flexible hinges displaying bendable properties. The structural aspect of the light harvesting machinery of a photosynthetic cryptophyte alga, Rhodomonas CS24, and the mobility of the antenna protein, PE545, in vivo were investigated. Information obtained

Study on photophysical properties of Eu(III) complexes with aromatic β-diketones – Role of charge transfer states in the energy migration

Energy Technology Data Exchange (ETDEWEB)

Räsänen, Markus, E-mail: mpvras@utu.fi [Department of Chemistry, University of Turku, FIN-20014 Turku (Finland); Takalo, Harri [DHR Finland Oy, Innotrac Diagnostics, Biolinja 12, FIN-20750 Turku (Finland); Rosenberg, Jaana; Mäkelä, Joonas [Department of Biochemistry and Food Chemistry, University of Turku, FIN-20014 Turku (Finland); Haapakka, Keijo; Kankare, Jouko [Department of Chemistry, University of Turku, FIN-20014 Turku (Finland)

2014-02-15

We synthesized a set of aromatic β-diketones and measured the photophysical properties of their europium(III) complexes. According to these photophysical properties, the europium complexes can be divided into two groups: the complexes with or without the freely rotating amino-group (FRAG). On the basis of the experimental results, it can be concluded that in the FRAG complexes, the ligand-centered excitation energy is most probably transferred from a ligand to a coordinated europium via the intraligand charge transfer (ILCT) state. The temperature dependency of the lifetimes of the emissive {sup 5}D{sub 0} state revealed that in the FRAG complexes, the energy of the emissive {sup 5}D{sub 0} state is back-transferred to the ligand-to-metal charge transfer (LMCT) state and in the non-FRAG complexes, to the triplet state of the ligand. The most efficient complex synthesized was the europium complex of carbazole derivative L{sup 6} with the quantum yield of 47% and molar absorption coefficient of 70,400 M{sup −1}cm{sup −1}. -- Highlights: • We synthesized a set of substituted aromatic β-diketones and their Eu(III) complexes. • We measured the photophysical properties of these Eu(III) complexes. • Carbazole derivative of β-diketone forms the brightest Eu(III) complex. • The Jablonski diagrams proposed for the luminescence of these complexes.

Physical and photophysical properties of mixed double- and triple-decker sandwiches of porphyrins and phthalocyanines

International Nuclear Information System (INIS)

Salabert, Isabelle

1995-01-01

The study of electron transfer and charge recombination processes in various oligomers of porphyrins and phthalocyanines is reported. Our objective is to determine the nature of processes which compete with electron transfer in such Systems. The first part of this thesis is devoted to the study of mixed double- and triple-decker sandwich compounds of porphyrins and phthalocyanines of cerium and praseodymium. The charge transfer reaction and geminated recombination from excited complexes in solution and in sublimated film are investigated by time-resolved absorption spectroscopy with femtosecond time scale resolution. These results show the influence of the magnetic nature of the metal ion and of the relative position of the chromophores in the complex on the photophysical processes. The physical and photophysical properties of complexes formed by pairing in solution porphyrins and porphyrazines bearing oppositely charged substituent are reported in the second part. The formation of mixed aggregates of high order (2 to 5) is observed and their nature are spectrally characterized. The photoproducts issued from these complexes are extremely stable. (author) [fr

Synthesis, characterization, and photophysical properties of a thiophene-functionalized bis(pyrazolyl) pyridine (BPP) tricarbonyl rhenium(I) complex.

Science.gov (United States)

Lytwak, Lauren A; Stanley, Julie M; Mejía, Michelle L; Holliday, Bradley J

2010-09-07

A bromo tricarbonyl rhenium(I) complex with a thiophene-functionalized bis(pyrazolyl) pyridine ligand (L), ReBr(L)(CO)(3) (1), has been synthesized and characterized by variable temperature and COSY 2-D (1)H NMR spectroscopy, single-crystal X-ray diffraction, and photophysical methods. Complex 1 is highly luminescent in both solution and solid-state, consistent with phosphorescence from an emissive (3)MLCT excited state with an additional contribution from a LC (3)(pi-->pi*) transition. The single-crystal X-ray diffraction structure of the title ligand is also reported.

The Gas-Phase Photophysics of Eosin Y and its Maleimide Conjugate.

Science.gov (United States)

Daly, Steven; Kulesza, Alexander; Knight, Geoffrey; MacAleese, Luke; Antoine, Rodolphe; Dugourd, Philippe

2016-05-26

The use of the xanthene family of dyes as fluorescent probes in a wide range of applications has provided impetus for the studying of their photophysical properties. In particular, recent advances in gas-phase techniques such as FRET that utilize such chromophores have placed a greater importance on the characterization of these properties in the gas phase. Additionally, the use of synthetic linker chains to graft the chromophores in a site-specific manner to their target system is ubiquitous. There is, however, often limited information on how the addition of such a linker chain may affect the photophysical properties of the chromophores, which is of fundamental importance for interpretation of experimental data reliant on grafted chromophores. Here, we present data on the optical spectroscopy of different protonation states of Eosin Y, a fluorescein derivative. We compare the photophysics of Eosin Y to its maleimide conjugate, and to the thioether product of the reaction of this conjugate with cysteamine. Comparison of the mass spectra following laser irradiation shows that very different relaxation takes place upon addition of the maleimide moiety but that the photophysics of the bare chromophore are restored upon addition of cysteamine. This radical change in the photophysics is interpreted in terms of charge-transfer states, whose energy relative to the S1 ← S0 transition of the chromophore is dependent on the conjugation of the maleimide moiety. We also show that the shape of the absorption band is unchanged in the gas-phase as compared to the solution-phase, showing a maximum with a shoulder toward the blue, and examination of isotope distributions of the isolated ions show that this shoulder cannot be due to the presence of dimers. Consideration of the fluorescence emission spectrum allows a tentative assignment of the shoulder to be due to a vibrational progression with a high Franck-Condon factor.

The effect of H- and J-aggregation on the photophysical and photovoltaic properties of small Thiophene–Pyridine–DPP molecules for bulk-heterojunction solar cells

NARCIS (Netherlands)

Más-Montoya, M.; Janssen, R.A.J.

2017-01-01

The performance of organic semiconductors in optoelectronic devices depends on the functional properties of the individual molecules and their mutual orientations when they are in the solid state. The effect of H- and J-aggregation on the photophysical properties and photovoltaic behavior of four

Enhancing photophysical and photochemical properties of zinc(II) phthalocyanine dyes by substitution of triptycene moieties

Energy Technology Data Exchange (ETDEWEB)

Al-Sohaimi, Bander Roshadan [Department of Chemistry, Faculty of Science, Taibah University, P.O. Box 344, Al-Madinah Al Munawwrah (Saudi Arabia); Pişkin, Mehmet [Çanakkale Onsekiz Mart University, Vocational School of Technical Sciences, Department of Food Technology, Çanakkale 17100 (Turkey); Aljuhani, Ateyatallah; Al-Raqa, Shaya Y. [Department of Chemistry, Faculty of Science, Taibah University, P.O. Box 344, Al-Madinah Al Munawwrah (Saudi Arabia); Durmuş, Mahmut, E-mail: durmus@gtu.edu.tr [Gebze Technical University, Department of Chemistry, P.O. Box 141, Gebze 41400, Kocaeli (Turkey)

2016-05-15

The symmetrical zinc(II) phthalocyanines conjugated with 9,10-dioctyl-6,7-dimethoxy-2,3-dioxytriptycene or 9,10-diundecyl-6,7-dimethoxy-2,3-dioxytriptycene moieties were synthesized in this study. These novel phthalocyanines were characterized by standard characterization techniques such as {sup 1}H-NMR, FT-IR, UV–vis, Mass and Elemental Analysis. All these phthalocyanines showed highly solubility and formed non-aggregated monomeric species in most of the organic solvents. Their photochemical properties such as singlet oxygen, and photodegradation quantum yields, and photophysical properties including fluorescence quantum yields and lifetimes were investigated in toluene. The fluorescence quenching behavior of the studied zinc(II) phthalocyanines by the addition of 1,4-benzoquinone were also described in toluene.

Enhancing photophysical and photochemical properties of zinc(II) phthalocyanine dyes by substitution of triptycene moieties

International Nuclear Information System (INIS)

Al-Sohaimi, Bander Roshadan; Pişkin, Mehmet; Aljuhani, Ateyatallah; Al-Raqa, Shaya Y.; Durmuş, Mahmut

2016-01-01

The symmetrical zinc(II) phthalocyanines conjugated with 9,10-dioctyl-6,7-dimethoxy-2,3-dioxytriptycene or 9,10-diundecyl-6,7-dimethoxy-2,3-dioxytriptycene moieties were synthesized in this study. These novel phthalocyanines were characterized by standard characterization techniques such as 1 H-NMR, FT-IR, UV–vis, Mass and Elemental Analysis. All these phthalocyanines showed highly solubility and formed non-aggregated monomeric species in most of the organic solvents. Their photochemical properties such as singlet oxygen, and photodegradation quantum yields, and photophysical properties including fluorescence quantum yields and lifetimes were investigated in toluene. The fluorescence quenching behavior of the studied zinc(II) phthalocyanines by the addition of 1,4-benzoquinone were also described in toluene.

Synthesis, photophysical property study of novel fluorescent 4-(1,3 ...

Indian Academy of Sciences (India)

Some of the benzoxazole derivatives exhibit diverse ... NSC-693638 and antibacterial agents;13 some exam- ples are UK-1, ..... 1H NMR (D2O Exchange of Comp .... test material in 10% (v/v) DMSO (usually a stock con- .... Refractive index of solvent for standard .... synthesis B M Trost, and I Flemming (eds) New York:.

Synthesis, crystal structure and photophysical properties of (E)-4-(4-(2-hydroxybenzylideneamino)benzyl)oxazolidin-2-one

International Nuclear Information System (INIS)

Kumari, Rekha; Varghese, Anitha; George, Louis

2016-01-01

A new Schiff base, (4-(benzylideneamino)benzyl)oxazolidin-2-one has been synthesised from 4-(4-aminobenzyl)oxazolidin-2-one and salicylaldehyde by a simple condensation reaction. Single-crystal X-ray analysis of (E)-4-(4-(2-hydroxybenzylideneamino) benzyl)oxazolidin-2-one (HBOA) revealed that there is a 1-D, slipped, face-to-face motif with off-set, head-to-tail stacked columns. Detailed studies on photophysical properties of the synthesised compound in solutions indicate their potential applications in the field of organic light emitting devices and nonlinear optical materials. Absorption and fluorescence study of HBOA has been conducted in a series of solvents with increasing polarity at room temperature. Ground and excited state dipole moments have been determined experimentally by using Lippert–Mataga polarity function, Bakhshiev solvent polarity parameter, Kawskii–Chamma–Viallet solvent polarity parameter and RichardtГ—Віs microscopic solvent polarity parameter. Due to the considerable π-electron density redistribution, the excited state dipole moment was found to be larger than that of the ground state. The ground state dipole moment value was determined by quantum chemical method which was used to estimate excited state dipole moment through solvatochromic correlations. Kamlet–Taft and Catalan methods were used to get the information of both non-specific solute–solvent interactions and hydrogen bonding interactions. TD-DFT (B3LYP/6-311G(d,p)) has been used for the determination of HOMO–LUMO energies. Mulliken charges and Molecular electrostatic potential were also evaluated from DFT calculations.

Synthesis, Photophysical and Electrochemical Properties of a Mixed Bipyridyl-Phenanthrolyl Ligand Ru(II Heteroleptic Complex Having trans-2-Methyl-2-butenoic Acid Functionalities

Directory of Open Access Journals (Sweden)

Adewale O. Adeloye

2011-09-01

Full Text Available In this work, two ligands: 4-(trans-2-Methyl-2-butenoic acid-2,2'-bipyridine (L1 and 5-(trans-2-methyl-2-butenoic acid-1,10-phenanthroline (L2, with the corresponding mixed-ligand heteroleptic Ru(II complex were synthesized and characterized by FT-IR, 1H-, 13C-NMR spectroscopy and elemental analysis. The influence of the mixed functionalized polypyridyl ruthenium(II complex on the photophysical and electrochemical properties were investigated and compared to individual single-ligand homoleptic complexes. Interestingly, the mixed-ligand complex formulated as [RuL1L2(NCS2] exhibits broad and intense metal-to-ligand charge transfer (MLCT absorption with a high molar extinction coefficient (λmax = 514 nm, ε = 69,700 M−1 cm−1, better than those of individual single-ligand complexes, [Ru(L12(NCS2] and [Ru(L22(NCS2], and a strong photoluminescence intensity ratio in the red region at λem = 686 nm. The electrochemical properties of the complex indicated that the redox processes are ligand-based.

Photophysics of organometallic platinum(II) derivatives of the diketopyrrolopyrrole chromophore

KAUST Repository

Goswami, Subhadip; Winkel, Russell W.; Alarousu, Erkki; Ghiviriga, Ion; Mohammed, Omar F.; Schanze, Kirk S.

2014-01-01

A pair of diketopyrrolopyrrole (DPP) chromophores that are end-functionalized with platinum containing "auxochromes" were subjected to electrochemical and photophysical study. The chromophores contain either platinum acetylide or ortho-metalated 2-thienylpyridinyl(platinum) end-groups (DPP-Pt(CC) and DPP-Pt(acac), respectively). The ground state redox potentials of the chromophores were determined by solution electrochemistry, and the HOMO and LUMO levels were estimated. The chromophores' photophysical properties were characterized by absorption, photoluminescence, and time-resolved absorption spectroscopy on time scales from sub-picoseconds to microseconds. Density functional theory (DFT) computations were performed to understand the molecular orbitals involved in both the singlet and triplet excited state photophysics. The results reveal that in both platinum DPP derivatives the organometallic auxochromes have a significant effect on the chromophores' photophysics. The most profound effect is a reduction in the fluorescence yields accompanied by enhanced triplet yields due to spin-orbit coupling induced by the metal centers. The effects are most pronounced in DPP-Pt(acac), indicating that the orthometalated platinum auxochrome is able to induce spin-orbital coupling to a greater extent compared to the platinum acetylide units. (Figure Presented).

Photophysics of organometallic platinum(II) derivatives of the diketopyrrolopyrrole chromophore

KAUST Repository

Goswami, Subhadip

2014-12-18

A pair of diketopyrrolopyrrole (DPP) chromophores that are end-functionalized with platinum containing "auxochromes" were subjected to electrochemical and photophysical study. The chromophores contain either platinum acetylide or ortho-metalated 2-thienylpyridinyl(platinum) end-groups (DPP-Pt(CC) and DPP-Pt(acac), respectively). The ground state redox potentials of the chromophores were determined by solution electrochemistry, and the HOMO and LUMO levels were estimated. The chromophores\\' photophysical properties were characterized by absorption, photoluminescence, and time-resolved absorption spectroscopy on time scales from sub-picoseconds to microseconds. Density functional theory (DFT) computations were performed to understand the molecular orbitals involved in both the singlet and triplet excited state photophysics. The results reveal that in both platinum DPP derivatives the organometallic auxochromes have a significant effect on the chromophores\\' photophysics. The most profound effect is a reduction in the fluorescence yields accompanied by enhanced triplet yields due to spin-orbit coupling induced by the metal centers. The effects are most pronounced in DPP-Pt(acac), indicating that the orthometalated platinum auxochrome is able to induce spin-orbital coupling to a greater extent compared to the platinum acetylide units. (Figure Presented).

Synthesis, photophysical and electrochemical properties of 2,8 ...

Indian Academy of Sciences (India)

dibenzothiophene derivatives for organic electronics. Pabitra K Nayak ... These molecules have electron withdrawing or electron donating groups at the para phenyl position, which alters the electronic properties of these derivatives. The quantum yield ...

How to prevent dimerization of laser dyes in water? Simulation and organic synthesis

International Nuclear Information System (INIS)

Dare-Doyen, S.

2000-01-01

Xanthenes are widely used as laser dyes in ethanol medium because their photophysical properties there are excellent. On the other hand, when they are dissolved in water, their fluorescence is almost zero on account of the dimerization phenomenon (aggregation of two molecules) which is specific in water although the interaction between the two molecules (these dyes are mainly cations) be repulsive. The first part of this work deals with the dimerization study of two dyes, the 6G rhodamine and the 6G pyronine. Molecular dynamics simulation results (AMBER software) have been compared with those of the NMR; thus it has been possible to describe the geometry of the 6G rhodamine dimer and to identify two structures present in equal quantities for the 6G pyronine dimer. It has been demonstrated that the role of water is essential in the aggregation mechanism; this role can be understood as resulting of the hydrophobic effect. The second part of this work concerns the synthesis of rhodamines which are soluble but not able to dimerize in water at the running concentrations of the laser dyes. At first, aminophenol precursors having hydrophilic ionic groups on modifiable sites have been synthesized without changing their photophysical properties. The synthesis sequence of the 3-(2-alkylamino-4-hydroxyphenyl)propionic acids has not given the waited products but N-(3'-hydroxyphenyl)amino-alkylsulfonic acids have been obtained. Their condensation with the phthalic anhydride has led to dyes of a charge -2 at a pH of 5 in water and which have photophysical properties similar to those of the rhodamine 575 in ethanol and laser emission properties in the emission spectral range of the rhodamine 6G in ethanol. This synthesis work has then led to the preparation of two laser dyes usable in water. (author) [fr

Photophysical Properties of Pheophorbide-a Derivatives and Their Photodynamic Therapeutic Effects on a Tumor Cell Line In Vitro

Directory of Open Access Journals (Sweden)

Kang-Kyun Wang

2014-01-01

Full Text Available Pheophorbide-a derivatives have been reported to be potential photosensitizers for photodynamic therapy (PDT. In this study, photophysics of pheophorbide-a derivatives (PaDs were investigated along with their photodynamic tumoricidal effect in vitro. PaDs were modified by changing the coil length and/or making the hydroxyl group (–OH substitutions. Their photophysical properties were studied by steady-state and time-resolved spectroscopic methods. The photodynamic tumoricidal effect was evaluated in the mouse breast cancer cell line (EMT6. Lifetime and quantum yield of fluorescence and quantum yields of triplet state and singlet oxygen were studied to determine the dynamic energy flow. The coil length of the substituted alkyl group did not significantly affect the spectroscopic properties. However, the substitution with the hydroxyl group increased the quantum yields of the triplet state and the singlet oxygen due to the enhanced intersystem crossing. In order to check the application possibility as a photodynamic therapy agent, the PaDs with hydroxyl group were studied for the cellular affinity and the photodynamic tumoricidal effect of EMT6. The results showed that the cellular affinity and the photodynamic tumoricidal effect of PaDs with the hydroxyl group depended on the coil-length of the substituted alkyl group.

Photophysical and photobiological properties of a sulfonated chlorin photosensitiser TPCS(2a) for photochemical internalisation (PCI).

Science.gov (United States)

Wang, Julie T-W; Berg, Kristian; Høgset, Anders; Bown, Stephen G; MacRobert, Alexander J

2013-03-01

This study investigated the photophysical and photobiological properties of a new amphiphilic chlorin photosensitiser, disulfonated tetraphenylchlorin (TPCS(2a)), for photochemical internalisation (PCI). The absorption and fluorescence spectra of TPCS(2a) were examined in a range of solvents together with fluorescence lifetime measurements. The fluorescence lifetime of TPCS(2a) was found to be 8.5 ns in methanol, whereas non-exponential decays were observed in distilled water due to sensitiser dimerisation. The singlet oxygen quantum yield of TPCS(2a) was determined as 0.62 in deuterated methanol by direct observation of singlet oxygen phosphorescence. In a human oral squamous carcinoma (HN5) cell line, intracellular co-localisation of TPCS(2a) and Alexa488-labelled saporin, a macromolecular toxin, was observed corresponding predominantly to a lysosomal distribution. Intracellular fluorescence redistribution of TPCS(2a) and Alexa488-saporin was observed after 405 nm irradiation. Using two-photon confocal microscopy at 840 nm, and fluorescence lifetime imaging (FLIM), the lifetime was measured as 6 ns in HN5 cells. PCI using TPCS(2a) was shown to be very effective, and a synergistic increase in saporin toxicity was achieved in HN5 cells where viability was significantly reduced after light exposure compared to saporin (25 nM) treatment alone. The results demonstrate the favourable photophysical and photobiological properties of TPCS(2a) for PCI, which induces the relocalisation of a macromolecular anti-cancer toxin inside cells and significantly enhances cell death.

Pincer-CNC mononuclear, dinuclear and heterodinuclear Au(III) and Pt(II) complexes supported by mono- and poly-N-heterocyclic carbenes: synthesis and photophysical properties.

Science.gov (United States)

Gonell, S; Poyatos, M; Peris, E

2016-04-07

A family of cyclometallated Au(iii) and Pt(ii) complexes containing a CNC-pincer ligand (CNC = 2,6-diphenylpyridine) supported by pyrene-based mono- or bis-NHC ligands have been synthesized and characterized, together with the preparation of a Pt-Au hetero-dimetallic complex based on a Y-shaped tris-NHC ligand. The photophysical properties of all the new species and of two related Ru(ii)-arene complexes were studied and compared. Whereas the pyrene-based complexes only exhibit emission in solution, those containing the Y-shaped tris-NHC ligand are only luminescent when dispersed in poly(methyl methacrylate) (PMMA). In particular, the pyrene-based complexes were found to be emissive in the range of 373-440 nm, with quantum yields ranging from 3.1 to 6.3%, and their emission spectra were found to be almost superimposable, pointing to the fluorescent pyrene-centered nature of the emission. This observation suggests that the emission properties of the pyrene fragment may be combined with some of the numerous applications of NHCs as supporting ligands allowing, for instance, the design of biological luminescent agents.

Solvent Effect, Photochemical and Photophysical Properties of Phthalocyanines with Different Metallic Nuclei

Directory of Open Access Journals (Sweden)

Charles Biral Silva

2017-12-01

Full Text Available Photophysical and photochemical properties of lithium phthalocyanine (1, gallium(III phthalocyanine chloride (2, titanium(IV phthalocyanine dichloride (3 and iron(II phthalocyanine (4 were investigated in dimethyl sulfoxide (DMSO, tetrahydrofuran (THF and DMSO-THF mixtures. The influence of the central metal on these properties was analyzed according to solvent type, axial ligands and their paramagnetic and diamagnetic effect. Fluorescence lifetimes were recorded using a time correlated single photon counting setup (TCSPC technique. In order to demonstrate the generation of reactive oxygen species under light irradiation, the indirect method (applying 1,3-diphenylisobenzofuran (DPBF as chemical suppressor and the direct method (analyzing the phosphorescence decay curves of singlete oxygen at 1270 nm were employed. Compounds 1, 2 and 3 showed a monomeric behavior in all media while compound 4 presented low aggregation in DMSO, but a very pronounced aggregation behavior in THF. Steady-state fluorescence anisotropy was compared with emission spectra and complex 4 presented values beyond the expected limits. DOI: http://dx.doi.org/10.17807/orbital.v9i5.1047 

Influence of bidentate structure of an aryl phosphine oxide ligand on photophysical properties of its Eu~Ⅲ complex

Institute of Scientific and Technical Information of China (English)

许辉; 魏莹; 赵保敏; 黄维

2010-01-01

The bidentate phosphine oxide ligand 1,8-bis(diphenylphosphino) naphthalene oxide (NAPO) and its EuⅢ complex 1 Eu(TTA)3(NAPO) (TTA=2-thenoyltrifluoroacetonate) were chosen to study the effect of bidentate phosphine oxide ligand on the photophysical properties of the corresponding complex. The intramolecular energy transfer processes of 1 were studied. The investigation showed that with bidentate structure NAPO could suppress solvent-induced quenching by enforcing the ligand-ligand interaction and the rigidi...

Synthesis, photophysical and electrochemical properties, and protein-binding studies of luminescent cyclometalated iridium(III) bipyridine estradiol conjugates.

Science.gov (United States)

Lo, Kenneth Kam-Wing; Zhang, Kenneth Yin; Chung, Chi-Keung; Kwok, Karen Ying

2007-01-01

A new series of luminescent cyclometalated iridium(III) bipyridine estradiol conjugates [Ir(N-C)2(N-N)](PF6) (N-N = 5-(4-(17alpha-ethynylestradiolyl)phenyl)-2,2'-bipyridine, bpy-est, HN-C = 2-phenylpyridine, Hppy (1 a), 1-phenylpyrazole, Hppz (2 a), 7,8-benzoquinoline, Hbzq (3 a), 2-phenylquinoline, Hpq (4 a), 2-((1,1'-biphenyl)-4-yl)benzothiazole, Hbsb (5 a); N-N = 4-(N-(6-(4-(17alpha-ethynylestradiolyl)benzoylamino)hexyl)aminocarbonyl)-4'-methyl-2,2'-bipyridine, bpy-C6-est, HN-C = Hppy (1 b), Hppz (2 b), Hbzq (3 b), Hpq (4 b), Hbsb (5 b)) was synthesized, characterized, and their photophysical and electrochemical properties studied. Upon photoexcitation, all the complexes displayed intense and long-lived emission in fluid solutions at 298 K and in low-temperature glass. The emission of complexes 1 a-3 a and 1 b-3 b was assigned to a triplet metal-to-ligand charge-transfer ((3)MLCT) (dpi(Ir)-->pi*(bpy-est and N-C-)) state mixed with some triplet intraligand ((3)IL) (pi-->pi*) (N-C- and N-N) character. However, the emissive states of the pq- and bsb- complexes 4 a, 4 b, 5 a, and 5 b showed substantial (3)IL (pi-->pi*) (pq-/bsb-) character. The lipophilicity of all the complexes was determined by reversed-phase HPLC. Upon binding to estrogen receptor alpha, all of these iridium(III) estradiol conjugates exhibited emission enhancement and lifetime extension, rendering them a novel series of luminescent probes for this receptor.

Photophysics of Organic-Inorganic Hybrid Lead Iodide Perovskite Single Crystals

NARCIS (Netherlands)

Fang, Honghua; Raissa, Raissa; Abdu-Aguye, Mustapha; Adjokatse, Sampson; Blake, Graeme R.; Even, Jacky; Loi, Maria Antonietta

2015-01-01

Hybrid organometal halide perovskites have been demonstrated to have outstanding performance as semiconductors for solar energy conversion. Further improvement of the efficiency and stability of these devices requires a deeper understanding of their intrinsic photophysical properties. Here, the

New naphthalene polyimide with unusual molar absorption coefficient and excited state properties: Synthesis, photophysics and electrochemistry

Energy Technology Data Exchange (ETDEWEB)

Ozser, Mustafa E. [Girne American University, Faculty of Engineering and Architecture, Department of Industrial Engineering, Girne, North Cyprus (Cyprus); Yucekan, Ilke; Bodapati, Jagadeesh B. [Eastern Mediterranean University, Faculty of Arts and Sciences, Department of Chemistry, Famagusta, North Cyprus (Cyprus); Icil, Huriye, E-mail: huriye.icil@emu.edu.tr [Eastern Mediterranean University, Faculty of Arts and Sciences, Department of Chemistry, Famagusta, North Cyprus (Cyprus)

2013-11-15

A high molecular weight 1,4,5,8-naphthalene polyimide (ENPI) by one-step polycondensation mechanism and for comparison its monomeric diimide (ENDI) were synthesized; the photophysical and electrochemical properties were studied in detail for ENPI. Monomer has shown unusual insolubility so that the characterization proven to be difficult, whereas ENPI has shown better solubility. The molecular weight data obtained by GPC for the polymer were M{sub n}=8240 and M{sub w}=34,000 g mol{sup −1} respectively with a polydispersity of 4.13. The polyimide exhibited outstandingly high molar absorption coefficients as 599,000, 1,021,000, and 972,700 M{sup −1} cm{sup −1}, which is first time reported in literature for the characteristic 0–2, 0–1, and 0–0 electronic transitions, respectively. ENPI showed concentration dependent and red shifted excimer emission in 1,1,2,2-tetrachloroethane (TCE). The polymer has undergone multielectron reductions in CHCl{sub 3} solution below 100 mV s{sup −1} scan rates which merged into two reversible one-electron reduction peaks at higher scan rates. In solid-state, similar scan rate dependent reduction peaks were noticed. The LUMO, HOMO and optical band gap values obtained for ENPI were −3.73, −6.91, and 3.18 eV respectively. ENDI polymer with striking features has great potential as new sensitizer for efficient dye sensitized organic cells. Highlights: • A high molecular weight naphthalene polyimide was synthesized (M{sub w}=34,000 g mol{sup −1}). • The oligoether polyimide exhibited outstanding molar absorptivity (972,700 M{sup −1} cm{sup −1}). • A red shifted excimer emission has been observed. • The polymer has undergone multielectron reductions.

The effect of the triblock properties on the morphologies and photophysical properties of nanoparticle loaded with carboxylic dendrimer phthalocyanine

Science.gov (United States)

Lv, Huafei; Chen, Zhe; Yu, Xinxin; Pan, Sujuan; Zhang, Tiantian; Xie, Shusen; Yang, Hongqin; Peng, Yiru

2016-09-01

Photodynamic therapy (PDT) is an emerging alternative treatment for various cancers and age-related macular degeneration. Phthalocyanines (Pcs) and their substituted derivatives are under intensive investigation as the second generation photosensitizers. A big challenge for the application of Pcs is poor solubility and limited accumulation in the tumor tissues, which severely reduced its PDT efficacy. Nano-delivery systems such as polymeric micelles are promising tools for increasing the solubility and improving delivery efficiency of Pcs for PDT application. In this paper, nanoparticles of amphiphilic triblock copolymer poly(L-lysine)-b-poly (ethylene glycol)-b-poly(L-lysine) were developed to encapsulate 1-2 generation carboxylic poly (benzyl aryl ether) dendrimer. The morphologies and photophysical properties of polymeric nanoparticles loaded with 1-2 generation dendritic phthalocyanines (G1-ZnPc(COOH)8/m and G2-ZnPc(COOH)16/m) were studied by AFM, UV/Vis and fluorescent spectroscopic method. The morphologies of self-assembled PLL-PEG-PLL aggregates exhibited concentration dependence. Its morphologies changed from cocoon-like to spheral. The diameters of G1-ZnPc(COOH)8/m and G2-ZnPc(COOH)16/m were in the range of 33-147 nm, increasing with the increase of the concentration of PLL-PEG-PLL. The morphologies of G2-ZnPc(COOH)16/m also changed from cocoon-like to sphere with the increase of the concentration of PLL-PEG-PLL. It was found that, the no obviously Q change was observed between the free phthalocyanines and nanoparticles. The fluorescence intensity of polymer nanoparticles were higher enhanced compared with free dendritic phthalocyanines. The dendrimer phthalocyanine loaded with poly(L-lysine)-b-poly (ethylene glycol)-b-poly(L-lysine) presented suitable physical stability, improved photophysical properties suggesting it may be considered as a promising formulation for PDT.

Photo-physical properties enhancement of bare and core-shell quantum dots

Energy Technology Data Exchange (ETDEWEB)

Mumin, Md Abdul, E-mail: pcharpentier@eng.uwo.ca; Akhter, Kazi Farida, E-mail: pcharpentier@eng.uwo.ca; Charpentier, Paul A., E-mail: pcharpentier@eng.uwo.ca [Chemical and Biochemical Engineering, Western University, London Ontario (Canada)

2014-03-31

Semiconductor nanocrystals (NCs) (also known as quantum dots, QDs) have attracted immense attention for their size-tunable optical properties that makes them impressive candidates for solar cells, light emitting devices, lasers, as well as biomedical imaging. However monodispersity, high and consistent photoluminescence, photostability, and biocompatibility are still major challenges. This work focuses on optimizing the photophysical properties and biocompatibility of QDs by forming core-shell nanostructures and their encapsulation by a carrier. Highly luminescent CdS and CdS-ZnS core-shell QDs with 5 nm sizes were synthesized using a facile approach based on pyrolysis of the single molecule precursors. After capping the CdS QDs with a thin layer of ZnS to reduce toxicity, the photoluminescence and photostability of the core-shell QDs was significantly enhanced. To make both the bare and core/shell structure QDs more resistant against photochemical reactions, a mesoporous silica layer was grown on the QDs through a reverse microemulsion technique based on hydrophobic interaction. This encapsulation enhanced the quantum yield and photostability compared to the bare QDs by providing much stronger resistance to oxidation and Oswald ripening of QDs. Encapsulation also improved biocompatibility of QDs that was evaluated with human umbilical vein endothelial cell lines (HUVEC)

Photoluminescent Copper(I) Complex Based on 3-(2-(Cyclohexylthio) ethoxy)pyridine: Synthesis, Structure, and Physical Properties

Energy Technology Data Exchange (ETDEWEB)

Park, Hyunjin; Kwon, Eunjin; Kang, Gihaeng; Kim, Jieun; Kim, Tae Ho [Gyeongsang National University, Jinju (Korea, Republic of)

2016-07-15

In recent years, the Cu(I) complexes, with d 10 electronic configuration, have been attracting interest due to their diverse structures and photophysical properties. A copper(I) coordination polymer 1 based on a sulfur-containing pyridyl ligand L was synthesized and identified by X-ray crystallography. Photophysical and thermal properties of 1 have been investigated. More Cu(I) coordination polymers based on mixed donor ligands are under investigation in order to discover factors governing luminescence wavelength, such as Cu[BOND]Cu distances, intermolecular interactions, structures of ligands, and so on.

One pot synthesis, X-ray crystal structure of 2-(2‧-hydroxyphenyl)oxazolo[4,5-b]pyridine derivatives and studies of their optical properties

Science.gov (United States)

Briseño-Ortega, Horacio; Juárez-Guerra, Lizbeth; Rojas-Lima, Susana; Mendoza-Huizar, Luis Humberto; Vázquez-García, Rosa A.; Farfán, Norberto; Arcos-Ramos, Rafael; Santillan, Rosa; López-Ruiz, Heralio

2018-04-01

A series of five 2-(2-hydroxyphenyl)oxazolo [4,5-b]pyridines (HPOP) (3a-e), where four are novel, were synthesized by a mild, one pot, phenylboronic acid-NaCN catalyzed reaction. Spectroscopic characterization and photophysical properties of these compounds are reported. Absorption and excitation spectra of the compounds were dependent on the substituents in the phenyl ring. Fluorescence quantum yields (0.009-0.538) were associated with the donor strength and the position of the substituents. Also, DFT analysis allowed us to determine the contribution of diethylamino and methoxy moieties to the π-system, which is in agreement with the experimental data analyzed in solution and by cyclic voltammetry. The results obtained in the solid state by single-crystal X-ray diffraction experiments indicate that, the quasi-planarity envisioned for the explored compounds is present, supporting the hypothesis that both the H-bonding of a hydroxyl group to the Cdbnd N moiety and a donor groups such as diethylamino and methoxy moieties favor an electronic communication. Due to the facile synthesis and their photophysical properties, the novel HPOP 3a-e have potential application as organic semiconductors.

A New Synthesis of Porphyrins with Extended Conjugation and their Photophysics

National Research Council Canada - National Science Library

Ono, Noboru

2005-01-01

.... These molecules useful non-linear optical and optoelectronic properties. The contractor used a synthesis method based on the retro Diels-Alder reaction of porphyrins fused with bicyclo[2.2.2]octadiene units...

Photophysical properties and localization of chlorins substituted with methoxy groups, hydroxyl groups and alkyl chains in liposome-like cellular membrane

Energy Technology Data Exchange (ETDEWEB)

Al-Omari, S [Department of Physics, Hashemite University, Zarqa 13115 (Jordan)

2007-06-01

Some of the photophysical properties (stationary absorbance and fluorescence, fluorescence decay times and singlet oxygen quantum yields) of chlorins substituted with methoxy groups, hydroxyl groups and hydrocarbonic chains were studied in ethanol and dipalmitoyl-phosphatidylcholine (DPPC) liposomes using steady-state and time-resolved fluorescence spectroscopies. The photophysical behaviors of the chlorins in liposomes like cellular membrane were compared with those obtained from chlorin-liposome systems delivered to Jurkat cells in order to select potent photosensitizers for the photodynamic treatment of cancer. The localization of the studied chlorins inside liposomes was found to depend strongly on the substituents of chlorins. Absorption spectra of chlorins embedded in DPPC-liposomes have been recorded in the temperature range of 20-70 deg. C. It is demonstrated that the location of the chlorin molecules depends on the phase state of the phospholipids. These observations are confirmed by the fluorescence lifetimes, singlet oxygen lifetimes and singlet oxygen quantum yields results.

Photophysical and physicochemical studies of rare earths complexes formed with calyx(n)arenes

International Nuclear Information System (INIS)

Ramirez, F.M.; Varbanov, S.; Corine, C.; Muller, G.; Fatin-Rouge, N.; Scopelliti, R.; Bunzli J, C.G.

2001-01-01

In this work, some of the photophysical and physicochemical properties are presented which are observed in the rare earths complexes that are formed with diverse functionalized calyx(n)arenes receptors where n=4-6 designed with predetermined properties and synthesized by own methods. (Author)

Synthesis and Luminescence Properties of Iridium(III Azide- and Triazole-Bisterpyridine Complexes

Directory of Open Access Journals (Sweden)

Timothy W. Schmidt

2013-07-01

Full Text Available We describe here the synthesis of azide-functionalised iridium(III bisterpyridines using the “chemistry on the complex” strategy. The resulting azide-complexes are then used in the copper(I-catalysed azide-alkyne Huisgen 1,3-dipolar cycloaddition “click chemistry” reaction to from the corresponding triazole-functionalised iridium(III bisterpyridines. The photophysical characteristics, including lifetimes, of these compounds were also investigated. Interestingly, oxygen appears to have very little effect on the lifetime of these complexes in aqueous solutions. Unexpectedly, sodium ascorbate acid appears to quench the luminescence of triazole-functionalised iridium(III bisterpyridines, but this effect can be reversed by the addition of copper(II sulfate, which is known to oxidize ascorbate under aerobic conditions. The results demonstrate that iridium(III bisterpyridines can be functionalized for use in “click chemistry” facilitating the use of these photophysically interesting complexes in the modification of polymers or surfaces, to highlight just two possible applications.

Tetraaryl-, Pentaaryl-, and Hexaaryl-1,4-dihydropyrrolo 3,2-b pyrroles: Synthesis and Optical Properties

DEFF Research Database (Denmark)

Krzeszewski, M.; Thorsted, B.; Brewer, J.

2014-01-01

. Strategic placement of electron-withdrawing substituents at the 2-, 3-, 5-, and 6-positions produced an acceptor donor acceptor type fluorophore. The resulting multiply substituted heteropentalenes displayed intriguing optical properties. The relationship between the structure and photophysical properties...

Photophysical properties of betaxanthins: Vulgaxanthin I in aqueous and alcoholic solutions

Energy Technology Data Exchange (ETDEWEB)

Wendel, Monika [Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614 (Poland); Szot, Dominika; Starzak, Karolina; Tuwalska, Dorota [Faculty of Chemical Engineering and Technology, Institute C-1, Section of Analytical Chemistry, Cracow University of Technology, Warszawska 24, Cracow 31-155 (Poland); Gapinski, Jacek [Molecular Biophysics Department, Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614 (Poland); Naskrecki, Ryszard [Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614 (Poland); Prukala, Dorota; Sikorski, Marek [Faculty of Chemistry, Adam Mickiewicz University in Poznan, Umultowska 89b, Poznan 61-614 (Poland); Wybraniec, Slawomir [Faculty of Chemical Engineering and Technology, Institute C-1, Section of Analytical Chemistry, Cracow University of Technology, Warszawska 24, Cracow 31-155 (Poland); Burdzinski, Gotard, E-mail: gotardb@amu.edu.pl [Quantum Electronics Laboratory, Faculty of Physics, Adam Mickiewicz University in Poznan, Umultowska 85, Poznan 61-614 (Poland)

2015-11-15

Betaxanthins are yellow pigments present in Caryophyllales plants and some higher fungi. We characterize photophysical properties of vulgaxanthin I and extracts of Amanita muscaria L. Vulgaxanthin I photoexcitation at λ{sub exc}=476 nm leads to the S{sub 1} excited state with the S{sub 1}→S{sub n} absorption bands at ca. 390 and 920 nm in both aqueous and alcoholic solutions. The S{sub 1} state lifetimes (2.9 and 37 ps in water) imply that vulgaxanthin I exists in two stereoisomeric forms. An increase in the solvent viscosity extends the S{sub 1} lifetimes and fluorescence quantum yields, probably due to hindered internal rotations in the dye. Internal conversion is the major S{sub 1} state deactivation path, with fluorescence being a minor channel, and S{sub 1}→T{sub 1} intersystem crossing not observed. Betaxanthins extracted from A. muscaria L. have similar properties. Efficient dissipation of the absorbed light energy as heat supports the postulate of photoprotective role of betaxanthins in vivo. - Highlights: • Betaxanthin S{sub 1} state deactivation mechanism is mainly radiationless. • S{sub 1} state shows absorption band with maxima at about 390 nm and 920 nm. • Solvent viscosity affects S{sub 1} state lifetime and fluorescence quantum yield. • Addition of potassium iodide to solution enhances ISC in betaxanthin.

Nucleic acid and nucleotide-mediated synthesis of inorganic nanoparticles

Science.gov (United States)

Berti, Lorenzo; Burley, Glenn A.

2008-02-01

Since the advent of practical methods for achieving DNA metallization, the use of nucleic acids as templates for the synthesis of inorganic nanoparticles (NPs) has become an active area of study. It is now widely recognized that nucleic acids have the ability to control the growth and morphology of inorganic NPs. These biopolymers are particularly appealing as templating agents as their ease of synthesis in conjunction with the possibility of screening nucleotide composition, sequence and length, provides the means to modulate the physico-chemical properties of the resulting NPs. Several synthetic procedures leading to NPs with interesting photophysical properties as well as studies aimed at rationalizing the mechanism of nucleic acid-templated NP synthesis are now being reported. This progress article will outline the current understanding of the nucleic acid-templated process and provides an up to date reference in this nascent field.

Synthesis, Crystal Structure and Luminescence Property of a New Silver(I) Dimer with Isonicotinic Acid

International Nuclear Information System (INIS)

Yuan, Qi; Liu, Bing

2005-01-01

The absorption spectrum was calculated from reflection spectrum by the Kubelka.Munk function. The energy gap of the title compound determined by extrapolation from the linear portion of the absorption edge in a (α/S) versus energy plot is 1.91 eV, which suggests that the title compound behaves as semiconductor. Isonicotinic acid (Iso), namely 4.pyridinecarboxylate, a multi.functional chelating and/or bridging ligand, has proved to be very powerful for the construction of multi. dimensional metal.organic coordination networks. Furthermore, The isonicotinic acid complexes has raised many interests in fluorescence probing with numerous potential applications for studies of microsecond diffusion and dynamics of membranes. Metal centers are potential carriers of electrochemical, magnetic, catalytic, or optical properties that may be introduced into the inorganic.organic hybrid materials. d"1"0 metals with rich photophysical and photochemical character have focused attentions to synthesize polynuclear complexes. Considering the versatile coordination abilities of Iso, we employ the ligand to coordinate with silver nitrate to fabricate a coordination complex with excellent fluorescence property. Herein we report the synthesis, crystal structure and fluorescence property of a new d"1"0 coordination dimer [Ag_2(Iso)_2(NO_3)_2

Synthesis, Photophysics, Electrochemistry and Electrogenerated Chemiluminescence of a Homologous Set of BODIPY-Appended Bipyridine Derivatives.

Science.gov (United States)

Rosenthal, Joel; Nepomnyashchii, Alexander B; Kozhukh, Julia; Bard, Allen J; Lippard, Stephen J

2011-09-15

Two new 2,2'-bipyridine (bpy) based ligands with ancillary BODIPY chromophores attached at the 4 and 4'-positions were prepared and characterized, which vary in the substitution pattern about the BODIPY periphery by either excluding (BB1) or including (BB2) a β-alkyl substituent. Both absorb strongly throughout the visible region and are strongly emissive. The basic photophysics and electrochemical properties of BB1 and BB2 are comparable to those of the BODIPY monomers on which they are based. The solid-state structures and electronic structure calculations both indicate that there is negligible electronic communication between the BODIPY moieties and the intervening bpy spacers. Electrogenerated chemiluminescence spectra of the two Bpy-BODIPY derivatives are similar to their recorded fluorescence profiles and are strongly influenced by substituents on the BODIPY chromophores. These 2,2'-bipyridine derivatives represent a new set of ligands that should find utility in applications including light-harvesting, photocatalysis, and molecular electronics.

Synthesis, characterization and photophysical properties

Indian Academy of Sciences (India)

and medicinal application such as photodynamic thera- py.9–11 Intramolecular ... resident metallo/metalloid ion of porphyrin.15–18 In con- trast, energy or electron ... or flash chromatography was used for compound purifi- cation. Where as a ...

Computational Investigation of the Influence of Halogen Atoms on the Photophysical Properties of Tetraphenylporphyrin and Its Zinc(II) Complexes.

Science.gov (United States)

De Simone, Bruna C; Mazzone, Gloria; Russo, Nino; Sicilia, Emilia; Toscano, Marirosa

2018-03-15

How the tetraphenylporphyrin (TPP) and its zinc(II) complexes (ZnTPP) photophysical properties (absorption energies, singlet-triplet energy gap and spin-orbit coupling contributions) can change due to the presence of an increasing number of heavy atoms in their molecular structures has been investigated by means of density functional theory and its time-dependent formulation. Results show that the increase of the atomic mass of the substituted halogen strongly enhances the spin-orbit coupling values, allowing a more efficient singlet-triplet intersystem crossing. Different deactivation channels have been considered and rationalized on the basis of El-Sayed and Kasha rules. Most of the studied compounds possess the appropriate properties to generate cytotoxic singlet molecular oxygen ( 1 Δ g ) and, consequently, they can be proposed as photosensitizers in photodynamic therapy.

Photo-physics study of an hydroxy-quinoline derivative as inhibitor of Pim-1 kinase

DEFF Research Database (Denmark)

Lamhasni, T.; Aitlyazidi, S.; Hnach, M.

2013-01-01

The photophysical properties of the antiviral 7-nicotinoyl-styrylquinoline (MB96) were investigated by means of UV-Vis linear dichroism (LD) spectroscopy on molecular samples aligned in stretched polyvinylalcohol (PVA), supported by Time Dependent Density Functional Theory (TD-DFT) calculations...

Environmental Effects on the Photophysics of Organic-Inorganic Halide Perovskites.

Science.gov (United States)

Galisteo-López, Juan F; Anaya, M; Calvo, M E; Míguez, H

2015-06-18

The photophysical properties of films of organic-inorganic lead halide perovskites under different ambient conditions are herein reported. We demonstrate that their luminescent properties are determined by the interplay between photoinduced activation and darkening processes, which strongly depend on the atmosphere surrounding the samples. We have isolated oxygen and moisture as the key elements in each process, activation and darkening, both of which involve the interaction with photogenerated carriers. These findings show that environmental factors play a key role in the performance of lead halide perovskites as efficient luminescent materials.

Synthesis, Crystal Structure and Luminescence Property of a New Silver(I) Dimer with Isonicotinic Acid

Energy Technology Data Exchange (ETDEWEB)

Yuan, Qi [Pharmacy College of Henan University, Kaifeng (China); Liu, Bing [Chinese Academy of Sciences, Fuzhou (China)

2005-10-15

The absorption spectrum was calculated from reflection spectrum by the Kubelka.Munk function. The energy gap of the title compound determined by extrapolation from the linear portion of the absorption edge in a (α/S) versus energy plot is 1.91 eV, which suggests that the title compound behaves as semiconductor. Isonicotinic acid (Iso), namely 4.pyridinecarboxylate, a multi.functional chelating and/or bridging ligand, has proved to be very powerful for the construction of multi. dimensional metal.organic coordination networks. Furthermore, The isonicotinic acid complexes has raised many interests in fluorescence probing with numerous potential applications for studies of microsecond diffusion and dynamics of membranes. Metal centers are potential carriers of electrochemical, magnetic, catalytic, or optical properties that may be introduced into the inorganic.organic hybrid materials. d{sup 10} metals with rich photophysical and photochemical character have focused attentions to synthesize polynuclear complexes. Considering the versatile coordination abilities of Iso, we employ the ligand to coordinate with silver nitrate to fabricate a coordination complex with excellent fluorescence property. Herein we report the synthesis, crystal structure and fluorescence property of a new d{sup 10} coordination dimer [Ag{sub 2}(Iso){sub 2}(NO{sub 3}){sub 2}].

Synthesis of new porphyrinoids for biomedical and materials applications

Science.gov (United States)

Stewart, Fraser

The facile synthesis of three non-hydrolysable thioglycosylated porphyrinoids is reported. Starting from meso perfluorophenylporphyrin (TPPF20), the non-hydrolysable thioglycosylated porphyrin (PGlc4), chlorin (CGlc4), isobacteriochlorin (IGlc4), and bacteriochlorin (BGlc4) can be made in 2-3 steps. The ability to append a wide range of targeting agents onto the perfluorophenyl moieties, the chemical stability, and the ability to fine-tune the photophysical properties of the chromophores make this a suitable platform for development of biochemical tags, diagnostics, or as photodynamic therapeutic agents. With reduction of one or two pyrrole double bonds, there is a red shift in the lowest energy absorption band and a significant increase in intensity. The fluorescence of these porphyrinoids is in the order PGlc4 = BGlc4 spectroscopy (DOSY) in solution. The hydrocarbon chains on the melamine mediate the formation of nanofilms on surfaces as the solvent slowly evaporates. A water soluble zinc (II) phthalocyanine symmetrically appended with eight thioglucose units was synthesized from commercially available hexadecafluoro-phthalocyaninato zinc(II) by controlled nucleophilic substitution of the peripheral fluoro groups by thio-sugars. The photophysical properties and cancer cell uptake studies of this nonhydrolyzable thioglycosylated phthalocyanine are reported. The new compound has amphiphilic character, is chemically and photochemically stable, and can potentially be used as a photosensitizer in photodynamic therapy. A porphyrin bearing pyridyl groups at the meso positions was synthesized using 2,6-diacetamido-4-formylpyridine. A new method has been developed for the synthesis of the precursor aldehyde that avoid much of the problems associated with the earlier synthesis. With this porphyrin it is possible to build hetero-complementary rigid, multi-porphyrin supramolecular arrays via hydrogen bonds. For example, when using naphthalenediimide (NDI) units a

Synthesis, characterization, and photo-physical properties of nano-crystallites of CdyZn1-yS semiconductors

International Nuclear Information System (INIS)

Cizeron, Joel

1996-01-01

This research thesis reports the study of the synthesis of particles of semiconductor with a hybrid composition (Cd y Zn 1-y S) in an inverse micellar system. This system is made of nano-scopic water droplets suspended in oil by Brownian movement. Inverse micelles of AOT/water/alkane have been successfully used in laboratory to synthesize semiconductor particles (CdS, Ag 2 S, AgI, PbS) and metallic particles (Ag, Cu, Co) with a diameter of few nanometers. The objective has been to demonstrate the feasibility of synthesises of solid solution with a composition controlled by colloidal techniques. It was then possible to identify new information on the mechanism which governs the size of semiconductor particles. Optical properties of these particles were then studied. These nano-particles exhibit a displacement of their exciton towards high energies; it is the so-called size quantum effect. This effect has been analysed for the particles and their fluorescence [fr

Photophysics of Carbon Nanotubes Interfaced with Organic and Inorganic Materials

CERN Document Server

Levitsky, Igor A; Karachevtsev, Victor A

2012-01-01

Photophysics of Carbon Nanotubes Interfaced with Organic and Inorganic Materials describes physical, optical and spectroscopic properties of the emerging class of nanocomposites formed from carbon nanotubes (CNTs)  interfacing with organic and inorganic materials. The three main chapters detail novel trends in  photophysics related to the interaction of  light with various carbon nanotube composites from relatively simple CNT/small molecule assemblies to complex hybrids such as CNT/Si and CNT/DNA nanostructures.   The latest experimental results are followed up with detailed discussions and scientific and technological perspectives to provide a through coverage of major topics including: ·   Light harvesting, energy conversion, photoinduced charge separation  and transport  in CNT based nanohybrids · CNT/polymer composites exhibiting photoactuation; and ·         Optical  spectroscopy  and structure of CNT/DNA complexes. Including original data and a short review of recent research, Phot...

Photophysics of ionic biochromophores

CERN Document Server

Brøndsted Nielsen, Steen

2014-01-01

This concise guide to studying ionic biochromophores features the first integrated overview of the photophysics of differing classes of biomolecules, from single amino acids to DNA. It includes an appraisal of the latest theories and experimental techniques.

Synthesis and Characterization of Polyfunctional Polyhedral Silsesquioxane Cages

Science.gov (United States)

Sulaiman, Santy

Recent studies on octameric polyhedral silsesquioxanes, (RSiO1.5 )8, indicate that the silsesquioxane cage is not just a passive component but appears to be involved in electron delocalization with conjugated organic tethers in the excited state. This dissertation presents the synthesis and characterization of (RSiO1.5)8 molecules with unique photophysical properties that provide support for the existence of conjugation that involves the (RSiO1.5)8 cage. The dissertation first discusses the elaboration of octavinylsilsesquioxane via cross-metathesis to form styrenyl-functionalized octasilsesquioxane molecules. Subsequent Heck coupling reactions of p-bromostyrenyl derivative provides vinylstilbene-functionalized octasilsesquioxane. The amino derivative, NH2VinylStilbeneOS, show highly red-shifted emission spectrum (100 nm from the simple organic analog p-vinylstilbene) and high two-photon absorption (TPA) cross-section value (100 GM/moiety), indicating charge-transfer processes involving the silsesquioxane cage as the electron acceptor. The unique photophysical properties of polyfunctional luminescent cubic silsesquioxanes synthesized from ortho-8-, (2,5)-16-, and 24-brominated octaphenylsilsesquioxane (OPS) via Heck coupling show how the steric interactions of the organic tethers at the silsesquioxane cage corner affect conjugation with the silsesquioxane cage. Furthermore, the high TPA cross-section (10 GM/moiety) and photoluminescence quantum yield (20%) of OPS functionalized with 24 acetoxystyrenyl groups suggest that the existence excited states in these molecules with similar energies and decay rates: normal radiative pi- pi* transition and charge transfer involving the silsesquioxane cage. The fluoride ion-catalyzed rearrangement reactions of cage and polymeric silsesquioxanes provide a convenient route to a mixture of deca- and dodecameric silsesquioxane molecules in high yields, giving us the opportunity to investigate the effect of silsesquioxane cage

Photophysics of GaN single-photon emitters in the visible spectral range

Science.gov (United States)

Berhane, Amanuel M.; Jeong, Kwang-Yong; Bradac, Carlo; Walsh, Michael; Englund, Dirk; Toth, Milos; Aharonovich, Igor

2018-04-01

In this work, we present a detailed photophysical analysis of recently discovered, optically stable single-photon emitters (SPEs) in gallium nitride (GaN). Temperature-resolved photoluminescence measurements reveal that the emission lines at 4 K are three orders of magnitude broader than the transform-limited width expected from excited-state lifetime measurements. The broadening is ascribed to ultrafast spectral diffusion. The photophysical study on several emitters at room temperature (RT) reveals an average brightness of (427 ±215 )kCounts /s . Finally, polarization measurements from 14 emitters are used to determine visibility as well as dipole orientation of defect systems within the GaN crystal. Our results underpin some of the fundamental properties of SPEs in GaN both at cryogenic and RT, and define the benchmark for future work in GaN-based single-photon technologies.

Study of the photophysical properties of composite film assembled of porphyrin and TiO{sub 2} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Feng, X -S; Kang, S -Z; Liu, H -G; Mu, J [Shandong Univ., Jinan (China). Key Lab. for Colloid and Interface Chem. of Education Ministry

1999-09-08

In this paper, the formation, structure, and photophysical properties of functional mixed film of 5,10,15,20-tetra-4-(2-decanoic acid)phenyl porphyrin (TDPP) with TiO{sub 2} nanoparticles formed from the 2D sol-gel process of tetrabutoxyltitanium (TBT) at the air/water interface is reported. The composite multilayer films were assembled by transferring the mixed monolayer onto quartz plates. The diameter distribution and crystallinity of TiO{sub 2} particles were estimated by TEM observation and electron diffraction. The sensitization of TDPP upon TiO{sub 2} nanoparticles was confirmed by the spectral changes of UV-visible absorption and fluorescence of TDPP in the composite films. Furthermore the photosensitization greatly affected the photocatalytic activity of TiO{sub 2} particles with respect to the degradation of methylene blue (MO). (orig.)

Photophysical and photochemical study of styrene dyes related to their laser efficiency

International Nuclear Information System (INIS)

Meyer, Martine

1989-01-01

The photophysical and photochemical properties of two styrene dyes: 4-dicyanomethylene-2-methyl-6-p-dimethylamino-styryl-4H-pyran (DCM) and 7-dimethylamino-3-(-p-formyl-styryl)-1,4-benzoxazine-2-one (DFSBO) have been studied. These molecules have electron donor and electron acceptor groups which give to their fluorescent excited state a charge transfer state character. The red shifts of the absorption and fluorescence spectra in polar solvents and the large Stokes shift related to the increase of the dipole moment from the ground state to the singlet excited state have been fully characterised. The absorption spectra of the first excited singlet and triplet states and the quantum yields of the intersystem crossing to the triplet state have been determined. The existence of conformers of the two dyes has been evidenced. The synthesis of DCM leads to the trans isomer which, under light exposure undergoes photo-isomerization to the cis-compound. Their fluorescence lifetimes and the photo-isomerization efficiency are solvent dependent. The DFSBO emission spectra depend greatly on the excitation wavelength. This effect can be explained by the occurrence of two rotational conformers one being stabilised by an intramolecular hydrogen bond. The spectral properties of these two molecules enable us to explain why DCM is a very good laser dye whereas DFSBO has a poor laser efficiency. (author) [fr

The steady-state and time-resolved photophysical properties of a dimeric indium phthalocyanine complex

International Nuclear Information System (INIS)

Chen Yu; Araki, Yasuyuki; Dini, Danilo; Liu Ying; Ito, Osamu; Fujitsuka, Mamoru

2006-01-01

The steady-state and time-resolved photophysical properties and some molecular orbital calculation results of a dimeric indium phthalocyanine complex with an indium-indium bond, i.e., [tBu 4 PcIn] 2 .2tmed, have been described. The results regarding triplet excited state lifetimes can be ascribed to strong intramolecular interactions existing only in the excited state of this dimer because no significant difference in the absorption spectra of the tBu 4 PcInCl monomer and the [tBu 4 PcIn] 2 .2tmed dimer is observed, suggesting that no ground-state interaction can be assessed. The deactivation processes of the excited singlet state of [tBu 4 PcIn] 2 .2tmed are apparently faster than that of μ-oxo-bridged PcIn dimer [tBu 4 PcIn] 2 O. Molecular orbital calculation on the PcIn dimer shows no node between two indium atoms was found in the HOMO - 2 of the PcIn-InPc dimer, suggesting that bonding electrons distribute between two indium atoms

Detonation-synthesis nanodiamonds: synthesis, structure, properties and applications

Energy Technology Data Exchange (ETDEWEB)

Dolmatov, Valerii Yu [Federal State Unitary Enterprise Special Design-Technology Bureau (FSUE SDTB) ' ' Tekhnolog' ' at the St Petersburg State Institute of Technology (Technical University) (Russian Federation)

2007-04-30

The review outlines the theoretical foundations and industrial implementations of modern detonation synthesis of nanodiamonds and chemical purification of the nanodiamonds thus obtained. The structure, key properties and promising fields of application of detonation-synthesis nanodiamonds are considered.

Detonation-synthesis nanodiamonds: synthesis, structure, properties and applications

International Nuclear Information System (INIS)

Dolmatov, Valerii Yu

2007-01-01

The review outlines the theoretical foundations and industrial implementations of modern detonation synthesis of nanodiamonds and chemical purification of the nanodiamonds thus obtained. The structure, key properties and promising fields of application of detonation-synthesis nanodiamonds are considered.

Synthesis and photophysical properties of indium(III) phthalocyanine derivatives

Energy Technology Data Exchange (ETDEWEB)

Özceşmeci, İbrahim, E-mail: ozcesmecii@itu.edu.tr [Department of Chemistry, Technical University of Istanbul, Maslak 34469, Istanbul (Turkey); Gelir, Ali [Department of Physics, Technical University of Istanbul, Maslak 34469, Istanbul (Turkey); Gül, Ahmet [Department of Chemistry, Technical University of Istanbul, Maslak 34469, Istanbul (Turkey)

2014-03-15

Three chloroindium(III) phthalocyanine derivatives bearing four aromatic (naphthalene or pyrene) or aliphatic (hexylthio) groups were prepared from corresponding phthalonitrile compounds. The indium(III) phthalocyanine derivatives were characterized with elemental analyses, mass, proton nuclear magnetic resonance ({sup 1}H NMR), Fourier transform infrared spectroscopy (FT-IR) and ultraviolet–visible spectroscopy (UV–vis) techniques. Quantum yields and the energy transfer from the substituents to phthalocyanine core were examined. No energy transfer was observed for 5. The energy transfer efficiency from pyrene units to indium phthalocyanine core was calculated as 0.27 for 6. Quantum yields of all samples were very small due to heavy atom effect of indium atom in the core. It was also observed that upon binding of pyrene and naphthalene units to indium phthalocyanine as substituents, the quantum yields of indium phthalocyanine parts of 5 and 6 decreased. -- Highlights: • Three chloroindium(III) phthalocyanines were prepared and characterized. • Aggregation properties of these compounds were investigated. • The energy transfer efficiency was examined. • Quantum yield of these systems were calculated.

Fabrication of Ag/ZnO heterostructure and the role of surface coverage of ZnO microrods by Ag nanoparticles on the photophysical and photocatalytic properties of the metal-semiconductor system

Energy Technology Data Exchange (ETDEWEB)

Sarma, Bikash; Sarma, Bimal K., E-mail: sarmabimal@gmail.com

2017-07-15

Highlights: • Fabrication of Ag/ZnO heterostructure by facile chemical processes. • Decoration of plasmonic Ag nanoparticles on ZnO microrods through direct attachment. • Quenching of photoluminescence is observed in Ag/ZnO heterostructure. • Extent of surface coverage governs photophysical and photochemical properties. - Abstract: This report presents findings on microstructural, photophysical, and photocatalytic properties of Ag/ZnO heterostructure grown on flexible and silicon substrates. ZnO microrods are prepared by thermal decomposition method for different solute concentrations and Ag/ZnO heterostructure are fabricated by photo-deposition of Ag nanoparticles on ZnO microrods. X-ray diffraction and electron microscopy studies confirm that ZnO microrods belong to the hexagonal wurtzite structure and grown along [001] direction with random alignment showing that majority microrods are aligned with (100) face parallel to the sample surface. Plasmonic Ag nanoparticles are attached to different faces of ZnO. In the optical reflection spectra of Ag/ZnO heterostructure, the surface plasmon resonance peak due to Ag nanoparticles appears at 445 nm. Due to the oxygen vacancies the band gaps of ZnO microrods turn out to be narrower compared to that of bulk ZnO. The presence of Ag nanoparticles decreases the photoluminescence intensity which might be attributed to the non-radiative energy and direct electron transfer in the plasmon–exciton system. The quenching of photoluminescence in Ag/ZnO heterostructure at different growth conditions depend on the extent of surface coverage of ZnO by plasmonic Ag nanoparticles. Photocatalytic degradation efficiency of Ag/ZnO heterostructure is higher than that of ZnO microrods. The extent of surface coverage of ZnO microrods by Ag nanoparticles is crucial for the observed changes in photophysical and photochemical properties.

Photophysical properties of novel small acceptor molecules and their application in hybrid small-molecular/polymeric organic solar cells

Energy Technology Data Exchange (ETDEWEB)

Inal, Sahika; Castellani, Mauro; Neher, Dieter [Universitaet Potsdam, Institut fuer Physik und Astronomie, Potsdam-Golm (Germany); Sellinger, Alan [Institute of Materials Research and Engineering, Singapore (Singapore)

2009-07-01

Recent experimental investigations revealed that the photovoltaic properties of our devices are related to the balance between recombination and field-induced dissociation of interfacial excited states such as exciplexes or geminate polaron pairs. This balance was shown to be affected by the nanomorphology at the heterojunction. We have analyzed the photophysical properties of a new materials couple comprising an electron-donating PPV copolymer and a vinazene-based small molecule acceptor. Steady state and time-resolved photoluminescence (PL) spectroscopy in solution and in the solid state showed the formation of excimers within the acceptor. The associated long-range diffusion promise efficient energy harvesting at the heterojunction. On the other hand, blends of the PPV-derivative and the small molecule revealed strong exciplex formation. Therefore, bilayered hybrid small-molecular/polymeric solar cells have been fabricated by consequently spin-coating the macromolecular donor and the small molecule acceptor from two different solvents. The bilayer architecture limits recombination processes enabling high FFs of around 44% and a technologically important open circuit voltage of 1Volt.

Studies on the photophysical properties of 1,8-naphthalimide derivative and aggregation induced emission recognition for casein

Energy Technology Data Exchange (ETDEWEB)

Sun, Yang, E-mail: 66160692@qq.com [Department of Chemistry and Chemical Engineering, Xi' an University of Arts and Science, No. 168, Taibai South Road, Xi' an, Shaanxi 710065 (China); Liang, Xuhua; Fan, Jun [School of Chemical Engineering, Northwest University, No. 229, Taibai North Road, Xi' an, Shaanxi 710069 (China); Han, Quan, E-mail: xahanq@hotmail.com [Department of Chemistry and Chemical Engineering, Xi' an University of Arts and Science, No. 168, Taibai South Road, Xi' an, Shaanxi 710065 (China)

2013-09-15

A novel water-soluble 1,8-naphthalimide derivative 1, bearing two acetic carboxylic groups, exhibited fluorescent turn-on recognition for casein micelle based on the aggregation induced emission (AIE) character. The photophysical properties of 1 consisting of donor and acceptor units were investigated by the solvation effect. Changing from polar to non-polar solvent increased the solvent interaction; both the excitation and emission spectra were shifted to shorter wavelength and intensity decreased through taking advantage of twisted intramolecular charge transfer (TICT) and self-association fluorescence emission. Moreover, the red-shift and quenching in protic solvent were caused by the excited-state hydrogen bond strengthening effect. The density functional theory (DFT) and time dependent density functional theory (TDDFT) were used to obtain the most stable structure, electronic excitation energy, dipole moments and charge distribution. The AIE mechanism of 1 with casein micelle was due to 1 docked in the hydrophobic cavity between sub-micelles and bound with amino acid residues, resulting in the aggregation of 1 on the casein micelle surface and emission enhancement, based on which, a novel casein assay method was developed. The proposed method exhibited a good linear range from 0.1 to 10.5 μg mL{sup −1}, with the detection limit of 3.0 ng mL{sup −1}. Satisfactory reproducibility, reversibility and a short response time were realized. This method was applied for the determination of casein in milk powder samples, avoiding the interferences from other components and illegal additives in milk. -- Highlights: • A water-soluble 1,8-naphthalimide-based fluorescent probe 1 was synthesized. • Photophysical characterization of 1 was studied. • Aggregation induced emission enhancement of 1 with casein was investigated. • A novel casein quantification method was developed.

Studies on the photophysical properties of 1,8-naphthalimide derivative and aggregation induced emission recognition for casein

International Nuclear Information System (INIS)

Sun, Yang; Liang, Xuhua; Fan, Jun; Han, Quan

2013-01-01

A novel water-soluble 1,8-naphthalimide derivative 1, bearing two acetic carboxylic groups, exhibited fluorescent turn-on recognition for casein micelle based on the aggregation induced emission (AIE) character. The photophysical properties of 1 consisting of donor and acceptor units were investigated by the solvation effect. Changing from polar to non-polar solvent increased the solvent interaction; both the excitation and emission spectra were shifted to shorter wavelength and intensity decreased through taking advantage of twisted intramolecular charge transfer (TICT) and self-association fluorescence emission. Moreover, the red-shift and quenching in protic solvent were caused by the excited-state hydrogen bond strengthening effect. The density functional theory (DFT) and time dependent density functional theory (TDDFT) were used to obtain the most stable structure, electronic excitation energy, dipole moments and charge distribution. The AIE mechanism of 1 with casein micelle was due to 1 docked in the hydrophobic cavity between sub-micelles and bound with amino acid residues, resulting in the aggregation of 1 on the casein micelle surface and emission enhancement, based on which, a novel casein assay method was developed. The proposed method exhibited a good linear range from 0.1 to 10.5 μg mL −1 , with the detection limit of 3.0 ng mL −1 . Satisfactory reproducibility, reversibility and a short response time were realized. This method was applied for the determination of casein in milk powder samples, avoiding the interferences from other components and illegal additives in milk. -- Highlights: • A water-soluble 1,8-naphthalimide-based fluorescent probe 1 was synthesized. • Photophysical characterization of 1 was studied. • Aggregation induced emission enhancement of 1 with casein was investigated. • A novel casein quantification method was developed

C-shaped diastereomers containing cofacial thiophene-substituted quinoxaline rings: synthesis, photophysical properties, and X-ray crystallography.

Science.gov (United States)

DeBlase, Catherine R; Finke, Ryan T; Porras, Jonathan A; Tanski, Joseph M; Nadeau, Jocelyn M

2014-05-16

Synthesis and characterization of two diastereomeric C-shaped molecules containing cofacial thiophene-substituted quinoxaline rings are described. A previously known bis-α-diketone was condensed with an excess of 4-bromo-1,2-diaminobenzene in the presence of zinc acetate to give a mixture of two C-shaped diastereomers with cofacial bromine-substituted quinoxaline rings. After chromatographic separation, thiophene rings were installed by a microwave-assisted Suzuki coupling reaction, resulting in highly emissive diastereomeric compounds that were studied by UV-vis, fluorescence, and NMR spectroscopy, as well as X-ray crystallography. The unique symmetry of each diastereomer was confirmed by NMR spectroscopy. NMR data indicated that the syn isomer has restricted rotation about the bond connecting the thiophene and quinoxaline rings, which was also observed in the solid state. The spectroscopic properties of the C-shaped diastereomers were compared to a model compound containing only a single thiophene-substituted quinoxaline ring. Ground state intramolecular π-π interactions in solution were detected by NMR and UV-vis spectroscopy. Red-shifted emission bands, band broadening, and large Stokes shifts were observed, which collectively suggest excited state π-π interactions that produce excimer-like emissions, as well as a remarkable positive emission solvatochromism, indicating charge-transfer character in the excited state.

Photophysics of aggregated 9-methylthiacarbocyanine bound to polyanions

Science.gov (United States)

Chibisov, Alexander K.; Görner, Helmut

2002-05-01

The photophysical properties of 3,3 '-diethyl-9-methylthiacarbocyanine (DTC) were studied in the presence of polystyrene sulfonate (PSS), polyacrylic acid (PAA) and polymethacrylic acid (PMA). The absorption spectra reflect a monomer/dimer equilibrium in neat aqueous solution and a shift towards bound H-aggregates, bound dimers and bound monomers on increasing the ratio of polyanion residue to dye concentrations ( r). These equilibria also determine the photodeactivation modes of DTC. The fluorescence intensity is reduced, when dimers and aggregates are present and strongly enhanced for low dye loading ( r=10 4). In contrast, the quantum yield of intersystem crossing is enhanced for bound dimers ( r=10 3).

Pyrene based D-π-A architectures: synthesis, density functional theory, photophysics and electron transfer dynamics.

Science.gov (United States)

Kathiravan, Arunkumar; Srinivasan, Venkatesan; Khamrang, Themmila; Velusamy, Marappan; Jaccob, Madhavan; Pavithra, Nagaraj; Anandan, Sambandam; Velappan, Kandavelu

2017-01-25

Pyrene derivatives show immense potential as sensitizers for dye-sensitized solar cells (DSCs). Therefore, this work focuses on the impact of π-spacers on the photophysical, electrochemical and photovoltaic properties of pyrene based D-π-A dyes, since the insertion of π-spacers is one of the doable strategies to improve the light harvesting properties of the dye. In this respect, three new pyrene based D-π-A dyes have been synthesized and characterized by 1 H, 13 C NMR, and elemental analyses and EI-MS spectrometry. The selected π-spacers are benzene, thiophene and furan. Compared with a benzene spacer, the introduction of a heterocyclic ring spacer reduces the band gap of the dye and brings about the broadening of the absorption spectra to the longer wavelength region through intramolecular charge-transfer (ICT). Combined experimental and theoretical studies were performed to investigate the ICT process involved in the pyrene derivatives. The profound solvatochromism with increased nonradiative rate constants (k nr ) has been construed in terms of ICT from the pyrene core to rhodanine-3-acetic acid via conjugated π-spacers. Electrochemical data also reveal that the HOMO and LUMO energy levels are fine-tuned by incorporating different π-spacers between pyrene and rhodanine-3-acetic acid. On the basis of the optimized DSC test conditions, the best performance was found for PBRA, in which a benzene group is the conjugated π-spacer. The divergence in the photovoltaic behaviors of these dyes was further explicated by femtosecond fluorescence and electrochemical impedance spectroscopy.

Synthesis, characterization and photophysical study of ethynyl pyrene derivatives as promising materials for organic optoelectronics

Energy Technology Data Exchange (ETDEWEB)

Gama, Paola E.; Corrêa, Rodrigo J.; Garden, Simon J., E-mail: garden@iq.ufrj.br

2015-05-15

Two series of pyrene derivatives, phenylethynyl (4–6) and the previously unknown ethynylcyclohexanol (7–9), were prepared by Sonogashira cross-coupling reactions. The introduction of an increasing number of ethynyl substituents resulted in a progressive bathochromic shift in the absorption and emission spectra which culminated in an inversion of the nature of the first two excited states ({sup 1}L{sub a} and {sup 1}L{sub b}) of the tetra-substituted derivatives (6 and 9) relative to pyrene. In solution, only for the mono-cyclohexanolethynyl pyrene (7) a sufficiently concentrated solution could be obtained so as to observe the excimer. Additionally, the emission band ratio I{sub 1}/I{sub 3} for 7 was found to be moderately sensitive to the nature of the solvent and the ratio directly correlated with the Py scale. TDDFT calculations were used to explore the variation of the properties of the low lying excited states. Fluorescence emission in the solid state, with the appropriate choice of materials, covers the entire visible region of the electromagnetic spectrum due to static excimer emission. A massive red-shift for solid state photoluminescence from 9 resulted in emission at longer wavelength than the more highly conjugated 6. - Highlights: • Phenyl and cyclohexanol ethynylpyrene derivatives: photophysically compared. • Excimer formation and solvent dependent emission from cyclohexanolethynylpyrene. • Systematic red shifting of solid state photoluminescence from static excimers. • Massive red-shift in the solid state photoluminescence of 9. • TDDFT calculations: properties of the lowest singlet states, systematic comparison.

Luminescent cyclometalated iridium(III) polypyridine indole complexes--synthesis, photophysics, electrochemistry, protein-binding properties, cytotoxicity, and cellular uptake.

Science.gov (United States)

Lau, Jason Shing-Yip; Lee, Pui-Kei; Tsang, Keith Hing-Kit; Ng, Cyrus Ho-Cheong; Lam, Yun-Wah; Cheng, Shuk-Han; Lo, Kenneth Kam-Wing

2009-01-19

A series of luminescent cyclometalated iridium(III) polypyridine indole complexes, [Ir(N--C)(2)(N--N)](PF(6)) (HN--C = 2-phenylpyridine (Hppy), N--N = 4-((2-(indol-3-yl)ethyl)aminocarbonyl)-4'-methyl-2,2'-bipyridine (bpy-ind) (1a), N--N = 4-((5-((2-(indol-3-yl)ethyl)aminocarbonyl)pentyl)aminocarbonyl)-4'-methyl-2,2'-bipyridine (bpy-C6-ind) (1b); HN--C = 7,8-benzoquinoline (Hbzq), N--N = bpy-ind (2a), N--N = bpy-C6-ind (2b); and HN--C = 2-phenylquinoline (Hpq), N--N = bpy-ind (3a), N--N = bpy-C6-ind (3b)), have been synthesized, characterized, and their photophysical and electrochemical properties and lipophilicity investigated. Photoexcitation of the complexes in fluid solutions at 298 K and in alcohol glass at 77 K resulted in intense and long-lived luminescence (lambda(em) = 540-616 nm, tau(o) = 0.13-5.15 mus). The emission of the complexes has been assigned to a triplet metal-to-ligand charge-transfer ((3)MLCT) (dpi(Ir) --> pi*(N--N)) excited state, probably with some mixing of triplet intraligand ((3)IL) (pi --> pi*) (pq) character for complexes 3a,b. Electrochemical measurements revealed that all the complexes showed an irreversible indole oxidation wave at ca. +1.1 V versus SCE, a quasi-reversible iridium(IV/III) couple at ca. +1.3 V, and a reversible diimine reduction couple at ca. -1.3 V. The interactions of these complexes with an indole-binding protein, bovine serum albumin (BSA), have been studied by emission titrations, and the K(a) values are on the order of 10(4) M(-1). Additionally, the cytotoxicity of the complexes toward human cervix epithelioid carcinoma (HeLa) cells has been examined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay. The IC(50) values of the complexes ranged from 1.1 to 6.3 microM, which are significantly smaller than that of cisplatin (30.7 microM) under the same experimental conditions. Furthermore, the cellular uptake of the complexes has been investigated by flow cytometry and laser

Triphenylamine Derived 3-Acetyl and 3-Benzothiazolyl Bis and Tris Coumarins: Synthesis, Photophysical and DFT Assisted Hyperpolarizability Study

Science.gov (United States)

Erande, Yogesh; Kothavale, Shantaram; Sreenath, Mavila C.; Chitrambalam, Subramaniyan; Joe, Isaac H.; Sekar, Nagaiyan

2018-02-01

Triphenylamine derived bis- and tris-branched donor-pi-acceptor coumarins with acetyl and benzothiazolyl acceptors are studied for their linear and nonlinear optical properties that originate from their photophysical and molecular structure. Plots of solvent polarities versus the Stokes shift, frontier molecular orbital analysis and Generalised Mulliken Hush analysis have established their strong charge transfer character supported by the strong emission solvatochromism of these chromophores. On the basis of excited state intramolecular charge transfer, the first-, second- and third-order polarizability of these dyes are determined by a solvatochromic method and supported by density functional theory calculations using CAM-B3LYP/6-31g(d). Compared to the acetyl group, the benzothiazolyl group is a strong acceptor, and its corresponding derivatives show enhanced absorption, emission maxima and non-linear optical response. Bond length alternation and bond order alternation analysis reveals that these chromophores approach the cyanine-like framework which is responsible for maximum perturbation to produce high nonlinear optical response. Third order nonlinear susceptibility for dyes 1 and 2 is determined by Z-scan measurement. All of these methods are used to determine the nonlinear optical properties, and thermogravimetric analysis suggests that these chromophores are thermally robust and efficient nonlinear optical materials.

Protein-based nanostructures as carriers for photo-physically active molecules in biosystems

OpenAIRE

Delcanale, Pietro

2017-01-01

In nature, many proteins function as carriers, being able to bind, transport and possibly release a ligand within a biological system. Protein-based carriers are interesting systems for drug delivery, with the remarkable advantage of being water-soluble and, as inherent components of biosystems, highly bio-compatible. This work focuses on the use of protein-based carriers for the delivery of hydrophobic photo-physically active molecules, whose structure and chemical properties lead to spontan...

Flow synthesis of a versatile fructosamine mimic and quenching studies of a fructose transport probe

Directory of Open Access Journals (Sweden)

Matthew B. Plutschack

2013-10-01

Full Text Available We describe the synthesis of 1-amino-2,5-anhydro-D-mannose (“mannitolamine”, a key intermediate to the 7-nitro-1,2,3-benzadiazole conjugate (NBDM, using commercially available fluidic devices to increase the throughput. The approach is the first example of a flow-based Tiffeneau–Demjanov rearrangement. Performing this step in flow enables a ~64-fold throughput enhancement relative to batch. The flow process enables the synthesis to be accomplished three times faster than the comparable batch route. The high throughput enabled the production of larger quantities of the fluorescent fructose transport probe NBDM, enabling us to measure key photophysical properties that will facilitate future uptake studies.

Photophysical properties of open-framework germanates templated by nickel complexes

KAUST Repository

Peskov, Maxim; Schwingenschlö gl, Udo

2014-01-01

Open-framework germanates are a group of germanium oxides with a well-defined porous structure, suitable for ion-exchange and gas adsorption applications. Recently, Ni incorporation into the porous structure by establishing Ge-O-Ni bonds with the molecular complexes [Ni(H 2N(CH2)2NH2)2] was realized. We investigate the optical and electronic features of these systems (SUT-1 and SUT-2) from first principles. To describe the photophysical behavior, we analyze the bonding between the Ni and nearest-neighboring atoms and simulate the absorption spectra. Because of their optical characteristics, germania-based nanomaterials are expected to be essential components of future optical and electronic devices. We discuss to what extent molecular transition-metal complexes embedded into porous germanium oxide can modify the optical response to potentially expand the area of applications. This journal is © the Partner Organisations 2014.

Nitrocyclopropanes: synthesis and properties

Energy Technology Data Exchange (ETDEWEB)

Averina, Elena B; Yashin, N V; Kuznetsova, Tamara S; Zefirov, Nikolai S [Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

2009-10-31

State-of-the-art data on the methods of synthesis, properties and transformations of nitro- and- dinitrocyclopropanes of different structure is generalized and described systematically. The attention is focused on stereoselective cyclopropanation methods, new approaches to the synthesis of natural products and their synthetic analogues with diversified biological activities, in particular, of aminocyclopropane acids based on nitrocyclopropanes, and the formation of structures of energetic compounds.

Photophysical properties of a surfactive long-chain styryl merocyanine dye as fluorescent probe

Energy Technology Data Exchange (ETDEWEB)

Ismail, L.F.M., E-mail: Lailafmi@yahoo.com [Al-Azhar University, Faculty of Science, Chemistry Department, Nasr City, 12 Ibrahim El-Nagar, El-Hegaz Sq. Heliopolis, Cairo 11315 (Egypt)

2012-09-15

This work deals with detailed investigations of the photophysical properties of a styryl merocyanine dye, namely 1-cetyl-4-[4 Prime -(methoxy) styryl]-pyridinium bromide (CMSPB) of molecular rotor type. The solvatochromic analyses of the data in different solvents using the Kamlet-Taft parameters ({alpha}, {beta}, {pi}{sup Low-Asterisk }) were discussed. Optical excitation of the studied merocyanine dye populates a CT S{sub 1} state with about 22.64 folds higher dipole moment value relative to that in the S{sub 0} state. Moreover, the effect of solvent viscosity (glycerol at various temperatures (299.0-351.0 K)) on CMSPB fluorescent properties is analyzed to understand the molecular mechanisms of the characteristic increase in CMSPB fluorescence intensity. The results indicate that CMSPB exhibits fluorescent properties typical for molecular rotors. The results show that torsional relaxation dynamics of molecular rotors in high-viscosity solvents cannot be described by the simple stick boundary hydrodynamics defined by the Debye-Stokes-Einstein (DSE) equation. The fluorescence depolarization behavior in glycerol at various temperatures (299.0-351.0 K) shows that the molecular rotational diffusion is controlled by the free volume of the medium. Furthermore, excited state studies in ethanol/chloroform mixture revealed the formation of weak complex with chloroform of stoichiometry 1:1 with formation constant of 0.004l mol{sup -1}. Moreover, the increase of the quantum yield values in micellar solutions of CTAB and SDS relative to that of water indicates that the guest dye molecules are microencapsulated into the hydrophobic interior of host micelle. The obtained non-zero values of fluorescence polarization in micellar solution imply reduced rotational depolarization of dye molecules via association with the surfactant. Upon comparing the spectral data in micelles with those in homogeneous solvent systems, more can be learned of the structural details of the micellar

Photo-physical and interactional behavior of two members of group B vitamins in different solvent media

Science.gov (United States)

Zakerhamidi, M. S.; Zare Haghighi, L.; Seyed Ahmadian, S. M.

2017-09-01

In this paper, absorption and fluorescence spectra of vitamin B12 (cyanocobalamin) and vitamin B6 (pyridoxine) were recorded in solvents with different polarity, at room temperature. These vitamins' photo-physical behavior depends strongly on the solvent's nature along with different attached groups in their structures. In order to investigate the solvent-solute interactions and environmental effect on spectral variations, linear solvation energy relationships concept, suggested by Kamlet and Taft was used. Solvatochromic method was also used for measuring the ground and excited state dipole moments of these vitamins. According to our experimental results, dipole moment of these groups of vitamins in excited state is larger than ground state. Furthermore, obtained photo-physical and interactional properties of used vitamins can give important information on how this group of vitamins behaves in biological systems.

Fatigue Property of Oxidized Photochromic Dithienylethene Derivative for Permanent Optical Recording

International Nuclear Information System (INIS)

Jeong, Yong Chul; Ahn, Kwang Hyun; Yang, Sung Ik; Kim, Eun Kyoung

2005-01-01

We have synthesized and characterized the photophysical and fatigue properties of DMTFO4. The results have shown that the photo-stability of DMTFO4 was significantly decreased compared with the unoxidized DMTF6. The possible application of DMTFO4 would be the development of permanent recording material based on a non-reversible photochromic conversion. Photochromic diarylethenes, such as 1,2-bis(2-methyl-1-benzothiophene-3-yl)perfluorocyclopentene (BTF6) and 1,2-bis(2,5-dimethylthien-3-yl)perfluorocyclopentene (DMTF6), have been extensively investigated in recent years in order to develop materials for molecular photonic devices such as optical memory and switch. In the design of photochromic materials, thermal stability and fatigue resistant are important features to be considered. The thiophene analogues undergo photochromic ring closure efficiently but the fatigue property is generally low, resulting irreversible photochromism. If the photochromism is in an irreversible manner it could be applied in the permanent optical recording such as write once read many (WORM) memory. This motivates us to examine the effect of oxidation in the photophysical properties of diarylethenes with thiophene unit. As the thiophene analogues, we chose DMTF6 and its oxidized analogue, 1,2-bis(2,5-dimethylthien-1,1-dioxide-3-yl)perfluorocyclopentene (DMTFO4). Herein we report the synthesis and characterization of the photochromic properties including the fatigue property of DMTFO4

Synthesis, photophysical analysis, and in vitro cytotoxicity assessment of the multifunctional (magnetic and luminescent) core@shell nanomaterial based on lanthanide-doped orthovanadates

International Nuclear Information System (INIS)

Szczeszak, Agata; Ekner-Grzyb, Anna; Runowski, Marcin; Mrówczyńska, Lucyna; Grzyb, Tomasz; Lis, Stefan

2015-01-01

Rare earths orthovanadates (REVO 4 ) doped with luminescent lanthanide ions (Ln 3+ ) play an important role as promising light-emitting materials. Gadolinium orthovanadate exhibits strong absorption of ultraviolet radiation and as a matrix doped with Eu 3+ ions is well known for its efficient and intense red emission, induced by energy transfer from the VO 4 3− groups to Eu 3+ ions. In the presented study, Fe 3 O 4 @SiO 2 @GdVO 4 :Eu 3+ 5 % nanomaterial was investigated. The core@shell structures demonstrate attractive properties, such as higher thermal stability, enhanced water solubility, increased optical response, higher luminescence, longer decay times, and magnetic properties. Silica coating may protect nanocrystals from the surrounding environment. Therefore, such silica-covered nanoparticles (NPs) are successfully utilized in biomedical research. Multifunctional magnetic nanophosphors are very interesting due to their potential biomedical applications such as magnetic resonance imaging, hyperthermic treatment, and drug delivery. Therefore, the aim of our study was to investigate photophysical, chemical, and biological properties of multifunctional REVO 4 doped with Ln 3+ . Moreover, the studied NPs did not affect erythrocyte sedimentation rate, cell membrane permeability, and morphology of human red blood cells

Synthesis, photophysical analysis, and in vitro cytotoxicity assessment of the multifunctional (magnetic and luminescent) core@shell nanomaterial based on lanthanide-doped orthovanadates

Science.gov (United States)

Szczeszak, Agata; Ekner-Grzyb, Anna; Runowski, Marcin; Mrówczyńska, Lucyna; Grzyb, Tomasz; Lis, Stefan

2015-03-01

Rare earths orthovanadates (REVO4) doped with luminescent lanthanide ions (Ln3+) play an important role as promising light-emitting materials. Gadolinium orthovanadate exhibits strong absorption of ultraviolet radiation and as a matrix doped with Eu3+ ions is well known for its efficient and intense red emission, induced by energy transfer from the VO4 3- groups to Eu3+ ions. In the presented study, Fe3O4@SiO2@GdVO4:Eu3+ 5 % nanomaterial was investigated. The core@shell structures demonstrate attractive properties, such as higher thermal stability, enhanced water solubility, increased optical response, higher luminescence, longer decay times, and magnetic properties. Silica coating may protect nanocrystals from the surrounding environment. Therefore, such silica-covered nanoparticles (NPs) are successfully utilized in biomedical research. Multifunctional magnetic nanophosphors are very interesting due to their potential biomedical applications such as magnetic resonance imaging, hyperthermic treatment, and drug delivery. Therefore, the aim of our study was to investigate photophysical, chemical, and biological properties of multifunctional REVO4 doped with Ln3+. Moreover, the studied NPs did not affect erythrocyte sedimentation rate, cell membrane permeability, and morphology of human red blood cells.

Photophysical properties of 1-acetoxy-8-hydroxy-1,4,4a,9a-tetrahydroanthraquinone: Evidence for excited state proton transfer reaction

International Nuclear Information System (INIS)

Singh, Rupashree Balia; Mahanta, Subrata; Guchhait, Nikhil

2007-01-01

The photophysical properties of 1-acetoxy-8-hydroxy-1,4,4a,9a-tetrahydroanthraquinone (HTHQ) have been investigated by steady state and time resolved spectroscopy in combination with quantum chemical calculations. The effects of various parameters such as the nature of solvent and pH of the medium on the spectral properties confirm the existence of different neutral and ionic species in the ground and excited states. In the ground state, HTHQ exists as intramolecularly hydrogen bonded closed conformer in non-polar and polar aprotic solvents. Apart from the closed conformer, the intermolecular hydrogen bonded solvated species and the anion of HTHQ are present in hydroxylic solvents. The closed conformer shows excited state intramolecular proton transfer in all solvents and the solvent polarity independent red shifted emission indicates only keto-enol tautomerism. Evaluation of the potential energy surfaces by quantum chemical calculation using density functional theory point towards the possibility of proton transfer reaction in the first excited state but not in the ground state

Photophysics Applied to Cavitands and Capsules.

Science.gov (United States)

Berryman, Orion B; Dube, Henry; Rebek, Julius

2011-07-01

The use of light as a stimulus to control functional materials or nano-devices is appealing as it provides convenient control of triggering events where and when they are desired without introducing extra components to the system. Many photophysical and photochemical processes are extremely fast, giving rise to nearly instantaneous onset of events. However, these fast processes can be challenging to engineer into chemical systems. Supramolecular chemistry offers a convenient way to study and control photoprocesses. Given the reversible and self-programmed nature of modern host-guest systems, a modular approach can be considered in which different photoprocesses are coupled to obtain complex functions that emerge and are controlled solely by light inputs. In this review, we highlight recent examples of photoswitching and photophysics applied in the context of supramolecular host-guest systems, with a particular emphasis on resorcinarene based cavitands and hydrogen bonded capsules.

Spectroscopy and photophysics of self-organized zinc porphyrin nanolayers. 1. Optical spectroscopy of excitonic interactions involving the soret band

NARCIS (Netherlands)

Donker, H.; Koehorst, R.B.M.; Schaafsma, T.J.

2005-01-01

The photophysical properties of excited singlet states of zinc tetra-(p-octylphenyl)-porphyrin in 5-25-nm-thick films spin-coated onto quartz slides have been investigated by optical spectroscopy. Analysis of the polarized absorption spectra using a dipole-dipole exciton model with two mutually

Facile synthesis of water-soluble curcumin nanocrystals

Directory of Open Access Journals (Sweden)

Marković Zoran M.

2015-01-01

Full Text Available In this paper, facile synthesis of water soluble curcumin nanocrystals is reported. Solvent exchange method was applied to synthesize curcumin nanocrystals. Different techniques were used to characterize the structural and photophysical properties of curcumin nanocrystals. We found that nanocurcumin prepared by this method had good chemical and physical stability, could be stored in the powder form at room temperature, and was freely dispersible in water. It was established that the size of curcumin nanocrystals was varied in the range of 20-500 nm. Fourier transform infrared spectroscopy and UV-Vis analyses showed the presence of tetrahydrofuran inside the curcumin nanocrystals. Also, it was found that nanocurcumin emitted photoluminescencewith yellow-green colour. [Projekat Ministarstva nauke Republike Srbije, br. 172003

Photophysics and lasing correlation of pyrromethene 567 dye in crosslinked polymeric networks

International Nuclear Information System (INIS)

Banuelos Prieto, J.; Lopez Arbeloa, F.; Garcia, O.; Arbeloa, I. Lopez

2007-01-01

The photophysical properties of the pyrromethene 567 dye incorporated in copolymers of methylmethacrylate with different acrylic and methacrylic crosslinking monomers are reported. In general, the solid matrices improve the fluorescence capacity of the dye, due to both an increase and a decrease in the radiative and non-radiative deactivation rate constants, respectively, as consequence of a more rigid environment. It is observed that there is an optimal crosslinking degree for the highest fluorescence efficiency, which depends on the nature of the crosslinking monomer. Taking into account the lasing properties for these systems, it is established a good correlation between the lasing and the fluorescence characteristics of the dye in agreement with previous conclusions obtained in liquid solutions

Photophysical properties, photodegradation characteristics, and lasing action for coumarin dye C540A in polymeric media

Science.gov (United States)

Jones, Guilford, II; Huang, Zhennian; Pacheco, Dennis P., Jr.; Russell, Jeffrey A.

2004-07-01

Tunable solid-state dye lasers operating in the blue-green spectral region are attractive for a variety of applications. An important consideration in assessing the viability of this technology is the service life of the gain medium, which is presently limited by dye photodegradation. In this study, solid polymeric samples consisting of the coumarin dye C540A in modified PMMA were subjected to controlled photodegradation tests. The excitation laser was a flashlamp-pumped dye laser operating at 440 nm with a pulse duration of 1 μs. A complementary set of data was obtained for dye in solution phase for comparison purposes. Photophysical properties of C540A in water solution of polymethacrylic acid (PMAA) have been investigated with a view to assess the suitability of the sequestering polymer (PMAA) as an effective additive to facilitate use of a water medium for highly efficient blue-green dye lasers. Lasing action of C540A in aqueous PMAA has been realized using flashlamp-pumped laser system, yielding excellent laser efficiencies superior to that achieved in ethanolic solutions with the same dye. Laser characterization of dye in media included measurement of laser threshold, slope efficiency, pulse duration and output wavelength.

Synthesis, photophysical analysis, and in vitro cytotoxicity assessment of the multifunctional (magnetic and luminescent) core@shell nanomaterial based on lanthanide-doped orthovanadates

Energy Technology Data Exchange (ETDEWEB)

Szczeszak, Agata [Adam Mickiewicz University, Department of Rare Earths, Faculty of Chemistry (Poland); Ekner-Grzyb, Anna [Adam Mickiewicz University, Department of Behavioural Ecology, Faculty of Biology (Poland); Runowski, Marcin [Adam Mickiewicz University, Department of Rare Earths, Faculty of Chemistry (Poland); Mrówczyńska, Lucyna [Adam Mickiewicz University, Department of Cell Biology, Faculty of Biology (Poland); Grzyb, Tomasz; Lis, Stefan, E-mail: blis@amu.edu.pl [Adam Mickiewicz University, Department of Rare Earths, Faculty of Chemistry (Poland)

2015-03-15

Rare earths orthovanadates (REVO{sub 4}) doped with luminescent lanthanide ions (Ln{sup 3+}) play an important role as promising light-emitting materials. Gadolinium orthovanadate exhibits strong absorption of ultraviolet radiation and as a matrix doped with Eu{sup 3+} ions is well known for its efficient and intense red emission, induced by energy transfer from the VO{sub 4}{sup 3−} groups to Eu{sup 3+} ions. In the presented study, Fe{sub 3}O{sub 4}@SiO{sub 2}@GdVO{sub 4}:Eu{sup 3+} 5 % nanomaterial was investigated. The core@shell structures demonstrate attractive properties, such as higher thermal stability, enhanced water solubility, increased optical response, higher luminescence, longer decay times, and magnetic properties. Silica coating may protect nanocrystals from the surrounding environment. Therefore, such silica-covered nanoparticles (NPs) are successfully utilized in biomedical research. Multifunctional magnetic nanophosphors are very interesting due to their potential biomedical applications such as magnetic resonance imaging, hyperthermic treatment, and drug delivery. Therefore, the aim of our study was to investigate photophysical, chemical, and biological properties of multifunctional REVO{sub 4} doped with Ln{sup 3+}. Moreover, the studied NPs did not affect erythrocyte sedimentation rate, cell membrane permeability, and morphology of human red blood cells.

The synthesis and properties of linear A-π-D-π-A type organic small molecule containing diketopyrrolopyrrole terminal units

Science.gov (United States)

Zhang, Shanshan; Niu, Qingfen; Sun, Tao; Li, Yang; Li, Tianduo; Liu, Haixia

2017-08-01

A novel linear A-π-D-π-A-type organic small molecule Ph2(PDPP)2 consisting diketopyrrolopyrrole (DPP) as acceptor unit, biphenylene as donor unit and acetylene unit as π-linkage has been successfully designed and synthesized. Its corresponding thermal, photophysical and electrochemical properties as well as the photoinduced charge-separation process were investigated. Ph2(PDPP)2 exhibits high thermal stability and it can be soluble in common organic solvents such as chloroform and tetrahydrofuran. The photophysical properties show that DPP2Ph2 harvests sunlight over the entire visible spectrum range in the thin-film state (300-800 nm). DPP2Ph2 has lower band gaps and appropriate energy levels to satisfy the requirement of solution-processable organic solar cells. The efficient photoinduced charge separation process was clearly observed between DPP2Ph2 with PC61BM and the Ksv value was found to be as high as 2.13 × 104 M- 1. Therefore, these excellent properties demonstrate that the designed A-π-D-π-A-type small molecule Ph2(PDPP)2 is the prospective candidate as donor material for organic photovoltaic material.

Acetone photophysics at 282 nm excitation at elevated pressure and temperature. II: Fluorescence modeling

Science.gov (United States)

Hartwig, Jason; Raju, Mandhapati; Sung, Chih-Jen

2017-07-01

This is the second in a series of two papers that presents an updated fluorescence model and compares with the new experimental data reported in the first paper, as well as the available literature data, to extend the range of acetone photophysics to elevated pressure and temperature conditions. This work elucidates the complete acetone photophysical model in terms of each and every competing radiative and non-radiative rate. The acetone fluorescence model is then thoroughly examined and optimized based on disparity with recently conducted elevated pressure and temperature photophysical calibration experiments. The current work offers insight into the competition between non-radiative and vibrational energy decay rates at elevated temperature and pressure and proposes a global optimization of model parameters from the photophysical model developed by Thurber (Acetone Laser-Induced Fluorescence for Temperature and Multiparameter Imaging in Gaseous Flows. PhD thesis, Stanford University Mechanical Engineering Department, 1999). The collisional constants of proportionality, which govern vibrational relaxation, are shown to be temperature dependent at elevated pressures. A new oxygen quenching rate is proposed which takes into account collisions with oxygen as well as the oxygen-assisted intersystem crossing component. Additionally, global trends in ketone photophysics are presented and discussed.

Photophysical and photochemical properties of Bauhinia megalandra (Caesalpinaceae) extracts as new PDT photosensitizer

Science.gov (United States)

Vargas Tovar, Franklin R.; Rivas, C.; Estrada, O.; Marcano O., Aristides A.; Echevarria, Lorenzo; Diaz, Yrene; Alexander, I.; Rodriguez, L.; Padron, L.; Rivera, I. R.

2004-10-01

Recently new photosensitizers, chlorophyll "a and b" derivatives, for photodynamic therapy (PDT) have been presented. It already passed complete pre-clinical investigations. This prompted us to carry out an extensive study of photophysical properties of chlorine derivatives, important both for optimization of their clinic applications and for study of mechanisms of chlorine PDT&. The fresh leaves of Bauhinia megalandra (Caesalpinaceae) were extracted with methanol by percolation, and re-extract with a mixture of methanol-water (1:1), the insoluble fraction was then separated by column chromatography [RP18/hexane-ethylacetate (9:1)] to obtain four fractions named 1 to 4. These compounds were identified by NMR data. We found that 3 and 4 efficiently generates singlet oxygen when irradiated with visible light. Detection of the singlet oxygen was fulfilled by its reaction with histidine and detected by bleaching p-nitrosodimethylaniline under 440 nm irradiation. The quantum yields of singlet oxygen determined by us were 0.088 (1), 0.151 (2), 0.219 (3) and 0.301 (4). We measured absorption and fluorescence spectra of compounds 1 to 4 (Mg-chlorophyll-a, Pheophytin, Mg-chlorophyll-b and chlorophyll-b respectively) in different media and in aqueous solutions of human serum albumin. The association constant of the compounds 1, 2, 3 and 4 in the presence of HSA were estimated. The binding and quenching studies suggest that only 1 and 3 may serve as a useful fluorescence probe for structure/function studies of different chlorophyll binding proteins. No photoinduced binding was observed after irradiation by all the studied compounds in presence of human serum albumin.

D-π-A-A-π-D prototype 2,2'-bipyridine dyads exhibiting large structure and environment-sensitive fluorescence: synthesis, photophysics, and computation.

Science.gov (United States)

Sarma, Monima; Chatterjee, Tanmay; Ghanta, Susanta; Das, Samar K

2012-01-06

A series of 4,4'-π-conjugated-2,2'-bipyridine chromophores (MS 1-8) were synthesized, and their photophysical and thermal properties were investigated. The title "push-pull' chromophores", except MS 1, were integrated with both alkoxy and alkylamino donor functionalities that differ in their donation capabilities. The oligophenylenevinylene (OPV) chromophores MS 4-8 are associated with a π-extended backbone in which the position and the number of alkoxy donors were systematically varied. All of the studied systems possess a D-π-A-A-π-D dyad archetype in which the A-A is the central 2,2'-bipyridine acceptor core that is electronically attached with the donor termini through π-linkers. The fluorescence quantum yields of the synthesized chromophores are found to be sensitive to the molecular archetype and the solvent medium. Out of the eight fluorescent compounds reported in this article, the compound MS 5 exhibits fluorescence in the solid state also. The modulating effect of the nature, position, and number of donor functionalities on the optical properties of these classes of compounds has further been comprehended on the basis of DFT and TD-DFT computation in a solvent reaction field.

A series of fluorene-based two-photon absorbing molecules: synthesis, linear and nonlinear characterization, and bioimaging

Science.gov (United States)

Andrade, Carolina D.; Yanez, Ciceron O.; Rodriguez, Luis; Belfield, Kevin D.

2010-01-01

The synthesis, structural, and photophysical characterization of a series of new fluorescent donor–acceptor and acceptor-acceptor molecules, based on the fluorenyl ring system, with two-photon absorbing properties is described. These new compounds exhibited large Stokes shifts, high fluorescent quantum yields, and, significantly, high two-photon absorption cross sections, making them well suited for two-photon fluorescence microscopy (2PFM) imaging. Confocal and two-photon fluorescence microscopy imaging of COS-7 and HCT 116 cells incubated with probe I showed endosomal selectivity, demonstrating the potential of this class of fluorescent probes in multiphoton fluorescence microscopy. PMID:20481596

Towards PSII analogs driven by ruthenium photophysics

International Nuclear Information System (INIS)

Olsson, Jerry

2002-01-01

A number of model complexes have been prepared in an attempt to develop models for photosystem II (PSII) in green plants. As replacement for the chlorophyll photosensitizer, we have used Ru(ll) tris-2,2-bipyridyl or Ru(ll) bis-2,2';6',2 - terpyridyl complexes linked to a pendant 2,2'-bipyridyl or 2,2';6',2''-terpyridyl moieties via spacers of varying lengths. Manganese (ll) has been covalently linked to the pendant 2,2'-bipyridyl /2,2';6',2''-terpyridyl moieties. The use of different ruthenium centres and spacers has made it possible to make assumptions about the way and how easily manganese is coordinated through self-assembly to the pendant 2,2'-bipyridyl or 2,2';6',2''-terpyridyl groups. Several polynuclear complexes containing a photoactive centre (Ru(ll) tris-2,2'-bipyridine or Ru(ll) bis-2,2';6',2''-terpyridine) or other metal ions (Co 2+ , Fe 2+ , Mn 2= ) have been prepared and characterised. The main work has been focused on organic synthesis and characterisation of polypyridine ligands and coordinated to different metal centres. The complexes have been investigated electrochemically and photophysically. Several new phenol-based ligands have been prepared by organic synthetic methods and characterised by various different methods. (author)

Synthesis and photophysical properties of a novel corrole–anthraquinone–corrole molecular system

International Nuclear Information System (INIS)

Sudhakar, Kolanu; Kanaparthi, Ravi Kumar; Kumar, Challa Kiran; Giribabu, Lingamallu

2014-01-01

A novel molecular triad (AQ-(H 3 ) 2 ) based on tritolylcorrole and anthraquinone having azomethine-bridge at the pyrrole-β position has been designed and synthesized by following a facile one step reaction. The molecular system, AQ-(H 3 ) 2 is characterized by elemental analysis, MALDI-MS, 1 H-NMR, UV–Visible and fluorescence spectroscopy (steady-state and time-resolved) as well as electrochemical methods. In absorption spectra, prominent changes such as red-shift (∼7 nm) and broadening of the both Soret and Q-bands with respect to their monomer units were observed. The present study supported by density functional theory calculations manifest that there exists a negligible electronic communication in the ground state between the donor tritolylcorrole and acceptor anthraquinone of the triad. However, interestingly, in the triad AQ-(H 3 ) 2 , fluorescence emission of the tritolylcorrole quenched significantly (17–80%) compared to their monomeric units. The emission quenching is attributed to the excited state intramolecular photoinduced electron transfer from donor tritolylcorrole to acceptor anthraquinone and the electron transfer rates (k ET ) are found in the range 4.1×10 8 to 2.4×10 9 s −1 and are found to be solvent dependent. - Highlights: • Molecular triad based on corrole and anthraquinone having azomethine-bridge at pyrrole-β position. • Ground state properties showed that there exist minimum π–π interactions. • Excited state properties showed intramolecular photoinduced electron transfer from corrole to anthraquinone

Photophysics and electrochemistry relevant to photocatalytic water splitting involved at solid–electrolyte interfaces

KAUST Repository

Shinagawa, Tatsuya

2016-08-04

Direct photon to chemical energy conversion using semiconductor-electrocatalyst-electrolyte interfaces has been extensively investigated for more than a half century. Many studies have focused on screening materials for efficient photocatalysis. Photocatalytic efficiency has been improved during this period but is not sufficient for industrial commercialization. Detailed elucidation on the photocatalytic water splitting process leads to consecutive six reaction steps with the fundamental parameters involved: The photocatalysis is initiated involving photophysics derived from various semiconductor properties (1: photon absorption, 2: exciton separation). The generated charge carriers need to be transferred to surfaces effectively utilizing the interfaces (3: carrier diffusion, 4: carrier transport). Consequently, electrocatalysis finishes the process by producing products on the surface (5: catalytic efficiency, 6: mass transfer of reactants and products). Successful photocatalytic water splitting requires the enhancement of efficiency at each stage. Most critically, a fundamental understanding of the interfacial phenomena is highly desired for establishing "photocatalysis by design" concepts, where the kinetic bottleneck within a process is identified by further improving the specific properties of photocatalytic materials as opposed to blind material screening. Theoretical modeling using the identified quantitative parameters can effectively predict the theoretically attainable photon-conversion yields. This article provides an overview of the state-of-the-art theoretical understanding of interfacial problems mainly developed in our laboratory. Photocatalytic water splitting (especially hydrogen evolution on metal surfaces) was selected as a topic, and the photophysical and electrochemical processes that occur at semiconductor-metal, semiconductor-electrolyte and metal-electrolyte interfaces are discussed.

Photo-physics of third-order nonlinear optical processes in organic dyes

International Nuclear Information System (INIS)

Delysse, Stephane

1997-01-01

We study some aspects of the nonlinear picosecond photo-physics in organic dyes using Kerr ellipsometry. The aim is to establish link between the photo-physics and nonlinear optics in these compounds. First, we study coherent processes directly linked to the third-order susceptibility. Thus, we measure two-photon absorption spectra of large internal charge transfer dyes. We take into account all coupling between three electronic states which can interfere to explain the particular response of some stilbene dyes. On the second hand, we expose a more photophysical approach to determine the S 1 → S n transition energies and moments using the measurement of excited state absorption cross sections. These results allow the prediction of the susceptibilities relevant to alternative nonlinear optical methods. Nevertheless, the stationary approach hides the complex relaxation processes which can take place in organic dyes. As an illustration, we study the formation and disappearance of a TICT (Twisted intramolecular charge transfer) in a pyrylium salt in solvents of increasing viscosity. (author) [fr

Synthesis and photophysical properties of a novel corrole–anthraquinone–corrole molecular system

Energy Technology Data Exchange (ETDEWEB)

Sudhakar, Kolanu [Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad-500007, Andhra Pradesh (India); Kanaparthi, Ravi Kumar [Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad-500007, Andhra Pradesh (India); Department of Chemistry, Central University of Kerala, Reverside Transit Campus, Padanakkad, Nileshwar Kasaragod District - 671 314 Kerala (India); Kumar, Challa Kiran [Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad-500007, Andhra Pradesh (India); Giribabu, Lingamallu, E-mail: giribabu@iict.res.in [Inorganic and Physical Chemistry Division, CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad-500007, Andhra Pradesh (India)

2014-09-15

A novel molecular triad (AQ-(H{sub 3}){sub 2}) based on tritolylcorrole and anthraquinone having azomethine-bridge at the pyrrole-β position has been designed and synthesized by following a facile one step reaction. The molecular system, AQ-(H{sub 3}){sub 2} is characterized by elemental analysis, MALDI-MS, {sup 1}H-NMR, UV–Visible and fluorescence spectroscopy (steady-state and time-resolved) as well as electrochemical methods. In absorption spectra, prominent changes such as red-shift (∼7 nm) and broadening of the both Soret and Q-bands with respect to their monomer units were observed. The present study supported by density functional theory calculations manifest that there exists a negligible electronic communication in the ground state between the donor tritolylcorrole and acceptor anthraquinone of the triad. However, interestingly, in the triad AQ-(H{sub 3}){sub 2}, fluorescence emission of the tritolylcorrole quenched significantly (17–80%) compared to their monomeric units. The emission quenching is attributed to the excited state intramolecular photoinduced electron transfer from donor tritolylcorrole to acceptor anthraquinone and the electron transfer rates (k{sub ET}) are found in the range 4.1×10{sup 8} to 2.4×10{sup 9} s{sup −1} and are found to be solvent dependent. - Highlights: • Molecular triad based on corrole and anthraquinone having azomethine-bridge at pyrrole-β position. • Ground state properties showed that there exist minimum π–π interactions. • Excited state properties showed intramolecular photoinduced electron transfer from corrole to anthraquinone.

Emission color tuning in AlQ3 complexes with extended conjugated chromophores.

Science.gov (United States)

Pohl, Radek; Anzenbacher, Pavel

2003-08-07

[reaction: see text] A new method for the synthesis of 5-arylethynyl-8-hydroxyquinoline ligands using Sonogashira-Hagihara coupling was developed. The electronic nature of arylethynyl substituents affects the emission color and quantum yield of the resulting Al(III) complex. Photophysical properties of the metallocomplexes correspond to the electron-withdrawing/-donating character of the arylethynyl substituents. Optical properties of such Al(III) complexes correlate with the Hammett constant values of the respective substituents. This strategy offers a powerful tool for the preparation of electroluminophores with predictable photophysical properties.

Synthesis and Characterization of a Heteroleptic Ru(II Complex of Phenanthroline Containing Oligo-Anthracenyl Carboxylic Acid Moieties

Directory of Open Access Journals (Sweden)

Peter A. Ajibade

2010-09-01

Full Text Available In an effort to develop new ruthenium(II complexes, this work describes the design, synthesis and characterization of a ruthenium(II functionalized phenanthroline complex with extended π-conjugation. The ligand were L1 (4,7-bis(2,3-dimethylacrylic acid-1,10-phenanthroline, synthesized by a direct aromatic substitution reaction, and L2 (4,7-bis(trianthracenyl-2,3-dimethylacrylic acid-1,10-phenanthroline, which was synthesized by the dehalogenation of halogenated aromatic compounds using a zero-valent palladium cross-catalyzed reaction in the absence of magnesium-diene complexes and/or cyclooctadienyl nickel (0 catalysts to generate a new carbon-carbon bond (C-C bond polymerized hydrocarbon units. The ruthenium complex [RuL1L2(NCS2] showed improved photophysical properties (red-shifted metal-to-ligand charge-transfer transition absorptions and enhanced molar extinction coefficients, luminescence and interesting electrochemical properties. Cyclic and square wave voltammetry revealed five major redox processes. The number of electron(s transferred by the ruthenium complex was determined by chronocoulometry in each case. The results show that processes I, II and III are multi-electron transfer reactions while processes IV and V involved one-electron transfer reaction. The photophysical property of the complex makes it a promising candidate in the design of chemosensors and photosensitizers, while its redox-active nature makes the complex a potential mediator of electron transfer in photochemical processes.

Synthesis, characterization and properties

Indian Academy of Sciences (India)

Unknown

work, we report herein the synthesis, structural cha- racterization and properties of a chiral Mn(IV) mononuclear ... atmosphere with a platinum disc working electrode, a platinum wire auxiliary electrode and a Ag/AgCl ... SMART APEX CCD area detector system [λ(Mo-. Kα) = 0⋅71073 Å], graphite monochromator, 2400.

Photophysics and Photochemistry of Canonical Nucleobases’ Thioanalogs: From Quantum Mechanical Studies to Time Resolved Experiments

Directory of Open Access Journals (Sweden)

Serra Arslancan

2017-06-01

Full Text Available Interest in understanding the photophysics and photochemistry of thiated nucleobases has been awakened because of their possible involvement in primordial RNA or their potential use as photosensitizers in medicinal chemistry. The interpretation of the photodynamics of these systems, conditioned by their intricate potential energy surfaces, requires the powerful interplay between experimental measurements and state of the art molecular simulations. In this review, we provide an overview on the photophysics of natural nucleobases’ thioanalogs, which covers the last 30 years and both experimental and computational contributions. For all the canonical nucleobase’s thioanalogs, we have compiled the main steady state absorption and emission features and their interpretation in terms of theoretical calculations. Then, we revise the main topographical features, including stationary points and interstate crossings, of their potential energy surfaces based on quantum mechanical calculations and we conclude, by combining the outcome of different spectroscopic techniques and molecular dynamics simulations, with the mechanism by which these nucleobase analogs populate their triplet excited states, which are at the origin of their photosensitizing properties.

Structural and optical properties of novel surfactant-coated Yb-TiO2 nanoparticles

International Nuclear Information System (INIS)

Calandra, P.; Lombardo, D.; Pistone, A.; Turco Liveri, V.; Trusso, S.

2011-01-01

In this paper a novel hybrid approach to synthesise composite nanoparticles is presented. It is based on the laser ablation of a bulk target (Yb) immersed in a reversed micellar solution which contains nanoparticles of a different host material (TiO 2 nanoparticles) previously synthesised by chemical method. This approach thus exploits the advantages of the chemical synthesis through reversed micellar solution (size control, nanoparticle stabilisation), and of the laser ablation (“clean” synthesis, no side reactions). Central role is played by the microscopic processes controlling the deposition of the ablated Yb atoms onto the surface of TiO 2 nanoparticles which actually behave as nucleation seeds. The structural features of the resulting Yb-TiO 2 composite nanoparticles have been studied by Transmission Electron Microscopy, whereas their peculiar optical properties have been explored by UV–Vis spectroscopy and steady-state fluorescence. Results consistently show the formation of Yb and TiO 2 glued nanodomains to form nearly spherical and non-interacting nanoparticles with enhanced photophysical properties.

Short-time synthesis of poly[4,6-bis(3′-(2-ethylhexyl)thien-2′-yl)thieno[3,4-c][1,2,5]thiadiazole-alt-9,9-dioctylfluorene], its photophysical, electrochemical and photovoltaic properties

Czech Academy of Sciences Publication Activity Database

Cimrová, Věra; Kmínek, Ivan; Výprachtický, Drahomír; Pokorná, Veronika

2015-01-01

Roč. 59, 24 February (2015), s. 298-304 ISSN 0032-3861 R&D Projects: GA ČR(CZ) GA13-26542S; GA ČR GAP106/12/0827 Institutional support: RVO:61389013 Keywords : low-bandgap thienothiadiazole copolymer * Suzuki coupling * photophysics and photovoltaics Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.586, year: 2015

Photophysics of charge transfer in a polyfluorene/violanthrone blend

Science.gov (United States)

Cabanillas-Gonzalez, J.; Virgili, T.; Lanzani, G.; Yeates, S.; Ariu, M.; Nelson, J.; Bradley, D. D. C.

2005-01-01

We present a study of the photophysical and photovoltaic properties of blends of violanthrone in poly[9, 9-bis (2-ethylhexyl)-fluorene-2, 7-diyl ] (PF2/6) . Photoluminescence quenching and photocurrent measurements show moderate efficiencies for charge generation, characteristic of such polymer/dye blends. Pump-probe measurements on blend films suggest that while ˜47% of the total exciton population dissociates within 4ps of photoexcitation, only ˜32% subsequently results in the formation of dye anions. We attribute the discrepancy to the likely formation of complex species with long lifetimes, such as stabilized interface charge pairs or exciplexes. This conclusion is supported by the appearance of a long lifetime component of 2.4ns in the dynamics of the photoinduced absorption signal associated to polarons in photoinduced absorption bands centered at 560nm .

Photophysical properties of fullerenes prepared in an atmosphere of pyrrole

Energy Technology Data Exchange (ETDEWEB)

Glenis, S.; Cooke, S.; Chen, X.; Labes, M.M. (Temple Univ., Philadelphia, PA (United States))

1994-10-01

Samples of C[sub 60] and C[sub 70] containing a variety of nitrogen-doped species were prepared by arc vaporization of graphite in the presence of pyrrole. Cage-doped fractions were isolated by column chromatography and characterized by mass spectroscopy, optical absorption, and fluorescence measurements. Mass spectra were consistent with the substitution of an even number of carbon atoms of the C[sub 60] and C[sub 70] cages by nitrogen atoms. Carbonaceous clusters including fragmented fullerenes containing hydrogen atoms were also formed. UV-visible spectral analysis indicated that there is an influence of the molecular weight on the fundamental [pi]-[pi]* electronic transition. Fluorescence spectra showed a broad band containing vibrational fine structure that is attributed to photoseparated charges in the fragmented fullerenes and a shoulder on the low-energy side that is related to intrinsic excitation in the nitrogen-doped species. Fluorescence results imply a bandgap of 2.36 eV for the N doped fullerenes and the existence of intermediate excitonic transitions below the optical bandgap. Although it has not yet been possible to isolate a pure cage-doped material, the photophysical studies add credence to their existence and the importance of further attempts at their isolation. 17 refs., 4 figs., 1 tab.

Metal-organic framework templated synthesis of Fe{sub 2}O{sub 3}/TiO{sub 2} nanocomposite for hydrogen production

Energy Technology Data Exchange (ETDEWEB)

Krafft, Kathryn E. de; Wang, Cheng; Lin, Wenbin [University of North Carolina, Chapel Hill, NC (United States). Department of Chemistry

2012-04-17

A new metal-organic framework (MOF)-templated method has been developed for the synthesis of a metal oxide nanocomposite with interesting photophysical properties. Fe-containing nanoscale MOFs are coated with amorphous titania, then calcined to produce crystalline Fe{sub 2}O{sub 3}/TiO{sub 2} composite nanoparticles. This material enables photocatalytic hydrogen production from water using visible light, which cannot be achieved by either Fe{sub 2}O{sub 3} or TiO{sub 2} alone or a mixture of the two. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Single-crystal structure, photophysical characteristics and electroluminescent properties of bis(2-(4-trifluoromethyl-2-hydroxyphenyl)benzothiazolate)zinc

International Nuclear Information System (INIS)

Xu Huixia; Yue, Yan; Wang Hua; Chen Liuqing; Hao Yuying; Xu Bingshe

2012-01-01

In this paper, a zinc (II) complex of Zn 2 (4-tfmBTZ) 4 (4-tfmBTZ=2-(4-trifluoromethyl-2-hydroxyphenyl)benzothiazolate) was reported. Via combination of experimental and theoretical approaches, its molecular structure, photophysical characteristics, electronic structure and electroluminescent properties were investigated. The results indicate that Zn 2 (4-tfmBTZ) 4 exists as five-coordinate geometric structure and two zinc atoms are bridged by oxygen atoms. The intense absorption band was located at 404 nm, which mainly originate from the transition HOMO−1 to LUMO+2. The blue-light emission was observed in tetrahydrofuran solution and thin film. White-light emission with four emission peaks was observed with CIE coordinate of (0.29, 0.33) and a higher CRI of 85.1 by fabricating bilayer device using Zn 2 (4-tfmBTZ) 4 as electron-transport and NPB as hole-transport material. - Highlights: ► The single-crystal and electronic structures of Zn 2 (4-tfmBTZ) 4 . ► The multicolor emission of Zn 2 (4-tfmBTZ) 4 were realized by the simple devices. ► White OLED is achieved with particularly high color rending index (CRI) by the emission of Zn 2 (4-tfmBTZ) 4 .

Synthesis, structural characterization, luminescent properties and theoretical study of three novel lanthanide metal-organic frameworks of Ho(III), Gd(III) and Eu(III) with 2,5-thiophenedicarboxylate anion

Energy Technology Data Exchange (ETDEWEB)

Marques, Lippy F. [Instituto de Química, Universidade do Estado do Rio de Janeiro, Rio de Janeiro 20550-013 (Brazil); Correa, Charlane C. [Departamento de Química-ICE, Universidade Federal de Juiz de Fora, Juiz de Fora-MG, 36036-330 (Brazil); Ribeiro, Sidney J.L.; Santos, Molíria V. dos [Institute of Chemistry, São Paulo State University − UNESP, CP 355 Araraquara-SP 14801-970 Brazil (Brazil); Dutra, José Diogo L.; Freire, Ricardo O. [Pople Computational Chemistry Laboratory, Departamento de Química, Universidade Federal de Sergipe, São Cristóvão-SE 49100-000 (Brazil); Machado, Flávia C., E-mail: flavia.machado@ufjf.edu.br [Departamento de Química-ICE, Universidade Federal de Juiz de Fora, Juiz de Fora-MG, 36036-330 (Brazil)

2015-07-15

In this paper, the synthesis of three new metal-organic frameworks of lanthanides (LnMOFs) ([Ln{sub 2}(2,5-tdc){sub 3}(dmso){sub 2}]·H{sub 2}O){sub n} (Ln=Ho (1); Gd (2); Eu (3); 2,5-tdc=2,5-thiophenedicarboxylate anion; dmso=dimethylsulfoxide), and their complete characterization, including single crystal X-ray diffraction, FTIR spectroscopy and thermogravimetric analysis are reported. In especial, photophysical properties of Eu(III) complex have been studied in detail via both theoretical and experimental approaches. Crystal structure of (1) reveals that each lanthanide ion is seven-coordinated by oxygen atoms in an overall distorted capped trigonal – prismatic geometry. The 2,5-tdc{sup 2−} ligands connect four Ln(III) centers, adopting (κ{sup 1}–κ{sup 1})–(κ{sup 1}–κ{sup 1})–μ{sub 4} coordination mode, generating an 8-connected uninodal 3D network. In addition, theoretical studies for Eu(III) complex were performed using the Sparkle model for lanthanide complexes. - Graphical abstract: Three new metal-organic frameworks of lanthanides (LnMOFs) ([Ln{sub 2}(2,5-tdc){sub 3}(dmso){sub 2}]·H{sub 2}O){sub n} (Ln=Ho (1); Gd (2); Eu (3); 2,5-tdc=2,5-thiophenedicarboxylate anion; dmso=dimethylsulfoxide), were synthesized and their complete characterization, including single crystal X-ray diffraction, FTIR spectroscopy and thermogravimetric analysis are reported. In especial, photophysical properties of Eu(III) complex have been studied in detail via both theoretical and experimental approaches. - Highlights: • Three new LnMOFs were synthesized and fully characterized. • Ho{sup 3+}, Gd{sup 3+} and Eu{sup 3+} complexes photoluminescence properties were investigated. • Theoretical approaches for Eu{sup 3+} complex luminescence has been performed. • An energy level diagram is used to establish the ligand-to-metal energy transfer. • These metal−organic frameworks can act as light conversion molecular devices.

Thermostability and photophysical properties of mixed-ligand carboxylate/benzimidazole Zn(II)-coordination polymers

International Nuclear Information System (INIS)

Barros, Bráulio Silva; Chojnacki, Jaroslaw; Macêdo Soares, Antonia Alice; Kulesza, Joanna; Lourenço da Luz, Leonis; Júnior, Severino Alves

2015-01-01

The reaction between Zn(NO 3 ) 2 ·6H 2 O or Zn(CH 3 COO) 2 ·2H 2 O and isophthalic acid (1,3-H 2 bdc) in the presence of benzimidazole (Hbzim) in dimethylformamide (DMF)/ethanol (EtOH)/H 2 O solvent mixture at room temperature yielded two structurally different coordination polymers: [Zn 2 (1,3-bdc) 2 (Hbzim) 2 ] (1) and [Zn 2 (1,3-bdc)(bzim) 2 ] (2). (1) is a 2D-layered framework with a molecule of benzimidazole coordinated to the Zn center, whereas (2) is a 3D framework with benzimidazolate species acting as a co-ligand and bridging two Zn(II) ions. Reactions performed at 90 °C led to the formation of coordination polymers structurally similar to (2), independently of the Zn(II) source used. In the absence of benzimidazole, the reaction between ZnAc 2 .2H 2 O and 1,3-H 2 bdc at 90 °C resulted in the formation of (3), a 3D coordination polymer Zn(HCOO) 3 (Me 2 NH 2 + ). It was observed that the thermostability and the photophysical properties of (1) and (2) are strongly dependent on the coordination modes and packing of benzimidazole in the solid state. These materials present photoluminescence in the wide range of the spectrum, from UV to IR. A full understanding of a physical process occurring in these intriguing systems, including complete energy level diagrams with possible transitions were provided. - Graphical abstract: Display Omitted - Highlights: • Structurally different Zn(II)-coordination polymers were prepared. • The formation of frameworks was counter anion and temperature dependent. • Photoluminescence in the wide range of the spectrum, from UV to IR was observed. • Thermostability and luminescence depended on bzim packing in the structure

Synthesis of PEGylated gold nanostars and bipyramids for intracellular uptake

International Nuclear Information System (INIS)

Navarro, Julien R G; Lerouge, Frédéric; Chaput, Frédéric; Micouin, Guillaume; Gabudean, Ana-Maria; Baldeck, Patrice L; Kamada, Kenji; Parola, Stephane; Manchon, Delphine; Mosset, Alexis; Cottancin, Emmanuel; Blanchard, Nicholas P; Marotte, Sophie; Leverrier, Yann; Marvel, Jacqueline

2012-01-01

A great number of works have focused their research on the synthesis, design and optical properties of gold nanoparticles for potential biological applications (bioimaging, biosensing). For this kind of application, sharp gold nanostructures appear to exhibit the more interesting features since their surface plasmon bands are very sensitive to the surrounding medium. In this paper, a complete study of PEGylated gold nanostars and PEGylated bipyramidal-like nanostructures is presented. The nanoparticles are prepared in high yield and their surfaces are covered with a biocompatible polymer. The photophysical properties of gold bipyramids and nanostars, in suspension, are correlated with the optical response of single and isolated objects. The resulting spectra of isolated gold nanoparticles are subsequently correlated to their geometrical structure by transmission electron microscopy. Finally, the PEGylated gold nanoparticles were incubated with melanoma B16-F10 cells. Dark-field microscopy showed that the biocompatible gold nanoparticles were easily internalized and most of them localized within the cells. (paper)

Hybrid Organic/Inorganic Perovskite–Polymer Nanocomposites: Toward the Enhancement of Structural and Electrical Properties

KAUST Repository

Privitera, Alberto; Righetto, Marcello; de Bastiani, Michele; Carraro, Francesco; Rancan, Marzio; Armelao, Lidia; Granozzi, Gaetano; Bozio, Renato; Franco, Lorenzo

2017-01-01

Hybrid organic/inorganic perovskite nanoparticles (NPs) have garnered remarkable research attention because of their promising photophysical properties. New and interesting properties emerge after combining perovskite NPs with semiconducting materials. Here, we report the synthesis and investigation of a composite material obtained by mixing CH3NH3PbBr3 nanocrystals with the semiconducting polymer poly(3-hexylthiophene) (P3HT). By the combination of structural techniques and optical and magnetic spectroscopies we observed multiple effects of the perovskite NPs on the P3HT: (i) an enlargement of P3HT crystalline domains, (ii) a strong p-doping of the P3HT, and (iii) an enhancement of interchain order typical of H-aggregates. These observations open a new avenue toward innovative perovskite NP-based applications.

Hybrid Organic/Inorganic Perovskite–Polymer Nanocomposites: Toward the Enhancement of Structural and Electrical Properties

KAUST Repository

Privitera, Alberto

2017-11-30

Hybrid organic/inorganic perovskite nanoparticles (NPs) have garnered remarkable research attention because of their promising photophysical properties. New and interesting properties emerge after combining perovskite NPs with semiconducting materials. Here, we report the synthesis and investigation of a composite material obtained by mixing CH3NH3PbBr3 nanocrystals with the semiconducting polymer poly(3-hexylthiophene) (P3HT). By the combination of structural techniques and optical and magnetic spectroscopies we observed multiple effects of the perovskite NPs on the P3HT: (i) an enlargement of P3HT crystalline domains, (ii) a strong p-doping of the P3HT, and (iii) an enhancement of interchain order typical of H-aggregates. These observations open a new avenue toward innovative perovskite NP-based applications.

Nonlinear absorbing cationic iridium(III) complexes bearing benzothiazolylfluorene motif on the bipyridine (N∧N) ligand: synthesis, photophysics and reverse saturable absorption.

Science.gov (United States)

Li, Yuhao; Dandu, Naveen; Liu, Rui; Hu, Lei; Kilina, Svetlana; Sun, Wenfang

2013-07-24

Four new heteroleptic cationic Ir(III) complexes bearing benzothiazolylfluorene motif on the bipyridine (N∧N) (1 and 2) and phenylpyridine (C∧N) (3 and 4) ligands are synthesized and characterized. The influence of the position of the substituent and the extent of π-conjugation on the photophysics of these complexes is systematically investigated by spectroscopic methods and simulated by time-dependent density functional theory (TDDFT). The complexes exhibit ligand-centered (1)π,π* transitions with admixtures of (1)ILCT (π(benzothiazolylfluorene) → π*(bpy)) and (1)MLCT (metal-to-ligand charge transfer) characters below 475 nm, and very weak (1,3)MLCT and (1,3)LLCT (ligand-to-ligand charge transfer) transitions above 475 nm. The emission of these complexes at room temperature in CH2Cl2 solutions is ascribed to be predominantly from the (3)MLCT/(3)LLCT states for 1 and from the (3)π,π* state for 2, while the emitting state of 3 and 4 are assigned to be an admixture of (3)MLCT, (3)LLCT, and (3)π,π* characters. The variations of the photophysical properties of 1-4 are attributed to different degrees of π-conjugation in the bipyridine and phenylpyridine ligands induced by different positions of the benzothiazolylfluorenyl substituents on the bipyridine ligand and different extents of π-conjugation in the phenylpyridine ligands, which alters the energy and lifetime of the lowest singlet and triplet excited states. 1-4 all possess broadband transient absorption (TA) upon nanosecond laser excitation, which extends from the visible to the NIR region. Therefore, 1-4 all exhibit strong reverse saturable absorption (RSA) at 532 nm for ns laser pulses. However, the TA of complexes 1, 2, and 3 are much stronger than that of 4. This feature, combined with the difference in ground-state absorption and triplet excited-state quantum yield, result in the difference in RSA strength, which follows this trend: 1 ≈ 2 ≈ 3 > 4. Therefore, complexes 1-3 are strong

Synthesis and tribological properties of antimony N, N-diethanoldithiocarbamate

Institute of Scientific and Technical Information of China (English)

李丽; 黄可龙; 瞿龙; 舒万艮

2001-01-01

Antimony N, N-diethanoldithiocarbamate was synthesized with diethanolamine, antimony trioxide and carbon disulfide. The influences of temperature, reaction time, solvents and their dosages were investigated, and the optimum synthesis conditions were: reaction temperature 15～20 ℃, reaction time 2.5 h, 250 mL CH3OH as solvent and the hot CH3OH as recrystallization solvent. Element analysis, IR, 1HNMR and 13CNMR spectra were used to study its chemical composition and molecular structure. Antimony N, N-diethanol-dithiocarbamate was added in the base oil, and its properties of wear resistance and extreme pressure were studied by FB, FD and WSD. The synthesis product behaves per fectly as wear resistance and extreme pressure additive and its extreme pressure property is superior to its wear resistance property. The mechanism of tribological action was discussed by using XPS and AES spectra, and the reason of good wear resistance and extreme pressure properties is that the synthesis product decompose element C, S and N.

Alternative Thieno[3,2-b][1]benzothiophene Isoindigo Polymers for Solar Cell Applications

KAUST Repository

Neophytou, Marios; Bryant, Daniel; Lopatin, Sergei; Chen, Hu; Hallani, Rawad K.; Cater, Lewis; McCulloch, Iain; Yue, Wan

2018-01-01

This work reports the synthesis, characterization, photophysical, and photovoltaic properties of five new thieno[3,2-b][1]benzothiophene isoindigo (TBTI)-containing low bandgap donor-acceptor conjugated polymers with a series of comonomers

Photophysical properties of [Ru(2,2′-bipyridine){sub 3}]{sup 2+} encapsulated within the Uio-66 zirconium based metal organic framework

Energy Technology Data Exchange (ETDEWEB)

Larsen, Randy W., E-mail: rwlarsen@usf.edu; Wojtas, Lukasz

2017-03-15

The ability to encapsulate photo-active guest molecules within the pores of metal organic frameworks (MOFs) affords the opportunity to develop robust photocatalysts as well as solar energy conversion systems. An important criteria for such systems is stability of the new materials towards moisture, high temperatures, etc which preclude the use of many MOF frameworks. Here, the ability to encapsulate [Ru(II)(2,2′-bipyridine){sub 3}]{sup 2+}([Ru(bpy){sub 3}]{sup 2+}) into the cavities of the zirconium based MOF Uio-66 as well as the photophysical properties of the complex are reported. The X-ray powder diffraction data of the orange Uio-66 powder are consistent with the formation of Uio-66 in the presence of [Ru(bpy){sub 3}]{sup 2+}. The steady state emission exhibits a significant bathochromic shift from 603 nm in ethanol to 610 nm in Uio-66. The corresponding emission decay of the encapsulated [Ru(bpy){sub 3}]{sup 2+} complex is biexponential with a fast component of 128 ns and a slower component of 1176 ns (20 deg C). The slow component is consistent with encapsulation of [Ru(bpy){sub 3}]{sup 2+} into cavities with restricted volume that prevents the population of a triplet ligand field transition that is anti-bonding with respect to the Ru-N bonds. The origin of the fast component is unclear but may involve interactions of the [Ru(bpy){sub 3}]{sup 2+} encapsulated within large cavities formed through missing ligand defect sites within the Uio-66 materials. Co-encapsulated quenchers contained within these larger cavities gives rise to the reduced lifetimes of the [Ru(bpy){sub 3}]{sup 2+} complexes. - Graphical abstract: One-pot synthesis of Ru(II)tris(2,2-bipyridine)@Uio-66 (left) and the effects of encapsulation on the excited state energy levels and decay pathways of the Ru(II)tris(2,2-bipyridine) complex (right).

Synthesis and luminescent properties of star-burst D-π-A compounds based on 1,3,5-triazine core and carbazole end-capped phenylene ethynylene arms

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zheng [Department of Applied Chemistry, Nanjing Tech University, Nanjing 210009 (China); Liu, Rui, E-mail: rui.liu@njtech.edu.cn [Department of Applied Chemistry, Nanjing Tech University, Nanjing 210009 (China); Zhu, Xiaolin [Department of Applied Chemistry, Nanjing Tech University, Nanjing 210009 (China); Li, Yuhao [Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433 (China); Chang, Jin [Queensland University of Technology, 2 George St., Brisbane 4000 (Australia); Zhu, Hongjun, E-mail: zhuhjnjut@hotmail.com [Department of Applied Chemistry, Nanjing Tech University, Nanjing 210009 (China); Ma, Liangwei; Lv, Wangjie; Guo, Jun [Department of Applied Chemistry, Nanjing Tech University, Nanjing 210009 (China)

2014-12-15

Two new star-burst compounds based on 1,3,5-triazine core and carbazole end-capped phenylene ethynylene arms (1a and 1b) were synthesized and characterized. Their photophysical properties were investigated systematically via spectroscopic and theoretical methods. Both compounds exhibit strong {sup 1}π–π{sup ⁎} transitions in the UV region and intense {sup 1}π–π{sup ⁎}/intramolecular charge transfer ({sup 1}ICT) absorption bands in the UV–vis region. Introducing the carbazole end-capped phenylene ethynylene arm on the 1,3,5-triazine core causes a slight bathochromic shift and enhanced molar extinction coefficient of the {sup 1}π–π{sup ⁎}/{sup 1}ICT transition band. Both compounds are emissive in solution at room temperature and 77 K, which exhibit pronounced positive solvatochromic effect. The emitting state could be ascribed to {sup 1}ICT state in more polar solvent, and {sup 1}π–π{sup ⁎} state in low-polarity solvent. The high emission quantum yields (Φ{sub em}=0.90∼1.0) of 1a and 1b (in hexane and toluene) make them potential candidates as efficient light-emitting materials. The spectroscopic studies and theoretical calculations indicate that the photophysical properties of these compounds can be tuned by the carbazole end-capped phenylene ethynylene arm, which would also be useful for rational design of photofunctional materials. - Highlights: • Star-burst compounds based on 1,3,5-triazine core and carbazole end-capped phenylene ethynylene arms. • Photophysical properties of target compounds were investigated systematically via spectroscopic and theoretical methods. • The relatively high fluorescence quantum yields make them potential candidates as light-emitting materials.

Nanosilicon properties, synthesis, applications, methods of analysis and control

CERN Document Server

Ischenko, Anatoly A; Aslalnov, Leonid A

2015-01-01

Nanosilicon: Properties, Synthesis, Applications, Methods of Analysis and Control examines the latest developments on the physics and chemistry of nanosilicon. The book focuses on methods for producing nanosilicon, its electronic and optical properties, research methods to characterize its spectral and structural properties, and its possible applications. The first part of the book covers the basic properties of semiconductors, including causes of the size dependence of the properties, structural and electronic properties, and physical characteristics of the various forms of silicon. It presents theoretical and experimental research results as well as examples of porous silicon and quantum dots. The second part discusses the synthesis of nanosilicon, modification of the surface of nanoparticles, and properties of the resulting particles. The authors give special attention to the photoluminescence of silicon nanoparticles. The third part describes methods used for studying and controlling the structure and pro...

DFT/TDDFT investigation on the electronic structures and photophysical properties of phosphorescent iridium(III) complexes with 2-(pyridin-2-yl)-benzo[d]imidazole ligand

Energy Technology Data Exchange (ETDEWEB)

Shang, Xiaohong, E-mail: shangxiaohong58@aliyun.com [College of Chemistry and Life Science, Changchun University of Technology, Changchun 130012 (China); Han, Deming [School of Life Science and Technology, Changchun University of Science and Technology, Changchun 130022 (China); Li, Dongfeng [College of Chemistry and Life Science, Changchun University of Technology, Changchun 130012 (China); Zhang, Gang [State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023 (China)

2014-03-15

We have reported a theoretical analysis of a series of heteroleptic iridium(III) complexes (mpmi){sub 2}Ir(pybi) [mpmi=1-(4-tolyl)-3-methyl-imidazole, pybi=2-(pyridin-2-yl)-benzo[d]imidazole] (1a), (fpmi){sub 2}Ir(pybi) [fpmi=1-(4-fluoro-phenyl)-3-methyl-imidazole] (1b), (tfpmi){sub 2}Ir(pybi) [tfpmi=1-methyl-3-(4-trifluoromethyl-phenyl)-imidazole] (1c), (pypmi){sub 2}Ir(pybi) [pypmi=3-(3-methyl-imidazol)-pyrazole] (2a), (phpymi){sub 2}Ir(pybi) [phpymi=3-(3-methyl-imidazol)-5-phenyl-pyrazole] (2b), and (inpymi){sub 2}Ir(pybi) [inpymi=3-(3-methyl-imidazol)-indeno[1,2-c]pyrazole] (2c) by using the density functional theory (DFT) method to investigate their electronic structures and photophysical properties and obtain further insights into the phosphorescent efficiency mechanism. By changing cyclometalated ligands, the conjugation length, and substituents of the cyclometalated ligands, one can tune the emission color from green (λ{sub em}=520 nm) to orange (λ{sub em}=592 nm). Complexes 1a, 1b, 2a, and 2b have the almost identical emission wavelength about 550 nm, while 592 nm for 1c and 520 nm for 2c are red shifted and blue shifted, respectively, relative to 1a. The calculated results indicate that, for 1b and 1c, the substituents of −F and −CF{sub 3} at the phenyl moiety cause a poor hole-injection ability compared with that of 1a. For all these complexes studied, the hole-transporting performances are better than the electron-transporting ones. The difference between reorganization energies for hole transport (λ{sub ih}) and reorganization energies for electron transport (λ{sub ie}) for complex 1c are relatively smaller, indicating that the hole and electron transfer balance could be achieved more easily in the emitting layer. The alteration of cyclometalated ligands with different conjugation lengths and substituents has an impact on the optoelectronic properties of these complexes. It is believed that the larger metal to ligand charge transfer (MLCT

Surface active monomers synthesis, properties, and application

CERN Document Server

Borzenkov, Mykola

2014-01-01

This brief includes information on the background?of and development of synthesis of various types of surface active monomers. The authors explain the importance of utilization of surface active monomers for creation of surface active polymers? and the various biomedical applications of such compounds . This brief introduces techniques for the synthesis of novel types of surface active monomers, their colloidal and polymerizable properties and application for needs of medicine and biology.

Single-crystal structure, photophysical characteristics and electroluminescent properties of bis(2-(4-trifluoromethyl-2-hydroxyphenyl)benzothiazolate)zinc

Energy Technology Data Exchange (ETDEWEB)

Xu Huixia, E-mail: xuhuixia0824@163.com [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024 (China); Yue, Yan [Department of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); Wang Hua [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024 (China); Chen Liuqing [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024 (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Hao Yuying [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024 (China); Department of Physics and Optoelectronics, Taiyuan University of Technology, Taiyuan 030024 (China); Xu Bingshe [Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Taiyuan 030024 (China); College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

2012-04-15

In this paper, a zinc (II) complex of Zn{sub 2}(4-tfmBTZ){sub 4} (4-tfmBTZ=2-(4-trifluoromethyl-2-hydroxyphenyl)benzothiazolate) was reported. Via combination of experimental and theoretical approaches, its molecular structure, photophysical characteristics, electronic structure and electroluminescent properties were investigated. The results indicate that Zn{sub 2}(4-tfmBTZ){sub 4} exists as five-coordinate geometric structure and two zinc atoms are bridged by oxygen atoms. The intense absorption band was located at 404 nm, which mainly originate from the transition HOMO-1 to LUMO+2. The blue-light emission was observed in tetrahydrofuran solution and thin film. White-light emission with four emission peaks was observed with CIE coordinate of (0.29, 0.33) and a higher CRI of 85.1 by fabricating bilayer device using Zn{sub 2}(4-tfmBTZ){sub 4} as electron-transport and NPB as hole-transport material. - Highlights: Black-Right-Pointing-Pointer The single-crystal and electronic structures of Zn{sub 2}(4-tfmBTZ){sub 4}. Black-Right-Pointing-Pointer The multicolor emission of Zn{sub 2}(4-tfmBTZ){sub 4} were realized by the simple devices. Black-Right-Pointing-Pointer White OLED is achieved with particularly high color rending index (CRI) by the emission of Zn{sub 2}(4-tfmBTZ){sub 4}.

Fabrication and Photocatalytic Properties of ZnSe Nanorod Films

Directory of Open Access Journals (Sweden)

Jiajia Yin

2016-01-01

Full Text Available ZnSe nanorod films grown on fused quartz glass substrates via a simple two-step synthesis protocol were demonstrated to be environmentally safe and effective recyclable photocatalysts. These films showed greatly enhanced photocatalytic activity compared to pulsed laser deposition ZnSe films in the degradation of methyl orange dye solutions. The well-crystalized ZnSe nanorods had a length of 15 µm and a diameter of 200 nm and were densely grown on the substrate. The morphology, crystal structure, crystal phase, and photophysical properties of the ZnSe nanorod films were investigated using field-emission scanning electron microscopy (FE-SEM, UV-Vis spectroscopy, X-ray diffraction (XRD, transmission electron microscopy (TEM, and high resolution transmission electron microscopy (HRTEM.

Synthesis, Spectral, Electrochemical and Theoretical Investigation of ...

Indian Academy of Sciences (India)

chemsci

and thermal properties along with computed HOMO-LUMO energy levels were studied for the synthesized compounds. ... anthraquinone (Chart 1) and their photophysical, elec- ... Indolo[2,3-b]quinoxaline based dyes as n–type materials. 485.

Fluorescent deep-blue and hybrid white emitting devices based on a naphthalene-benzofuran compound

KAUST Repository

Yang, Xiaohui; Zheng, Shijun; Chae, HyunSik; Li, Sheng; Mochizuki, Amane; Jabbour, Ghassan E.

2013-01-01

We report the synthesis, photophysics and electrochemical properties of naphthalene-benzofuran compound 1 and its application in organic light emitting devices. Fluorescent deep-blue emitting devices employing 1 as the emitting dopant embedded in 4

Property Based Process and Product Synthesis and Design

DEFF Research Database (Denmark)

Eden, Mario Richard

2003-01-01

in terms of the constitutive (synthesis/design) variables instead of the process variables, thus providing the synthesis/design targets. The second reverse problem (reverse property prediction) solves the constitutive equations to identify unit operations, operating conditions and/or products by matching......This thesis describes the development of a general framework for solving process and product design problems. Targeting the desired performance of the system in a systematic manner relieves the iterative nature of conventional design techniques. Furthermore, conventional component based methods...... are not capable of handling problems, where the process or product objectives are driven by functionalities or properties rather than chemical constituency. The framework is meant to complement existing composition based methods by being able to handle property driven problems. By investigating the different...

Non-empirical Prediction of the Photophysical and Magnetic Properties of Systems with Open d- and f-Shells Based on Combined Ligand Field and Density Functional Theory (LFDFT).

Science.gov (United States)

Daul, Claude

2014-09-01

Despite the important growth of ab initio and computational techniques, ligand field theory in molecular science or crystal field theory in condensed matter offers the most intuitive way to calculate multiplet energy levels arising from systems with open shells d and/or f electrons. Over the past decade we have developed a ligand field treatment of inorganic molecular modelling taking advantage of the dominant localization of the frontier orbitals within the metal-sphere. This feature, which is observed in any inorganic coordination compound, especially if treated by Density Functional Theory calculation, allows the determination of the electronic structure and properties with a surprising good accuracy. In ligand field theory, the theoretical concepts consider only a single atom center; and treat its interaction with the chemical environment essentially as a perturbation. Therefore success in the simple ligand field theory is no longer questionable, while the more accurate molecular orbital theory does in general over-estimate the metal-ligand covalence, thus yields wave functions that are too delocalized. Although LF theory has always been popular as a semi-empirical method when dealing with molecules of high symmetry e.g. cubic symmetry where the number of parameters needed is reasonably small (3 or 5), this is no more the case for molecules without symmetry and involving both an open d- and f-shell (# parameters ∼90). However, the combination of LF theory and Density Functional (DF) theory that we introduced twenty years ago can easily deal with complex molecules of any symmetry with two and more open shells. The accuracy of these predictions from 1(st) principles achieves quite a high accuracy (<5%) in terms of states energies. Hence, this approach is well suited to predict the magnetic and photo-physical properties arbitrary molecules and materials prior to their synthesis, which is the ultimate goal of each computational chemist. We will illustrate the

Plasma synthesis of nanostructures for improved thermoelectric properties

International Nuclear Information System (INIS)

Petermann, Nils; Hecht, Christian; Schulz, Christof; Wiggers, Hartmut; Stein, Niklas; Schierning, Gabi; Theissmann, Ralf; Stoib, Benedikt; Brandt, Martin S

2011-01-01

The utilization of silicon-based materials for thermoelectrics is studied with respect to the synthesis and processing of doped silicon nanoparticles from gas phase plasma synthesis. It is found that plasma synthesis enables the formation of spherical, highly crystalline and soft-agglomerated materials. We discuss the requirements for the formation of dense sintered bodies, while keeping the crystallite size small. Small particles a few tens of nanometres and below that are easily achievable from plasma synthesis, and a weak surface oxidation, both lead to a pronounced sinter activity about 350 K below the temperature usually needed for the successful densification of silicon. The thermoelectric properties of our sintered materials are comparable to the best results found for nanocrystalline silicon prepared by methods other than plasma synthesis.

Spectroscopic and nonlinear photophysical characterization of organic octupolar-compounds supported by anodic-alumina nanotube-arrays

International Nuclear Information System (INIS)

Morales-Saavedra, O.G.; Ontiveros-Barrera, F.G.; Hennrich, G.; Mata-Zamora, M.E.; Rodriguez-Rosales, A.A.; Banuelos, J.G.

2011-01-01

Highlights: → Preparation of organic-inorganic nanostructured hybrid materials. → Insertion of octupolar compounds in alumina nanotube arrays. → Linear and nonlinear photophysical characterization of solid-state hybrid structures. → Fabrication of photonic materials. - Abstract: Amorphous anodic alumina membranes (AAM) comprising highly ordered nanometric porous arrays (porous anodic aluminas: PAA) with 1D-nanotube dimensions of ∼75 nm in diameter and 45 microns in depth were successfully prepared and used as nanostructured host networks for different functionalized octupolar chromophores (named here Oct-(n)). Atomic force microscopy (AFM) studies performed on the developed hybrid systems confirmed a homogeneous insertion of these organic molecules into the PAA nanotube-arrays. Samples with high structural quality were selected for several photophysical characterizations: Comprehensive X-ray diffraction (XRD) and optical spectroscopic characterizations performed according to UV-vis absorption, photoluminescent (PL) and Raman measurements revealed the structural and optical performance of these molecules within the PAA-confinement. Since the implemented optical chromophores were specifically functionalized for nonlinear optical (NLO) applications, the obtained Oct-(n)/PAA-based amorphous hybrids were also characterized according to cubic NLO-techniques such as third harmonic generation (THG) and the Z-Scan method. PAA-confined octupolar chromophores have shown interesting linear and NLO optical properties which have not yet been intensively investigated in bulk hybrid systems; hence, the obtained hybrid nanostructures represent a promising field of investigation in the route to functional octupolar-based materials, where different self-assembled molecular structures may be formed, giving rise to enhanced linear and NLO-properties.

Theoretical Characterization of Sulfur-to-Selenium Substitution in an Emissive RNA Alphabet: Impact on H-bonding Potential and Photophysical Properties

KAUST Repository

Chawla, Mohit

2018-02-23

We employ density functional theory (DFT) and time-dependent DFT (TDDFT) calculations to investigate the structural, energetic and optical properties of a new computationally designed RNA alphabet, where the nucleobases,tsA, tsG, tsC, and tsU (ts-bases), have been derived by replacing sulfur with selenium in the previously reported tz-bases, based on the isothiazolo[4.3-d]pyrimidine heterocycle core. We find out that the modeled non-natural bases have minimal impact on the geometry and energetics of the classical Watson-Crick base pairs, thus potentially mimicking the natural bases in a RNA duplex in terms of H-bonding. In contrast, our calculations indicate that H-bonded base pairs involving the Hoogsteen edge of purines are destabilized as compared to their natural counterparts. We also focus on the photophysical properties of the non-natural bases and correlate their absorption/emission peaks to the strong impact of the modification on the energy of the lowest unoccupied molecular orbital. It is indeed stabilized by roughly 1.1-1.6 eV as compared to the natural analogues, resulting in a reduction of the gap between the highest occupied and the lowest unoccupied molecular orbital from 5.3-5.5 eV in the natural bases to 3.9-4.2 eV in the modified ones, with a consequent bathochromic shift in the absorption and emission spectra. Overall, our analysis clearly indicates that the newly modelled ts-bases are expected to exhibit better fluorescent properties as compared to the previously reported tz-bases, while retaining similar H-bonding properties. In addition, we show that a new RNA alphabet based on size-extended benzo-homologated ts-bases can also form stable Watson-Crick base pairs with the natural complementary nucleobases.

Synthesis of fluorinated ReCl(4,4'-R2-2,2'-bipyridine)(CO)3 complexes and their photophysical characterization in CH3CN and supercritical CO2.

Science.gov (United States)

Doherty, Mark D; Grills, David C; Fujita, Etsuko

2009-03-02

Two new CO(2)-soluble rhenium(I) bipyridine complexes bearing the fluorinated alkyl ligands 4,4'-(C(6)F(13)CH(2)CH(2)CH(2))(2)-2,2'-bipyridine (1a), and 4,4'-(C(8)F(17)CH(2)CH(2)CH(2))(2)-2,2'-bipyridine (1b) have been prepared and their photophysical properties investigated in CH(3)CN and supercritical CO(2). Electrochemical and spectroscopic characterization of these complexes in CH(3)CN suggests that the three methylene units effectively insulate the bipyridyl rings and the rhenium center from the electron-withdrawing effect of the fluorinated alkyl chains. Reductive quenching of the metal-to-ligand charge-transfer excited states with triethylamine reveals quenching rate constants in supercritical CO(2) that are only 6 times slower than those in CH(3)CN.

Influence of Bridgehead Substitution and Ring Annelation on the Photophysical Properties of Polycyclic DBO-Type Azoalkanes.

Science.gov (United States)

Adam, Waldemar; Nikolaus, Achim; Sauer, Jürgen

1999-05-14

The photophysical data for the polycyclic, bridgehead-substituted derivatives 1-10 of the photoreluctant diazabicyclo[2.2.2]oct-2-ene (DBO) are presented. Substitution on the bridgehead positions with radical-stabilizing substituents enhances the photoreactivity (Phi(r)) and decreases the fluorescence quantum yields (Phi(f)) and lifetimes (tau) compared to the parent DBO. The annelated rings have no influence on the photoreactivity, except when steric interactions with an alpha substituent hinder the optimal radical-stabilizing conformation. The fused rings and some of the bridgehead substituents reduce the solvent-induced quenching of the singlet-excited azo chromophore by steric shielding of the azo group and, thus, increase the fluorescence quantum yields and lifetimes.

Synthesis and properties of bimetallic aluminium alkoxides

International Nuclear Information System (INIS)

Vyshinskaya, K.I.; Vasil'ev, G.A.; Vishnyakova, T.A.

1997-01-01

A single stage method of aluminium bimetallic alkoxide synthesis, which consists in activated aluminium reaction with metal salts in the relevant alcohols, has been developed. Properties of the compounds prepared are described

Photophysics and photochemistry of Riboflavin-induced corneal Cross-Linking

DEFF Research Database (Denmark)

Breitenbach, Thomas

In this talk, we will describe general pathways involved in the photophysics of a photosensitized process, which can lead to crosslinking due to light excitation of Riboflavin in the cornea. Furthermore, we will show the contribution of singlet molecular oxygen O2(a1Δg) to this phenomena and show...

Properties and synthesis of milrinone

Directory of Open Access Journals (Sweden)

Mirković Jelena M.

2013-01-01

Full Text Available Milrinone, 1,6-dihydro-2-methyl-6-oxo-[3,4’-bipyridine]-5-carbonitrile, is a positive inotropic cardiotonic agent with vasodilator properties that acts as selective phosphodiesterase 3 inhibitor in cardiac and vascular smooth muscle. Trade names of milrinone are Primacor, Corotrop, Corotrope, and Milrila. Milrinone, an amrinone derivative, is 20 to 50 times more active than amrinone and possesses reduced propensity to side effects. The use of milrinone has created controversy in the medical as the result of increased mortality rate among patients that received high amounts of milrinone in oral form. Reaserch show that it can be benifitial for patients with severe congestive heart failure when used as short-time intravenous therapy. Milrinone properties, stability, as well as mechanism of action and synthesis under laboratory and industry conditions have been described in this paper. For industrial purposes milrinone is synthesized by condensation of cyanoacetamide with 4-(dimethylamino-3-(4-pyridinyl-3-buten-2-one and 4-ethoxy-3-(4-pyridinyl-3-buten-2-one in presence of a base, or by the reaction of 1-(4-pyridinyl- 2-propanone with ethoxymethylenmalononitrile or 4-alkoxy-3-(4-pyridinyl-3-buten-2-one with malononitrile without the use of external base. The starting compound for these syntheses is 4-picoline. Alternative synthesis of milrinone starts from 2-methyl-3-(4-pyridylidiene-1,1,5-tricyano-1,4-pentadiene-5-carboxamide and 2-methyl-6-oxo-1,6-dihydro-3,4’-bipyridine-5-carboxamide. Lastly, methods for milrinone synthesis in laboratory, injection preparation and purification have been summarized.

Synthesis, microstructures and properties of {gamma}-aluminum oxynitride

Energy Technology Data Exchange (ETDEWEB)

Wang Xidong; Wang Fuming; Li Wenchao

2003-02-15

This paper deals with the synthesis, microstructures and properties of {gamma}-aluminum oxynitride (AlON). The thermodynamic properties of AlON were analyzed and the Gibbs energy of AlON with different compositions and temperatures were evaluated. Based on thermodynamic studies, AlON has been synthesized. The microstructures, mechanical properties and oxidation resistance of the synthetic AlON have been examined and discussed.

Ibuprofen: Synthesis, production and properties

Directory of Open Access Journals (Sweden)

Mijin Dušan Ž.

2003-01-01

Full Text Available Since its introduction in 1969, ibuprofen has become one of the most common painkillers in the world. Ibuprofen in an NSAID (non-steroidal anti-inflammatory drug and like other drugs of its class it possesses analgetic, antipyretic and anti-inflammatory properties. While ibuprofen is a relatively simple molecule, there is still sufficient structural complexity to ensure that a large number of different synthetic approaches are possible. Since the introduction of pharmaceutical products containing ibuprofen, industrial and academic scientists have developed many potential production processes. This paper describes the history, synthesis and production, as well as the properties and stability of ibuprofen.

2D and 3D organisation of nano-particles: synthesis and specific properties

International Nuclear Information System (INIS)

Taleb, Abdelhafed

1998-01-01

The first part of this research thesis addresses the synthesis of nano-particles of silver and cobalt in the inverse micellar system, and highlights the feasibility of two- and three-dimensional structures of these particles. The author first presents the micellar system (micro-emulsions, surfactant, properties of inverse micelles, functionalized inverse micelles, application to the synthesis of nano-particles), and then reports the study of the synthesis and organisation of colloids in 2D and 3D. He also reports the study of optical properties of metallic colloids: free electron approximation, optical properties of electron gases, optical properties of colloids, optical response of two-dimensional and three-dimensional nano-structures. The magnetic properties of colloids are then studied: magnetism of the massive metallic state, magnetic properties of nano-particles (influence of size, interactions and field, notions of magnetic order and disorder), effect of organisation. The second part of this thesis is made of a set of published articles: Synthesis of highly mono-disperse silver nano-particles from AOT reverse micelles (a way to 2D and 3D self-organisation), Optical properties of self-assembled 2D and 3D super-lattices of silver nano-particles, Collective optical properties of silver nano-particles organised in 2D super-lattices, Self assembled in 2D cobalt nano-sized particles, Self organisation of magnetic nano-sized cobalt particles, Organisation in 2D cobalt nano-particles (synthesis, characterization and magnetic properties) [fr

Design, synthesis and photophysical studies of dipyrromethene-based materials: insights into their applications in organic photovoltaic devices.

Science.gov (United States)

Bessette, André; Hanan, Garry S

2014-05-21

This review article presents the most recent developments in the use of materials based on dipyrromethene (DPM) and azadipyrromethenes (ADPM) for organic photovoltaic (OPV) applications. These chromophores and their corresponding BF2-chelated derivatives BODIPY and aza-BODIPY, respectively, are well known for fluorescence-based applications but are relatively new in the field of photovoltaic research. This review examines the variety of relevant designs, synthetic methodologies and photophysical studies related to materials that incorporate these porphyrinoid-related dyes in their architecture. The main idea is to inspire readers to explore new avenues in the design of next generation small-molecule and bulk-heterojunction solar cell (BHJSC) OPV materials based on DPM chromophores. The main concepts are briefly explained, along with the main challenges that are to be resolved in order to take full advantage of solar energy.

Electronic structures and photophysics of d8-d8 complexes

Czech Academy of Sciences Publication Activity Database

Gray, H. B.; Záliš, Stanislav; Vlček, Antonín

2017-01-01

Roč. 345, AUG 2017 (2017), s. 297-317 ISSN 0010-8545 R&D Projects: GA MŠk LH13015 Grant - others:COST(XE) CM1405 Institutional support: RVO:61388955 Keywords : excitation * electronic structures * photophysics Subject RIV: CG - Electrochemistry OBOR OECD: Physical chemistry Impact factor: 13.324, year: 2016

The Chameleonic Nature of Platinum(II) Imidazopyridine Complexes.

Science.gov (United States)

Pinter, Piermaria; Pittkowski, Rebecca; Soellner, Johannes; Strassner, Thomas

2017-10-12

The synthesis and characterization of cyclometalated C^C* platinum(II) complexes with unique photophysical properties, aggregation induced enhancement of the quantum yields with a simultaneous decrease of phosphorescence lifetimes, is reported. Additionally, a change of emission color is induced by variation of the excitation wavelength. The aggregation behavior of these complexes is controlled by the steric demand of the substituents. The photophysical properties of these complexes are investigated through emission-excitation matrix analysis (EEM). The monomeric complexes are excellent room temperature phosphorescent blue emitters with emission maxima below 470 nm and quantum yields of up to 93 %. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of π-conjugation attenuation on the photophysics and exciton dynamics of poly(p-phenylenevinylene) polymers incorporating 2,2'-bipyridines

International Nuclear Information System (INIS)

Chen, L. X.; Jager, W. J.; Niemczyk, M. P.; Wasielewski, M. R.

1999-01-01

The effect of π-conjugation attenuation on the photophysics and exciton dynamics of two conjugated polymers 1 and 2 are examined in solution. The structures of polymers 1 and 2 have 2,2'-bipyridyl-5-vinylene units that alternate with one and three 2,5-bis(n-decyloxy)-1,4-phenylenevinylene monomer units, respectively. The photophysics and exciton dynamics of polymers 1 and 2 were compared to those of the homopolymer, poly(2,5-bis(2'-ethylhexyloxy)-1,4-phenylenevinylene) (BEH-PPV). A series of changes in the photophysics of polymers 1 and 2 were found as a result of π-conjugation attenuation. These changes include blue shifts in absorption and emission spectra, spectral diffusion in stimulated emission, enhancement in photoluminescence quantum yields and lifetimes, and increases in photoinduced absorption intensities and lifetimes. These changes are systematically more pronounced in polymer 1 than in polymer 2 and are correlated with π-conjugation attenuation in the polymers due to twisting of the 2,2'-bipyridine groups about the 2,2' single bond. An exciton dynamics model involving an ensemble of initial exciton states localized on oligomeric segments within the polymer with different conjugation lengths is proposed to describe the observed differences between polymers 1 and 2 and BEH-PPV. When the electronic coupling between these segments is strong, the polymer displays characteristics that are close to those of a one-dimensional semiconductor. However, when these couplings are weakened by groups, such as the 2,2'-bipyridine that attenuate π-conjugation, the polymer displays properties of an ensemble of oligomers

Synthesis, microstructure, and physical properties of metallic barcode nanowires

Science.gov (United States)

Park, Bum Chul; Kim, Young Keun

2017-05-01

With rapid progress in nanotechnology, nanostructured materials have come closer to our life. Single-component nanowires are actively investigated because of their novel properties, attributed to their nanoscale dimensions and adjustable aspect ratio, but their technical limitations cannot be resolved easily. Heterostructured nanomaterials gained attention as alternatives because they can improve the existing single-component structure or add new functions to it. Among them, barcode nanowires (BNWs), comprising at least two different functional segments, can perform multiple functions for use in biomedical sensors, information encoding and security, and catalysts. BNW applications require reliable response to the external field. Hence, researchers have been attempting to improve the reliability of synthesis and regulate the properties precisely. This article highlights the recent progress and prospects for the synthesis, properties, and applications of metallic BNWs with focus on the dependence of the magnetic, optical, and mechanical properties on material, composition, shape, and microstructure.

Specific solvent effect on lumazine photophysics: A combined fluorescence and intrinsic reaction coordinate analysis

Energy Technology Data Exchange (ETDEWEB)

Moyon, N. Shaemningwar; Gashnga, Pynsakhiat Miki; Phukan, Smritakshi; Mitra, Sivaprasad, E-mail: smitra@nehu.ac.in

2013-06-27

Highlights: • Correlation of lumazine photophysics with multiparametric Kamlet–Taft equation. • Solvent basicity (β) contributes maximum towards the hydrogen bonding (HB) effect. • HB interaction occurs at N1 and N3 proton in S{sub 0} and S{sub 1} state, respectively. • IRC calculation for different tautomerization processes both in S{sub 0} and S{sub 1} states. • Process related to riboflavin biosynthesis is thermodynamically feasible. - Abstract: The photophysical properties and tautomerization behavior of neutral lumazine were studied by fluorescence spectroscopy and density functional theory calculation. A quantitative estimation of the contributions from different solvatochromic parameters, like solvent polarizibility (π{sup ∗}), hydrogen bond donation (α) and hydrogen bond accepting (β) ability of the solvent, was made using linear free energy relationships based on the Kamlet–Taft equation. The analysis reveals that the hydrogen bond acceptance ability of the solvent is the most important parameter characterizing the excited state behavior of lumazine. Theoretical calculations result predict an extensive charge redistribution of lumazine upon excitation corresponding to the N3 and N1 proton dissociation sites by solvents in the ground and excited states, respectively. Comparison of S{sub 0} and S{sub 1} state potential energy curves constructed for several water mediated tautomerization processes by intrinsic reaction coordinate analysis of lumazine-H{sub 2}O cluster shows that (3,2) and (1,8) hydrogen migrations are the most favorable processes upon excitation.

A study on the redox, spectroscopic, and photophysical characteristics of a series of octahedral hexamolybdenum(ii) clusters: [{Mo6X8}Y6]2- (X, Y = Cl, Br, or I).

Science.gov (United States)

Akagi, Soichiro; Fujii, Sho; Kitamura, Noboru

2018-01-23

We report a systematic study on the redox, spectroscopic, and photophysical properties of a series of [{Mo 6 X 8 }Y 6 ] 2- (X, Y = Cl, Br, or I. 1-9). All of the [{Mo 6 X 8 }Y 6 ] 2- clusters show intense and long-lived phosphorescence in both CH 3 CN and crystalline phases at 298 K. We found that the emission quantum yields (Φ em ) of 1-9 increase in the sequences X = Cl Br Br Br < Cl for given {Mo 6 X 8 } 4+ -core clusters. The present data demonstrate that arbitrary combinations of X and Y in [{Mo 6 X 8 }Y 6 ] 2- could tune τ em and Φ em in the ranges of 85-300 μs and 0.09-0.47, respectively. Both capping (X) and terminal ligand (Y) effects on the photophysical properties of the clusters are discussed on the basis of the energy gap (i.e., emission energy) dependence of the nonradiative decay rate constant.

Optical, photo-physical properties and photostability of pyrromethene (PM-597) in ionic liquids as benign green-solvents

International Nuclear Information System (INIS)

AL-Aqmar, Dalal M.; Abdelkader, H.I.; Abou Kana, Maram T.H.

2015-01-01

Laser dye pyrromethene-597 was dissolved with different concentrations in three types of ionic liquids (ILs): 1-Butyl-3-methylimidazolium chloride (BMIM Cl), 1-butyl-3-methylimidazolium tetrachloroaluminate (BMIM AlCl 4 ) and 1-butyl-3-methylimidazolium tetrafluoro-borate (BMIM BF 4 ) in addition to ethanol as reference solvent. This paper investigates optical spectra and some photo-physical parameters of PM-597 in BMIM Cl, BMIM AlCl 4 , BMIM BF 4 and ethanol. These parameters are absorption and emission cross sections, fluorescence lifetime and quantum yield. The amplified spontaneous emission (ASE) was studied using the second harmonic Nd-YAG laser of 532 nm. Also, the gain and energy conversion efficiencies were investigated. Relatively high efficiency was obtained with good photostability in case of PM-597 in BMIM BF 4 that was a decrease to ~90% of the initial amplified spontaneous emission. This output energy was observed after pumping by 75,000 shots at a relatively high repetition rate of 10 Hz and pumping energy of 37 mJ. The composition and properties of the matrix of ILs were found to lead to optimize the laser performance and photostability of the investigated laser dye. In this study, we considered ionic liquids as the environmentally benign green solvents in place of volatile toxic organic solvents. - Highlights: • Pyrromethen-597 as laser dye was dissolved in three types of ionic liquids (ILs): BMIM Cl, BMIM AlCl 4 and BMIM BF 4 as benign green-solvent in addition to ethanol as reference solvent. • Important spectroscopic properties of PM-597 dye such as quantum yield, fluorescence lifetime, radiative and nonradiative rate, transition dipole moment, attenuation length and oscillator strength were affected by changing the host material. • The dye laser gain, quantum yield, peak intensity of ASE and photostability were found to be better in BMIM BF 4 than in BMIM Cl and in ethanol. • ILs may be used as ideal hosts for dye laser systems to

Synthesis and properties of nickel cobalt boron nanoparticles

Science.gov (United States)

Patel, J.; Pankhurst, Q. A.; Parkin, I. P.

2005-01-01

Amorphous cobalt nickel boride nanoparticles were synthesised by chemical reduction synthesis in aqueous solution. Careful control of synthesis conditions and post reaction oxidation enabled the nanoparticles to be converted into a core-shell structure comprising of an amorphous Co-Ni-B core and an outer metal oxide sheet. These particles had interesting magnetic properties including saturation magnetisations and coercivities of the order of 80 emu/g and 170 Oe respectively, making them suitable for a potential use as an exchange-pinned magnetic material.

1,2,4-Triazines in the Synthesis of Bipyridine Bisphenolate ONNO Ligands and Their Highly Luminescent Tetradentate Pt(II) Complexes for Solution-Processable OLEDs.

Science.gov (United States)

Pander, Piotr; Bulmer, Rachel; Martinscroft, Ross; Thompson, Stuart; Lewis, Frank W; Penfold, Thomas J; Dias, Fernando B; Kozhevnikov, Valery N

2018-04-02

This article describes a convenient method for the synthesis of ONNO-type tetradentate 6,6'-bis(2-phenoxy)-2,2'-bipyridine (bipyridine bisphenolate, BpyBph) ligands and their platinum(II) complexes. The methodology includes the synthesis of 1,2,4-triazine precursors followed by their transformation to functionalized pyridines by the Boger reaction. Two complementary routes employing 3,3'- and 5,5'-bis-triazines allow a modification of the central pyridine rings in different positions, which was exemplified by the introduction of cyclopentene rings. The new ligands were used to prepare highly luminescent ONNO-type Pt(II) complexes. The position of the cyclopentene rings significantly influences the solubility and photophysical properties of these complexes. Derivatives with closely positioned cyclopentene rings are soluble in organic solvents and proved to be the best candidate for solution-processable organic light-emitting devices (OLEDs), showing efficient single-dopant candlelight electroluminescence.

Structural Ceramic Nanocomposites: A Review of Properties and Powders’ Synthesis Methods

Science.gov (United States)

Palmero, Paola

2015-01-01

Ceramic nanocomposites are attracting growing interest, thanks to new processing methods enabling these materials to go from the research laboratory scale to the commercial level. Today, many different types of nanocomposite structures are proposed in the literature; however, to fully exploit their exceptional properties, a deep understanding of the materials’ behavior across length scales is necessary. In fact, knowing how the nanoscale structure influences the bulk properties enables the design of increasingly performing composite materials. A further key point is the ability of tailoring the desired nanostructured features in the sintered composites, a challenging issue requiring a careful control of all stages of manufacturing, from powder synthesis to sintering. This review is divided into four parts. In the first, classification and general issues of nanostructured ceramics are reported. The second provides basic structure–property relations, highlighting the grain-size dependence of the materials properties. The third describes the role of nanocrystalline second-phases on the mechanical properties of ordinary grain sized ceramics. Finally, the fourth part revises the mainly used synthesis routes to produce nanocomposite ceramic powders, underlining when possible the critical role of the synthesis method on the control of microstructure and properties of the sintered ceramics. PMID:28347029

Chromophore photophysics and dynamics in fluorescent proteins of the GFP family

International Nuclear Information System (INIS)

Nienhaus, Karin; Nienhaus, G Ulrich

2016-01-01

Proteins of the green fluorescent protein (GFP) family are indispensable for fluorescence imaging experiments in the life sciences, particularly of living specimens. Their essential role as genetically encoded fluorescence markers has motivated many researchers over the last 20 years to further advance and optimize these proteins by using protein engineering. Amino acids can be exchanged by site-specific mutagenesis, starting with naturally occurring proteins as templates. Optical properties of the fluorescent chromophore are strongly tuned by the surrounding protein environment, and a targeted modification of chromophore-protein interactions requires a profound knowledge of the underlying photophysics and photochemistry, which has by now been well established from a large number of structural and spectroscopic experiments and molecular-mechanical and quantum-mechanical computations on many variants of fluorescent proteins. Nevertheless, such rational engineering often does not meet with success and thus is complemented by random mutagenesis and selection based on the optical properties. In this topical review, we present an overview of the key structural and spectroscopic properties of fluorescent proteins. We address protein-chromophore interactions that govern ground state optical properties as well as processes occurring in the electronically excited state. Special emphasis is placed on photoactivation of fluorescent proteins. These light-induced reactions result in large structural changes that drastically alter the fluorescence properties of the protein, which enables some of the most exciting applications, including single particle tracking, pulse chase imaging and super-resolution imaging. We also present a few examples of fluorescent protein application in live-cell imaging experiments. (topical review)

Chromophore photophysics and dynamics in fluorescent proteins of the GFP family

Science.gov (United States)

Nienhaus, Karin; Nienhaus, G. Ulrich

2016-11-01

Proteins of the green fluorescent protein (GFP) family are indispensable for fluorescence imaging experiments in the life sciences, particularly of living specimens. Their essential role as genetically encoded fluorescence markers has motivated many researchers over the last 20 years to further advance and optimize these proteins by using protein engineering. Amino acids can be exchanged by site-specific mutagenesis, starting with naturally occurring proteins as templates. Optical properties of the fluorescent chromophore are strongly tuned by the surrounding protein environment, and a targeted modification of chromophore-protein interactions requires a profound knowledge of the underlying photophysics and photochemistry, which has by now been well established from a large number of structural and spectroscopic experiments and molecular-mechanical and quantum-mechanical computations on many variants of fluorescent proteins. Nevertheless, such rational engineering often does not meet with success and thus is complemented by random mutagenesis and selection based on the optical properties. In this topical review, we present an overview of the key structural and spectroscopic properties of fluorescent proteins. We address protein-chromophore interactions that govern ground state optical properties as well as processes occurring in the electronically excited state. Special emphasis is placed on photoactivation of fluorescent proteins. These light-induced reactions result in large structural changes that drastically alter the fluorescence properties of the protein, which enables some of the most exciting applications, including single particle tracking, pulse chase imaging and super-resolution imaging. We also present a few examples of fluorescent protein application in live-cell imaging experiments.

Influence of the synthesis parameters on the physico-chemical and catalytic properties of cerium oxide for application in the synthesis of diethyl carbonate

International Nuclear Information System (INIS)

Leino, Ewelina; Kumar, Narendra; Mäki-Arvela, Päivi; Aho, Atte; Kordás, Krisztián; Leino, Anne-Riikka; Shchukarev, Andrey; Murzin, Dmitry Yu.; Mikkola, Jyri-Pekka

2013-01-01

Synthesis of cerium (IV) oxide by means of room temperature precipitation method was carried out. The effect of preparation variables such as synthesis time, calcination temperature and pH of the solution on resulting CeO 2 properties was discussed. Moreover, the comparison of CeO 2 samples prepared in a static and rotation mode of synthesis is presented. The solid catalysts were characterized by means of X-ray powder diffraction, scanning electron microscopy, transmission electron microscope, nitrogen physisorption, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy using pyridine as a probe molecule and temperature programmed desorption of CO 2 . Significant variations in physico-chemical properties of CeO 2 by varying the preparation conditions were observed. Furthermore, the catalytic performances of CeO 2 catalysts were compared in the synthesis of diethyl carbonate starting from ethanol and CO 2 using butylene oxide as a dehydrating agent. The dependence of CeO 2 properties on its catalytic activity is evaluated in detail. - Highlights: • Synthesis of cerium (IV) oxide by precipitation method. • Influence of synthesis time, calcination temperature, mode of stirring and solution pH on properties. • Characterization by XRD, SEM, TEM, nitrogen physisorption, XPS, FTIR. • Catalytic performance diethyl carbonate synthesis from ethanol and CO 2

Synthesis and spectral properties of Methyl-Phenyl pyrazoloquinoxaline fluorescence emitters: Experiment and DFT/TDDFT calculations

Science.gov (United States)

Gąsiorski, P.; Matusiewicz, M.; Gondek, E.; Uchacz, T.; Wojtasik, K.; Danel, A.; Shchur, Ya.; Kityk, A. V.

2018-01-01

Paper reports the synthesis and spectroscopic studies of two novel 1-Methyl-3-phenyl-1H-pyrazolo[3,4-b]quinoxaline (PQX) derivatives with 6-substituted methyl (MeMPPQX) or methoxy (MeOMPPQX) side groups. The optical absorption and fluorescence emission spectra are recorded in solvents of different polarity. Steady state and time-resolved spectroscopy provide photophysical characterization of MeMPPQX and MeOMPPQX dyes as materials for potential luminescence or electroluminescence applications. Measured optical absorption and fluorescence emission spectra are compared with quantum-chemical DFT/TDDFT calculations using long-range corrected xc-functionals, LRC-BLYP and CAM-B3LYP in combination with self-consistent reaction field model based on linear response (LR), state specific (SS) or corrected linear response (CLR) solvations. Performances of relevant theoretical models and approaches are compared. The reparameterized LRC-BLYP functional (ω = 0.231 Bohr-1) in combination with CLR solvation provides most accurate prediction of both excitation and emission energies. The MeMPPQX and MeOMPPQX dyes represent efficient fluorescence emitters in blue-green region of the visible spectra.

Statistical nuclear properties and synthesis of 138La

Directory of Open Access Journals (Sweden)

Kheswa B. V.

2015-01-01

Full Text Available The synthesis of the neutron deficient 138La nucleus has been a puzzle for a long time. It has not been clear whether it is produced through photodisintegration processes or neutrino induced reactions due to unavailability of experimental data for nuclear level densities and γ strength functions of 138,139La nuclei. In the present work these nuclear properties have been measured and are used to investigate the synthesis of 138La. The results support the neutrino interactions as a dominant production process for 138La.

Photo-physical and structural interactions between viologen phosphorus-based dendrimers and human serum albumin

International Nuclear Information System (INIS)

Ciepluch, Karol; Katir, Nadia; El Kadib, Abdelkrim; Weber, Monika; Caminade, Anne-Marie; Bousmina, Mostapha; Pierre Majoral, Jean; Bryszewska, Maria

2012-01-01

This work deals with photo-physical and structural interactions between viologen phosphorus dendrimers and human serum albumin (HSA). Viologens are derivatives of 4,4′-bipyridinium salts. Aiming to rationalize the parameters governing such interactions eight types of these polycationic dendrimers in which the generation, the number of charges, the nature of the core and of the terminal groups vary from one to another, were designed and used. The influence of viologen-based dendrimers' on human serum albumin has been investigated. The photo-physical interactions of the two systems have been monitored by fluorescence quenching of free L-tryptophan and of HSA tryptophan residue. Additionally, using circular dichroism (CD) the effect of dendrimers on the secondary structure of albumin was measured. The obtained results show that viologen dendrimers interact with human serum albumin quenching its fluorescence either by collisional (dynamic) way or by forming complexes in a ground state (static quenching). In some cases the quenching is accompanied by changes of the secondary structure of HSA. - Highlights: ► Photo-physical interactions between viologen phosphorus dendrimers and human serum albumin (HSA) were investigated. ► The viologen dendrimers can quench the fluorescence of tryptophan in HSA. ► CD spectra to explain the changes in secondary structure of albumin after exposition of dendrimers.

Synthesis, characterization and emission properties of quinolin-8 ...

Indian Academy of Sciences (India)

Unknown

chelated ruthenium organometallics. BIKASH KUMAR PANDA. Department of Inorganic ... Ruthenium organometallics; quinolin-8-olato chelation; emission properties; trivalent ruthenium. 1. Introduction. There is continuing ... chem.istry of orthometallated ruthenium compounds is of current interest in the context of synthesis ...

Modeling of alkynes: synthesis and theoretical properties

Directory of Open Access Journals (Sweden)

Renato Rosseto

2003-06-01

Full Text Available In this paper we present the synthesis and simulation of alkynes derivatives. Semiempirical calculations were carried out for the ground and first excited states, including the spectroscopic properties of the absorption and emission (fluorescence and phosphorescence spectra by INDO/S-CI and DNdM-INDO/S-CI methods with geometries fully optimized by PM3/CI. The fact that the theoretical spectra are in accord with the experimental absorption spectra gives us a new possible approach on how structure modifications could affect the non-linear optical properties of alkynes.

Synthesis and properties of heterocyclic type I photoinitiators

International Nuclear Information System (INIS)

Liska, R.; Knaus, S.; Wendrinsky, J.

1999-01-01

The synthesis and properties of a series of new heterocyclic hydroxyalkylphenone-analogous photoinitiators (PIs) is described. The PIs are obtained by reaction of aromatic organolithium compounds with nitriles or by Friedel-Craft's-acylation. Preliminary photocalorimetric tests and UV absorption data are included

Precipitation synthesis and magnetic properties of self-assembled magnetite-chitosan nanostructures

Energy Technology Data Exchange (ETDEWEB)

Bezdorozhev, Oleksii; Kolodiazhnyi, Taras; Vasylkiv, Oleg, E-mail: oleg.vasylkiv@nims.go.jp

2017-04-15

This paper reports the synthesis and magnetic properties of unique magnetite-chitosan nanostructures synthesized by the chemical precipitation of magnetite nanoparticles in the presence of chitosan. The influence of varying synthesis parameters on the morphology of the magnetic composites is determined. Depending on the synthesis parameters, magnetite-chitosan nanostructures of spherical (9–18 nm), rice-seed-like (75–290 nm) and lumpy (75–150 nm) shapes were obtained via self-assembly. Spherical nanostructures encapsulated by a 9–15 nm chitosan layer were assembled as well. The prospective morphology of the nanostructures is combined with their excellent magnetic characteristics. It was found that magnetite-chitosan nanostructures are ferromagnetic and pseudo-single domain. Rice-seed-like nanostructures exhibited a coercivity of 140 Oe and saturation magnetization of 56.7 emu/g at 300 K. However, a drop in the magnetic properties was observed for chitosan-coated spherical nanostructures due to the higher volume fraction of chitosan. - Highlights: • Magnetite-chitosan nanostructures are synthesized via self-assembly. • Different morphology can be obtained by adjusting the synthesis parameters. • An attractive combination of magnetic properties and morphology is obtained. • Magnetite-chitosan nanostructures are ferrimagnetic and pseudo-single domain.

Precipitation synthesis and magnetic properties of self-assembled magnetite-chitosan nanostructures

International Nuclear Information System (INIS)

Bezdorozhev, Oleksii; Kolodiazhnyi, Taras; Vasylkiv, Oleg

2017-01-01

This paper reports the synthesis and magnetic properties of unique magnetite-chitosan nanostructures synthesized by the chemical precipitation of magnetite nanoparticles in the presence of chitosan. The influence of varying synthesis parameters on the morphology of the magnetic composites is determined. Depending on the synthesis parameters, magnetite-chitosan nanostructures of spherical (9–18 nm), rice-seed-like (75–290 nm) and lumpy (75–150 nm) shapes were obtained via self-assembly. Spherical nanostructures encapsulated by a 9–15 nm chitosan layer were assembled as well. The prospective morphology of the nanostructures is combined with their excellent magnetic characteristics. It was found that magnetite-chitosan nanostructures are ferromagnetic and pseudo-single domain. Rice-seed-like nanostructures exhibited a coercivity of 140 Oe and saturation magnetization of 56.7 emu/g at 300 K. However, a drop in the magnetic properties was observed for chitosan-coated spherical nanostructures due to the higher volume fraction of chitosan. - Highlights: • Magnetite-chitosan nanostructures are synthesized via self-assembly. • Different morphology can be obtained by adjusting the synthesis parameters. • An attractive combination of magnetic properties and morphology is obtained. • Magnetite-chitosan nanostructures are ferrimagnetic and pseudo-single domain.

Two-dimensional tantalum disulfide: controlling structure and properties via synthesis

Science.gov (United States)

Zhao, Rui; Grisafe, Benjamin; Krishna Ghosh, Ram; Holoviak, Stephen; Wang, Baoming; Wang, Ke; Briggs, Natalie; Haque, Aman; Datta, Suman; Robinson, Joshua

2018-04-01

Tantalum disulfide (TaS2) is a transition metal dichalcogenide (TMD) that exhibits phase transition induced electronic property modulation at low temperature. However, the appropriate phase must be grown to enable the semiconductor/metal transition that is of interest for next generation electronic applications. In this work, we demonstrate direct and controllable synthesis of ultra-thin 1T-TaS2 and 2H-TaS2 on a variety of substrates (sapphire, SiO2/Si, and graphene) via powder vapor deposition. The synthesis process leads to single crystal domains ranging from 20 to 200 nm thick and 1-10 µm on a side. The TaS2 phase (1T or 2H) is controlled by synthesis temperature, which subsequently is shown to control the electronic properties. Furthermore, this work constitutes the first demonstration of a metal-insulator phase transition in directly synthesized 1T-TaS2 films and domains by electronic means.

Inorganic-whisker-reinforced polymer composites synthesis, properties and applications

CERN Document Server

Sun, Qiuju

2015-01-01

Inorganic-Whisker-Reinforced Polymer Composites: Synthesis, Properties and Applications gives a comprehensive presentation of inorganic microcrystalline fibers, or whiskers, a polymer composite filler. It covers whisker synthesis, surface modification, applications for reinforcing polymer-matrix composites, and analysis of resulting filled polymer composites. It focuses on calcium carbonate whiskers as a primary case study, introducing surface treatment methods for calcium carbonate whiskers and factors that influence them. Along with calcium carbonate, the book discusses potassium titanate and aluminum borate whiskers, which also comprise the new generation of inorganic whiskers. According to research results, composites filled by inorganic whiskers show improved strength, wear-resistance, thermal conductivity, and antistatic properties. It explains the importance of modifying polymer materials for use with inorganic whiskers and describes preparation and evaluation methods of polymers filled with inorganic ...

Spectroscopy and photophysics of flavin related compounds: Riboflavin and iso-(6,7)-riboflavin

International Nuclear Information System (INIS)

Sikorska, Ewa; Khmelinskii, Igor; Komasa, Anna; Koput, Jacek; Ferreira, Luis F.V.; Herance, Jose R.; Bourdelande, Jose L.; Williams, Sian L.; Worrall, David R.; Insinska-Rak, MaIgorzata; Sikorski, Marek

2005-01-01

The photochemistry and photophysics of isoalloxazines (10-substituted 2,3,4,10-tetrahydro-benzo[g]pteridine-2,4-diones), and especially flavins (7,8-dimethyl substituted isoalloxazines), are of considerable interest due to the biological relevance of these compounds. In this paper we report data concerning the photophysics of riboflavin and iso-(6,7)-riboflavin (10-(2,3,4,5-tetrahydroxypentyl)-6,7-dimethylbenzo[g]pteridine-2,4(3H,10H) -dione), and correlate the spectroscopic observations with theoretical calculations performed using time-dependent density functional theory. On the basis of these calculations the lowest excited singlet and triplet states are both assigned (π,π*) symmetry, and this result is used to explain the relatively low singlet oxygen quantum yields in comparison with alloxazines. Time-resolved emission studies have indicated 6,7-dimethylalloxazine a photodegradation product of iso-(6,7)-riboflavin

Synthesis and properties of porous zeolite aluminosilicate adsorbents

International Nuclear Information System (INIS)

Shilina, A.S.; Milinchuk, V.K.; Burukhin, S.B.; Gordienko, A.B.

2015-01-01

Environmentally safe non-energy-intensive methods of the synthesis have been developed and the properties of solid inorganic nanostructured zeolite-like adsorbents of a broad spectrum have been studied. The sorption capacities of the adsorbents with respect to various components of water pollution have been determined [ru

Phosphorene – The two-dimensional black phosphorous: Properties, synthesis and applications

International Nuclear Information System (INIS)

Khandelwal, Apratim; Mani, Karthick; Karigerasi, Manohar Harsha; Lahiri, Indranil

2017-01-01

Highlights: • Reviews recent progress in phosphorene research, a new 2D material. • Anisotropic properties are reviewed and compared with other 2D materials. • Synthesis methods of black phosphorus and phosphorene are discussed. • Prospective applications inspired from the intrinsic properties are also discussed. • Challenges and future scope for this promising material is included. - Abstract: Black phosphorus (BP) is known to human beings for almost a century. It started receiving more attention of scientists and researchers worldwide in last three years, with its ability to exist in two-dimensional (2D) form, popularly known as phosphorene. In the post-graphene-discovery period, phosphorene is probably receiving most attention, owing to its excellent properties and hence, high potential for practical applications in the field of electronics, energy and infrastructure. In this article, attractive properties of phosphorene, which makes it unique and comparable with graphene or transition metal dichalcogenides (TMDs), are highlighted. As the question of its environmental instability remains critical, a comprehensive overview of synthesis methods of phosphorene and black phosphorus are presented, to inspire in-situ methods of phosphorene synthesis and fabrication towards improving further investigation into this wonder material. In addition, the article also focuses on opportunities in nano-electronics, optoelectronics, energy conversion/storage, sensors etc arising from phosphorene’s remarkable properties.

Phosphorene – The two-dimensional black phosphorous: Properties, synthesis and applications

Energy Technology Data Exchange (ETDEWEB)

Khandelwal, Apratim; Mani, Karthick; Karigerasi, Manohar Harsha; Lahiri, Indranil, E-mail: indrafmt@iitr.ac.in

2017-07-15

Highlights: • Reviews recent progress in phosphorene research, a new 2D material. • Anisotropic properties are reviewed and compared with other 2D materials. • Synthesis methods of black phosphorus and phosphorene are discussed. • Prospective applications inspired from the intrinsic properties are also discussed. • Challenges and future scope for this promising material is included. - Abstract: Black phosphorus (BP) is known to human beings for almost a century. It started receiving more attention of scientists and researchers worldwide in last three years, with its ability to exist in two-dimensional (2D) form, popularly known as phosphorene. In the post-graphene-discovery period, phosphorene is probably receiving most attention, owing to its excellent properties and hence, high potential for practical applications in the field of electronics, energy and infrastructure. In this article, attractive properties of phosphorene, which makes it unique and comparable with graphene or transition metal dichalcogenides (TMDs), are highlighted. As the question of its environmental instability remains critical, a comprehensive overview of synthesis methods of phosphorene and black phosphorus are presented, to inspire in-situ methods of phosphorene synthesis and fabrication towards improving further investigation into this wonder material. In addition, the article also focuses on opportunities in nano-electronics, optoelectronics, energy conversion/storage, sensors etc arising from phosphorene’s remarkable properties.

Photo-physical and structural interactions between viologen phosphorus-based dendrimers and human serum albumin

Energy Technology Data Exchange (ETDEWEB)

Ciepluch, Karol, E-mail: ciepluch@biol.uni.lodz.pl [Department of General Biophysics, University of Lodz, 141/143 Pomorska St., 90-236 Lodz (Poland); Katir, Nadia [Laboratoire de Chimie de Coordination du CNRS (LCC), 205 route de Narbonne, F-31077 Toulouse cedex 4 (France); Institute of Nanomaterials and Nanotechnology (INANOTECH)-MAScIR (Moroccan Foundation for Advanced Science, Innovation and Research), ENSET, Avenue de l' Armee Royale, Madinat El Irfane, 10100 Rabat (Morocco); El Kadib, Abdelkrim [Institute of Nanomaterials and Nanotechnology (INANOTECH)-MAScIR (Moroccan Foundation for Advanced Science, Innovation and Research), ENSET, Avenue de l' Armee Royale, Madinat El Irfane, 10100 Rabat (Morocco); Weber, Monika [Department of General Biophysics, University of Lodz, 141/143 Pomorska St., 90-236 Lodz (Poland); Caminade, Anne-Marie [Laboratoire de Chimie de Coordination du CNRS (LCC), 205 route de Narbonne, F-31077 Toulouse cedex 4 (France); Bousmina, Mostapha [Hassan II Academy of Sciences and Technology, Avenue MVI, Km4, 10220 Rabat (Morocco); Pierre Majoral, Jean [Laboratoire de Chimie de Coordination du CNRS (LCC), 205 route de Narbonne, F-31077 Toulouse cedex 4 (France); Hassan II Academy of Sciences and Technology, Avenue MVI, Km4, 10220 Rabat (Morocco); Bryszewska, Maria [Department of General Biophysics, University of Lodz, 141/143 Pomorska St., 90-236 Lodz (Poland)

2012-06-15

This work deals with photo-physical and structural interactions between viologen phosphorus dendrimers and human serum albumin (HSA). Viologens are derivatives of 4,4 Prime -bipyridinium salts. Aiming to rationalize the parameters governing such interactions eight types of these polycationic dendrimers in which the generation, the number of charges, the nature of the core and of the terminal groups vary from one to another, were designed and used. The influence of viologen-based dendrimers' on human serum albumin has been investigated. The photo-physical interactions of the two systems have been monitored by fluorescence quenching of free L-tryptophan and of HSA tryptophan residue. Additionally, using circular dichroism (CD) the effect of dendrimers on the secondary structure of albumin was measured. The obtained results show that viologen dendrimers interact with human serum albumin quenching its fluorescence either by collisional (dynamic) way or by forming complexes in a ground state (static quenching). In some cases the quenching is accompanied by changes of the secondary structure of HSA. - Highlights: Black-Right-Pointing-Pointer Photo-physical interactions between viologen phosphorus dendrimers and human serum albumin (HSA) were investigated. Black-Right-Pointing-Pointer The viologen dendrimers can quench the fluorescence of tryptophan in HSA. Black-Right-Pointing-Pointer CD spectra to explain the changes in secondary structure of albumin after exposition of dendrimers.

Optical, photo-physical properties and photostability of pyrromethene (PM-597) in ionic liquids as benign green-solvents

Energy Technology Data Exchange (ETDEWEB)

AL-Aqmar, Dalal M. [Physics Department, Ibb University, Ibb (Yemen); Physics Department, Faculty of Science, Mansoura University, Mansoura (Egypt); Abdelkader, H.I. [Physics Department, Faculty of Science, Mansoura University, Mansoura (Egypt); Abou Kana, Maram T.H., E-mail: mabou202@niles.edu.eg [National Institute of Laser Enhanced Sciences, Cairo University, Giza (Egypt)

2015-05-15

Laser dye pyrromethene-597 was dissolved with different concentrations in three types of ionic liquids (ILs): 1-Butyl-3-methylimidazolium chloride (BMIM Cl), 1-butyl-3-methylimidazolium tetrachloroaluminate (BMIM AlCl{sub 4}) and 1-butyl-3-methylimidazolium tetrafluoro-borate (BMIM BF{sub 4}) in addition to ethanol as reference solvent. This paper investigates optical spectra and some photo-physical parameters of PM-597 in BMIM Cl, BMIM AlCl{sub 4}, BMIM BF{sub 4} and ethanol. These parameters are absorption and emission cross sections, fluorescence lifetime and quantum yield. The amplified spontaneous emission (ASE) was studied using the second harmonic Nd-YAG laser of 532 nm. Also, the gain and energy conversion efficiencies were investigated. Relatively high efficiency was obtained with good photostability in case of PM-597 in BMIM BF{sub 4} that was a decrease to ~90% of the initial amplified spontaneous emission. This output energy was observed after pumping by 75,000 shots at a relatively high repetition rate of 10 Hz and pumping energy of 37 mJ. The composition and properties of the matrix of ILs were found to lead to optimize the laser performance and photostability of the investigated laser dye. In this study, we considered ionic liquids as the environmentally benign green solvents in place of volatile toxic organic solvents. - Highlights: • Pyrromethen-597 as laser dye was dissolved in three types of ionic liquids (ILs): BMIM Cl, BMIM AlCl{sub 4} and BMIM BF{sub 4} as benign green-solvent in addition to ethanol as reference solvent. • Important spectroscopic properties of PM-597 dye such as quantum yield, fluorescence lifetime, radiative and nonradiative rate, transition dipole moment, attenuation length and oscillator strength were affected by changing the host material. • The dye laser gain, quantum yield, peak intensity of ASE and photostability were found to be better in BMIM BF{sub 4} than in BMIM Cl and in ethanol. • ILs may be used as ideal

Synthesis, Structure and Fluorescence Properties of 5,17-Distyryl-25,26,27,28-tetraproproxycalix[4]arenes in the Cone Conformation

DEFF Research Database (Denmark)

Larsen, Mogens; Krebs, Frederik C; Jørgensen, Mikkel

1998-01-01

The HWE (Horner-Wadsworth-Emmons) reaction performed on the easily obtainable 5,17-diformyl- calix[4]arenes (cone) with arylmethyl phosphorus ylides yielded 5,17-distyryl-25,26,27, 28-tetrapropoxycalix[4]arenes (cone) in high yield and purely in the E/E configuration. Compounds 2-5 were prepared...... this way containing bromine. Subsequent bromine-lithium exchange and reaction with trimethoxyborane yielded the boryl- substituted 5,17-distyrylcalix[4] arenes 6-7a. The structures of 3, 5, and 7a were determined by X-ray diffraction. The photophysical properties of 2 were established by absorption...

Hybrid nanostructures: synthesis, morphology and functional properties

International Nuclear Information System (INIS)

Povolotskaya, A V; Povolotskiy, A V; Manshina, A A

2015-01-01

Hybrid nanostructures representing combinations of different materials and possessing properties that are absent in separate components forming the hybrid are discussed. Particular attention is given to hybrid structures containing plasmonic and magnetic nanoparticles, methods of their synthesis and the relationship between the composition, structure and properties. The functional features of the hybrid nanomaterials of various morphology (with core–shell structures, with encapsulated metal nanoparticles and with metal nanoparticles on the surface) are considered. The unique properties of these hybrid materials are demonstrated, which are of interest for solving problems of catalysis and photocatalysis, detecting impurities in various media, in vivo visualization, bioanalysis, as well as for the design of optical labels and multifunctional diagnostic nanoplatforms. The bibliography includes 182 references

Barium hexaferrite nanoparticles: Synthesis and magnetic properties

International Nuclear Information System (INIS)

Martirosyan, K.S.; Galstyan, E.; Hossain, S.M.; Wang Yiju; Litvinov, D.

2011-01-01

Carbon combustion synthesis is applied to rapid and energy efficient fabrication of crystalline barium hexaferrite nanoparticles with the average particle size of 50-100 nm. In this method, the exothermic oxidation of carbon nanoparticles with an average size of 5 nm with a surface area of 80 m 2 /g generates a self-propagating thermal wave with maximum temperatures of up to 1000 deg. C. The thermal front rapidly propagates through the mixture of solid reactants converting it to the hexagonal barium ferrite. Carbon is not incorporated in the product and is emitted from the reaction zone as a gaseous CO 2 . The activation energy for carbon combustion synthesis of BaFe 12 O 19 was estimated to be 98 kJ/mol. A complete conversion to hexagonal barium ferrite is obtained for carbon concentration exceeding 11 wt.%. The magnetic properties H c ∼3000 Oe and M s ∼50.3 emu/g of the compact sintered ferrites compare well with those produced by other synthesis methods.

Generalized colloidal synthesis of high-quality, two-dimensional cesium lead halide perovskite nanosheets and their applications in photodetectors

Science.gov (United States)

Lv, Longfei; Xu, Yibing; Fang, Hehai; Luo, Wenjin; Xu, Fangjie; Liu, Limin; Wang, Biwei; Zhang, Xianfeng; Yang, Dong; Hu, Weida; Dong, Angang

2016-07-01

All-inorganic cesium lead halide perovskite (CsPbX3, X = Cl, Br, and I) nanocrystals (NCs) are emerging as an important class of semiconductor materials with superior photophysical properties and wide potential applications in optoelectronic devices. So far, only a few studies have been conducted to control the shape and geometry of CsPbX3 NCs. Here we report a general approach to directly synthesize two-dimensional (2D) CsPbX3 perovskite and mixed perovskite nanosheets with uniform and ultrathin thicknesses down to a few monolayers. The key to the high-yield synthesis of perovskite nanosheets is the development of a new Cs-oleate precursor. The as-synthesized CsPbX3 nanosheets exhibit bright photoluminescence with broad wavelength tunability by composition modulation. The excellent optoelectronic properties of CsPbX3 nanosheets combined with their unique 2D geometry and large lateral dimensions make them ideal building blocks for building functional devices. To demonstrate their potential applications in optoelectronics, photodetectors based on CsPbBr3 nanosheets are fabricated, which exhibit high on/off ratios with a fast response time.All-inorganic cesium lead halide perovskite (CsPbX3, X = Cl, Br, and I) nanocrystals (NCs) are emerging as an important class of semiconductor materials with superior photophysical properties and wide potential applications in optoelectronic devices. So far, only a few studies have been conducted to control the shape and geometry of CsPbX3 NCs. Here we report a general approach to directly synthesize two-dimensional (2D) CsPbX3 perovskite and mixed perovskite nanosheets with uniform and ultrathin thicknesses down to a few monolayers. The key to the high-yield synthesis of perovskite nanosheets is the development of a new Cs-oleate precursor. The as-synthesized CsPbX3 nanosheets exhibit bright photoluminescence with broad wavelength tunability by composition modulation. The excellent optoelectronic properties of CsPbX3 nanosheets

Synthesis, spectral and third-order nonlinear optical properties of terpyridine Zn(II) complexes based on carbazole derivative with polyether group

Science.gov (United States)

Kong, Ming; Liu, Yanqiu; Wang, Hui; Luo, Junshan; Li, Dandan; Zhang, Shengyi; Li, Shengli; Wu, Jieying; Tian, Yupeng

2015-01-01

Four novel Zn(II) terpyridine complexes (ZnLCl2, ZnLBr2, ZnLI2, ZnL(SCN)2) based on carbazole derivative group were designed, synthesized and fully characterized. Their photophysical properties including absorption and one-photon excited fluorescence, two-photon absorption (TPA) and optical power limiting (OPL) were further investigated systematically and interpreted on the basis of theoretical calculations (TD-DFT). The influences of different solvents on the absorption and One-Photon Excited Fluorescence (OPEF) spectral behavior, quantum yields and the lifetime of the chromophores have been investigated in detail. The third-order nonlinear optical (NLO) properties were investigated by open/closed aperture Z-scan measurements using femtosecond pulse laser in the range from 680 to 1080 nm. These results revealed that ZnLCl2 and ZnLBr2 exhibited strong two-photon absorption and ZnLCl2 showed superior optical power limiting property.

Intramolecular didehydro-Diels-Alder reaction and its impact on the structure-function properties of environmentally sensitive fluorophores.

Science.gov (United States)

Brummond, Kay M; Kocsis, Laura S

2015-08-18

Reaction discovery plays a vital role in accessing new chemical entities and materials possessing important function.1 In this Account, we delineate our reaction discovery program regarding the [4 + 2] cycloaddition reaction of styrene-ynes. In particular, we highlight our studies that lead to the realization of the diverging reaction mechanisms of the intramolecular didehydro-Diels-Alder (IMDDA) reaction to afford dihydronaphthalene and naphthalene products. Formation of the former involves an intermolecular hydrogen atom abstraction and isomerization, whereas the latter is formed via an unexpected elimination of H2. Forming aromatic compounds by a unimolecular elimination of H2 offers an environmentally benign alternative to typical oxidation protocols. We also include in this Account ongoing work focused on expanding the scope of this reaction, mainly its application to the preparation of cyclopenta[b]naphthalenes. Finally, we showcase the synthetic utility of the IMDDA reaction by preparing novel environmentally sensitive fluorophores. The choice to follow this path was largely influenced by the impact this reaction could have on our understanding of the structure-function relationships of these molecular sensors by taking advantage of a de novo construction and functionalization of the aromatic portion of these compounds. We were also inspired by the fact that, despite the advances that have been made in the construction of small molecule fluorophores, access to rationally designed fluorescent probes or sensors possessing varied and tuned photophysical, spectral, and chemical properties are still needed. To this end, we report our studies to correlate fluorophore structure with photophysical property relationships for a series of solvatochromic PRODAN analogs and viscosity-sensitive cyanoacrylate analogs. The versatility of this de novo strategy for fluorophore synthesis was demonstrated by showing that a number of functional groups could be installed at

A class of fluorescent heterocyclic dyes revisited: photophysics, structure, and solvent effects

DEFF Research Database (Denmark)

Zhu, Lianjie; Jensen, Hans-Christian Becker; Henriksen, Lars

2009-01-01

The photophysical behavior of a series of 2-methylthio-5-(Z-carbonyl)thieno-[3,4-e]-3,4-dihydro-1,2,3-triazine-4-ones was investigated by absorption and emission spectroscopy in a range of solvents representing a systematic variation in polarity, polarizability, as well as hydrogen bond donating ...

Photophysical investigation of cyano-substituted terrylenediimide derivatives.

Science.gov (United States)

Kennes, Koen; Baeten, Yannick; Vosch, Tom; Sempels, Wouter; Yordanov, Stoyan; Stappert, Sebastian; Chen, Long; Müllen, Klaus; Hofkens, Johan; Van der Auweraer, Mark; Fron, Eduard

2014-12-18

Two new terrylenediimide (TDI) chromophores with cyano substituents in the bay and core area (BCN-TDI and OCN-TDI, respectively) have been characterized by a wide range of techniques, and their applicability for stimulated emission depletion (STED) microscopy has been tested. By cyano substitution an increase of the fluorescence quantum yield and a decrease of the nonradiative rate constant is achieved and attributed to a reduced charge-transfer character of the excited state due to a lower electron density of the TDI core. For BCN-TDI, the substitution in the bay area induces a strong torsional twist in the molecule which, similar to phenoxy bay-perylenediimide (PDI), has a strong effect on the fluorescence lifetime but appears to prevent the aggregation that is observed for OCN-TDI. The single-molecule photobleaching stability of BCN- and OCN-TDI is lower than that of a reference TDI without cyano substitution (C7-TDI), although less so for OCN-TDI. The photophysical properties of the excited singlet state are only slightly influenced by the cyano groups. The observed intense stimulated emission, the pump-dump-probe experiments, and STED single-molecule imaging indicate that STED experiments with the cyano-substituted TDIs are possible. However, because of aggregation and more efficient photobleaching, the performance of BCN- and OCN-TDI is worse than that of the reference compound without cyano groups (C7-TDI). Bay-substituted TDIs are less suitable for STED microscopy.

Photophysical Properties of Novel Organic, Inorganic, and Hybrid Semiconductor Materials

Science.gov (United States)

Chang, Angela Yenchi

For the past 200 years, novel materials have driven technological progress, and going forward these advanced materials will continue to deeply impact virtually all major industrial sectors. Therefore, it is vital to perform basic and applied research on novel materials in order to develop new technologies for the future. This dissertation describes the results of photophysical studies on three novel materials with electronic and optoelectronic applications, namely organic small molecules DTDCTB with C60 and C70, colloidal indium antimonide (InSb) nanocrystals, and an organic-inorganic hybrid perovskite with the composition CH3NH3PbI 3-xClx, using transient absorption (TA) and photoluminescence (PL) spectroscopy. In chapter 2, we characterize the timescale and efficiency of charge separation and recombination in thin film blends comprising DTDCTB, a narrow-band gap electron donor, and either C60 or C70 as an electron acceptor. TA and time-resolved PL studies show correlated, sub-picosecond charge separation times and multiple timescales of charge recombination. Our results indicate that some donors fail to charge separate in donor-acceptor mixed films, which suggests material manipulations may improve device efficiency. Chapter 3 describes electron-hole pair dynamics in strongly quantum-confined, colloidal InSb nanocrystal quantum dots. For all samples, TA shows a bleach feature that, for several picoseconds, dramatically red-shifts prior to reaching a time-independent position. We suggest this unusual red-shift relates transient population flow through two energetically comparable conduction band states. From pump-power-dependent measurements, we also determine biexciton lifetimes. In chapter 4, we examine carrier dynamics in polycrystalline methylammonium lead mixed halide perovskite (CH3NH3PbI3-xCl x) thin films as functions of temperature and photoexcitation wavelength. At room temperature, the long-lived TA signals stand in contrast to PL dynamics, where the

Graphene-Reinforced Aluminum Matrix Composites: A Review of Synthesis Methods and Properties

Science.gov (United States)

Chen, Fei; Gupta, Nikhil; Behera, Rakesh K.; Rohatgi, Pradeep K.

2018-03-01

Graphene-reinforced aluminum (Gr-Al) matrix nanocomposites (NCs) have attracted strong interest from both research and industry in high-performance weight-sensitive applications. Due to the vastly different bonding characteristics of the Al matrix (metallic) and graphene (in-plane covalent + inter-plane van der Waals), the graphene phase has a general tendency to agglomerate and phase separate in the metal matrix, which is detrimental for the mechanical and chemical properties of the composite. Thus, synthesis of Gr-Al NCs is extremely challenging. This review summarizes the different methods available to synthesize Gr-Al NCs and the resulting properties achieved in these NCs. Understanding the effect of processing parameters on the realized properties opens up the possibility of tailoring the synthesis methods to achieve the desired properties for a given application.

Graphene-Reinforced Aluminum Matrix Composites: A Review of Synthesis Methods and Properties

Science.gov (United States)

Chen, Fei; Gupta, Nikhil; Behera, Rakesh K.; Rohatgi, Pradeep K.

2018-06-01

Graphene-reinforced aluminum (Gr-Al) matrix nanocomposites (NCs) have attracted strong interest from both research and industry in high-performance weight-sensitive applications. Due to the vastly different bonding characteristics of the Al matrix (metallic) and graphene (in-plane covalent + inter-plane van der Waals), the graphene phase has a general tendency to agglomerate and phase separate in the metal matrix, which is detrimental for the mechanical and chemical properties of the composite. Thus, synthesis of Gr-Al NCs is extremely challenging. This review summarizes the different methods available to synthesize Gr-Al NCs and the resulting properties achieved in these NCs. Understanding the effect of processing parameters on the realized properties opens up the possibility of tailoring the synthesis methods to achieve the desired properties for a given application.

Pathways and Mechanisms Underlying the Photophysics and Photochemistry of Riboflavin induced cornea crosslinking

DEFF Research Database (Denmark)

Breitenbach, Thomas; Ogilby, Peter Remsen

In this talk, we will describe general pathways involved in the photophysics of a photosensitized process, which can lead to crosslinking due to light excitation of Riboflavin in the cornea. Furthermore, we will elucidate different aspects of reactions that can produce crosslinks, with respect...

Open-chain poly(organophosphazenes). Synthesis and properties

International Nuclear Information System (INIS)

Vinogradova, Svetlana V; Tur, Dzidra R; Vasnev, Valery A

1998-01-01

Various methods for the synthesis of open-chain poly(organophosphazenes) are considered. The mechanism of polymerisation of hexachlorocyclotriphosphazene and the basic principles of formation of poly(organophosphazene) macromolecules by polymeranalogous reactions of poly(dichloro-phosphazene) with various nucleophilic reagents are analysed from a new viewpoint. The potential of this synthetic method for targeted design of poly(organophosphazenes) of various structures is shown. The possibility of synthesising poly(organophosphazenes) by polymerisation of cyclophosphazenes is also discussed. The problem of unit non-uniformity of poly(organophosphazenes) and its influence on the properties of these polymers are considered. The properties of poly(organophosphazenes) are considered in detail and it is shown that these polymers possess unusual valuable properties, which provide opportunities for their successful practical application. The bibliography includes 276 references.

Microwave-assisted synthesis and antioxidant properties of hydrazinyl thiazolyl coumarin derivatives

Directory of Open Access Journals (Sweden)

Osman Hasnah

2012-04-01

Full Text Available Abstract Background Coumarin derivatives exhibit a wide range of biological properties including promising antioxidant activity. Furthermore, microwave-assisted organic synthesis has delivered rapid routes to N- and O-containing heterocycles, including coumarins and thiazoles. Combining these features, the use of microwave-assisted processes will provide rapid access to a targeted coumarin library bearing a hydrazino pharmacophore for evaluation of antioxidant properties Results Microwave irradiation promoted 3 of the 4 steps in a rapid, convergent synthesis of a small library of hydrazinyl thiazolyl coumarin derivatives, all of which exhibited significant antioxidant activity comparable to that of the natural antioxidant quercetin, as established by DPPH and ABTS radical assays Conclusions Microwave dielectric heating provides a rapid and expedient route to a series of hydrazinyl thiazolyl coumarins to investigate their radical scavenging properties. Given their favourable properties, in comparison with known antioxidants, these coumarin derivatives are promising leads for further development and optimization.

A new photoactive Ru(II)tris(2,2'-bipyridine) templated Zn(II) benzene-1,4-dicarboxylate metal organic framework: structure and photophysical properties.

Science.gov (United States)

Whittington, Christi L; Wojtas, Lukasz; Gao, Wen-Yang; Ma, Shengqian; Larsen, Randy W

2015-03-28

It has now been demonstrated that Ru(ii)tris(2,2'-bipyridine) (RuBpy) can be utilized to template the formation of new metal organic framework (MOF) materials containing crystallographically resolved RuBpy clusters with unique photophysical properties. Two such materials, RWLC-1 and RWLC-2, have now been reported from our laboratory and are composed of RuBpy encapsulated in MOFs composed of Zn(ii) ions and 1,3,5-tris(4-carboxyphenyl)benzene ligands (C. L. Whittington, L. Wojtas and R. W. Larsen, Inorg. Chem., 2014, 53, 160-166). Here, a third RuBpy templated photoactive MOF is described (RWLC-3) that is derived from the reaction between Zn(ii) ions and 1,4-dicarboxybenzene in the presence of RuBpy. Single Crystal X-ray diffraction studies determined the position of RuBpy cations within the crystal lattice. The RWLC-3 structure is described as a 2-fold interpenetrated pillared honeycomb network (bnb) containing crystallographically resolved RuBpy clusters. The two bnb networks are weakly interconnected. The encapsulated RuBpy exhibits two emission decay lifetimes (τ-fast = 120 ns, τ-slow = 453 ns) and a bathochromic shift in the steady state emission spectrum relative to RuBpy in ethanol.

Synthesis and magnetic properties of Zn Spinel ceramics

Czech Academy of Sciences Publication Activity Database

Huber, Š.; Sofer, Z.; Nádherný, L.; Jankovský, O.; Šimek, P.; Sedmidubský, D.; Maryško, Miroslav

2013-01-01

Roč. 57, č. 2 (2013), s. 162-166 ISSN 0862-5468 R&D Projects: GA ČR GA13-17538S; GA MŠk(CZ) 7AMB12FR019 Institutional support: RVO:68378271 Keywords : Zn spinel * synthesis * magnetic properties * antiferromagnet * bulk ZnO Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.434, year: 2013

Synthesis, Characterization and Photophysical Properties of Pyridine-Carbazole Acrylonitrile Derivatives

Science.gov (United States)

Pérez-Gutiérrez, Enrique; Percino, M. Judith; Chapela, Víctor M.; Cerón, Margarita; Maldonado, José Luis; Ramos-Ortiz, Gabriel

2011-01-01

We synthesized three novel highly fluorescent compounds, 2-(2’-pyridyl)-3-(N-ethyl-(3’-carbazolyl))acrylonitrile, 2-(3”-pyridyl)-3-(N-ethyl-(3’-carbazolyl))acrylonitrile, and 2-(4-pyridyl)-3-(N-ethyl-(3’-carbazolyl))acrylonitrile by Knoevenagel condensation. The first two were synthesized without solvent in the presence of piperidine as a catalyst; the third was synthesized without a catalyst and with N,N-dimethylformamide as a solvent. In solution, the molar absorption coefficients showed absorptions at 380, 378, and 396 nm, respectively; in solid state, absorptions were at 398, 390, and 442 nm, respectively. The fluorescence emission was at 540, 540 and 604 nm, respectively, the 2-(4-pyridyl)-3-(N-ethyl-(3’-carbazolyl))acrylonitrile showed a red shift in the emission of 64 nm compared to the other two compounds. The fluorescence quantum yield for the compounds in powder form showed values of 0.05, 0.14, and 0.006, respectively; compared with the value measured for the Alq3 reference, 2-(3”-pyridyl)-3-(N-ethyl-(3’-carbazolyl))acrylonitrile had a lightly higher value. The third harmonic generation measurement for 2-(2’-pyridyl)-3-(N-ethyl-(3’-carbazolyl))acrylonitrile yielded a χ(3) value of 5.5 × 10−12 esu, similar to that reported for commercial polymers. PMID:28880006

Synthesis, Characterization and Photophysical Properties of Pyridine-Carbazole Acrylonitrile Derivatives

Directory of Open Access Journals (Sweden)

Gabriel Ramos-Ortiz

2011-03-01

Full Text Available We synthesized three novel highly fluorescent compounds, 2-(2’-pyridyl-3-(N-ethyl-(3’-carbazolylacrylonitrile, 2-(3”-pyridyl-3-(N-ethyl-(3’-carbazolylacrylonitrile, and 2-(4-pyridyl-3-(N-ethyl-(3’-carbazolylacrylonitrile by Knoevenagel condensation. The first two were synthesized without solvent in the presence of piperidine as a catalyst; the third was synthesized without a catalyst and with N,N-dimethylformamide as a solvent. In solution, the molar absorption coefficients showed absorptions at 380, 378, and 396 nm, respectively; in solid state, absorptions were at 398, 390, and 442 nm, respectively. The fluorescence emission was at 540, 540 and 604 nm, respectively, the 2-(4-pyridyl-3-(N-ethyl-(3’-carbazolylacrylonitrile showed a red shift in the emission of 64 nm compared to the other two compounds. The fluorescence quantum yield for the compounds in powder form showed values of 0.05, 0.14, and 0.006, respectively; compared with the value measured for the Alq3 reference, 2-(3”-pyridyl-3-(N-ethyl-(3’-carbazolylacrylonitrile had a lightly higher value. The third harmonic generation measurement for 2-(2’-pyridyl-3-(N-ethyl-(3’-carbazolylacrylonitrile yielded a χ(3 value of 5.5 × 10−12 esu, similar to that reported for commercial polymers.

In vivo photoacoustic tumor tomography using a quinoline-annulated porphyrin as NIR molecular contrast agent.

Science.gov (United States)

Luciano, Michael; Erfanzadeh, Mohsen; Zhou, Feifei; Zhu, Hua; Bornhütter, Tobias; Röder, Beate; Zhu, Quing; Brückner, Christian

2017-01-25

The synthesis and photophysical properties of a tetra-PEG-modified and freely water-soluble quinoline-annulated porphyrin are described. We previously demonstrated the ability of quinoline-annulated porphyrins to act as an in vitro NIR photoacoustic imaging (PAI) contrast agent. The solubility of the quinoline-annulated porphyrin derivative in serum now allowed the assessment of the efficacy of the PEGylated derivative as an in vivo NIR contrast agent for the PAI of an implanted tumor in a mouse model. A multi-fold contrast enhancement when compared to the benchmark dye ICG could be shown, a finding that could be traced to its photophysical properties (short triplet lifetimes, low fluorescence and singlet oxygen sensitization quantum yields). A NIR excitation wavelength of 790 nm could be used, fully taking advantage of the optical window of tissue. Rapid renal clearance of the dye was observed. Its straight-forward synthesis, optical properties with the possibility for further optical fine-tuning, nontoxicity, favorable elimination rates, and contrast enhancement make this a promising PAI contrast agent. The ability to conjugate the PAI chromophore with a fluorescent tag using a facile and general conjugation strategy was also demonstrated.

Synthesis, Properties Characterization and Applications of Various Organobismuth Compounds

Directory of Open Access Journals (Sweden)

Jingfei Luan

2011-05-01

Full Text Available Organobismuth chemistry was emphasized in this review article due to the low price, low toxicity and low radioactivity characteristics of bismuth. As an environmentally-friendly class of organometallic compounds, different types of organobismuth compounds have been used in organic synthesis, catalysis, materials, etc. The synthesis and property characterization of many organobismuth compounds had been summarized. This review article also presented a survey of various applications of organobismuth compounds in organic transformations, as reagents or catalysts. The reactivity, reaction pathways and mechanisms of reactions with organobismuths were discussed. Less common and limiting aspects of organobismuth compounds were also briefly mentioned.

Synthesis and thermal properties of strontium and calcium peroxides

Science.gov (United States)

Philipp, Warren H.; Kraft, Patricia A.

1989-01-01

A practical synthesis and a discussion of some chemical properties of pure strontium peroxide and calcium peroxide are presented. The general synthesis of these peroxides involves precipitation of their octahydrates by addition of H2O2 to aqueous ammoniacal Sr(NO3)2 or CaCl2. The octahydrates are converted to the anhydrous peroxides by various dehydration techniques. A new x-ray diffraction powder pattern for CaO2 x 8H2O is given from which lattice parameters a=6.212830 and c=11.0090 were calculated on the basis of the tetragonal crystal system.

Polyfuran Conducting Polymers: Synthesis, Properties, and Applications.

OpenAIRE

González-Tejera, M.J.; Sánchez de la Blanca, Emilia; Carrillo Ramiro, Isabel

2008-01-01

In this review, polyfuran (PFu) synthesis methods and the nucleation mechanism; the electrochemical, structural, morphological, and magnetic properties of PFu; thermal behavior; theoretical calculations on PFu, as well as its applications reported to date, have been compiled. Not only PFu homopolymers have been reviewed, but also PFu co-polymers, PFu bipolymers, and PFu composites. The results are listed, discussed, and compared. It is hoped that this assembly of all the relevant data might e...

Molecular clips based on propanediurea : synthesis and physical properties

NARCIS (Netherlands)

Jansen, Robertus Johannes

2002-01-01

This thesis describes the synthesis and physical properties of a series of molecular clips derived from the concave molecule propanediurea. These molecular clips are cavity-containing receptors that can bind a variety of aromatic guests. This binding is a result of hydrogen bonding and pi-pi

A novel photo-active Cd:1,4-benzene dicarboxylate metal organic framework templated using [Ru(ii)(2,2'-bipyridine)3]2+: synthesis and photophysics of RWLC-5.

Science.gov (United States)

Larsen, Randy W; Mayers, Jacob M; Wojtas, Lukasz

2017-09-26

The development of photoactive porous materials is of significant importance for applications ranging from sustainable energy to pharmaceutical development and catalysis. A particularly attractive class of photo-active materials is the metal-organic framework (MOF)-based platform in which the photo-active elements are components of the framework itself or photo-active guests encapsulated within the MOF cavities. It has now been demonstrated that the photo-active [Ru(2,2'-bipyridine) 3 ] 2+ (RuBpy) complex can template the formation of MOFs with varying three dimensional structures. Here we report the synthesis and structural and photo-physical characterization of a new RuBpy-templated MOF composed of Cd 2+ ions with 1,4-benzenedicarboxylate ligands (RWLC-5) that contains crystallographically resolved RuBpy complexes. The new material displays a biphasic emission decay (130 ns and 1180 ns, T = 20 °C) and a bathochromically shifted emission maximum, relative to RuBpy in solution (603 nm for RuBpy in ethanol vs. 630 nm for RWLC-5). The emission lifetimes also do not display temperature-dependent decays which are characteristic of RuBpy type complexes as well as other RuBpy templated MOFs. The lack of temperature dependence is consistent with the complete deactivation of the 3 LF state of the encapsulated RuBpy complex due to a constrained environment. The fast phase decay is attributed to a water molecule hydrogen bonded to a bipyridine ligand associated with ∼38% of the encapsulated RuBpy complexes resulting in the nonradiative deactivation of the 3 MLCT state.

Lanthanide(III) complexes of bis-semicarbazone and bis-imine-substituted phenanthroline ligands: solid-state structures, photophysical properties, and anion sensing.

Science.gov (United States)

Nadella, Sandeep; Selvakumar, Paulraj M; Suresh, Eringathodi; Subramanian, Palani S; Albrecht, Markus; Giese, Michael; Fröhlich, Roland

2012-12-21

Phenanthroline-based hexadentate ligands L(1) and L(2) bearing two achiral semicarbazone or two chiral imine moieties as well as the respective mononuclear complexes incorporating various lanthanide ions, such as La(III), Eu(III), Tb(III), Lu(III), and Y(III) metal ions, were synthesized, and the crystal structures of [ML(1)Cl(3)] (M=La(III), Eu(III), Tb(III), Lu(III), or Y(III)) complexes were determined. Solvent or water molecules act as coligands for the rare-earth metals in addition to halide anions. The big Ln(III) ion exhibits a coordination number (CN) of 10, whereas the corresponding Eu(III), Tb(III), Lu(III), and Y(III) centers with smaller ionic radii show CN=9. Complexes of L(2), namely [ML(2)Cl(3)] (M=Eu(III), Tb(III), Lu(III), or Y(III)) ions could also be prepared. Only the complex of Eu(III) showed red luminescence, whereas all the others were nonluminescent. The emission properties of the Eu derivative can be applied as a photophysical signal for sensing various anions. The addition of phosphate anions leads to a unique change in the luminescence behavior. As a case study, the quenching behavior of adenosine-5'-triphosphate (ATP) was investigated at physiological pH value in an aqueous solvent. A specificity of the sensor for ATP relative to adenosine-5'-diphosphate (ADP) and adenosine-5'-monophosphate (AMP) was found. (31)P NMR spectroscopic studies revealed the formation of a [EuL(2)(ATP)] coordination species. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Impact of charge carrier injection on single-chain photophysics of conjugated polymers

Energy Technology Data Exchange (ETDEWEB)

Hofmann, Felix J.; Vogelsang, Jan, E-mail: jan.vogelsang@physik.uni-regensburg.de; Lupton, John M. [Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg (Germany)

2016-06-27

Charges in conjugated polymer materials have a strong impact on the photophysics and their interaction with the primary excited state species has to be taken into account in understanding device properties. Here, we employ single-molecule spectroscopy to unravel the influence of charges on several photoluminescence (PL) observables. The charges are injected either stochastically by a photochemical process or deterministically in a hole-injection sandwich device configuration. We find that upon charge injection, besides a blue-shift of the PL emission and a shortening of the PL lifetime due to quenching and blocking of the lowest-energy chromophores, the non-classical photon arrival time distribution of the multichromophoric chain is modified towards a more classical distribution. Surprisingly, the fidelity of photon antibunching deteriorates upon charging, whereas one would actually expect the opposite: the number of chromophores to be reduced. A qualitative model is presented to explain the observed PL changes. The results are of interest to developing a microscopic understanding of the intrinsic charge-exciton quenching interaction in devices.

Synthesis, structural and optical properties of nanoparticles (Al, V ...

Indian Academy of Sciences (India)

The synthesis by the sol–gel method, structural and optical properties of ZnO, Zn0.99Al0.01O (AlZ),. Zn0.9V0.1O (VZ) ... drops of the resulting suspension containing the synthesized .... ZnO films on silicon substrate, they thought that this emis-.

Photophysical Properties of II-VI Semiconductor Nanocrystals

Science.gov (United States)

Gong, Ke

As it is well known, semiconductor nanocrystals (also called quantum dots, QDs) are being actively pursued for use in many different types of luminescent optical materials. These materials include the active media for luminescence downconversion in artificial lighting, lasers, luminescent solar concentrators and many other applications. Chapter 1 gives general introduction of QDs, which describe the basic physical properties and optical properties. Based on the experimental spectroscopic study, a semiquantitative method-effective mass model is employed to give theoretical prediction and guide. The following chapters will talks about several topics respectively. A predictive understanding of the radiative lifetimes is therefore a starting point for the understanding of the use of QDs for these applications. Absorption intensities and radiative lifetimes are fundamental properties of any luminescent material. Meantime, achievement of high efficiency with high working temperature and heterostructure fabrication with manipulation of lattice strain are not easy and need systematic investigation. To make accurate connections between extinction coefficients and radiative recombination rates, chapter 2 will consider three closely related aspects of the size dependent spectroscopy of II-VI QDs. First, it will consider the existing literature on cadmium selenide (CdSe) QD absorption spectra and extinction coefficients. From these results and fine structure considerations Boltzmann weighted radiative lifetimes are calculated. These lifetimes are compared to values measured on very high quality CdSe and CdSe coated with zinc selenide (ZnSe) shells. Second, analogous literature data are analyzed for cadmium telluride (CdTe) nanocrystals and compared to lifetimes measured for very high quality QDs. Furthermore, studies of the absorption and excitation spectra and measured radiative lifetimes for CdTe/CdSe Type-II core/shell QDs are reported. These results are also analyzed in

Effect of the substituents on the photophysical, electrochemical and electroluminescence properties of OLED dopant Iridium bis(2-phenylbenzothiozolato- N,C2')(acetylacetonate)

Science.gov (United States)

Ivanov, P.; Tomova, R.; Petrova, P.

2014-12-01

The effect of two substituents: clorine and 1,3-diphenylpropane-1,3-dionate, placed on different position in the molecule of Iridium (III) bis(2-phenylbenzothiozolato-N,C2')- (acetylacetonate) (bt)2Ir(acac), on its electrochemical behaviour, photophysical and electroluminescence properties were investigated. Three complexes (bt)2Ir(acac), Iridium (III) bis[2-(4-chlorophenyl)benzothiazolato-N,C2']-acetylacetonate (Clbt)2Ir(acac), in which the Cl atom was introduced on the 4-position in the benzothiazole ring, and the new Iridium (Ill) bis[2 -phenylbenzothiazolato -N,C2'] -(1,3 -diphenylpropane-1,3 -dionate) (bt)2Ir(dbm), where ancillary acetylacetonate ligand was replaced by 1,3-diphenylpropane-1,3-dionate, were synthesized and characterised by 1H-NMR and elemental analysis. The HOMO/LUMO energy levels of the complexes were determined by cyclic voltammetry (CV) and their properties were established by UV-Visible and fluorescence spectroscopy. The application of (Clbt)2Ir(acac), (bt)2Ir(bsm) and (bt)2Ir(acac) as dopants in hole transporting layer (HTL) of Organic light- emitting diodes(OLEDs). It was found that with respect to the reference (bt)2Ir(acac): both LUMO and HOMO of the substituted complexes were shifted to more positive values accordingly with 0.23 and 0.19 eV for (Clbt)2Ir(acac) and 0.14 and 0.12 eV for (bt)2Ir(dbm). OLEDs doped with 1 w% of the complexes irradiated the warm white light with Commission internationale de l'eclairage (CIE) coordinates: 0.24;0.38 for (Clbt)2Ir(acac), 0.30;0.44 for (bt)2Ir(acac) and 0.28;0.46 for (bt)2Ir(dbm). Devices doped with 10 w% of all complexes irradiated in the yellow orange region of the spectrum.

Review on Synthesis, Thermo-Physical Property, and Heat Transfer Mechanism of Nanofluids

Directory of Open Access Journals (Sweden)

Mahesh Suresh Patil

2016-10-01

Full Text Available Nanofluids are suspended nano-sized particles in a base fluid. With increasing demand for more high efficiency thermal systems, nanofluids seem to be a promising option for researchers. As a result, numerous investigations have been undertaken to understand the behaviors of nanofluids. Since their discovery, the thermo-physical properties of nanofluids have been under intense research. Inadequate understanding of the mechanisms involved in the heat transfer of nanofluids has been the major obstacle for the development of sophisticated nanofluids with the desired properties. In this comprehensive review paper, investigations on synthesis, thermo-physical properties, and heat transfer mechanisms of nanofluids have been reviewed and presented. Results show that the thermal conductivity of nanofluids increases with the increase of the operating temperature. This can potentially be used for the efficiency enhancement of thermal systems under higher operating temperatures. In addition, this paper also provides details concerning dependency of the thermo-physical properties as well as synthesis and the heat transfer mechanism of the nanofluids.

Synthesis and properties of lyotropic poly(amide-block-aramid) copolymers

NARCIS (Netherlands)

De Ruijter, C.

2006-01-01

This thesis describes the synthesis and properties of liquid crystalline block copolymers comprised of alternating rigid and flexible blocks for the preparation of self-reinforcing materials. The incentive for this work was the expectation that the rigid segments would phase separate on a

Photophysical characterization of cumarin-doped poly (lactic acid) microparticles and visualization of the biodistribution

International Nuclear Information System (INIS)

Abe, Shigeaki; Kiba, Takayuki; Hosokawa, Kiyotada; Nitobe, Satoru; Hirota, Takashi; Kobayashi, Hirohisa; Akasaka, Tsukasa; Uo, Motohiro; Kuboki, Yoshinori; Sato, Shin-Ichiro; Watari, Fumio; Rosca, Iosif D.

2010-01-01

We prepared fluorescent coumarin dye-doped poly (acrylic acid) microparticles, which are well known as a biodegradable polyester, and the photophysical properties were characterized by scanning electron microscope, atomic force microscope and spectroscopic investigation. Spherical particles with diameters ranging from 0.5 to a few μm were obtained. Based on spectroscopic investigation, the internal environment was close to that of a polar solvent such as methanol, and the dyes were dispersed without aggregation inside the particles. The obtained particles were administered to a mouse through the tail vein, and the biodistribution was then observed after some organs were excited at 1-day and 1-week post-injection. The particles were accumulated in the organs, especially in the lung and spleen. After injection, the particles were trapped temporally in the lung, and then seemed to be transported to other organs by blood circulation. This tendency is similar to the biodistribution of TiO 2 microparticles that we have reported previously.

Photophysical study of a cyclophane displaying intramolecular exciplex emission

International Nuclear Information System (INIS)

Galindo, Francisco; Isabel Burguete, M.; Luis, Santiago V.

2004-01-01

The photophysical behavior of cyclophane 1, comprised by two L-valine units and one naphthalene ring, has been studied. It displays exciplex (EX) emission with a maximum in the range 390-460 nm, depending on solvent polarity. From this dependence a dipole moment of 19.4 D for the excited charge-transfer state has been calculated. Fluorescence quantum yields in organic media ranging from 0.012 to 0.038 have been measured. This phenomenon has been interpreted taking into account the rigidity imposed by the cyclophane framework which could pre-orient the donor and the acceptor subunits for a favorable interaction

Photophysical study of a cyclophane displaying intramolecular exciplex emission

Energy Technology Data Exchange (ETDEWEB)

Galindo, Francisco; Isabel Burguete, M.; Luis, Santiago V

2004-07-12

The photophysical behavior of cyclophane 1, comprised by two L-valine units and one naphthalene ring, has been studied. It displays exciplex (EX) emission with a maximum in the range 390-460 nm, depending on solvent polarity. From this dependence a dipole moment of 19.4 D for the excited charge-transfer state has been calculated. Fluorescence quantum yields in organic media ranging from 0.012 to 0.038 have been measured. This phenomenon has been interpreted taking into account the rigidity imposed by the cyclophane framework which could pre-orient the donor and the acceptor subunits for a favorable interaction.

Synthesis of diketopyrrolopyrrole containing copolymers: a study of their optical and photovoltaic properties.

Science.gov (United States)

Kanimozhi, Catherine; Balraju, P; Sharma, G D; Patil, Satish

2010-03-11

The diketopyrrolopyrrole-based copolymers PDPP-BBT and TDPP-BBT were synthesized and used as a donor for bulk heterojunction photovoltaic devices. The photophysical properties of these polymers showed absorption in the range 500-600 nm with a maximum peak around 563 nm, while TDPP-BBT showed broadband absorption in the range 620-800 nm with a peak around 656 nm. The power conversion efficiencies (PCE) of the polymer solar cells based on these copolymers and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) were 0.68% (as cast PDPP-BBT:PCBM), 1.51% (annealed PDPP-BBT:PCBM), 1.57% (as cast TDPP-BBT:PCBM), and 2.78% (annealed TDPP-BBT:PCBM), under illumination of AM 1.5 (100 mW/cm(2)). The higher PCE for TDPP-BBT-based polymer solar cells has been attributed to the low band gap of this copolymer as compared to PDPP-BBT, which increases the numbers of photogenerated excitons and corresponding photocurrent of the device. These results indicate that PDPP-BBT and TDPP-BBT act as excellent electron donors for bulk heterojunction devices.

An ultrahigh vacuum monochromator for photophysics beamline

International Nuclear Information System (INIS)

Meenakshi Raja Rao, P.; Padmanabhan, Saraswathy; Raja Sekhar, B.N.; Shastri, Aparna; Khan, H.A.; Sinha, A.K.

2000-08-01

The photophysics beamline designed for carrying out photoabsorption and fluorescence studies using the 450 MeV Synchrotron Radiation Source (SRS), INDUS-1, uses a 1 metre monochromator as premonochromator for monochromatising the continuum. An ultra high vacuum compatible monochromator in Seya-Namioka mount has been designed and fabricated indigenously. The monochromator was assembled and tested for its performance. Wavelength scanning mechanism was tested for its reproducibility and the monochromator was tested for its resolution using UV and VUV sources. An average spectral resolution of 2.5 A was achieved using a 1200 gr/mm grating. A wavelength repeatability of ± 1A was obtained. An ultra high vacuum of 2 X 10 -8 mbar was also achieved in the monochromator. Details of fabrication, assembly and testing are presented in this report. (author)

Green synthesis of ZnO nanoparticles by Aspalathus linearis: Structural & optical properties

International Nuclear Information System (INIS)

Diallo, A.; Ngom, B.D.; Park, E.; Maaza, M.

2015-01-01

This contribution reports for the 1st time on the synthesis and the main physical properties of ZnO nanoparticles synthesized by an entirely green physical-chemistral process using Aspalathus linearis's natural extract as an efficient reduction/oxidizing agent. Their structural and optical properties by electron microscopy, X-rays diffraction, Raman and X-rays photoemission spectroscopies as well as room temperature photoluminescence are reported. - Highlights: • 1st time report on synthesis of ZnO nanoparticles by a green process via Aspalathus linearis extract. • A. linearis's natural extract was used as an effective reduction/oxidizing agent. • Wurtzite nature of ZnO nanoparticles was confirmed via XRD, Raman, XPS and PL

Green synthesis of ZnO nanoparticles by Aspalathus linearis: Structural & optical properties

Energy Technology Data Exchange (ETDEWEB)

Diallo, A.; Ngom, B.D. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Park, E. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa); Nelson Mandela African Institute for Science & Technology, Arusha (Tanzania, United Republic of); Maaza, M., E-mail: Maaza@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk Ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure road, Somerset West 7129, PO Box 722, Somerset West, Western Cape (South Africa)

2015-10-15

This contribution reports for the 1st time on the synthesis and the main physical properties of ZnO nanoparticles synthesized by an entirely green physical-chemistral process using Aspalathus linearis's natural extract as an efficient reduction/oxidizing agent. Their structural and optical properties by electron microscopy, X-rays diffraction, Raman and X-rays photoemission spectroscopies as well as room temperature photoluminescence are reported. - Highlights: • 1st time report on synthesis of ZnO nanoparticles by a green process via Aspalathus linearis extract. • A. linearis's natural extract was used as an effective reduction/oxidizing agent. • Wurtzite nature of ZnO nanoparticles was confirmed via XRD, Raman, XPS and PL.

Synthesis, transport and dielectric properties of polyaniline/Co3O4 ...

Indian Academy of Sciences (India)

TECS

Synthesis, transport and dielectric properties of polyaniline/Co3O4 composites ... Initial increment in conductivity is due to extended chain length of polyaniline where polarons possess .... Figure 3 displays the scanning electron micrograph of.

Graphene optoelectronics synthesis, characterization, properties, and applications

CERN Document Server

bin M Yusoff, Abdul Rashid

2014-01-01

This first book on emerging applications for this innovative material gives an up-to-date account of the many opportunities graphene offers high-end optoelectronics.The text focuses on potential as well as already realized applications, discussing metallic and passive components, such as transparent conductors and smart windows, as well as high-frequency devices, spintronics, photonics, and terahertz devices. Also included are sections on the fundamental properties, synthesis, and characterization of graphene. With its unique coverage, this book will be welcomed by materials scientists, solid-

Three coordination polymers based on a star-like geometry 4, 4', 4'' -nitrilotribenzoic acid ligand and their framework dependent luminescent properties

Science.gov (United States)

Hu, Zhiyong; Zhao, Meng; Su, Jian; Xu, Shasha; Hu, Lei; Liu, Hui; Zhang, Qiong; Zhang, Jun; Wu, Jieying; Tian, Yupeng

2018-02-01

Three novel coordination polymers, [Zn(μ2-HTCA)(Phen)]n (1), {[Cd(μ3-HTCA)(Phen)]·2H2O}n (2), [Mn(μ2-HTCA)(Phen)(H2O)]n (3) were prepared by hydrothermal synthesis from the 4, 4', 4''-nitrilotribenzoicacid (H3TCA) and 1, 10-phenanthroline monohydrate (Phen) with different transition metal salts, which were characterized by elemental analysis, IR spectra, powder and single-crystal X-ray diffraction and thermogravimetric analysis. The photophysical properties of the complexes were investigated by solid-state diffuse reflectance spectra, photoluminescent properties, lifetime and quantum yield. For these complexes, it was found that the band gaps follow the order: 3 ＜ 2 ＜ 1 ＜ 2.80 eV, fluorescence intensity order: 1 ＞ H3TCA ＞ 2 ＞ 3; quantum yield order: H3TCA ＞ 1 ＞ 2 ＞ 3; while the lifetime order: 1 ＞ 2 ＞ H3TCA ＞ 3.

A diamine ligand with long 'arms' and its corresponding dinuclear rhenium(I) complex: Synthesis, characterization, photophysical property, and sensing activity towards molecular oxygen

Energy Technology Data Exchange (ETDEWEB)

Xu Xiaoyong, E-mail: dreamxxy01@163.com [Center for Functional Materials of Pingxiang, Pingxiang 337055 (China) and College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Xiao Hanning [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)

2012-09-15

In this paper, we synthesize a novel diamine ligand of 4,7-dinonadecyl-1,10-phenanthroline (DN-Phen) with two long alkyl chain arms serving as a shield and its corresponding dinuclear Re(I) complex of Re{sub 2}(CO){sub 6}(bpy)(DN-Phen){sub 2} (bpy=4,4 Prime -bipyridine), aiming at an optical sensor immune to the surrounding interferences. Its geometric and electronic structures are investigated, which suggest that the introduced long alkyl chains act as a shield for the excited state of emissive center. The promising photophysical parameters of Re{sub 2}(CO){sub 6}(bpy)(DN-Phen){sub 2}, including the immunity of emission towards the surrounding interferences and long excited state lifetime, make itself a potential probe for oxygen detection. By doping Re{sub 2}(CO){sub 6}(bpy)(DN-Phen){sub 2} into two silica matrixes of MCM-41 and SBA-15, oxygen sensing performances of the resulted composite materials are investigated. Finally, a high sensitivity of 20.1 is realized, with short response/recovery time of 8 s/42 s. Here, sensitivity is defined as the ratio of emission maximum under pure nitrogen to emission minimum under pure oxygen, response and recovery times are the times for a sample to lose (response time) or recover (recovery time) 95% of its emission maximum upon periodically changed atmosphere. - Highlights: Black-Right-Pointing-Pointer A ligand with two long alkyl chain arms serving as a shield is synthesized. Black-Right-Pointing-Pointer The shield protects the excited state emissive center. Black-Right-Pointing-Pointer The emission of Re(I) complex is immune towards surrounding interference. Black-Right-Pointing-Pointer A high sensitivity of 20.1 is realized.

Exciplex dynamics in a blend of π-conjugated polymers with electron donating and accepting properties: MDMO-PPV and PCNEPV

NARCIS (Netherlands)

Offermans, T.; Hal, van P.A.; Meskers, S.C.J.; Koetse, M.M.; Janssen, R.A.J.

2005-01-01

The photophysical properties of a solution processed blend of two semiconducting polymers with electron donating and electron accepting properties, respectively, as used in polymer photovoltaic devices have been investigated. We show that in the binary mixture of

Synthesis, Properties, and Applications of Low-Dimensional Carbon-Related Nanomaterials

Directory of Open Access Journals (Sweden)

Ali Mostofizadeh

2011-01-01

Full Text Available In recent years, many theoretical and experimental studies have been carried out to develop one of the most interesting aspects of the science and nanotechnology which is called carbon-related nanomaterials. The goal of this paper is to provide a review of some of the most exciting and important developments in the synthesis, properties, and applications of low-dimensional carbon nanomaterials. Carbon nanomaterials are formed in various structural features using several different processing methods. The synthesis techniques used to produce specific kinds of low-dimensional carbon nanomaterials such as zero-dimensional carbon nanomaterials (including fullerene, carbon-encapsulated metal nanoparticles, nanodiamond, and onion-like carbons, one-dimensional carbon nanomaterials (including carbon nanofibers and carbon nanotubes, and two-dimensional carbon nanomaterials (including graphene and carbon nanowalls are discussed in this paper. Subsequently, the paper deals with an overview of the properties of the mainly important products as well as some important applications and the future outlooks of these advanced nanomaterials.

Effects of alkyl or alkyloxy side chains in poly[4,6-bis(3´-dodecylthien-2´-yl)thieno-[3,4-c][1,2,5]thiadiazole-5´,5´-diyl-alt-2,5-di(alkyl or alkyloxy)-1,4-phenylene]: synthesis, photophysics, and spectroelectrochemical and photovoltaic properties

Czech Academy of Sciences Publication Activity Database

Cimrová, Věra; Pokorná, Veronika; Výprachtický, Drahomír

2017-01-01

Roč. 118, 2 June (2017), s. 180-191 ISSN 0032-3861 R&D Projects: GA ČR(CZ) GA13-26542S Institutional support: RVO:61389013 Keywords : low-bandgap thienothiadiazole copolymers * photophysics * spectroelectrochemistry Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.684, year: 2016

A Review of the Synthesis and Photoluminescence Properties of Hybrid ZnO and Carbon Nanomaterials

Directory of Open Access Journals (Sweden)

Protima Rauwel

2016-01-01

Full Text Available Photoluminescent ZnO carbon nanomaterials are an emerging class of nanomaterials with unique optical properties. They each, ZnO and carbon nanomaterials, have an advantage of being nontoxic and environmentally friendly. Their cost-effective production methods along with simple synthesis routes are also of interest. Moreover, ZnO presents photoluminescence emission in the UV and visible region depending on the synthesis routes, shape, size, deep level, and surface defects. When combined with carbon nanomaterials, modification of surface defects in ZnO allows tuning of these photoluminescence properties to produce, for example, white light. Moreover, efficient energy transfer from the ZnO to carbon nanostructures makes them suitable candidates not only in energy harvesting applications but also in biosensors, photodetectors, and low temperature thermal imaging. This work reviews the synthesis and photoluminescence properties of 3 carbon allotropes: carbon quantum or nanodots, graphene, and carbon nanotubes when hybridized with ZnO nanostructures. Various synthesis routes for the hybrid materials with different morphologies of ZnO are presented. Moreover, differences in photoluminescence emission when combining ZnO with each of the three different allotropes are analysed.

Highly Luminescent Lanthanide Complexes of 1 Hydroxy-2-pyridinones

Energy Technology Data Exchange (ETDEWEB)

University of California, Berkeley; Lawrence National Laboratory; Raymond, Kenneth; Moore, Evan G.; Xu, Jide; Jocher, Christoph J.; Castro-Rodriguez, Ingrid; Raymond, Kenneth N.

2007-11-01

The synthesis, X-ray structure, stability, and photophysical properties of several trivalent lanthanide complexes formed from two differing bis-bidentate ligands incorporating either alkyl or alkyl ether linkages and featuring the 1-hydroxy-2-pyridinone (1,2-HOPO) chelate group in complex with Eu(III), Sm(III) and Gd(III) are reported. The Eu(III) complexes are among some of the best examples, pairing highly efficient emission ({Phi}{sub tot}{sup Eu} {approx} 21.5%) with high stability (pEu {approx} 18.6) in aqueous solution, and are excellent candidates for use in biological assays. A comparison of the observed behavior of the complexes with differing backbone linkages shows remarkable similarities, both in stability and photophysical properties. Low temperature photophysical measurements for a Gd(III) complex were also used to gain insight into the electronic structure, and were found to agree with corresponding TD-DFT calculations for a model complex. A comparison of the high resolution Eu(III) emission spectra in solution and from single crystals also revealed a more symmetric coordination geometry about the metal ion in solution due to dynamic rotation of the observed solid state structure.

Molecular Polygons Probe the Role of Intramolecular Strain in the Photophysics of π-Conjugated Chromophores.

Science.gov (United States)

Wilhelm, Philipp; Vogelsang, Jan; Poluektov, Georgiy; Schönfelder, Nina; Keller, Tristan J; Jester, Stefan-Sven; Höger, Sigurd; Lupton, John M

2017-01-24

π-Conjugated segments, chromophores, are the electronically active units of polymer materials used in organic electronics. To elucidate the effect of the bending of these linear moieties on elementary electronic properties, such as luminescence color and radiative rate, we introduce a series of molecular polygons. The π-system in these molecules becomes so distorted in bichromophores (digons) that these absorb and emit light of arbitrary polarization: any part of the chain absorbs and emits radiation with equal probability. Bending leads to a cancellation of transition dipole moment (TDM), increasing excited-state lifetime. Simultaneously, fluorescence shifts to the red as radiative transitions require mixing of the excited state with vibrational modes. However, strain can become so large that excited-state localization on shorter units of the chain occurs, compensating TDM cancellation. The underlying correlations between shape and photophysics can only be resolved in single molecules. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and characterization of biodegradable lignin nanoparticles with tunable surface properties

NARCIS (Netherlands)

Richter, Alexander P.; Bharti, Bhuvnesh; Armstrong, Hinton B.; Brown, Joseph S.; Plemmons, Dayne; Paunov, Vesselin N.; Stoyanov, Simeon D.; Velev, Orlin D.

2016-01-01

Lignin nanoparticles can serve as biodegradable carriers of biocidal actives with minimal environmental footprint. Here we describe the colloidal synthesis and interfacial design of nanoparticles with tunable surface properties using two different lignin precursors, Kraft (Indulin AT) lignin and

Theory of interfacial charge-transfer complex photophysics in π-conjugated polymer-fullerene blends

Science.gov (United States)

Aryanpour, K.; Psiachos, D.; Mazumdar, S.

2010-03-01

We present a theory of the electronic structure and photophysics of 1:1 blends of derivatives of polyparaphenylenevinylene and fullerenes [1]. Within the same Coulomb-correlated Hamiltonian applied previously to interacting chains of single-component π-conjugated polymers [2], we find an exciplex state that occurs below the polymer's optical exciton. Weak absorption from the ground state occurs to the exciplex. We explain transient photoinduced absorptions in the blend [3], observed for both above-gap and below-gap photoexcitations, within our theory. Photoinduced absorptions for above-gap photoexcitation are from the optical exciton as well as the exciplex, while for below-gap photoexcitation induced absorptions are from the exciplex alone. In neither case are free polarons generated in the time scale of the experiment. Importantly, the photophysics of films of single-component π-conjugated polymers and blends can both be understood by extending Mulliken's theory of ground state charge-transfer to the case of excited state charge-transfer. [1] K. Aryanpour, D. Psiachos, and S. Mazumdar, arXiv:0908.0366 [2] D. Psiachos and S. Mazumdar, Phys. Rev. B. 79 155106 (2009) [3] T. Drori et al., Phys. Rev. Lett. 101, 037402 (2008)

Photophysics of three delocalized lipophilic cations in reverse micelles: A fluorescence spectroscopy study

Energy Technology Data Exchange (ETDEWEB)

Li, Dong-Wei [State Key Laboratory of Virology and College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Qi, Zu-De [State Key Laboratory of Virology and College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China); Ding, Xin-Liang; Li, Jia-Han; Jiang, Feng-Lei [State Key Laboratory of Virology and College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Liu, Yi, E-mail: prof.liuyi@263.net [State Key Laboratory of Virology and College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Kwong, Daniel W.J. [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China); Wong, Wai-Kwok, E-mail: wkwong@hkbu.edu.hk [Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong (China)

2013-02-15

In this paper, aiming at the trans-membrane transport properties of the different DLCs related with the cytotoxicities, we have studied photophysics of DLCs in RMs. MTT assays indicated that DLC 1 were more cytotoxic than DLC 2 and 3. Steady-state absorption and fluorescence method have been used to characterize the binding model of three DLCs (1, 2, and 3) in RMs and bovine serum albumin (BSA). The progressive red-shift of compound 1 indicated that it can experience the hydrophilic and hydrophobic environment owing to the rigid structure, thus it can more easily cross the double membrane of cell than compounds 2 and 3. In conclusion, we simulated a model of compound 1 in RMs. The present study of F16 derivatives in microenvironment would provide some useful information to the cell membrane simulation and design of DLCs. - Graphical abstract: Aiming at the trans-membrane transport properties of the different DLCs related with the antitumor properties, MTT assay, steady-state absorption and fluorescence method have been used to characterize the binding model of three DLCs (1, 2, and 3) in reverse micelles (RMs) and bovine serum albumin (BSA). Highlights: Black-Right-Pointing-Pointer The drugs penetrating into the reverse micelles core were used to mimic the feature of drug trans-membrane transport. Black-Right-Pointing-Pointer Compound 1 was incorporated into the Stern Layer of reverse micelles, while compound 3 was not. Black-Right-Pointing-Pointer Reverse micelles would be used as a biomimic for drug designing and screening.

Molecular structure, photoluminescent and electroluminescent properties of bis(2-(4-methyl-2-hydroxyphenyl)benzothiazolate) zinc with excellent electron-transport characteristics

International Nuclear Information System (INIS)

Xu Huixia; Xu Bingshe; Fang Xiaohong; Yue Yan; Chen Liuqing; Wang Hua; Hao Yuying

2011-01-01

Highlights: → The synthesis, crystal structure and photophysical properties of Zn(4-MeBTZ) 2 were reported. → The electron-transport property was investigated by theoretical calculations and experimental. → We found that Zn(4-MeBTZ) 2 has a higher electron mobility than that of [Zn(BTZ) 2 ] 2 and the devices based on it have a lower turn-on voltage. - Abstract: In this article, the molecular structure, photoluminescent and electroluminescent properties of bis(2-(4-methyl-2-hydroxyphenyl) benzothiazolate) zinc (Zn(4-MeBTZ) 2 ) with good electron-transport characteristics were reported. This complex was identified as triclinic structure with the strong intermolecular π-π stacking interactions between the benzothiazolate/phenoxido rings and weak intramolecular hydrogen bonds by X-ray single-crystal diffraction. Quantum chemical method has been employed to investigate electron structure and charge transport property. The blue-green light emission was observed by fabricating double-layer devices using Zn(4-MeBTZ) 2 as electron-transport and NPB as hole-transport material. The performance of organic light-emitting devices based on Zn(4-MeBTZ) 2 is much better than that of the devices based on [Zn(BTZ) 2 ] 2 .

Green synthesis of silver nanoparticles using a Melissa officinalis leaf extract with antibacterial properties

Directory of Open Access Journals (Sweden)

Álvaro de Jesús Ruíz-Baltazar

Full Text Available The exceptional properties of the silver nanoparticles offer several applications in the biomedicine field. The development of antibiotics which are clinically useful against bacteria and drug resistant microorganisms, it is one of the main approaches of silver nanoparticles. However, it is necessary to develop environmentally friendly methods for their synthesis. In this sense, the main objective of this work is focused on to propose a simplified and efficient green synthesis of silver nanoparticles with proven antibacterial properties. The green synthesis route is based on the use of the Melissa officinalis as reducing agent of the silver ions in aqueous solution at room temperature. Complementary, the antibacterial activity of the silver nanoparticles against Staphylococcus aureus and Escherichia coli was confirmed. The silver nanoparticles obtained were characterized by transmission electron microscopy, X-ray diffraction, UV–vis, Raman and FT-IR spectroscopy. The observed results suggested that using Melissa officinalis, it is possible to performed silver nanoparticles with controlled characteristics and with significant inhibitory activity against the Staphylococcus aureus and Escherichia coli. Keywords: Green synthesis, Nanoparticles, Antibacterial effect

Photophysical properties of columnar phases formed by triphenylene derivatives

International Nuclear Information System (INIS)

Sigal, Herve

1997-01-01

This research thesis reports the study of the spectroscopic properties and of the migration of excitation energy in the singlet state in columnar phases formed by alkyloxy and alkylthio derivatives of triphenylene. First, the author studied the spectroscopic properties of chromophores in solutions, and characterized excited states by using computation codes (CS-INDO-CIPSI). Then, by using the excitonic theory in the case of the considered triphenylene derivatives, the author studied the influence of molecular movements and of the intra-columnar order on the spectroscopic properties. In some circumstances, the non-radiative transfer of excitation energy is governed by a mechanism displaying a random evolution. This stochastic movement is studied by using Monte Carlo simulations. The author shows that the energy migration is one-dimensional on short times, and then becomes three-dimensional. The evolution of excitation energy in space and in time is determined [fr

Synthesis and properties of novel 4,5-diaminonaphthalimides

International Nuclear Information System (INIS)

Morris, I.P.

1999-07-01

This thesis presents work carried out into the synthesis and properties of Novel 4,5-diaminonaphthalimides. Previous work had identified that these compounds could be synthesised through a short reaction sequence but a very limited number of examples had been produced. With some modifications, the structure of 4,5-diaminonaphthalimides suggests a number of applications. The diamine functionality suggests the formation of complexes and if chiral amines were used asymmetric synthesis is a possibility. Naphthalimides are known to intercalate into DNA and so compounds of this nature may have interesting anti-cancer activity. Finally diaminonaphthalimides are strongly fluorescent and this in combination with the chelation potential of the diamine functionality may afford ion and molecular sensors. The first section of this thesis reviews these areas of research and demonstrates how diaminonaphthalimides might contribute to these areas. The second section describes the synthesis of 4,5-diaminonaphthalimides and illustrates the variety of compounds that may be synthesised. In addition this section explores the applications to fluorescence sensing and asymmetric synthesis. 4,5-Diaminonaphthalimides are shown to undergo chelation enhanced quenching (CHEQ) and chelation enhanced fluorescence (CHEF) with various transition metal ions. The precise features are shown to be dependent on the metal ion present. The mass spectroscopic results discussed in this section show 4,5-diaminonaphthalimides to be a new class of supramolecular compound as they show pre-assembly around alkali earth metal ions. 4,5-Diaminonaphthalimides were also used as catalysts in asymmetric reactions where they show some catalytic activity in the addition of diethylzinc to benzaldehyde. (author)

Synthesis and radioactive properties of the heaviest nuclei

International Nuclear Information System (INIS)

Oganesyan, Yu.Ts.

1996-01-01

Experimental investigations on the synthesis and study of properties of faraway transactinide elements confirm the predictions of macro-microscopic theory on the existence of closed shells in the region of heavy deformed nuclei. It has been demonstrated experimentally that nuclear structure plays a decisive role in the stability of superheavy nuclides. Based on the experimental confirmation of the main provisions of the theory and after the introduction of a necessary correction into the calculation the properties of heavier nuclides in the region of spherical shells Z=114 and N=180-184 have been predicted. Here a substantial increase in the stability of nuclei is also expected. All the nuclei synthesized by now, were obtained in fusion reactions with a formation of a compound nucleus, the transition of which to the ground state takes place with the emission of neutrons and gamma-rays. Both the reactions of cold and hot fusion of nuclei can be used for the synthesis of new nuclei. Nevertheless, new experimental data on the fusion mechanism are required, since a number of theoretical descriptions of the fusion dynamics of complex nuclear systems need a substantial revising. One can assume that the reactions of the type 244 Pu, 248 Cm + 48 Ca are still within the current potential of the accelerators and experimental technique. This potential, nevertheless, is still to be implemented. 37 refs., 6 figs

PETI-298 Prepared by Microwave Synthesis: Neat Resin and Composite Properties

Science.gov (United States)

Smith, Joseph G.; Connell, John W.; Li, Chao-Jun; Wu, Wei; Criss, Jim M., Jr.

2004-01-01

PETI-298 is a high temperature/high performance matrix resin that is processable into composites by resin transfer molding (RTM), resin infusion and vacuum assisted RTM techniques. It is typically synthesized in a polar aprotic solvent from the reaction of an aromatic anhydride and a combination of diamines and endcapped with phenylethynylphthalic anhydride. Microwave synthesis of PETI-298 was investigated as a means to eliminate solvent and decrease reaction time. The monomers were manually mixed and placed in a microwave oven for various times to determine optimum reaction conditions. The synthetic process was subsequently scaled-up to 330g. Three batches were synthesized and combined to give 1 kg of material that was characterized for thermal and rheological properties and compared to PETI-298 prepared by the classic solution based synthetic method. The microwave synthesized PETI-298 was subsequently used to fabricate flat laminates on T650 carbon fabric by RTM. The composite panels were analyzed and mechanical properties determined and compared with those fabricated from PETI-298 prepared by the classic solution method. The microwave synthesis process and characterization of neat resin and carbon fiber reinforced composites fabricated by RTM will be presented. KEY WORDS: Resin Transfer Molding, High Temperature Polymers, Phenylethynyl Terminated Imides, Microwave Synthesis

Design, synthesis and application of novel fluorescent nucleosides

OpenAIRE

Greco, Nicholas Joseph

2008-01-01

Nucleic acids, the biomolecules of life, have demanded the attention of chemists and biologists for greater than a century. The ability to investigate, in detail, the structure, function and the interplay between the two has driven the development of novel approaches for the investigation of these concepts. Fluorescence spectroscopy, a technique that protein chemists have utilized for many years due to the inherent favorable photophysical properties of select naturally occurring amino acids, ...

Photophysical properties and excited state intramolecular proton transfer in 2-hydroxy-5-[(E)-(4-methoxyphenyl)diazenyl]benzoic acid in homogeneous solvents and micro-heterogeneous environments

Energy Technology Data Exchange (ETDEWEB)

Gashnga, Pynsakhiat Miki [Centre for Advanced Studies, Department of Chemistry, North-Eastern Hill University, Shillong 793022, Meghalaya (India); Singh, T. Sanjoy [Department of Chemistry, Assam University, Silchar 788011, Assam (India); Baul, Tushar S. Basu [Centre for Advanced Studies, Department of Chemistry, North-Eastern Hill University, Shillong 793022, Meghalaya (India); Mitra, Sivaprasad, E-mail: smitra@nehu.ac.in [Centre for Advanced Studies, Department of Chemistry, North-Eastern Hill University, Shillong 793022, Meghalaya (India)

2014-04-15

A systematic study on the photophysical properties and excited state intramolecular proton transfer (ESIPT) behavior of 2-hydroxy-5-[(E)-(4-methoxyphenyl)diazenyl]benzoic acid, is reported using steady-state and time-resolved fluorescence spectroscopy in homogeneous solvents as well as in different micro-heterogeneous environments. Depending on the nature of intramolecular hydrogen bond (IHB), the salicylic acid derivative may exist in two different ground state conformers (I and II). Structure I having IHB between the carbonyl oxygen and phenolic hydrogen can undergo ESIPT upon excitation as evidenced by largely Stokes-shifted fluorescence at ∼455 nm; whereas, normal fluorescence in the blue side of the spectrum (∼410 nm) is due to the spontaneous emission from conformer II. The results in homogeneous solvents were compared with those in bio-mimicking environments of β-cyclodextrin (CD) and surfactants. The intensity of the ESIPT fluorescence increases substantially upon encapsulation of the probe into the cyclodextrin as well as micellar nano-cavities. Detailed analysis of the spectroscopic data indicates that the probe forms 1:1 complex with CD in aqueous medium. Binding constant of the probe with the micelles as well as critical micelle concentration was obtained from the variation of fluorescence intensity on increasing concentration of different surfactants in aqueous medium. -- Highlights: • Steady state and time resolved fluorescence study on ESIPT in HMBA. • Dual fluorescence corresponding to the pro- and non-ESIPT structures. • Modulation of ESIPT fluorescence in micro-heterogeneous environments. • 1:1 stoichiometry for interaction with cyclodextrin. • Calculation of binding constant and other physico-chemical properties from fluorescence titration data in surfactants.

Photophysical properties and excited state intramolecular proton transfer in 2-hydroxy-5-[(E)-(4-methoxyphenyl)diazenyl]benzoic acid in homogeneous solvents and micro-heterogeneous environments

International Nuclear Information System (INIS)

Gashnga, Pynsakhiat Miki; Singh, T. Sanjoy; Baul, Tushar S. Basu; Mitra, Sivaprasad

2014-01-01

A systematic study on the photophysical properties and excited state intramolecular proton transfer (ESIPT) behavior of 2-hydroxy-5-[(E)-(4-methoxyphenyl)diazenyl]benzoic acid, is reported using steady-state and time-resolved fluorescence spectroscopy in homogeneous solvents as well as in different micro-heterogeneous environments. Depending on the nature of intramolecular hydrogen bond (IHB), the salicylic acid derivative may exist in two different ground state conformers (I and II). Structure I having IHB between the carbonyl oxygen and phenolic hydrogen can undergo ESIPT upon excitation as evidenced by largely Stokes-shifted fluorescence at ∼455 nm; whereas, normal fluorescence in the blue side of the spectrum (∼410 nm) is due to the spontaneous emission from conformer II. The results in homogeneous solvents were compared with those in bio-mimicking environments of β-cyclodextrin (CD) and surfactants. The intensity of the ESIPT fluorescence increases substantially upon encapsulation of the probe into the cyclodextrin as well as micellar nano-cavities. Detailed analysis of the spectroscopic data indicates that the probe forms 1:1 complex with CD in aqueous medium. Binding constant of the probe with the micelles as well as critical micelle concentration was obtained from the variation of fluorescence intensity on increasing concentration of different surfactants in aqueous medium. -- Highlights: • Steady state and time resolved fluorescence study on ESIPT in HMBA. • Dual fluorescence corresponding to the pro- and non-ESIPT structures. • Modulation of ESIPT fluorescence in micro-heterogeneous environments. • 1:1 stoichiometry for interaction with cyclodextrin. • Calculation of binding constant and other physico-chemical properties from fluorescence titration data in surfactants

Synthesis and photophysical properties of aluminium tris-(4-morpholine-8-hydroxyquinoline).

Science.gov (United States)

Omar, Walaa A E

2013-11-01

Aluminium tris(4-morpholinyl-8-hydroxyquinoline) has been synthesized and characterized. The photoluminescence measurements showed that the new derivative is blue shifted and has relative photoluminescence quantum yield two times higher compared to the pristine Al tris(8-hydroxyquinoline). Deferential scanning colorimetric studies revealed that the newly synthesized Alq3 derivative in this work is amorphous material with the highest transition glass temperature value among the reported amorphous Alq3 derivatives.

Synthesis and photophysical properties of aluminium tris-(4-morpholine-8-hydroxyquinoline

Directory of Open Access Journals (Sweden)

Walaa A.E. Omar

2013-11-01

Full Text Available Aluminium tris(4-morpholinyl-8-hydroxyquinoline has been synthesized and characterized. The photoluminescence measurements showed that the new derivative is blue shifted and has relative photoluminescence quantum yield two times higher compared to the pristine Al tris(8-hydroxyquinoline. Deferential scanning colorimetric studies revealed that the newly synthesized Alq3 derivative in this work is amorphous material with the highest transition glass temperature value among the reported amorphous Alq3 derivatives.

Tetra- and octa-[4-(2-hydroxyethyl)phenoxy bearing novel metal-free and zinc(II) phthalocyanines: Synthesis, characterization and investigation of photophysicochemical properties

Energy Technology Data Exchange (ETDEWEB)

Köksoy, Baybars [Marmara University, Department of Chemistry, 34722 Kadıköy, Istanbul (Turkey); Durmuş, Mahmut [Gebze Technical University, Department of Chemistry, 41400 Gebze, Kocaeli (Turkey); Bulut, Mustafa, E-mail: mbulut@marmara.edu.tr [Marmara University, Department of Chemistry, 34722 Kadıköy, Istanbul (Turkey)

2015-05-15

In this study, four novel phthalonitriles (1–4) and their corresponding metal-free (5–8) and zinc(II) phthalocyanine derivatives (9–12) bearing 4-(hydroxyethyl)phenoxy groups were synthesized. These novel compounds were characterized by IR, elemental analyses, {sup 1}H-NMR, UV–vis, and MALDI-TOF spectral data. Furthermore, photophysical (fluorescence quantum yields and lifetimes) and photochemical properties (singlet oxygen generation and photodegradation quantum yields) of these phthalocyanines were investigated in dimethylsulfoxide. The studied zinc(II) phthalocyanines generated highly singlet oxygen which is very important for the photodynamic therapy (PDT) of cancer. The fluorescence quenching behaviour of the newly synthesized phthalocyanine compounds were also investigated using 1,4-benzoquinone. - Highlights: • Octa and tetra 4-(hydroxyethyl)phenoxy substituted metal-free and zinc(II) phthalocyanines. • Study of photophysicochemical properties of eight new phthalocyanines. • Highly singlet oxygen generation for novel zinc(II) phthalocyanine photosensitizers.

Understanding Microstructural Properties of Perovskite Ceramics through Their Wet-Chemical Synthesis

NARCIS (Netherlands)

Stawski, Tomasz

2011-01-01

This thesis comprises of seven full research chapters on the morphology, properties and processing of sol-gel precursor systems of barium titanate and lead zirconate titanate thin films and powders. In all the considered problems, the synthesis leading to nano-sized perovskite ceramics constitutes

Poly(o-aminophenol) film electrodes synthesis, transport properties and practical applications

CERN Document Server

Tucceri, Ricardo

2014-01-01

This review book is concerned with the synthesis, charge transport properties and practical applications of poly (o-aminophenol) (POAP) film electrodes. It is divided into three parts. The first one has a particular emphasis on problems of synthesis and structure of POAP. The second part deals with the mechanism of charge transfer and charge transport processes occurring in the course of the redox reactions of POAP. The third part describes the promising applications of POAP in the different fields of sensors, electrocatalysis, bioelectrochemistry, corrosion protection, among others. This review covers the literature on POAP in the time period comprised between 1987 and 2013.

Biosorption of arsenic from groundwater using Vallisneria gigantea plants. Kinetics, equilibrium and photophysical considerations.

Science.gov (United States)

Iriel, Analia; Lagorio, M Gabriela; Fernández Cirelli, Alicia

2015-11-01

Arsenic (V) uptake from groundwater by using Vallisneria gigantea plants was studied using batch experiments. Reflectance and fluorescence of intact plants were investigated and changes in photophysical properties following arsenic absorption were reported. Good correlations have been found between arsenic concentration in groundwater and parameters derived from reflectance and fluorescence measurements. This system reached its equilibrium after seven days when the removal quantities were strongly dependent on the initial arsenic concentration. Interestingly, Vallisneria plants were able to accumulate from 100 to 600 mg As kg(-1) in roots and fronds although the translocation factors were low (0.6-1.6). Kinetic data for biosorption process followed a first-order law. At low arsenic concentrations the uptake in plants was governed by diffusion aspects. Langmuir, Freundlich and Dubinin-Radushkevich models were applied and results demonstrated that arsenic uptake was better described by the Langmuir model. As a final remark we concluded that a plant of this species should be able to remove 1mg As per week. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sky-blue emitting bridged diiridium complexes: beneficial effects of intramolecular π-π stacking.

Science.gov (United States)

Congrave, Daniel G; Hsu, Yu-Ting; Batsanov, Andrei S; Beeby, Andrew; Bryce, Martin R

2018-02-06

The potential of intramolecular π-π interactions to influence the photophysical properties of diiridium complexes is an unexplored topic, and provides the motivation for the present study. A series of diarylhydrazide-bridged diiridium complexes functionalised with phenylpyridine (ppy)-based cyclometalating ligands is reported. It is shown by NMR studies in solution and single crystal X-ray analysis that intramolecular π-π interactions between the bridging and cyclometalating ligands rigidify the complexes leading to high luminescence quantum efficiencies in solution and in doped films. Fluorine substituents on the phenyl rings of the bridge promote the intramolecular π-π interactions. Notably, these non-covalent interactions are harnessed in the rational design and synthesis of the first examples of highly emissive sky-blue diiridium complexes featuring conjugated bridging ligands, for which they play a vital role in the structural and photophysical properties. Experimental results are supported by computational studies.

The Synthesis and Luminescence-spectroscopic Properties of Fluorescent Condensation Polymers

Science.gov (United States)

Barashkov, Nikolai N.

1985-07-01

The results of studies on the synthesis of polycondensation phosphorus-containing aliphatic and aromatic polymers as well as the products of polymer-analogue transformations with phosphorus-groups in the side chain are examined. The light absorption and luminescent properties of the polymers obtained and of model compounds having an analogous structure are discussed. The bibliography includes 108 references.

Synthesis, properties and reactivity of intramolecular hypercoordinate silicon complexes

International Nuclear Information System (INIS)

Nikolin, A A; Negrebetsky, V V

2014-01-01

The state of the art of the chemistry of hypercoordinate silicon compounds is analyzed. Published data on the current top-priority approaches to the preparative synthesis of these compounds and on their properties, structures and reactivity are summarized and generalized. Relying on the results obtained by modern physicochemical methods, the possible mechanisms of stereodynamic processes occurring in the coordination units of hypercoordinate silicon complexes are discussed. The bibliography includes 157 references

Crystal chemistry, properties and synthesis of microporous silicates containing transition elements

International Nuclear Information System (INIS)

Chukanov, Nikita V; Pekov, Igor V; Rastsvetaeva, Ramiza K

2004-01-01

The review surveys and generalises recent data on synthesis methods, physicochemical properties and crystal chemistry of silicate microporous materials containing transition elements (amphoterosilicates). The frameworks of these materials, unlike those of usual aluminosilicate zeolites, are built from tetrahedrally coordinated atoms along with atoms of various elements (Ti, Nb, Zr, Ta, Sn, W, Fe, Mn, Zn, etc.) with coordination numbers of 6 or 5. Many amphoterosilicates possess ion-exchange properties and can serve as catalysts for redox reactions, sorbents, etc. The structural diversity of synthetic and natural amphoterosilicates provides the basis for the preparation of microporous materials with different properties.

Effects of synthesis variables on the magnetic properties of CoFe{sub 2}O{sub 4} nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Briceno, Sarah, E-mail: sarahbriara@gmail.com [Laboratorio de Fisica de la Materia Condensada, Centro de Fisica, Instituto Venezolano de Investigaciones Cientificas (IVIC), Apartado 20632, Caracas 1020-A (Venezuela, Bolivarian Republic of); Braemer-Escamilla, Werner; Silva, Pedro [Laboratorio de Fisica de la Materia Condensada, Centro de Fisica, Instituto Venezolano de Investigaciones Cientificas (IVIC), Apartado 20632, Caracas 1020-A (Venezuela, Bolivarian Republic of); Delgado, Gerzon E. [Laboratorio de Cristalografia, Departamento de Quimica, Facultad de Ciencias, Universidad de Los Andes, Merida 5101-A (Venezuela, Bolivarian Republic of); Plaza, Eric [Laboratorio de Microscopia Electronica. Instituto Zuliano de Investigaciones Tecnologicas. Apartado 331. Km. 15. La Canada (Venezuela, Bolivarian Republic of); Palacios, Jordana [Laboratorio de Polimeros, Centro de Quimica, Instituto Venezolano de Investigaciones Cientificas (IVIC), Apartado 20632, Caracas 1020-A (Venezuela, Bolivarian Republic of); Canizales, Edgard [Area de Analisis Quimico Inorganico. PDVSA. INTEVEP. Los Teques 1070-A (Venezuela, Bolivarian Republic of)

2012-09-15

Cobalt ferrite nanoparticles (CoFe{sub 2}O{sub 4}) have been synthesized using precipitation in water solution with polyethylene glycol as surfactant. Influence of various synthesis variables included pH, reaction time and annealing temperature on the magnetic properties and particle sizes has also been studied. Structural identification of the samples was carried out using Thermogravimetric and Differential thermal analysis, X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy, High resolution transmission electron microscopy. Vibrating sample magnetometer was used for the magnetic investigation of the samples. Magnetic properties of nanoparticles show strong dependence on the particle size. The magnetic properties increase with pH of the precipitating medium and annealing temperature while the coercivity goes through a maximum, peaking at around 25 nm. - Highlights: Black-Right-Pointing-Pointer CoFe{sub 2}O{sub 4} have been synthesized via chemical synthesis route using PEG as surfactant. Black-Right-Pointing-Pointer Influence of various synthesis variables on the magnetic properties has been studied. Black-Right-Pointing-Pointer Magnetic properties of nanoparticles show strong dependence on the particle size. Black-Right-Pointing-Pointer Magnetic properties increase with pH and annealing temperature.

Metal Oxide Nano structures: Synthesis, Properties, and Applications

International Nuclear Information System (INIS)

Xu, L. H.; Patil, D. S.; Yang, J.; Xiao, J.

2015-01-01

In recent years, nano structured materials have attracted wide attention due to their fascinating optical and electrical properties, which make these materials potentially suitable for applications in electronics, optics, photonics, and sensors. Some metal oxides show a wide variety of morphologies such as nano wires, nano rods, nano tubes, nano rings, and nano belts. Synthesis and investigation of these metal-oxide nano structures are beneficial not only for understanding the fundamental phenomena in low dimensional systems, but also for developing new-generation nano devices with high performance.

Photophysical processes and light extraction in organic light emitting devices; Photophysikalische Prozesse und Lichtextraktion in organischen Leuchtdioden

Energy Technology Data Exchange (ETDEWEB)

Reinke, Nils Andre

2008-11-10

Alq{sub 3} is the most commonly used material for electron transport and as an emission layer in organic LEDs. However many of its photophysical properties are still unknown. The phosphorescence - known as a low temperature effect - was measured at room temperature for the first time. A new experimental method is presented to identify and characterize a new molecular conversion process into an unknown dark state. This conversion process represents an additional fundamental energy loss channel which is especially important for the development of organic lasers. A physically intuitive model was developed, which allows the calculation of light emission from OLEDs. In addition, a new method for the quantification of optical losses in OLEDs based on an dipole approach has been implemented and verified experimentally. The use of OLEDs was demonstrated for the first time in a chemical sensor, which is based on the detection of the surface plasmon resonance. (orig.)

Synthesis and properties of highly branched Jatropha curcas L. oil derivatives

NARCIS (Netherlands)

Daniel, Louis; Ardiyanti, Agnes R.; Schuur, Boelo; Manurung, Robert; Broekhuis, Antonius A.; Heeres, Hero J.

The synthesis and properties of a number of novel branched Jatropha curcas L. oil (JO) derivatives containing vicinal di-ester units in the fatty acid chains are reported. Both the length (acetyl vs. hexanoyl) and the stereochemistry of the vicinal di-ester units (cis vs. trans) were varied. The

Synthesis and colloidal properties of anisotropic hydrothermal barium titanate

Science.gov (United States)

Yosenick, Timothy James

2005-11-01

Nanoparticles of high dielectric constant materials, especially BaTiO3, are required to achieve decreased layer thickness in multilayer ceramic capacitors (MLCCs). Tabular metal nanoparticles can produce thin metal layers with low surface roughness via electrophoretic deposition (EPD). To achieve similar results with dielectric layers requires the synthesis and dispersion of tabular BaTiO3 nanoparticles. The goal of this study was to investigate the deposition of thin BaTiO3 layers using a colloidal process. The synthesis, interfacial chemistry and colloidal properties of hydrothermal BaTiO3 a model particle system, was investigated. After characterization of the material system particulates were deposited to form thin layers using EPD. In the current study, the synthesis of BaTiO3 has been investigated using a hydrothermal route. TEM and AFM analyses show that the synthesized particles are single crystal with a majority of the particle having a zone axis and {111} large face. The particles have a median thickness of 5.8 +/- 3.1 nm and face diameter of 27.1 +/- 12.3 nm. Particle growth was likely controlled by the formation of {111} twins and the synthesis pH which stabilizes the {111} face during growth. With limited growth in the direction, the particles developed a plate-like morphology. Physical property characterization shows the powder was suitable for further processing with high purity, low hydrothermal defect concentration, and controlled stoichiometry. TEM observations of thermally treated powders indicate that the particles begin to loose the plate-like morphology by 900 °C. The aqueous passivation, dispersion, and doping of nanoscale BaTiO 3 powders was investigated. Passivation BaTiO3 was achieved through the addition of oxalic acid. The oxalic acid selectively adsorbs onto the particle surface and forms a chemically stable 2-3 nm layer of barium oxalate. The negative surface charge of the oxalate effectively passivated the BaTiO3 providing a surface

Simulation of some dynamical aspects of the photophysics of dye molecules encapsulated in a dendrimer

Energy Technology Data Exchange (ETDEWEB)

Teobaldi, Gilberto [Dipartimento di Chimica ' G. Ciamician' , Universita di Bologna, Via F. Selmi 2, Bologna I-40126 (Italy); Zerbetto, Francesco [Dipartimento di Chimica ' G. Ciamician' , Universita di Bologna, Via F. Selmi 2, Bologna I-40126 (Italy)]. E-mail: francesco.zerbetto@unibo.it

2005-03-15

We use a combination of molecular dynamics and quantum chemical calculations to investigate the photophysics of Eosin Y encapsulated in a fourth generation of poly-propylene amine dendrimer functionalized in the periphery with dansyl units. Once in contact with the macromolecule, the guests display a double exponential decay of the excited states that is reproduced by the present model.

Simulation of some dynamical aspects of the photophysics of dye molecules encapsulated in a dendrimer

International Nuclear Information System (INIS)

Teobaldi, Gilberto; Zerbetto, Francesco

2005-01-01

We use a combination of molecular dynamics and quantum chemical calculations to investigate the photophysics of Eosin Y encapsulated in a fourth generation of poly-propylene amine dendrimer functionalized in the periphery with dansyl units. Once in contact with the macromolecule, the guests display a double exponential decay of the excited states that is reproduced by the present model

Influence of synthesis energy on physical properties of the oxide nanoparticles

International Nuclear Information System (INIS)

Medeiros, A.A.S.; Mello, V.S. e; Trajano, M.F.; Alves, S.M.

2014-01-01

Nanoparticles are present in many research areas giving a range of applications, one of them is lubricant technology. Oxide nanoparticles have been used as extreme pressure additives in boundary lubrication with good results. The great challenge of this technology is in control of the nanoparticles dispersion to ensure their actions as anti-wear additive. This study goal was to evaluate the influence of the amount of energy synthesis in the dispersive properties, size and shape of nanoparticles synthesized by microwave, varying the amount of energy transferred during the synthesis process. The morphology of the nanoparticles was evaluated by SEM and XRD spectrum was used to identify the crystallite size and the formation of copper oxides. The results showed that the size and shape of the particle, and consequently the dispersion, are directly related to amount of energy used in the synthesis are directly related. (author)

Probing DNA-stabilized fluorescent silver nanocluster spectral heterogeneity by time-correlated single photon counting

DEFF Research Database (Denmark)

Carro, Miguel; Paolucci, Valentina; Hooley, Emma Nicole

2016-01-01

DNA-stabilized silver nanoclusters (DNA-AgNCs) are promising fluorophores whose photophysical properties and synthesis procedures have received increased attention in the literature. However, depending on the preparation conditions and the DNA sequence, the DNA-AgNC samples can host a range...... the spectral heterogeneity of other fluorophores, such as luminescent colloidal nanoparticles, and to assess the reproducibility of a synthetic procedure containing an unknown distribution of emissive species....

Synthesis and properties of butadiene-alpha-methylstyrene thermoplastic elastomer

Directory of Open Access Journals (Sweden)

A. V. Firsova

2016-01-01

Full Text Available Butadiene-α-methylstyrene block – copolymer – a thermoplastic elastomer (TPE-R DMST occupies a special place among the ethylene – vinyl aromatic block copolymers. TPE-R DMST comprising as plastic – poly-α-methylstyrene unit and elastic – polybutadiene block. TPE-R DMST has high heat resistance, flexibility, abrasion resistance compared to butadiene-styrene thermoplastic elastomer (TPE DST. The synthesis of block copolymers of butadiene and α-methylstyrene was carried out. The process of polymerization the α-methylstyrene characterized the high speed of polymerization in polar medium and low reaction speed in hydrocarbon solvents. Anionic catalyst nbutyllithium (n-BuLi and high concentration – 60–80% α-methylstyrene in the mixture influenced by synthesis of the 1st block of TPE-R DMST, it’s technologically difficult. Found that the low temperature of polymerization α-methylstyrene (+61 o C, the reversibility of these reactions and the high concentration of residual monomer are very importance. It was revealed that a high polymerization rate α-methylstyrene can be achieved by conducting the reaction in a hydrocarbon solvent with polar additives compounds such as tetrahydrofuran (THF and methyl tert-butyl ether (MTBE. The conditions for the synthesis of P-DMST were developed. The kinetics of polymerization for the first DMST-P unit was obtained. Analysis of physical and mechanical properties DMST-P samples was conducted. The optimum content of bound α-methylstyrene block copolymer provides a good combination of properties in a relatively wide temperature range. The tensile strength at normal and elevated temperatures, the hardness and the stiffness of the polymer increased by increasing the content of bound α-methylstyrene. The elongation and the elasticity reduced by increasing the content of bound α-methylstyrene.

Synthesis, structural and ferromagnetic properties of La1–x Kx ...

Indian Academy of Sciences (India)

2016-08-26

Aug 26, 2016 ... Synthesis, structural and ferromagnetic properties of La1–KMnO3 (0.0≤ 0.25) phases by solution combustion method ... Structural parameters were determined by the Rietveld refinement method using powder XRD data. Parent ... The ratio of the Mn3+/Mn4+ was determined by the iodometric titration.

Synthesis and Exciton Dynamics of Donor-Orthogonal Acceptor Conjugated Polymers: Reducing the Singlet–Triplet Energy Gap

KAUST Repository

Freeman, David M. E.; Musser, Andrew J.; Frost, Jarvist M.; Stern, Hannah L.; Forster, Alexander K.; Fallon, Kealan J.; Rapidis, Alexandros G.; Cacialli, Franco; McCulloch, Iain; Clarke, Tracey M.; Friend, Richard H.; Bronstein, Hugo

2017-01-01

The presence of energetically low-lying triplet states is a hallmark of organic semiconductors. Even though they present a wealth of interesting photophysical properties, these optically dark states significantly limit optoelectronic device performance. Recent advances in emissive charge-transfer molecules have pioneered routes to reduce the energy gap between triplets and

Synthesis and Exciton Dynamics of Donor-Orthogonal Acceptor Conjugated Polymers: Reducing the Singlet–Triplet Energy Gap

KAUST Repository

Freeman, David M. E.

2017-06-09

The presence of energetically low-lying triplet states is a hallmark of organic semiconductors. Even though they present a wealth of interesting photophysical properties, these optically dark states significantly limit optoelectronic device performance. Recent advances in emissive charge-transfer molecules have pioneered routes to reduce the energy gap between triplets and

Controllable synthesis of Eu{sup 3+}/Tb{sup 3+} activated lutetium fluorides nanocrystals and their photophysical properties

Energy Technology Data Exchange (ETDEWEB)

Lin, Jintai; Huo, Jiansheng [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Cai, Yuepeng [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Qianming, E-mail: qmwang@scnu.edu.cn [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, Guangzhou 510006 (China)

2013-12-15

In this paper, phosphors of LuF{sub 3}:Eu{sup 3+}/Tb{sup 3+} have been successfully synthesized with small chelator ethylenediaminetetra acetic acid (EDTA) or amphiphilic polymer (polyethylene glycol, PEG-1000) as templates via a hydrothermal method. X-ray powder diffraction (XRD), scanning electronic microscope (SEM), and photo-luminescent spectra techniques (PL) were used to characterize the as-prepared samples. XRD patterns showed that well crystallized lanthanide fluorides with hexagonal phase were achieved. SEM images revealed that different regular microstructures were achieved. The photo-luminescent properties of LuF{sub 3}:Eu{sup 3+} demonstrated that there are significant energy transfers from fluorides to Eu{sup 3+}. The results presented that EDTA as the template will lead to the highest emission intensities. -- Highlights: • Various templates were used to synthesize LuF{sub 3}:Eu{sup 3+}/Tb{sup 3+}. • All the phosphors were red or green emissive. • Different morphologies were acquired and controllable.

Synthesis and Properties of Group IV Graphane Analogues

Science.gov (United States)

Goldberger, Joshua

Similar to how carbon networks can be sculpted into low-dimensional allotropes such as fullerenes, nanotubes, and graphene with fundamentally different properties, it is possible to create similar ligand terminated sp3-hybridized honeycomb graphane derivatives containing Ge or Sn that feature unique and tunable properties. Here, we will describe our recent success in the creation of hydrogen and organic-terminated group IV graphane analogues, from the topochemical deintercalation of precursor Zintl phases, such as CaGe2. We will discuss how the optical, electronic, and thermal properties of these materials can be systematically controlled by substituting either the surface ligand or via alloying with other Group IV elements. Additionally, we have also developed an epitopotaxial approach for integrating precise thicknesses of germanane layers onto Ge wafers that combines the epitaxial deposition of CaGe2 precursor phases with the topotactic interconversion into the 2D material. Finally, we will describe our recent efforts on the synthesis and crystal structures of Sn-containing graphane alloys in order to access novel topological phenomena predicted to occur in these graphanes.

Synthesis and fluorescence properties of some difluoroboron β-diketonate complexes and composite containing PMMA

Science.gov (United States)

Xing, Dongye; Hou, Yanjun; Niu, Haijun

2018-03-01

A series of difluoroboron β-diketonate complexes, containing the indon-β-diketonate ligand carrying methyl or methoxyl substituents was synthesized. The crystal structures of the complexes were confirmed by single crystal X-ray diffraction studies. The fluorescence properties of compounds were studied in solution state, solid state and on PMMA polymer matrix. The photophysical data of compounds 2a-2d exhibited strong fluorescence and photostability under the ultraviolet light (Hg lamp). The complex 2b showed higher fluorescence intensity in solution state as compared to other complexes of the series. The complexes 2c and 2d showed higher fluorescence intensity in the solid state, which are ascribed to the stronger π-π interactions between ligands in the solid state. The introduction of methoxyl or methyl groups on the benzene rings enhanced the absorption intensity, emission intensity, quantum yields and fluorescence lifetimes due to their electron-donating nature. Furthermore, the complex 2b was doped into the PMMA to produce hybrid materials, where the PMMA matrix acted as sensitizer for the central boron ion to enhance the fluorescence emission intensity and quantum yields.

Synthesis and optical properties of polyurethane foam modified with silver nanoparticles

International Nuclear Information System (INIS)

Apyari, V V; Volkov, P A; Dmitrienko, S G

2012-01-01

This paper for the first time describes peculiarities of synthesis of polyurethane foam modified with silver nanoparticles as a potential material for optical sensors in analytical chemistry. We found that the unique sorptional properties of polyurethane foam gave an opportunity to perform such a synthesis by two different approaches. The first one was based on sorption of previously synthesized in-solution nanoparticles by polyurethane foam, the second one consisted in preparation of nanoparticles directly in polyurethane foam matrix. This possibility is novel and interesting for practical use because the nanoparticles in polyurethane foam are capable of surface plasmon resonance. The influence of different factors during the synthesis was investigated and the optimal conditions were found. The samples prepared were characterized by diffuse reflectance spectroscopy and scanning electron microscopy. On the basis of the results obtained we first suggested that this material is attractive from the viewpoint of analytical chemistry as a convenient analytical form for determination of oxidants and reductants

Thioxanthone based 9-[2-(methyl-phenyl-amino)-acetyl]-thia-naphthacene-12-one as a visible photoinitiator

International Nuclear Information System (INIS)

Doğruyol, Sevnur Keskin; Doğruyol, Zekeriya; Arsu, Nergis

2013-01-01

Photoinitiators that operate in the visible range of the electromagnetic spectrum have widespread applications. Thioxanthone based 9-[2-(methyl-phenyl-amino)-acetyl]-thia-naphthacene-12-one (TX-MPA) was synthesized and the characterization of this initiator was confirmed by spectral analysis methods. TX-MPA has excellent absorption properties in the visible range (ε 480 nm =3576 L/mol.cm). Photophysical studies; fluorescence quantum yield (φ f =0.22, DPA), phosphorescence lifetime (τ p =115 ms) and triplet lifetime (τ=190 ns) were explored. To explore the initiation mechanism of TX-MPA, besides the photophysical and photochemical studies, the polymer (PMMA) obtained from the photopolymerization studies was subjected to a phosphorescence study and τ p was found to be 105 ms compared to 115 ms for the initiator TX-MPA which proved attachment of the initiator to the polymer. Possibly both intermolecular and intramolecular hydrogen abstraction, occur during the initiation stage depending on the concentration of the initiator. Highlights: ► Synthesis and photophysical properties of a visible photoinitiator (TX-MPA) are proposed. ► TX-MPA has high molar absorption values in the visible region. ► TX-MPA can initiate photopolymerization of methylmethacrylate monomer under UV and sunlight. ► Inter or intramolecular hydrogen abstraction mechanisms occur depending on initiator concentration

Microwave-assisted hydrothermal synthesis of CePO4 nanostructures: Correlation between the structural and optical properties

International Nuclear Information System (INIS)

Palma-Ramírez, D.; Domínguez-Crespo, M.A.; Torres-Huerta, A.M.; Dorantes-Rosales, H.; Ramírez-Meneses, E.; Rodríguez, E.

2015-01-01

Highlights: • An enhancement in the hydrothermal synthesis for obtaining of CePO 4 is presented. • Microwave energy can replace the energy by convection for obtaining CePO 4 . • CePO 4 demonstrates to be an option to increase the optical properties of polymers. • Adjusting the pH, the sintering process is not necessary to obtain the desire phase. • CePO 4 morphologies undergo evolution from nanorods to semispherical nanoparticles. - Abstract: In this work, the microwave-assisted hydrothermal method is proposed as an alternative to the synthesis of cerium phosphate (CePO 4 ) nanostructures to evaluate the influence of different synthesis parameters on both the structural and optical properties. In order to reach this goal, two different sets of experiments were designed, varying the reaction temperature (130 and 180 °C), synthesis time (15 and 30 min) and sintering temperature (400 and 600 °C), maintaining a constant pH = 3. Thereafter, two experimental conditions were selected to assess changes in the properties of CePO 4 nanopowders with pH (1, 5, 9 and 11). The crystal structure and morphology of the nanostructures were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. Diffuse reflectance properties of CePO 4 with different microstructures were studied. The results demonstrated that by using the microwave-assisted hydrothermal method, the shape, size and structural phase of CePO 4 can be modulated by using relatively low synthesis temperatures and short reaction times, and depending on pH, a sintering process is not needed to obtain either a desired phase or size. Under the selected experimental conditions, the materials underwent an evolution from nanorods to semispherical nanoparticles, accompanied by a phase transition from hexagonal to monoclinic

Synthesis, Properties, and Applications of Low-Dimensional Carbon-Related Nano materials

International Nuclear Information System (INIS)

Mostofizadeh, A.; Li, Y.; Song, B.; Huang, Y.; Mostofizadeh, A.

2011-01-01

In recent years, many theoretical and experimental studies have been carried out to develop one of the most interesting aspects of the science and nano technology which is called carbon-related nano materials. The goal of this paper is to provide a review of some of the most exciting and important developments in the synthesis, properties, and applications of low-dimensional carbon nano materials. Carbon nano materials are formed in various structural features using several different processing methods. The synthesis techniques used to produce specific kinds of low-dimensional carbon nano materials such as zero-dimensional carbon nano materials (including fullerene, carbon-encapsulated metal nanoparticles, nano diamond, and onion-like carbons), one-dimensional carbon nano materials (including carbon nano fibers and carbon nano tubes), and two-dimensional carbon nano materials (including graphene and carbon nano walls) are discussed in this paper. Subsequently, the paper deals with an overview of the properties of the mainly important products as well as some important applications and the future outlooks of these advanced nano materials.

Semiconductor nanoparticles with spatial separation of charge carriers: synthesis and optical properties

International Nuclear Information System (INIS)

Vasiliev, Roman B; Dirin, Dmitry N; Gaskov, Alexander M

2011-01-01

The results of studies on core/shell semiconductor nanoparticles with spatial separation of photoexcited charge carriers are analyzed and generalized. Peculiarities of the electronic properties of semiconductor/semiconductor heterojunctions formed inside such particles are considered. Data on the effect of spatial separation of charge carriers on the optical properties of nanoparticles including spectral shifts of the exciton bands, absorption coefficients and electron–hole pair recombination times are presented. Methods of synthesis of core/shell semiconductor nanoparticles in solutions are discussed. Specific features of the optical properties of anisotropic semiconductor nanoparticles with the semiconductor/semiconductor junctions are noted. The bibliography includes 165 references.

GRAPHENE BASED METAL AND METAL OXIDE NANOCOMPOSITES: SYNTHESIS, PROPERTIES AND THEIR APPLICATIONS

KAUST Repository

Khan, Mujeeb; Tahir, Muhammad Nawaz; Adil, Syed F; Khan, Hadayat Ullah; Siddiqui, Rafiq H; Al-Warthan, Abdulrahman Abdullah; Tremel, Wolfgang

2015-01-01

Graphene, an atomically thin two-dimensional carbonaceous material, has attracted tremendous attention in the scientific community, due to its exceptional electronic, electrical, and mechanical properties. Indeed, with the recent explosion of methods for a large-scale synthesis of graphene, the number of publications related to graphene and other graphene based materials have increased exponentially. Particularly the easy preparation of graphene like materials, such as, highly reduced graphene oxide (HRG) via reduction of graphite oxide (GO), offers a wide range of possibilities for the preparation of graphene based inorganic nanocomposites by the incorporation of various functional nanomaterials for a variety of applications. In this review, we discuss the current development of graphene based metal and metal oxide nanocomposites, with a detailed account of their synthesis and properties. Specifically, much attention has been given to their wide range of applications in various fields, including, electronics, electrochemical and electrical fields. Overall, by the inclusion of various references, this review covers in detail aspects of the graphene-based inorganic nanocomposites.

GRAPHENE BASED METAL AND METAL OXIDE NANOCOMPOSITES: SYNTHESIS, PROPERTIES AND THEIR APPLICATIONS

KAUST Repository

Khan, Mujeeb

2015-06-11

Graphene, an atomically thin two-dimensional carbonaceous material, has attracted tremendous attention in the scientific community, due to its exceptional electronic, electrical, and mechanical properties. Indeed, with the recent explosion of methods for a large-scale synthesis of graphene, the number of publications related to graphene and other graphene based materials have increased exponentially. Particularly the easy preparation of graphene like materials, such as, highly reduced graphene oxide (HRG) via reduction of graphite oxide (GO), offers a wide range of possibilities for the preparation of graphene based inorganic nanocomposites by the incorporation of various functional nanomaterials for a variety of applications. In this review, we discuss the current development of graphene based metal and metal oxide nanocomposites, with a detailed account of their synthesis and properties. Specifically, much attention has been given to their wide range of applications in various fields, including, electronics, electrochemical and electrical fields. Overall, by the inclusion of various references, this review covers in detail aspects of the graphene-based inorganic nanocomposites.

Application of CAPEC Lipid Property Databases in the Synthesis and Design of Biorefinery Networks

DEFF Research Database (Denmark)

Bertran, Maria-Ona; Cunico, Larissa; Gani, Rafiqul

Petroleum is currently the primary raw material for the production of fuels and chemicals. Consequently, our society is highly dependent on fossil non-renewable resources. However, renewable raw materials are recently receiving increasing interest for the production of chemicals and fuels, so a n...... of biorefinery networks. The objective of this work is to show the application of databases of physical and thermodynamic properties of lipid components to the synthesis and design of biorefinery networks.......]. The wide variety and complex nature of components in biorefineries poses a challenge with respect to the synthesis and design of these types of processes. Whereas physical and thermodynamic property data or models for petroleum-based processes are widely available, most data and models for biobased...

The Synthesis and Decay Properties of the Heaviest Elements

CERN Document Server

Oganessian, Yu T

2000-01-01

The synthesis and the study of radioactive properties of new elements is considered with respect to the existence of the "islands of stability" of hypothetical superheavy elements predicted by the theory more than 35 years ago. Experimental data demonstrating an enhanced stability of nuclei in the vicinity of deformed shells with Z=108 and N=162 is discussed from the point of view of advent into more heavy and much more stable nuclides near the predicted spherical shells Z=114-122 and N=184 following after the doubly magic nucleus ^{208}Pb. The author presents the results of experiments on the synthesis of isotopes of elements 114 and 116 in the fusion reactions with ^{48}Ca. In these reactions the decay chains of heavy atoms consisting of sequential alpha-decays interrupted by spontaneous fission have been observed. The decay energies and probabilities are compared with predictions of different theoretical models describing the structure of heavy nuclei. The obtained results are considered as the first exper...

Fluorescent organic dyes as radiation converters in scintillation counting and laser techniques

International Nuclear Information System (INIS)

Guesten, H.

1989-01-01

PMP (1-phenyl-3-mesityl-2-pyrazoline) was selected as color quenching from the category of the sterically hindered 1,3-diphenyl-2-pyrazoline by means of comparative optimization between photo-physical and scintillation-spectroscopic and chemical properties and the costs of synthesis. It is applied in liquid scintillation detectors for the detection of β (T, C-14) and in large-volume liquid scintillators for the detection of neutrinos (Rutherford Lab.). (HP) [de

Synthesis of water-soluble, ring-substituted squaraine dyes and their evaluation as fluorescent probes and labels

Energy Technology Data Exchange (ETDEWEB)

Tatarets, Anatoliy L. [SSI ' Institute for Single Crystals' of the National Academy of Sciences of Ukraine, 60 Lenin Ave., Kharkov 61001 (Ukraine); Fedyunyayeva, Irina A. [SSI ' Institute for Single Crystals' of the National Academy of Sciences of Ukraine, 60 Lenin Ave., Kharkov 61001 (Ukraine); Dyubko, Tatyana S. [SSI ' Institute for Single Crystals' of the National Academy of Sciences of Ukraine, 60 Lenin Ave., Kharkov 61001 (Ukraine); Povrozin, Yevgeniy A. [SSI ' Institute for Single Crystals' of the National Academy of Sciences of Ukraine, 60 Lenin Ave., Kharkov 61001 (Ukraine); Doroshenko, Andrey O. [Institute of Chemistry, V.N. Karazin National University, 4 Svobody Sq., Kharkov 61077 (Ukraine); Terpetschnig, Ewald A. [SETA BioMedicals, LLC, 2014 Silver Ct East, Urbana, IL 61801 (United States) and ISS, Inc., 1602 Newton Drive, Champaign, IL 61822 (United States)]. E-mail: ewaldte@juno.com; Patsenker, Leonid D. [SSI ' Institute for Single Crystals' of the National Academy of Sciences of Ukraine, 60 Lenin Ave., Kharkov 61001 (Ukraine); SETA BioMedicals, LLC, 2014 Silver Ct East, Urbana, IL 61801 (United States)

2006-06-16

A series of ring-substituted squaraines absorbing and emitting in the red and NIR spectral region was synthesized and their spectral and photophysical properties (quantum yields, fluorescence lifetimes) and photostabilities were measured and compared to Cy5, a commonly used fluorescent label. The absorption maxima in aqueous media were found to be between 628 and 667 nm and the emission maxima are between 642 and 685 nm. Squaraine dyes exhibit high extinction coefficients (163,000-265,000 M{sup -1} cm{sup -1}) and lower quantum yields (2-7%) in aqueous buffer but high quantum yields (up to 45%) and long fluorescence lifetimes (up to 3.3 ns) in presence of BSA. Dicyanomethylene- and thio-substituted squaraines exhibit an additional absorption around 400 nm with extinction coefficients between 21,500 and 44,500 M{sup -1} cm{sup -1}. These dyes are excitable not only with red but also with blue diode lasers or light emitting diodes. Due to the favourable spectral and photophysical properties these dyes can be used as fluorescent probes and labels for intensity- and fluorescence lifetime-based biomedical applications.

A series of luminescent Re(I) complexes with electron-donor/acceptor moieties: Synthesis, characterization, and photoluminescence

International Nuclear Information System (INIS)

Ge Hu; Qing She; Lei Guo

2012-01-01

In this paper, we synthesize three Re(I) complexes of Re(CO) 3 (PPO)Br, Re(CO) 3 (PTO)Br, and Re(CO) 3 (PBI)Br, where PPO=2-phenyl-5-(pyridin-2-yl)-1,3,4-oxadiazole, PTO=2-(pyridin-2-yl)-5-p-tolyl-1,3,4-oxadiazole, PBI=2-(pyridin-2-yl)-1H-benzo[d]imidazole. Their single crystals and photophysical properties are measured and discussed in detail. The correlation between ligand structure and corresponding PL characteristics of Re(I) complex has been investigated. It is found that a ligand with strong electron-donor can efficiently increase both absorption and emissive energy of Re(I) complex. In addition, electron-rich ligand can increase the electron density of the complex and thus enhance the oscillator strength of electronic transition, improving the photoluminescence performance. - Highlights: ► Three novel phosphorescent Re(I) complexes are synthesized. ► Molecular structures, photophysical, and electronic properties are studied. ► Strong electron-donor can increase emissive energy. ► Electron-rich ligand can enhance the oscillator strength of electronic transition.

Synthesis of water-soluble, ring-substituted squaraine dyes and their evaluation as fluorescent probes and labels

International Nuclear Information System (INIS)

Tatarets, Anatoliy L.; Fedyunyayeva, Irina A.; Dyubko, Tatyana S.; Povrozin, Yevgeniy A.; Doroshenko, Andrey O.; Terpetschnig, Ewald A.; Patsenker, Leonid D.

2006-01-01

A series of ring-substituted squaraines absorbing and emitting in the red and NIR spectral region was synthesized and their spectral and photophysical properties (quantum yields, fluorescence lifetimes) and photostabilities were measured and compared to Cy5, a commonly used fluorescent label. The absorption maxima in aqueous media were found to be between 628 and 667 nm and the emission maxima are between 642 and 685 nm. Squaraine dyes exhibit high extinction coefficients (163,000-265,000 M -1 cm -1 ) and lower quantum yields (2-7%) in aqueous buffer but high quantum yields (up to 45%) and long fluorescence lifetimes (up to 3.3 ns) in presence of BSA. Dicyanomethylene- and thio-substituted squaraines exhibit an additional absorption around 400 nm with extinction coefficients between 21,500 and 44,500 M -1 cm -1 . These dyes are excitable not only with red but also with blue diode lasers or light emitting diodes. Due to the favourable spectral and photophysical properties these dyes can be used as fluorescent probes and labels for intensity- and fluorescence lifetime-based biomedical applications

Photophysical studies of the interactions of poly(amidoamine) generation zero (PAMAM G0) with copper and zinc ions

Energy Technology Data Exchange (ETDEWEB)

López-Cabaña, Z.E. [Laboratory of Asymmetric Synthesis, Chemistry Institute of Natural Resources, University of Talca (Chile); Valdés, O. [Nanobiotechnology Division at University of Talca, Fraunhofer Chile Research Foundation – Center for Systems Biotechnology, FCR-CSB, P.O. Box 747 Talca (Chile); Vergara, C.E. [Laboratory of Asymmetric Synthesis, Chemistry Institute of Natural Resources, University of Talca (Chile); Camarada, M.B. [Universidad Andrés Bello, Facultad de Biología, Center for Bioinformatics and Integrative Biology (CBIB), República 239, Santiago (Chile); Fundación Fraunhofer Chile Research, M. Sánchez Fontecilla 310 piso 14, Las Condes (Chile); Nachtigall, F.M. [Nanobiotechnology Division at University of Talca, Fraunhofer Chile Research Foundation – Center for Systems Biotechnology, FCR-CSB, P.O. Box 747 Talca (Chile); González-Nilo, F.D. [Universidad Andrés Bello, Facultad de Biología, Center for Bioinformatics and Integrative Biology (CBIB), República 239, Santiago (Chile); Fundación Fraunhofer Chile Research, M. Sánchez Fontecilla 310 piso 14, Las Condes (Chile); Santos, Leonardo S., E-mail: lssantos@utalca.cl [Laboratory of Asymmetric Synthesis, Chemistry Institute of Natural Resources, University of Talca (Chile); Nanobiotechnology Division at University of Talca, Fraunhofer Chile Research Foundation – Center for Systems Biotechnology, FCR-CSB, P.O. Box 747 Talca (Chile)

2015-08-15

This study reports the photophysical behavior of poly(amidoamine) generation zero (PAMAM G0) in the presence of Cu(II) and Zn(II) ions in aqueous solutions using absorption and fluorescence spectroscopy. Theoretical and experimental results confirmed the presence of a strong covalent metal–ligand interaction between PAMAM G0 and copper ion that favored the formation of a ligand–metal charge transfer band coordination complex. In the case of Zn(II), no complex formation with PAMAM G0 was registered. Structure analysis identified the presence of aggregate like PAMAM G0–Zn moieties that generated an enhancement in the fluorescence emission of PAMAM G0. - Highlights: • Photophysical behavior of PAMAM G0 dendrimer with Cu and Zn ions was studied. • Strong covalent metal–ligand interaction was confirmed between PAMAM G0–Cu(II). • No complex formation with PAMAM G0 was registered in the case of Zn(II). • Dendrimer aggregate generated an enhancement in fluorescence emission.

Photophysical studies of the interactions of poly(amidoamine) generation zero (PAMAM G0) with copper and zinc ions

International Nuclear Information System (INIS)

López-Cabaña, Z.E.; Valdés, O.; Vergara, C.E.; Camarada, M.B.; Nachtigall, F.M.; González-Nilo, F.D.; Santos, Leonardo S.

2015-01-01

This study reports the photophysical behavior of poly(amidoamine) generation zero (PAMAM G0) in the presence of Cu(II) and Zn(II) ions in aqueous solutions using absorption and fluorescence spectroscopy. Theoretical and experimental results confirmed the presence of a strong covalent metal–ligand interaction between PAMAM G0 and copper ion that favored the formation of a ligand–metal charge transfer band coordination complex. In the case of Zn(II), no complex formation with PAMAM G0 was registered. Structure analysis identified the presence of aggregate like PAMAM G0–Zn moieties that generated an enhancement in the fluorescence emission of PAMAM G0. - Highlights: • Photophysical behavior of PAMAM G0 dendrimer with Cu and Zn ions was studied. • Strong covalent metal–ligand interaction was confirmed between PAMAM G0–Cu(II). • No complex formation with PAMAM G0 was registered in the case of Zn(II). • Dendrimer aggregate generated an enhancement in fluorescence emission

Gold icosahedral nanocages: Facile synthesis, optical properties, and fragmentation under ultrasonication

Science.gov (United States)

Yang, Xuan; Gilroy, Kyle D.; Vara, Madeline; Zhao, Ming; Zhou, Shan; Xia, Younan

2017-09-01

Because of their unique optical properties, gold nanocages are excellent candidates for biomedical applications. Traditionally, they are prepared using a method that involves the galvanic replacement reaction between Ag nanocubes and HAuCl4. Here we demonstrate a different approach for the facile synthesis of Au icosahedral nanocages containing twin boundaries, as well as a compact size below 15 nm and ultrathin walls of only a few atomic layers thick. Their optical properties could be tuned by simply controlling the etching time, a result that was also validated by computational modeling. We further evaluated the feasibility of fragmenting the nanocages using ultrasonication.

Synthesis and Properties of Cross-Linked Polyamide Aerogels

Science.gov (United States)

Williams, Jarrod C.; Meador, Mary Ann; McCorkle, Linda

2015-01-01

We report the first synthesis of cross-linked polyamide aerogels through step growth polymerization using a combination of diamines, diacid chloride and triacid chloride. Polyamide oligomers endcapped with amines are prepared as stable solutions in N-methylpyrrolidinone from several different diamine precursors and 1,3-benzenedicarbonyl dichloride. Addition of 1,3,5-benzenetricarbonyl trichloride yields gels which form in under five minutes according to the scheme shown. Solvent exchange of the gels into ethanol, followed by drying using supercritical CO2 extraction gives colorless aerogels with densities around 0.1 to 0.2 gcm3. Thicker monolithes of the polyamide aerogels are stiff and strong, while thin films of certain formulations are highly flexible, durable, and even translucent. These materials may have use as insulation for deployable space structures, rovers, habitats or extravehicular activity suits as well as in many terrestrial applications. Strucure property relationships of the aerogels, including surface area, mechanical properties, and thermal conductivity will be discussed.

Microwave-assisted hydrothermal synthesis of CePO{sub 4} nanostructures: Correlation between the structural and optical properties

Energy Technology Data Exchange (ETDEWEB)

Palma-Ramírez, D. [Instituto Politécnico Nacional, CICATA-Unidad Altamira, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Domínguez-Crespo, M.A., E-mail: mdominguezc@ipn.mx [Instituto Politécnico Nacional, CICATA-Unidad Altamira, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Torres-Huerta, A.M. [Instituto Politécnico Nacional, CICATA-Unidad Altamira, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico); Dorantes-Rosales, H. [Instituto Politécnico Nacional, ESIQIE, Departamento de Metalurgia, C.P. 07300 México D.F. (Mexico); Ramírez-Meneses, E. [Universidad Iberoamericana, Departamento de Ingeniería y Ciencias Químicas, Prolongación Paseo de la Reforma 880, Lomas de Santa Fe, C.P. 01219 México D.F. (Mexico); Rodríguez, E. [Instituto Politécnico Nacional, CICATA-Unidad Altamira, Km 14.5, Carretera Tampico-Puerto Industrial Altamira, C.P. 89600 Altamira, Tamps (Mexico)

2015-09-15

Highlights: • An enhancement in the hydrothermal synthesis for obtaining of CePO{sub 4} is presented. • Microwave energy can replace the energy by convection for obtaining CePO{sub 4}. • CePO{sub 4} demonstrates to be an option to increase the optical properties of polymers. • Adjusting the pH, the sintering process is not necessary to obtain the desire phase. • CePO{sub 4} morphologies undergo evolution from nanorods to semispherical nanoparticles. - Abstract: In this work, the microwave-assisted hydrothermal method is proposed as an alternative to the synthesis of cerium phosphate (CePO{sub 4}) nanostructures to evaluate the influence of different synthesis parameters on both the structural and optical properties. In order to reach this goal, two different sets of experiments were designed, varying the reaction temperature (130 and 180 °C), synthesis time (15 and 30 min) and sintering temperature (400 and 600 °C), maintaining a constant pH = 3. Thereafter, two experimental conditions were selected to assess changes in the properties of CePO{sub 4} nanopowders with pH (1, 5, 9 and 11). The crystal structure and morphology of the nanostructures were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM), respectively. Diffuse reflectance properties of CePO{sub 4} with different microstructures were studied. The results demonstrated that by using the microwave-assisted hydrothermal method, the shape, size and structural phase of CePO{sub 4} can be modulated by using relatively low synthesis temperatures and short reaction times, and depending on pH, a sintering process is not needed to obtain either a desired phase or size. Under the selected experimental conditions, the materials underwent an evolution from nanorods to semispherical nanoparticles, accompanied by a phase transition from hexagonal to monoclinic.

Dependence of Exciton Diffusion Length and Diffusion Coefficient on Photophysical Parameters in Bulk Heterojunction Organic Solar Cells

Science.gov (United States)

Yeboah, Douglas; Singh, Jai

2017-11-01

Recently, the dependence of exciton diffusion length (LD ) on some photophysical parameters of organic solids has been experimentally demonstrated, however no systematic theoretical analysis of this phenomenon has been carried out. We have conducted a theoretical study by using the Förster resonance energy transfer and Dexter carrier transfer mechanisms together with the Einstein-Smoluchowski diffusion equation to derive analytical models for the diffusion lengths (LD ) and diffusion coefficients (D) of singlet (S) and triplet (T) excitons in organic solids as functions of spectral overlap integral (J) , photoluminescence (PL) quantum yield (φD ) , dipole moment (μT ) and refractive index (n) of the photoactive material. The exciton diffusion lengths and diffusion coefficients in some selected organic solids were calculated, and we found that the singlet exciton diffusion length (LDS ) increases with φD and J, and decreases with n. Also, the triplet exciton diffusion length (LDT ) increases with φD and decreases with μT . These may be achieved through doping the organic solids into broad optical energy gap host materials as observed in previous experiments. The calculated exciton diffusion lengths are compared with experimental values and a reasonably good agreement is found between them. The results presented are expected to provide insight relevant to the synthesis of new organic solids for fabrication of bulk heterojunction organic solar cells characterized by better power conversion efficiency.

Synthesis characterization, and properties of rubber lattices; a review

International Nuclear Information System (INIS)

Khan, S.M.; Chughtai, A.; Sattar, A.

2008-01-01

Latex is a stable dispersion of polymeric material in an aqueous medium. Lattices are present in natural as well as in synthetic forms. The range of applications of latex is extensive in carpet underlay, fabric back-coating, paper and paints coatings, adhesive, binder, leather finish, floor polish, waterproof clothing, bounded fiber, pigment printing, latex thread, cement and asphalt, foam scraps binders, can closure, thickeners, box toes and shoes counters, sealant and mastics, modifiers, protein reduction, enzyme treatment and peroxide vulcanization. In this review we are presenting synthesis, characterization, properties, manufacturing and processing of latex. (author)

Synthesis and photophysical properties of phosphorus(V) porphyrins functionalized with axial carbazolylvinylnaphthalimides.

Science.gov (United States)

Zhan, Yong; Cao, Kaiyu; Wang, Chenguang; Jia, Junhui; Xue, Pengchong; Liu, Xingliang; Duan, Xuemei; Lu, Ran

2012-11-21

We have synthesized new D-A-D type phosphorus(V) porphyrin derivatives and functionalized with axial carbazolylvinylnaphthalimide units. The absorption bands of the obtained phosphorus(V) porphyrins were in the range 250-640 nm with high molar absorption coefficients, meaning strong light-harvesting abilities. Notably, it is found that the devices based on phosphorus(V) porphyrins with a configuration structure of [ITO/PEDOT : PSS/organic active film/LiF/Al] give an incident-photon-to-current conversion efficiency (IPCE) response. The maximal IPCE value reaches 2.76% for the device based on compound , which is much higher than that of 0.20% for compound . The reason might be due to the low oxidation potential and the strong light-harvesting ability of the enlarged conjugation of the axial units in compound . Therefore, we deduced that photo-induced electron transfer happened in phosphorus(V) porphyrins bearing axial conjugated donor units, which would make them good candidates for photovoltaic materials that could be applied in solar cells.

Effect of synthesis conditions on the nanopowder properties of Ce{sub 0.9}Zr{sub 0.1}O{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Zimicz, M.G.; Fabregas, I.O.; Lamas, D.G. [CINSO (Centro de Investigaciones en Solidos) CONICET-CITEFA J.B. de La Salle 4397, 1603 Villa Martelli, Pcia. de Buenos Aires (Argentina); Larrondo, S.A., E-mail: susana@di.fcen.uba.ar [Laboratorio de Procesos Cataliticos, Departamento de Ingenieria Quimica, Facultad de Ingenieria, Universidad de Buenos Aires, Pabellon de Industrias, Ciudad Universitaria, 1428 Buenos Aires (Argentina)

2011-06-15

Graphical abstract: . The synthesis of nanocrystalline Ce{sub 0.9}Zr{sub 0.1}O{sub 2} powders via the gel-combustion method, using different fuels, and following either stoichiometric or non-stoichiometric pH-controlled routes is investigated. Research highlights: {yields} All samples exhibited the fluorite-type crystal structure, nanometric average crystallite size and negligible carbon content. {yields} Synthesis conditions strongly affect the average crystallite size, the degree of agglomeration, the specific surface area and the pore volume. {yields} Our results indicate that, by controlling the synthesis conditions it is possible to obtain solids with custom-made morphological properties. -- Abstract: In this work, the synthesis of nanocrystalline Ce{sub 0.9}Zr{sub 0.1}O{sub 2} powders via the gel-combustion method, using different fuels, and following either stoichiometric or non-stoichiometric pH-controlled routes is investigated. The objective is to evaluate the effect of synthesis conditions on the textural and morphological properties, and the crystal structure of the synthesized materials. The solids were characterized by nitrogen physisorption, Scanning Electron Microscopy (SEM), X-ray powder diffraction (XPD), and Carbon-Hydrogen-Nitrogen Elemental Analysis (CHN). All the powders exhibited nanometric crystallite size, fluorite-type structure and negligible carbon content. Synthesis conditions strongly affect the average crystallite size, the degree of agglomeration, the specific surface area and the pore volume. Our results indicate that, by controlling the synthesis conditions it is possible to obtain solids with custom-made morphological properties.

Synthesis, characterization and magnetic properties of room-temperature nanofluid ferromagnetic graphite

OpenAIRE

Souza, N. S.; Sergeenkov, S.; Speglich, C.; Rivera, V. A. G.; Cardoso, C. A.; Pardo, H.; Mombru, A. W.; Rodrigues, A. D.; de Lima, O. F.; Araujo-Moreira, F. M.

2009-01-01

We report the chemical synthesis route, structural characterization, and physical properties of nanofluid magnetic graphite (NFMG) obtained from the previously synthesized bulk organic magnetic graphite (MG) by stabilizing the aqueous ferrofluid suspension with an addition of active cationic surfactant. The measured magnetization-field hysteresis curves along with the temperature dependence of magnetization confirmed room-temperature ferromagnetism in both MG and NFMG samples. (C) 2009 Americ...

Chemistry of Fluorinated Carbon Acids: Synthesis, Physicochemical Properties, and Catalysis.

Science.gov (United States)

Yanai, Hikaru

2015-01-01

The bis[(trifluoromethyl)sulfonyl]methyl (Tf2CH; Tf=SO2CF3) group is known to be one of the strongest carbon acid functionalities. The acidity of such carbon acids in the gas phase is stronger than that of sulfuric acid. Our recent investigations have demonstrated that this type of carbon acids work as novel acid catalysts. In this paper, recent achievements in carbon acid chemistry by our research group, including synthesis, physicochemical properties, and catalysis, are summarized.

Comparing the photophysics of the two forms of the Orange Carotenoid Protein using 2D electronic spectroscopy

Directory of Open Access Journals (Sweden)

Mathies R.A.

2013-03-01

Full Text Available Broadband two-dimensional electronic spectroscopy is applied to investigate the photophysics of the photoactive orange carotenoid protein, which is involved in nonphotochemical quenching in cyanobacteria. Differences in dynamics between the light and dark forms arise from the different structure of the carotenoid in the protein pocket, with consequences for the biological role of the two forms.

Photophysical study of a charge transfer oxazole dye in micelles: Role of surfactant headgroups

Energy Technology Data Exchange (ETDEWEB)

Maiti, Jyotirmay [Department of Chemistry, West Bengal State University, Barasat, Kolkata 700126 (India); Sarkar, Yeasmin; Parui, Partha Pratim [Department of Chemistry, Jadavpur University, Kolkata 700032 (India); Chakraborty, Sandipan [Department of Microbiology, University of Calcutta, Kolkata 700019 (India); Biswas, Suman [Department of Chemistry, West Bengal State University, Barasat, Kolkata 700126 (India); Das, Ranjan, E-mail: ranjan.das68@gmail.com [Department of Chemistry, West Bengal State University, Barasat, Kolkata 700126 (India)

2015-07-15

Photophysics of 5-(4′′-dimethylaminophenyl)-2-(4′-sulfophenyl)oxazole, sodium salt (DMO) which undergoes intramolecular charge transfer in the excited state was studied in micelles. In the cationic and the nonionic micelles, significantly higher fluorescence quantum yield is observed in comparison to the anionic micelles, due to much lower accessibility of DMO to the water molecules in the former micelles than the latter. Time-resolved fluorescence decays were characterized by a fast (τ{sub 1}) and a slow (τ{sub 2}) component of decay in all the micelles. The fast decay component (τ{sub 1}) increases significantly in going from the anionic micelles to the cationic micelles, because of the poorly hydrated headgroup region of the latter micelles compared to the former. Furthermore, much higher value of the slow component of decay (τ{sub 2}) is observed for the cationic and the neutral micelles than the anionic micelles. This is attributed to the increased penetration of water molecules into the micellar core of the anionic micelles compared to the cationic and the neutral micelles. - Highlights: • Photophysics of the fluorophore are remarkably different in the cationic and the anionic micelles. • Differential hydration of the surfactant headgroups gives rise to significantly different fluorescence quantum yield and lifetime in oppositely charged micelles. • Electrostatic interactions fine tune location of the fluorophore in the micelle–water interface of ionic micelles.

Synthesis, characterization and magnetic properties of selected Laves and MAX phases

International Nuclear Information System (INIS)

Hamm, Christin Maria

2017-01-01

In this work the rare-earth free Laves phases Ti 2 M 3 Si with M = Mn, Fe, Co, Ni were synthesized by microwave heating and were structurally and magnetically characterized. Furthermore, the solid solution Ti 2 (Co 1-x Fe x ) 3 Si was synthesized by arc melting and spark plasma sintering, as well as their magnetic behavior was studied. In addition to the Laves phases, the focus was on the synthesis and characterization of aluminum-based MAX phases. For the first time the ternary carbides were prepared by microwave heating. The phase-pure representation of MAX phases was particularly challenging for synthetic solid-state chemistry. The susceptor-assisted microwave heating allows the synthesis of high-quality samples, which was shown in this work on M 2 AlC (M = Ti, V, Cr) and V 4 AlC 3 . Furthermore, for the first time, the doping of these materials with Mn and Fe was successful. In addition to the structural characterization of the new phases, the microstructure and magnetic properties are discussed in this work. Using these doped compounds as well as the compound V 4 AlC 3 , it has been shown that field-activated synthesis, particularly susceptor-assisted microwave heating, are a very good synthesis method for compounds which are hard or sometimes not synthesized by conventional methods.

Facile synthesis of biocompatible gold nanoparticles with organosilicone-coated surface properties

Energy Technology Data Exchange (ETDEWEB)

Xia Lijin; Yi Sijia; Lenaghan, Scott C.; Zhang Mingjun, E-mail: mjzhang@utk.edu [University of Tennessee, Department of Mechanical, Aerospace and Biomedical Engineering (United States)

2012-07-15

In this study, a simple method for one-step synthesis of gold nanoparticles has been developed using an organosilicone surfactant, Silwet L-77, as both a reducing and capping agent. Synthesis of gold nanoparticles using this method is rapid and can be conducted conveniently at ambient temperature. Further refinement of the method, through the addition of sodium hydroxide and/or silver nitrate, allowed fine control over the size of spherical nanoparticles produced. Coated on the surface with organosilicone, the as-prepared gold nanoparticles were biocompatible and stable over the pH range from 5 to 12, and have been proven effective at transportation into MC3T3 osteoblast cells. The proposed method is simple, fast, and can produce size-controlled gold nanoparticles with unique surface properties for biomedical applications.

Facile synthesis of biocompatible gold nanoparticles with organosilicone-coated surface properties

International Nuclear Information System (INIS)

Xia Lijin; Yi Sijia; Lenaghan, Scott C.; Zhang Mingjun

2012-01-01

In this study, a simple method for one-step synthesis of gold nanoparticles has been developed using an organosilicone surfactant, Silwet L-77, as both a reducing and capping agent. Synthesis of gold nanoparticles using this method is rapid and can be conducted conveniently at ambient temperature. Further refinement of the method, through the addition of sodium hydroxide and/or silver nitrate, allowed fine control over the size of spherical nanoparticles produced. Coated on the surface with organosilicone, the as-prepared gold nanoparticles were biocompatible and stable over the pH range from 5 to 12, and have been proven effective at transportation into MC3T3 osteoblast cells. The proposed method is simple, fast, and can produce size-controlled gold nanoparticles with unique surface properties for biomedical applications.

Facile synthesis of biocompatible gold nanoparticles with organosilicone-coated surface properties

Science.gov (United States)

Xia, Lijin; Yi, Sijia; Lenaghan, Scott C.; Zhang, Mingjun

2012-07-01

In this study, a simple method for one-step synthesis of gold nanoparticles has been developed using an organosilicone surfactant, Silwet L-77, as both a reducing and capping agent. Synthesis of gold nanoparticles using this method is rapid and can be conducted conveniently at ambient temperature. Further refinement of the method, through the addition of sodium hydroxide and/or silver nitrate, allowed fine control over the size of spherical nanoparticles produced. Coated on the surface with organosilicone, the as-prepared gold nanoparticles were biocompatible and stable over the pH range from 5 to 12, and have been proven effective at transportation into MC3T3 osteoblast cells. The proposed method is simple, fast, and can produce size-controlled gold nanoparticles with unique surface properties for biomedical applications.

Photoluminescence properties of ‘red’ emitting La{sub 2}Zr{sub 2}O{sub 7}:Eu pyrochlore ceramics for potential phosphor application

Energy Technology Data Exchange (ETDEWEB)

Mohapatra, M., E-mail: manojm@barc.gov.in; Rajeswari, B.; Hon, N.S.; Kadam, R.M.; Natarajan, V.

2015-10-15

Lanthanum zirconate (La{sub 2}Zr{sub 2}O{sub 7}=LZO) pyrochlores doped with varying concentrations of Eu were synthesized using a low temperature gel-combustion synthesis route and characterized using X-ray diffraction, scanning electron microscopic and photoluminescence techniques. The final annealing temperature of the system could be brought down to 700 °C to produce a single phase compound. In addition, the optimum activator ion concentration for maximum luminescence yield was evaluated for the system. The site occupancy for the Eu ions was also investigated which suggested that at 500 °C, the ions were on the surface of the LZO host and later diffused into the lattice and replaced the La{sup 3+} ions on annealing at 700 °C 5 h. However, due to difference in the ionic radii, the doped RE ions were of the inversion center forming a D{sub 2d} symmetry around them. For the first time the radiative properties and the commercial utility of the LZO system have been investigated. These parameters were used to get an idea about the M–L bond covalency in the system. The radiative properties suggested the system can be used as a potential ‘red’ emitting phosphor. - Highlights: • Synthesis of lanthanum zirconate pyrochlores doped with Eu using gel-combustion route. • Optimization of dopant ion concentration and annealing temperature and evaluation of its local site symmetry. • Evaluation of various photo-physical properties for the Eu-LZO system to investigate the M–L bond covalency. • Investigation of the commercial utility of the system by calculating the color coordinates. • Comparison of the emission properties with commercial sample.

Investigating the Synthesis, Structure, and Catalytic Properties of Versatile Gold-Based Nanocatalvsts

Science.gov (United States)

Pretzer, Lori A.

Transition metal nanomaterials are used to catalyze many chemical reactions, including those key to environmental, medicinal, and petrochemical fields. Improving their catalytic properties and lifetime would have significant economic and environmental rewards. Potentially expedient options to make such advancements are to alter the shape, size, or composition of transition metal nanocatalysts. This work investigates the relationships between structure and catalytic properties of synthesized Au, Pd-on-Au, and Au-enzyme model transition metal nanocatalysts. Au and Pd-on-Au nanomaterials were studied due to their wide-spread application and structure-dependent electronic and geometric properties. The goal of this thesis is to contribute design procedures and synthesis methods that enable the preparation of more efficient transition metal nanocatalysts. The influence of the size and composition of Pd-on-Au nanoparticles (NPs) was systematically investigated and each was found to affect the catalyst's surface structure and catalytic properties. The catalytic hydrodechlorination of trichloroethene and reduction of 4-nitrophenol by Pd-on-Au nanoparticles were investigated as these reactions are useful for environmental and pharmaceutical synthesis applications, respectively. Structural characterization revealed that the dispersion and oxidation state of surface Pd atoms are controlled by the Au particle size and concentration of Pd. These structural changes are correlated with observed Pd-on-Au NP activities for both probe reactions, providing new insight into the structure-activity relationships of bimetallic nanocatalysts. Using the structure-dependent electronic properties of Au NPs, a new type of light-triggered biocatalyst was prepared and used to remotely control a model biochemical reaction. This biocatalyst consists of a model thermophilic glucokinase enzyme covalently attached to the surface of Au nanorods. The rod-like shape of the Au nanoparticles made the

Responsive copolymers for enhanced petroleum recovery

Energy Technology Data Exchange (ETDEWEB)

McCormick, Charles; Hester, Roger

2000-06-13

The objectives of this work were to: synthesize responsive, amphiphilic systems; characterize molecular structure and solution behavior; measure rheological properties of the aqueous fluids including behavior in fixed geometry flow profiles and beds; and to tailor final polymer compositions for in situ rheology control under simulated reservoir conditions. This report focuses on the first phase of the research emphasizing synthesis and the development of photophysical techniques and rheological means of following segmental organization at the structural level.

The impact of the chemical synthesis on the magnetic properties of intermetallic PdFe nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Castellanos-Rubio, I.; Insausti, M.; Muro, I. Gil de [Universidad del País Vasco, UPV/EHU, Dpto. de Química Inorgánica (Spain); Arias-Duque, D. Carolina; Hernández-Garrido, Juan Carlos [Universidad de Cadiz, Departamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica, Facultad de Ciencias (Spain); Rojo, T.; Lezama, L., E-mail: luis.lezama@ehu.es [Universidad del País Vasco, UPV/EHU, Dpto. de Química Inorgánica (Spain)

2015-05-15

Palladium-rich Iron nanoparticles in the 4–8 nm range have been produced by a combination of two methods: the thermal decomposition of organometallic precursors and the reduction of metallic salts by a polyol. Herein, it is shown how the details of the synthesis have a striking impact on the magnetic and morphological properties of the final products. In the synthesis of these bimetallic nanoparticles, the use of high reaction temperatures plays an essential role in attaining good chemical homogeneity, which has proved to have a key influence on the magnetic properties. Magnetic characterization has been performed by electron magnetic resonance and magnetization measurements, which have confirmed the superparamagnetic-like behavior at room temperature. No clear traces of magnetic polarization in palladium atoms have been detected. The combination of long-term stability and homogeneous chemical and magnetic properties makes these particles very suitable for a wide range of applications in nanotechnology.

The impact of the chemical synthesis on the magnetic properties of intermetallic PdFe nanoparticles

International Nuclear Information System (INIS)

Castellanos-Rubio, I.; Insausti, M.; Muro, I. Gil de; Arias-Duque, D. Carolina; Hernández-Garrido, Juan Carlos; Rojo, T.; Lezama, L.

2015-01-01

Palladium-rich Iron nanoparticles in the 4–8 nm range have been produced by a combination of two methods: the thermal decomposition of organometallic precursors and the reduction of metallic salts by a polyol. Herein, it is shown how the details of the synthesis have a striking impact on the magnetic and morphological properties of the final products. In the synthesis of these bimetallic nanoparticles, the use of high reaction temperatures plays an essential role in attaining good chemical homogeneity, which has proved to have a key influence on the magnetic properties. Magnetic characterization has been performed by electron magnetic resonance and magnetization measurements, which have confirmed the superparamagnetic-like behavior at room temperature. No clear traces of magnetic polarization in palladium atoms have been detected. The combination of long-term stability and homogeneous chemical and magnetic properties makes these particles very suitable for a wide range of applications in nanotechnology

Synthesis, Photophysical and Computational Study of Novel Coumarin-based Organic Dyes.

Science.gov (United States)

Kumbar, Mahadev N; Sannaikar, Madivalagouda S; Shaikh, Saba Kauser J; Kamble, Atulkumar A; Wari, Manjunath N; Inamdar, Sanjeev R; Qiao, Qiquan; Revanna, Bhavya N; Madegowda, Mahendra; Dasappa, Jagadeesh P; Kamble, Ravindra R

2018-03-01

A series of novel coumarin pyrazoline moieties combined with tetrazoles, 3-(1-phenyl-4-(1H-tetrazol-5-yl)-1H-pyrazol-3-yl)-2H-chromen-2-one, 6-chloro-3-(1-phenyl-4-(1H-tetrazol-5-yl)-1H-pyrazol-3-yl)-2H-chromen-2-one, 6-bromo-3-(1-phenyl-4-(1H-tetrazol-5-yl)-1H-pyrazol-3-yl)-2H-chromen-2-one and 6-bromo-3-(1-(4-bromophenyl)-4-(1H-tetrazol-5-yl)-1H pyrazol-3-yl)-2H-chromen-2-one7(a-d), were designed and synthesized. Single crystal X-ray diffraction and their interactions were studied by Hirshfeld surface analysis. Thermal stabilities and electrochemical properties of these compounds were examined from differential scanning calorimetry (DSC), thermogravimetric (TGA) and cyclic voltammetric (CV) studies. Their spectroscopic properties were analyzed in various alcohols and general solvents by UV-Vis absorption, fluorescence and time-resolved spectroscopy. In addition, the ground and excited state electronic properties were investigated using density functional theory (DFT). The calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and energy band gap (E g ) values have revealed the effect of substitution of halogens. The substitution has equally affected the ground and excited states of 7(a-d) compounds. The solvatochromism on absorption, fluorescence spectra and fluorescence lifetimes of these compounds was investigated. All these results showed the chromen-2-one of pyrazoline tetrazole derivatives could play an important role in photonic and electronic devices. © 2017 The American Society of Photobiology.

Photophysical studies of oxicam group of NSAIDs: piroxicam, meloxicam and tenoxicam

Science.gov (United States)

Banerjee, Rona; Chakraborty, Hirak; Sarkar, Munna

2003-04-01

Oxicam group of non steroidal anti-inflammatory drugs has been chosen as a prototype molecular group that shows diverse biological functions and dynamic structural features. Photophysical studies of three drugs from this group viz., piroxicam, meloxicam and tenoxicam have been carried out in different solvents with varying polarity, H-bond character and viscosity. The spectral responses of different prototropic forms of these drugs towards varying solvent parameters have been studied, with the aim to characterize their interaction in biomimetic environment non-invasively. The nature of the lowest transition has been identified. The extinction coefficient, quantum yield and viscosity dependence on the nature of the solvents, all indicate the extreme sensitivity of these drugs to their microenvironment.

Zeolite-like metal–organic frameworks (ZMOFs): design, synthesis, and properties

KAUST Repository

Eddaoudi, Mohamed; Sava, Dorina F.; Eubank, Jarrod F.; Adil, Karim; Guillerm, Vincent

2014-01-01

This review highlights various design and synthesis approaches toward the construction of ZMOFs, which are metal–organic frameworks (MOFs) with topologies and, in some cases, features akin to traditional inorganic zeolites. The interest in this unique subset of MOFs is correlated with their exceptional characteristics arising from the periodic pore systems and distinctive cage-like cavities, in conjunction with modular intra- and/or extra-framework components, which ultimately allow for tailoring of the pore size, pore shape, and/or properties towards specific applications.

Zeolite-like metal–organic frameworks (ZMOFs): design, synthesis, and properties

KAUST Repository

Eddaoudi, Mohamed

2014-10-24

This review highlights various design and synthesis approaches toward the construction of ZMOFs, which are metal–organic frameworks (MOFs) with topologies and, in some cases, features akin to traditional inorganic zeolites. The interest in this unique subset of MOFs is correlated with their exceptional characteristics arising from the periodic pore systems and distinctive cage-like cavities, in conjunction with modular intra- and/or extra-framework components, which ultimately allow for tailoring of the pore size, pore shape, and/or properties towards specific applications.

Chemical synthesis, characterization and evaluation of antimicrobial properties of Cu and its oxide nanoparticles

CSIR Research Space (South Africa)

Motlatle, Abesach M

2016-10-01

Full Text Available of Nanoparticle Research, vol. 18: DOI: 10.1007/s11051-016-3614-8 Chemical synthesis, characterization and evaluation of antimicrobial properties of Cu and its oxide nanoparticles Motlatle AM Kesevan Pillai S Scriba MR Ray SS ABSTRACT: Cu...

Aqueous Synthesis of PEGylated Quantum Dots with Increased Colloidal Stability and Reduced Cytotoxicity.

Science.gov (United States)

Ulusoy, Mehriban; Jonczyk, Rebecca; Walter, Johanna-Gabriela; Springer, Sergej; Lavrentieva, Antonina; Stahl, Frank; Green, Mark; Scheper, Thomas

2016-02-17

Ligands used on the surface of colloidal nanoparticles (NPs) have a significant impact on physiochemical properties of NPs and their interaction in biological environments. In this study, we report a one-pot aqueous synthesis of 3-mercaptopropionic acid (MPA)-functionalized CdTe/CdS/ZnS quantum dots (Qdots) in the presence of thiol-terminated methoxy polyethylene glycol (mPEG) molecules as a surface coordinating ligand. The resulting mPEG-Qdots were characterized by using ζ potential, FTIR, thermogravimetric (TG) analysis, and microscale thermophoresis (MST) studies. We investigated the effect of mPEG molecules and their grafting density on the Qdots photophysical properties, colloidal stability, protein binding affinity, and in vitro cellular toxicity. Moreover, cellular binding features of the resulting Qdots were examined by using three-dimensional (3D) tumor-like spheroids, and the results were discussed in detail. Promisingly, mPEG ligands were found to increase colloidal stability of Qdots, reduce adsorption of proteins to the Qdot surface, and mitigate Qdot-induced side effects to a great extent. Flow cytometry and confocal microscopy studies revealed that PEGylated Qdots exhibited distinctive cellular interactions with respect to their mPEG grafting density. As a result, mPEG molecules demonstrated a minimal effect on the ZnS shell deposition and the Qdot fluorescence efficiency at a low mPEG density, whereas they showed pronounced effect on Qdot colloidal stability, protein binding affinity, cytotoxicity, and nonspecific binding at a higher mPEG grafting amount.

Nitridomanganates of alkaline-earth metals. Synthesis, structure, and physical properties

Energy Technology Data Exchange (ETDEWEB)

Ovchinnikov, Alexander

2016-12-02

The main goal of the present work was the synthesis of alkaline-earth nitridomanganates (AE{sub x}Mn{sub y}N{sub z}) with extended anionic structures and the characterization of their electronic and magnetic properties. Up to now, only compounds with isolated nitridomanganate anions have been reported in the discussed ternary systems. A systematic exploratory synthesis, employing high-temperature treatment of AE nitrides and Mn under controlled N2 pressure, yielded more than ten new nitridomanganates. Their crystal structures contain anionic building blocks of different dimensionalities, ranging from isolated species to three-dimensional frameworks. In general, the formation of Mn-rich compositions was found to be driven by the emergence of Mn-Mn interactions, which creates a link between nitridometalates and transition-metal-rich binary nitrides. The obtained nitridomanganates display a plethora of interesting phenomena, such as large spin-orbit coupling, magnetic frustration, quenching of magnetism due to Mn-Mn interactions, and metal-insulator transition.

Thioxanthone based 9-[2-(methyl-phenyl-amino)-acetyl]-thia-naphthacene-12-one as a visible photoinitiator

Energy Technology Data Exchange (ETDEWEB)

Doğruyol, Sevnur Keskin [Department of Chemistry, Yıldız Technical University, Davutpasa Campus, Esenler, 34220 Istanbul (Turkey); Doğruyol, Zekeriya [Department of Engineering Science, Istanbul University, 34850, Avcılar, Istanbul (Turkey); Arsu, Nergis, E-mail: narsu@yildiz.edu.tr [Department of Chemistry, Yıldız Technical University, Davutpasa Campus, Esenler, 34220 Istanbul (Turkey)

2013-06-15

Photoinitiators that operate in the visible range of the electromagnetic spectrum have widespread applications. Thioxanthone based 9-[2-(methyl-phenyl-amino)-acetyl]-thia-naphthacene-12-one (TX-MPA) was synthesized and the characterization of this initiator was confirmed by spectral analysis methods. TX-MPA has excellent absorption properties in the visible range (ε{sub 480} {sub nm}=3576 L/mol.cm). Photophysical studies; fluorescence quantum yield (φ{sub f}=0.22, DPA), phosphorescence lifetime (τ{sub p}=115 ms) and triplet lifetime (τ=190 ns) were explored. To explore the initiation mechanism of TX-MPA, besides the photophysical and photochemical studies, the polymer (PMMA) obtained from the photopolymerization studies was subjected to a phosphorescence study and τ{sub p} was found to be 105 ms compared to 115 ms for the initiator TX-MPA which proved attachment of the initiator to the polymer. Possibly both intermolecular and intramolecular hydrogen abstraction, occur during the initiation stage depending on the concentration of the initiator. Highlights: ► Synthesis and photophysical properties of a visible photoinitiator (TX-MPA) are proposed. ► TX-MPA has high molar absorption values in the visible region. ► TX-MPA can initiate photopolymerization of methylmethacrylate monomer under UV and sunlight. ► Inter or intramolecular hydrogen abstraction mechanisms occur depending on initiator concentration.

Investigation on the electronic structures and photophysical properties of a series of cyclometalated iridium(III) complexes based on DFT/TDDFT calculations

Energy Technology Data Exchange (ETDEWEB)

Shang, Chunyu, E-mail: shang.chun.yu@163.com; Xu, Jie; Du, Yanqiu; Zhao, Jie

2016-07-15

The electronic structures and photophysical properties of a series of cyclometalated iridium (III) complexes Ir(C{sup ∧}N){sub 2}(H{sub 2}NNHCOO), including 1 [C{sup ∧}N=2-phenyl-pyridine], 2 [C{sup ∧}N=5-fluoro-2-phenylpyridine], 3 [C{sup ∧}N=2-phenyl-5-trifluoromethylpyridine], 4 [C{sup ∧}N=6-phenyl-[2, 3] bipyridinyl], 5 [C{sup ∧}N=7-phenyl-cyclopenta [4] dipyridine] and 6 [C{sup ∧}N=8-phenyl-[1, 9] phenanthroline], have been theoretically investigated based on density functional theory (DFT) and time-dependent DFT. The characteristics in phosphorescent performances have been outlined for each of the complexes in the applications in OLED. On the basis of the two simplifications presented in this paper and the available experimental data, the magnitudes of phosphorescent radiative rates for complexes 1–6 were approximately calculated to be: 5.56×10{sup 5} s{sup −1}, 2.68×10{sup 5} s{sup −1}, 1.17×10{sup 6} s{sup −1}, 9.78×10{sup 4} s{sup −1}, 5.30×10{sup 6} s{sup −1} and 6.71×10{sup 6} s{sup −1}, respectively. Meanwhile, the sequence of phosphorescent quantum efficiencies was obtained to be: Φ{sub PL}(4)<Φ{sub PL}(2)<Φ{sub PL}(1)<Φ{sub PL}(3)<Φ{sub PL}(5)<Φ{sub PL}(6), in which Φ{sub PL}(4) is by far the lowest, Φ{sub PL}(5) is much larger and Φ{sub PL}(6) is by far the largest. In contrast to complex 1, the emission wavelengths are slightly red-shifted for 2 and 3 and significantly red-shifted for 4 and 5, while the emission wavelength of 6 is slightly blue-shifted. In comparison, complexes 6 and 5 may be singled out to be the most efficient phosphorescence emitters for the applications in OLED.

Hydrogen-bonding effects on film structure and photoelectrochemical properties of porphyrin and fullerene composites on nanostructured TiO 2 electrodes

NARCIS (Netherlands)

Kira, Aiko; Tanaka, Masanobu; Umeyama, Tomokazu; Matano, Yoshihiro; Yoshimoto, Naoki; Zhang, Yi; Ye, Shen; Lehtivuori, Heli; Tkachenko, Nikolai V.; Lemmetyinen, Helge; Imahori, Hiroshi

2007-01-01

Hydrogen-bonding effects on film structures and photophysical, photoelectrochemical, and photovoltaic properties have been examined in mixed films of porphyrin and fullerene composites with and without hydrogen bonding on nanostructured TiO2 electrodes. The nanostructured TiO2 electrodes modified

The synthesis of high yield Au nanoplate and optimized optical properties

Science.gov (United States)

Ni, Yuan; Kan, Caixia; Xu, Juan; Liu, Yang

2018-02-01

The applications of Au nanoplates based on the tunable plasmon properties and enhanced electromagnetic field at the sharp tip and straight edges, have generated a great deal of interest in recent years, especially in the fields of the bio-chemical sensing and imaging. In this review, we focus on the synthesis of nanoscale platelike structures by multiple synthetic strategies (such as thermal solution method, seed-mediated method, seedless method, and some greener methods), and explore corresponding growth mechanism in different synthetic approaches. Other than to review the fabrication of Au nanoplates, the purification strategies are also discussed in order to support the applications in various fields. Modifying synthetic method to obtain well-defined nanoplates can tuned optical absorption from visible to near-infrared region. Moreover, the Au nanoplate dimers (vertex-to-vertex and edge-by-edge assemblies) can induce more specific plasmon properties and stronger localized field due to coupling of interparticles. Compared with 0D quasi-spherical nanoparticles and 1D nanorods, the 2D nanoplates can be applied as a good surface-enhanced Raman scattering (SERS) substrate because of the sharp corners and straight edges. This review will provide background information for the controllable synthesis of anisotropic nanoparticles and advance the application of coupled nanostructures.

The Effect of a Fluorophore Photo-Physics on the Lipid Vesicle Diffusion Coefficient Studied by Fluorescence Correlation Spectroscopy.

Science.gov (United States)

Drabik, Dominik; Przybyło, Magda; Sikorski, Aleksander; Langner, Marek

2016-03-01

Fluorescence Correlation Spectroscopy (FCS) is a technique, which allows determination of the diffusion coefficient and concentration of fluorescent objects suspended in the solution. The measured parameter is the fluctuation of the fluorescence signal emitted by diffusing molecules. When 100 nm DOPC vesicles labeled with various fluorescent dyes (Fluorescein-PE, NBD-PE, Atto488 DOPE or βBodipy FL) were measured, different values of diffusion coefficients have been obtained. These diffusion coefficients were different from the expected values measured using the dynamic light scattering method (DLS). The FCS was initially developed for solutions containing small fluorescent molecules therefore the observed inconsistency may result from the nature of vesicle suspension itself. The duration of the fluorescence signal may depend on the following factors: the exposure time of the labeled object to the excitation beam, the photo-physical properties (e.g., stability) of a fluorophore, the theoretical model used for the calculations of the diffusion coefficient and optical properties of the vesicle suspension. The diffusion coefficients determined for differently labeled liposomes show that its dependence on vesicle size and quantity of fluorescent probed used for labeling was significant demonstrating that the fluorescence properties of the fluorophore itself (bleaching and/or blinking) were critical factors for a correct outcome of FCS experiment. The new, based on combined FCS and DLS measurements, method for the determination of the focal volume prove itself to be useful for the evaluation of a fluorescence dye with respect to its applicability for FCS experiment.

Synthesis and photocatalytic properties of graphitic carbon nitride nanofibers using porous anodic alumina templates

Science.gov (United States)

Suchitra, S. M.; Udayashankar, N. K.

2017-12-01

In the present study, we describe an effective method for the synthesis of Graphitic carbon nitride (GCN) nanostructures using porous anodic alumina (AAO) membrane as template by simple thermal condensation of cyanamide. Synthesized nanostructure was fully analysed by various techniques to detect its crystalline nature, morphology, luminescent properties followed by the evaluation of its photocatalytic activity in the degradation of Methylene blue dye. Structural analysis of synthesized GCNNF was systematically carried out using x-ray powder diffraction (XRD) and scanning electron microscope (SEM), and. The results confirmed the growth of GCN inside the nanochannels of anodic alumina templates. Luminescent properties of GCNNF were studied using photoluminescence (PL) spectroscopy. PL analysis showed the presence of a strong emission peak in the wavelength range of 350-600 nm in blue region. GCNNF displays higher photocatalytic performance in the photodegradation of methylene blue compare to the bulk GCN. Highlights 1. In the present paper, we report the synthesis of graphitic carbon nitride nanofibers (GCNNF) using porous anodic aluminium oxide membranes as templates through thermal condensation of cyanamide at 500 °C. 2. The synthesis of Graphitic carbon nitride nanofibers using porous andic alumina template is the efficient approach for increasing crystallinity and surface area. 3. The high surface area of graphitic carbon nitride nanofibers has a good impact on novel optical and photocatalytic properties of the bulkGCN. 4. AAO templating of GCN is one of the versatile method to produce tailorable GCN nanostructures with higher surface area and less number of structural defects. 5. Towards photocatalytic degradation of dyes, the tuning of physical properties is very essential thing hence we are succeeded in achieving better catalytic performance of GCN nanostructures by making use of AAO templates.

The importance of charge-transfer interactions in determining chromophoric dissolved organic matter (CDOM) optical and photochemical properties.

Science.gov (United States)

Sharpless, Charles M; Blough, Neil V

2014-04-01

Absorption of sunlight by chromophoric dissolved natural organic matter (CDOM) is environmentally significant because it controls photic zone depth and causes photochemistry that affects elemental cycling and contaminant fate. Both the optics (absorbance and fluorescence) and photochemistry of CDOM display unusual properties that cannot easily be ascribed to a superposition of individual chromophores. These include (i) broad, unstructured absorbance that decreases monotonically well into the visible and near IR, (ii) fluorescence emission spectra that all fall into a single envelope regardless of the excitation wavelength, and (iii) photobleaching and photochemical quantum yields that decrease monotonically with increasing wavelength. In contrast to a simple superposition model, these phenomena and others can be reasonably well explained by a physical model in which charge-transfer interactions between electron donating and accepting chromophores within the CDOM control the optical and photophysical properties. This review summarizes current understanding of the processes underlying CDOM photophysics and photochemistry as well as their physical basis.

Advanced optical measurements for characterizing photophysical properties of single nanoparticles.

Energy Technology Data Exchange (ETDEWEB)

Polsky, Ronen; Davis, Ryan W.; Arango, Dulce C.; Brozik, Susan Marie; Wheeler, David Roger

2009-09-01

Formation of complex nanomaterials would ideally involve single-pot reaction conditions with one reactive site per nanoparticle, resulting in a high yield of incrementally modified or oriented structures. Many studies in nanoparticle functionalization have sought to generate highly uniform nanoparticles with tailorable surface chemistry necessary to produce such conjugates, with limited success. In order to overcome these limitations, we have modified commercially available nanoparticles with multiple potential reaction sites for conjugation with single ssDNAs, proteins, and small unilamellar vesicles. These approaches combined heterobifunctional and biochemical template chemistries with single molecule optical methods for improved control of nanomaterial functionalization. Several interesting analytical results have been achieved by leveraging techniques unique to SNL, and provide multiple paths for future improvements for multiplex nanoparticle synthesis and characterization. Hyperspectral imaging has proven especially useful for assaying substrate immobilized fluorescent particles. In dynamic environments, temporal correlation spectroscopies have been employed for tracking changes in diffusion/hydrodynamic radii, particle size distributions, and identifying mobile versus immobile sample fractions at unbounded dilution. Finally, Raman fingerprinting of biological conjugates has been enabled by resonant signal enhancement provided by intimate interactions with nanoparticles and composite nanoshells.

Water soluble peripheral and non-peripheral tetrasubstituted zinc phthalocyanines: Synthesis, photochemistry and bovine serum albumin binding behavior

Energy Technology Data Exchange (ETDEWEB)

Çakır, Volkan; Çakır, Dilek [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Pişkin, Mehmet [Department of Food Technology, Çanakkale Vocational School of Technical Sciences, Çanakkale Onsekiz Mart University, 17100 Çanakkale (Turkey); Durmuş, Mahmut [Gebze Institute of Technology, Department of Chemistry, PO Box 141, Gebze 41400, Kocaeli (Turkey); Bıyıklıoğlu, Zekeriya, E-mail: zekeriya_61@yahoo.com [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)

2014-10-15

The new peripherally and non-peripherally tetra-1,3-bis[3-(diethylamino)phenoxy]propan-2-ol substituted zinc(II) phthalocyanine complexes (2a and 3a) and their quaternized amphiphilic derivatives (2b and 3b) have been synthesized and characterized using UV–vis, FT-IR, {sup 1}H-NMR, {sup 13}C-NMR, MS spectroscopic data and elemental analysis for the first time. The quaternized complexes (2b and 3b) show excellent solubility in water and DMSO which makes them potential photosensitizers for use in photodynamic therapy (PDT) of cancer. The photochemical (singlet oxygen generation and photodegradation under light irradiation) properties of these novel phthalocyanines are investigated in dimethylsulfoxide (DMSO) for non-quaternized complexes and in DMSO, phosphate buffered solution (PBS) or PBS+triton X-100 (TX) solution for quaternized complexes. In this study, the effects of the aggregation of the molecules, quaternization, position of the substituents (peripherally or non-peripherally) and nature of the solvents (DMSO, PBS or PBS+triton X-100) on the photochemical parameters of the zinc (II) phthalocyanines are also reported. In addition, a spectroscopic investigation of the binding behavior of the quaternized zinc(II) phthalocyanine complexes to bovine serum albumin (BSA) is also presented in this work. - Highlights: • Synthesis of zinc phthalocyanines is performed. • Photophysical and photochemical properties of phthalocyanines are studied. • Photodynamic therapy studies are performed.

Water soluble peripheral and non-peripheral tetrasubstituted zinc phthalocyanines: Synthesis, photochemistry and bovine serum albumin binding behavior

International Nuclear Information System (INIS)

Çakır, Volkan; Çakır, Dilek; Pişkin, Mehmet; Durmuş, Mahmut; Bıyıklıoğlu, Zekeriya

2014-01-01

The new peripherally and non-peripherally tetra-1,3-bis[3-(diethylamino)phenoxy]propan-2-ol substituted zinc(II) phthalocyanine complexes (2a and 3a) and their quaternized amphiphilic derivatives (2b and 3b) have been synthesized and characterized using UV–vis, FT-IR, 1 H-NMR, 13 C-NMR, MS spectroscopic data and elemental analysis for the first time. The quaternized complexes (2b and 3b) show excellent solubility in water and DMSO which makes them potential photosensitizers for use in photodynamic therapy (PDT) of cancer. The photochemical (singlet oxygen generation and photodegradation under light irradiation) properties of these novel phthalocyanines are investigated in dimethylsulfoxide (DMSO) for non-quaternized complexes and in DMSO, phosphate buffered solution (PBS) or PBS+triton X-100 (TX) solution for quaternized complexes. In this study, the effects of the aggregation of the molecules, quaternization, position of the substituents (peripherally or non-peripherally) and nature of the solvents (DMSO, PBS or PBS+triton X-100) on the photochemical parameters of the zinc (II) phthalocyanines are also reported. In addition, a spectroscopic investigation of the binding behavior of the quaternized zinc(II) phthalocyanine complexes to bovine serum albumin (BSA) is also presented in this work. - Highlights: • Synthesis of zinc phthalocyanines is performed. • Photophysical and photochemical properties of phthalocyanines are studied. • Photodynamic therapy studies are performed

Synthesis, Properties and Potential Applications of Porous Graphene: A Review

Institute of Scientific and Technical Information of China (English)

Paola Russo; Anming Hu; Giuseppe Compagnini

2013-01-01

Since the discovery of graphene, many efforts have been done to modify the graphene structure for integrating this novel material to nanoelectronics, fuel cells, energy storage devices and in many other applications. This leads to the production of different types of graphene-based materials, which possess properties different from those of pure graphene. Porous graphene is an example of this type of materials. It can be considered as a graphene sheet with some holes/pores within the atomic plane. Due to its spongy structure, porous graphene can have potential applications as membranes for molecular sieving, energy storage components and in nanoelectronics. In this review, we present the recent progress in the synthesis of porous graphene. The properties and the potential applications of this new material are also discussed.

Influence of push-pull group substitution patterns on excited state properties of donor-acceptor co-monomers and their trimers

NARCIS (Netherlands)

de Gier, Hilde D.; Rietberg, Bernd J.; Broer, Ria; Havenith, Remco W. A.

2014-01-01

Organic electronics form a very promising new generation of cheap, lightweight and flexible devices. Of special interest is the ability to engineer photo-physical properties of organic molecules by chemical modification. In this regard, the purpose of this research is to understand the influence of

Nanometric solid solutions of the fluorite and perovskite type crystal structures: Synthesis and properties

Directory of Open Access Journals (Sweden)

Snežana Bošković

2012-09-01

Full Text Available In this paper a short review of our results on the synthesis of nanosized CeO2, CaMnO3 and BaCeO3 solid solutions are presented. The nanopowders were prepared by two innovative methods: self propagating room temperature synthesis (SPRT and modified glycine/nitrate procedure (MGNP. Different types of solid solutions with rare earth dopants in concentrations ranging from 0–0.25 mol% were synthesized. The reactions forming solid solutions were studied. In addition, the characteristics of prepared nanopowders, phenomena during sintering and the properties of sintered samples are discussed.

Computational Photophysics in the Presence of an Environment

Science.gov (United States)

Nogueira, Juan J.; González, Leticia

2018-04-01

Most processes triggered by ultraviolet (UV) or visible (vis) light in nature take place in complex biological environments. The first step in these photophysical events is the excitation of the absorbing system or chromophore to an electronically excited state. Such an excitation can be monitored by the UV-vis absorption spectrum. A precise calculation of the UV-vis spectrum of a chromophore embedded in an environment is a challenging task that requires the consideration of several ingredients, besides an accurate electronic-structure method for the excited states. Two of the most important are an appropriate description of the interactions between the chromophore and the environment and accounting for the vibrational motion of the whole system. In this contribution, we review the most common theoretical methodologies to describe the environment (including quantum mechanics/continuum and quantum mechanics/molecular mechanics models) and to account for vibrational sampling (including Wigner sampling and molecular dynamics). Further, we illustrate in a series of examples how the lack of these ingredients can lead to a wrong interpretation of the electronic features behind the UV-vis absorption spectrum.

The synthesis and decay properties of the heaviest elements

International Nuclear Information System (INIS)

Oganesyan, Yu.Ts.

2000-01-01

The synthesis and the study of radioactive properties of new elements is considered with respect to the existence of the 'islands of stability' of hypothetical superheavy elements predicted by the theory more than 35 years ago. Experimental data demonstrating an enhanced stability of nuclei in the vicinity of deformed shells with Z=108 and N=162 is discussed from the point of view of advent into more heavy and much more stable nuclides near the predicted spherical shells Z=114-122 and N=184 following after the doubly magic nucleus 208 Pb. The author presents the results of experiments on the synthesis of isotopes of elements 114 and 116 in the fusion reactions with 48 Ca. In these reactions the decay chains of heavy atoms consisting of sequential α-decays interrupted by spontaneous fission have been observed. The decay energies and probabilities are compared with predictions of different theoretical models describing the structure of heavy nuclei. The obtained results are considered as the first experimental evidence of the existence of domains of stability of superheavy nuclei which substantially extends the boundaries of existence of chemical elements

Effective photosensitized energy transfer of nonanuclear terbium clusters using methyl salicylate derivatives.

Science.gov (United States)

Omagari, Shun; Nakanishi, Takayuki; Seki, Tomohiro; Kitagawa, Yuichi; Takahata, Yumie; Fushimi, Koji; Ito, Hajime; Hasegawa, Yasuchika

2015-03-12

The photophysical properties of the novel nonanuclear Tb(III) clusters Tb-L1 and Tb-L2 involving the ligands methyl 4-methylsalicylate (L1) and methyl 5-methylsalicylate (L2) are reported. The position of the methyl group has an effect on their photophysical properties. The prepared nonanuclear Tb(III) clusters were identified by fast atom bombardment mass spectrometry and powder X-ray diffraction. Characteristic photophysical properties, including photoluminescence spectra, emission lifetimes, and emission quantum yields, were determined. The emission quantum yield of Tb-L1 (Φ(ππ*) = 31%) was found to be 13 times larger than that of Tb-L2 (Φ(ππ*) = 2.4%). The photophysical characterization and DFT calculations reveal the effect of the methyl group on the electronic structure of methylsalicylate ligand. In this study, the photophysical properties of the nonanuclear Tb(III) clusters are discussed in relation to the methyl group on the aromatic ring of the methylsalicylate ligand.

Synthesis and property characterization of two novel side-chain isoindigo copolymers for polymer solar cells

Directory of Open Access Journals (Sweden)

X. Liu

2015-11-01

Full Text Available Two novel side-chain conjugated polymers, PTBT-TID and PTBT-TTID, based on the new synthetic thiophene-benzne-thiophene (TBT unit, side-chain isoindigo (ID unit, and the introduced thiophene π-bridge, have been designed and synthesized. The photophysical, electrochemical and photovoltaic properties of the two polymers have been systematically investigated. The two polymers possess relatively good solubility as well as excellent thermal stability up to 380°C, and all of the polymer solar cell (PSC devices based on the two polymers obtain high open circuit voltage (Voc of about 0.8 V. The polymer solar cells based on the polymer PTBT-TID show relatively higher efficiencies than the PTBT-TTID-based ones, due to the broader absorption spectrum, a relatively higher hole mobility, a lower HOMO (the highest occupied molecular orbital energy level, a stronger IPCE (the incident photon to current conversion efficiency response and a better microphase separation, Consequently, the device based on PTBT-TID:PC61BM (1:2, by weight gives the best power conversion efficiency (PCE of 2.04%, with a short-circuit current density (Jsc of 5.39 mA·cm–2, an open-circuit voltage (Voc of 0.83 V, and a fill factor (FF of 0.45.

Influence of some additions on zircon synthesis and its properties

International Nuclear Information System (INIS)

Goryacheva, Z.E.; Poplevina, O.G.; Suvorov, S.A.; Toropov, A.N.

1978-01-01

Kinetics of zircon synthesis from pure ZrO 2 and SiO 2 is studied in the presence of additions of magnesium, calcium and rare earth oxides. The addition introduction accelerates zircon formation, its yield reaching 97% at 1600 deg C. Constants of zircon formation reaction rate are determined in the presence of additions of various oxides. It is shown that synthetic zircon surpasses the natural one in tensile and density properties at similar thermostability. It is stable to the effect of molten alkaline borosilicate glass and does not polute it

Synthesis, Properties and Mineralogy of Important Inorganic Materials

DEFF Research Database (Denmark)

Warner, Terence Edwin

chosen so as to illustrate the large variety of physico-chemical properties encountered in inorganic materials, and to provide practical experience covering a wide range of preparative methods, with an emphasis on high-temperature techniques. The majority of the materials described in the book relate...... in extending their repertoire of teaching material into the realms of high-temperature synthesis. It is also of interest to professional chemists, physicists, materials scientists and technologists, ceramicists, mineralogists, geologists, geochemists, archaeologists, metallurgists, engineers, and non......-specialists, who are interested in learning more about how technological ceramic materials and artificial minerals are made. Finally, the author assumes that the reader is familiar with the basic principles and concepts of materials chemistry (or at least has access to such knowledge), such as; thermodynamic...

Synthesis of Some Green Dopants for OLEDs Based on Arylamine 2,3-disubstituted Bithiophene Derivatives

Directory of Open Access Journals (Sweden)

Mi-Seon Song

2013-11-01

Full Text Available A series of green dopants based on 2,2-diphenylvinyl end-capped bithiophene and three different arylamine moieties (9-phenylcarbazole, triphenylamine, and N,N’-di-(p-tolylbenzeneamine were successfully synthesized by the Suzuki and Wittig coupling reactions. The photophysical properties of these compounds are reported. The strongest PL emitting compound with the 9-phenylcarbazole moiety has been used for fabricating an OLED device with good overall performance.

Evidence for the existence of sulfur-doped fullerenes from elucidation of their photophysical properties

Energy Technology Data Exchange (ETDEWEB)

Glenis, S.; Cooke, S.; Chen, X.; Labes, M.M. [Temple Univ., Philadelphia, PA (United States)

1996-01-01

Cage carbon atoms of fullerenes were substituted by sulfur in sulfur-doped fullerenes synthesized by the authors. The synthesis method was based on the arc evaporation of graphite in the presence of thiophene or 3-methylthiophene. Structural characterization was accomplished through mass spectrometry and fluorescence spectroscopy and crude purification regimens using column chromatography were established. 24 refs., 4 figs., 1 tab.

The Photo-Physics of Polythiophene Nanoparticles for Biological Applications.

Science.gov (United States)

Bargigia, Ilaria; Zucchetti, Elena; Srimath Kandada, Ajay Ram; Moreira, Miguel; Bossio, Caterina; Wong, Walter; Miranda, Paulo; Decuzzi, Paolo; Soci, Cesare; D'Andrea, Cosimo; Lanzani, Guglielmo

2018-05-01

In this work the photo-physics of poly(3-hexyltiophene) nanoparticles (NPs) is investigated in the context of their biological applications. The NPs made as colloidal suspensions in aqueous buffers present a distinct absorption band in the low energy region. Based on systematic analysis of absorption and transient absorption spectra taken under different pH conditions, this band is associated to charge transfer states generated by the polarization of loosely bound polymer chains and originated from complexes formed with electron withdrawing species. Importantly, the ground state depletion of these states upon photo-excitation is active even in the microsecond timescales, suggesting that they act as precursor states for long-living polarons which could be beneficial for cellular stimulation. Preliminary results of transient absorption microscopy of NPs internalized within the cells reveal the presence of long-living species, further substantiating their relevance in bio-interfaces. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, Structure, and Properties of Refractory Hard-Metal Borides

Science.gov (United States)

Lech, Andrew Thomas

As the limits of what can be achieved with conventional hard compounds, such as tungsten carbide, are nearing reach, super-hard materials are an area of increasing industrial interest. The refractory hard metal borides, such as ReB2 and WB4, offer an increasingly attractive alternative to diamond and cubic boron nitride as a next-generation tool material. In this Thesis, a thorough discussion is made of the progress achieved by our laboratory towards understanding the synthesis, structure, and properties of these extremely hard compounds. Particular emphasis is placed on structural manipulation, solid solution formation, and the unique crystallographic manifestations of what might also be called "super-hard metals".

Photophysics of conjugated polymers: interplay between Förster energy migration and defect concentration in shaping a photochemical funnel in PPV.

Science.gov (United States)

Saini, Sangeeta; Bagchi, Biman

2010-07-21

Recent single molecule experiments have suggested the existence of a photochemical funnel in the photophysics of conjugated polymers, like poly[2-methoxy-5-(2'-ethylhexyl)oxy-1,4-phenylenevinylene] (MEH-PPV). The funnel is believed to be a consequence of the presence of conformational or chemical defects along the polymer chain and efficient non-radiative energy transfer among different chromophore segments. Here we address the effect of the excitation energy dynamics on the photophysics of PPV. The PPV chain is modeled as a polymer with the length distribution of chromophores given either by a Gaussian or by a Poisson distribution. We observe that the Poisson distribution of the segment lengths explains the photophysics of PPV better than the Gaussian distribution. A recently proposed version of an extended 'particle-in-a-box' model is used to calculate the exciton energies and the transition dipole moments of the chromophores, and a master equation to describe the excitation energy transfer among different chromophores. The rate of energy transfer is assumed to be given here, as a first approximation, by the well-known Förster expression. The observed excitation population dynamics confirms the photochemical funneling of excitation energy from shorter to longer chromophores of the polymer chain. The time scale of spectral shift and energy transfer for our model polymer, with realistic values of optical parameters, is in the range of 200-300 ps. We find that the excitation energy may not always migrate towards the longest chromophore segments in the polymer chain as the efficiency of energy transfer between chromophores depends on the separation distance between the two and their relative orientation.

Conjugated Polymers Containing BODIPY and Fluorene Units for Sensitive Detection of CN− Ions: Site-Selective Synthesis, Photo-Physical and Electrochemical Properties

Directory of Open Access Journals (Sweden)

Tian He

2017-10-01

Full Text Available Conjugated polymers containing distinct molecular units are expected to be very interesting because of their unique properties endowed by these units and the formed conjugated polymers. Herein, four new conjugated copolymers based on fluorene and 4,4’-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY have been designed and synthesized via Sonogashira polymerization. The fluorene unit was attached to the 3,5- or 2,6-positions of BODIPY by ethynylenes or p-diacetylenebenzene. The obtained polymers show good thermal stability and broad absorption in the wavelength range from 300 to 750 nm. The effects of site-selective copolymerization and conjugation length along the polymer backbone on the optoelectronic and electrochemical properties of these copolymers were systematically studied by UV-Vis spectroscopy, photoluminescence (PL and cyclic voltammetry. Besides, it is found that the BODIPY-based copolymers exhibit selectively sensitive responses to cyanide anions, resulting in obvious change of UV-Vis absorption spectra and significant fluorescence quenching of the polymers among various common anions.

Optical filtering and luminescence property of some molybdates prepared by combustion synthesis

Energy Technology Data Exchange (ETDEWEB)

Yadav, P. J., E-mail: yadav.pooja75@yahoo.in [Department of Electronics, RTM Nagpur University, Nagpur (India); Joshi, C. P. [Physics Department, RCOEM, Nagpur (India); Moharil, S. V., E-mail: svmoharil@yahoo.com [Physics Department, RTM Nagpur University, Nagpur (India)

2014-10-15

As an important class of lanthanide inorganic compounds, rare earth ions doped molybdates have gained much attention due to their attractive luminescence and structural properties, supporting various promising applications as phosphor materials in the fields such as white light-emitting diodes, optical fibers, biolabel, lasers, and so on. The molybdate family has promising trivalent cation conducting properties and most of the optical properties result from electron transitions of the 4f shell, which are greatly affected by the composition and structures of rare-earth compounds. In this paper we report the molybdate CaMoO{sub 4}:Eu{sup 3+} for red SSL and Bi{sub 1.4}Y{sub 0.6}MoO{sub 6}, Y{sub 6}MoO{sub 12} for optical filtering, prepared by one step combustion synthesis.

Synthesis and properties of superheavy elements

CERN Document Server

Hofmann, S

2003-01-01

The nuclear shell model predicts that the next doubly magic shell-closure beyond sup 2 sup 0 sup 8 Pb is at a proton number Z = 114, 120, or 126 and at a neutron number N = 172 or 184. The outstanding of experimental investigations is the exploration of this region of spherical 'SuperHeavy Elements' (SHEs). Experimental methods are described which allowed for the identification of elements 107 to 112 in studies of cold fusion reactions based on lead and bismuth targets. Also presented are data which were obtained on the synthesis of elements 112, 114, and 116 in investigation of hot fusion reactions using actinide targets. The decay data reveal that for the heaviest elements, the dominant decay mode is alpha emission, not fission. Decay properties as well as reaction cross- sections are compared with the results of theoretical studies. Finally, plans are presented for the further development of the experimental set-up and the application of new techniques. At a higher sensitivity, the exploration of the regio...

Development of Fe/Nb-based solar photocatalysts for water treatment: impact of different synthesis routes on materials properties.

Science.gov (United States)

Ribeiro, Marília C M; Amorim, Camila C; Moreira, Regina F P M; Oliveira, Luiz C A; Henriques, Andréia B; Leão, Mônica M D

2018-04-27

Semiconductors based on Fe/Nb oxides can present both solar sensitivity and high catalytic activity. However, there is still a lack regarding the comparison between different routes to produce Fe/Nb-based solar photocatalysts and the evaluation of the impact of the synthesis operating conditions on the material properties. In this work, Fe/Nb 2 O 5 ratio, type of precipitating agent, presence/absence of washing stage, and temperature of calcination were verified to be the most relevant parameters in the synthesis by the co-precipitation method. These factors led to remarkable differences in the properties and performance of the photocatalysts produced by each distinct synthesis route. Composition, iron species present in the materials, crystallinity characteristics, and pH of the catalysts were affected, leading to different photocatalytic activities under UV-Vis light. Due to their characteristics, the synthesized materials are potential photocatalysts for application in solar processes. Graphical abstract ᅟ.

Synthesis of Beam Lines with Necessary Properties

CERN Document Server

Andrianov, Serge

2005-01-01

In this paper a new approach to the problem of synthesis of beam lines is discussed. Usually this problem can be overcome by the use of numerical simulation and optimal control theory methods. But this results in sufficiently great number of variable parameters and functions. Obviously, that this degrades quality of a modeling procedure. The suggested approach is demonstrated on a problem of a microprobe design problem. Essence of the problem is that necessary to design a high precision focusing system which satisfies some additional conditions. For solution of this problem we use an algebraic treatment based on Lie algebraic methods and computer algebra techniques. Using the symmetry ideology this approach allows rewriting beam properties to enough simple conditions for control parameters and functions. This leads a set of desired solutions and show results in some most suitable form. Moreover, this approach decreases the number of variable parameters.

Synthesis and photophysical and electroluminescent properties of poly(1,4-phenylene–ethynylene)-alt-poly(1,4-phenylene–vinylene)s with various dissymmetric substitution of alkoxy side chains

Czech Academy of Sciences Publication Activity Database

Bouguerra, N.; Růžička, Aleš; Ulbricht, C.; Enengl, C.; Enengl, S.; Pokorná, Veronika; Výprachtický, Drahomír; Tordin, E.; Aitout, R.; Cimrová, Věra; Egbe, D. A. M.

2016-01-01

Roč. 49, č. 2 (2016), s. 455-464 ISSN 0024-9297 R&D Projects: GA ČR(CZ) GA13-26542S; GA ČR(CZ) GAP106/12/0827 Institutional support: RVO:61389013 Keywords : poly(1,4-phenylene-ethynylene)-alt-poly(1,4-phenylene-vinylene)s * dissymmetric side chains * synthesis Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.835, year: 2016

Synthesis of ZnS thin films from aqueous caustic of trisodium citrate and their properties

Directory of Open Access Journals (Sweden)

Martyn A. Sozanskyi

2015-12-01

Full Text Available Zinc sulfide (ZnS thin films due to their properties are widely used in various electronic optical devices. They are produced by several methods, among which – vacuum sublimation, high frequency sputtering method, quasiclosed volume method, sol-gel method, electrodeposition. These methods have high energy consumption which increases the price of ZnS thin films. Aim: The aim of this work is to establish the optimal parameters of the synthesis of ZnS thin films of the aqueous caustic and the correlation between content of zinc in the synthesized films determined by the method of stripping voltammetry and thickness, structural, morphological and optical parameters. Materials and Methods: The ZnS thin films were obtained from aqueous caustics of zinc-containing salt using chemical deposition. Fresh solution of zinc-containing salt, trisodium citrate (Na3C6H5O7 as a complexing agent, thiourea ((NH22CS and ammonium hydroxide (NH4OH was used for the synthesis of ZnS films by chemical deposition. The deposition was performed on prepared glass substrates with the area of 5,76 cm2. Results: The phase mixture of the films has been determined. It showed the presence of ZnS compounds in the cubic modification (sphalerite. Stripping voltammetry was used to determine the mass of zinc in the ZnS films on various conditions of synthesis, namely on the concentration of the initial zinc-containing salt, trisodium citrate, thiourea, deposition time and temperature. The surface morphology, optical properties, the thickness of the ZnS resulting films have been studied. Conclusions: The optimal conditions for the synthesis of ZnS films were found based on these data. Three-dimensional surface morphology of ZnS film studies showed its smoothness, uniformity, integrity and confirmed the correctness of determining the optimal synthesis parameters.

Zinc Porphyrins Possessing Three p-Carboxyphenyl Groups: Effect of the Donor Strength of Push-Groups on the Efficiency of Dye Sensitized Solar Cells

Directory of Open Access Journals (Sweden)

Ram B. Ambre

2016-06-01

Full Text Available Zinc porphyrins decorated with three p-carboxyphenyl anchoring groups and various “push” substituents of varied electron-donating strengths were prepared in good yields by facile and straightforward ways. The effect of electron-donating strength of the donor molecules on the overall power conversion efficiency was evaluated with the help of photophysical, electrochemical, photovoltaic spectroscopy and quantum chemical calculations. It is observed from the photophysical and Infrared (IR spectroscopic data that multi-anchoring dyes are more stable and bind more strongly to the TiO2 surface than their one-anchor counterparts. The properties like a three-step synthesis, high overall yields, possible mass production on a gram-scale and strong binding affinities with TiO2 surfaces make them a suitable choice for commercial applications. Zn1NH3A, with electron donating and anti-aggregation characteristics, achieved the highest efficiency of 6.50%.

Photoluminescence and cathodoluminescence properties of Y2O3:Eu nanophosphors prepared by combustion synthesis

International Nuclear Information System (INIS)

Vu, Nguyen; Kim Anh, Tran; Yi, Gyu-Chul; Strek, W.

2007-01-01

Eu-doped Y 2 O 3 nanophosphors were prepared using combustion synthesis. In this method, urea was employed as a fuel. The particle size was estimated to be in the range of 10-20 nm as determined by X-ray diffractometry and transmission electron microscopy. The photoluminescent and cathodoluminescent spectra are described by the well-known 5 D 0 →7 F J transition (J=0, 1, 2, etc.) of Eu 3+ ions with the strongest emission for J=2. The optical properties of nanophosphors were compared with commercial with an order of micrometer size. The effects of urea-to-metal nitrate molar ratio and the other synthesis conditions on the particle size and luminescent properties will be discussed in detail. The red emission of Eu-doped Y 2 O 3 nanophosphors is promising materials not only in high-resolution screen but also in telecomunication as well as in biosensor

Carbon-Based Nanomaterials/Allotropes: A Glimpse of Their Synthesis, Properties and Some Applications

Science.gov (United States)

Zainal, Zulkarnain; Yusof, Nor Azah

2018-01-01

Carbon in its single entity and various forms has been used in technology and human life for many centuries. Since prehistoric times, carbon-based materials such as graphite, charcoal and carbon black have been used as writing and drawing materials. In the past two and a half decades or so, conjugated carbon nanomaterials, especially carbon nanotubes, fullerenes, activated carbon and graphite have been used as energy materials due to their exclusive properties. Due to their outstanding chemical, mechanical, electrical and thermal properties, carbon nanostructures have recently found application in many diverse areas; including drug delivery, electronics, composite materials, sensors, field emission devices, energy storage and conversion, etc. Following the global energy outlook, it is forecasted that the world energy demand will double by 2050. This calls for a new and efficient means to double the energy supply in order to meet the challenges that forge ahead. Carbon nanomaterials are believed to be appropriate and promising (when used as energy materials) to cushion the threat. Consequently, the amazing properties of these materials and greatest potentials towards greener and environment friendly synthesis methods and industrial scale production of carbon nanostructured materials is undoubtedly necessary and can therefore be glimpsed as the focal point of many researchers in science and technology in the 21st century. This is based on the incredible future that lies ahead with these smart carbon-based materials. This review is determined to give a synopsis of new advances towards their synthesis, properties, and some applications as reported in the existing literatures. PMID:29438327

Carbon-Based Nanomaterials/Allotropes: A Glimpse of Their Synthesis, Properties and Some Applications

Directory of Open Access Journals (Sweden)

Salisu Nasir

2018-02-01

Full Text Available Carbon in its single entity and various forms has been used in technology and human life for many centuries. Since prehistoric times, carbon-based materials such as graphite, charcoal and carbon black have been used as writing and drawing materials. In the past two and a half decades or so, conjugated carbon nanomaterials, especially carbon nanotubes, fullerenes, activated carbon and graphite have been used as energy materials due to their exclusive properties. Due to their outstanding chemical, mechanical, electrical and thermal properties, carbon nanostructures have recently found application in many diverse areas; including drug delivery, electronics, composite materials, sensors, field emission devices, energy storage and conversion, etc. Following the global energy outlook, it is forecasted that the world energy demand will double by 2050. This calls for a new and efficient means to double the energy supply in order to meet the challenges that forge ahead. Carbon nanomaterials are believed to be appropriate and promising (when used as energy materials to cushion the threat. Consequently, the amazing properties of these materials and greatest potentials towards greener and environment friendly synthesis methods and industrial scale production of carbon nanostructured materials is undoubtedly necessary and can therefore be glimpsed as the focal point of many researchers in science and technology in the 21st century. This is based on the incredible future that lies ahead with these smart carbon-based materials. This review is determined to give a synopsis of new advances towards their synthesis, properties, and some applications as reported in the existing literatures.

Microemulsion synthesis and magnetic properties of FexNi(1-x) alloy nanoparticles

Science.gov (United States)

Beygi, H.; Babakhani, A.

2017-01-01

This paper investigates synthesis of FexNi(1-x) bimetallic nanoparticles by microemulsion method. Through studying the mechanism of nanoparticles formation, it is indicated that synthesis of nanoparticles took placed by simultaneous reduction of metal ions and so nanoparticles structure is homogeneous alloy. FexNi(1-x) nanoparticles with different sizes, morphologies and compositions were synthesized by changing the microemulsion parameters such as water/surfactant/oil ratio, presence of co-surfactant and NiCl2·6H2O to FeCl2·4H2O molar ratio. Synthesized nanoparticles were characterized by transmission electron microscopy, particle size analysis, X-ray diffraction, atomic absorption and thermogravimetric analyses. The results indicated that, presence of butanol as co-surfactant led to chain-like arrangement of nanoparticles. Also, finer nanoparticles were synthesized by decreasing the amount of oil and water and increasing the amount of CTAB. The results of vibrating sample magnetometer suggested that magnetic properties of FexNi(1-x) alloy nanoparticles were affected by composition, size and morphology of the particles. Spherical and chain-like FexNi(1-x) alloy nanoparticles were superparamagnetic and ferromagnetic, respectively. Furthermore, higher iron in the composition of nanoparticles increases the magnetic properties.

Synthesis and optical properties of novel organic-inorganic hybrid nanolayer structure semiconductors

International Nuclear Information System (INIS)

Zhang Sanjun; Lanty, Gaetan; Lauret, Jean-Sebastien; Deleporte, Emmanuelle; Audebert, Pierre; Galmiche, Laurent

2009-01-01

We report on the synthesis of some novel organic-inorganic hybrid 2D perovskite semiconductors (R-(CH 2 ) n NH 3 ) 2 PbX 4 . These semiconductors are self-assembled intercalation nanolayers and have a multi-quantum-well energy level structure. We systematically vary the characteristic of organic groups (R-(CH 2 ) n NH 3 + ) to study the relationship between their structures and the optical properties of (R-(CH 2 ) n NH 3 ) 2 PbX 4 . From optical absorption and photoluminescence spectroscopy experiments performed on series of samples, we find some trends of choosing the organic groups to improve the optical performance of (R-(CH 2 ) n NH 3 ) 2 PbX 4 . A new organic group, which allows synthesis of nanolayer perovskite semiconductors with quite high photoluminescence efficiency and better long-term stability, has been found.

Synthesis and optoelectronic characterization of some triphenylamine-based compounds containing strong acceptor substituents

Energy Technology Data Exchange (ETDEWEB)

Grigoras, Mircea, E-mail: grim@icmpp.ro; Ivan, Teofilia; Vacareanu, Loredana; Catargiu, Ana Maria; Tigoianu, Radu

2014-09-15

Three novel triphenylamine-based compounds containing strong electron acceptor groups have been synthesized and their comparative photophysical properties are presented. These compounds were obtained by a two-step method: (i) triphenylamine compounds with one, two and three phenylacetylene arms were synthesized by Sonogashira reaction between iodine-substituted triphenylamines and phenylacetylene, followed by (ii) post-modification of these electron-rich alkynes by addition of the strong electron acceptor, tetracyanoethylene. Characterization of all oligomers was made by FTIR, {sup 1}H-NMR, UV–vis and fluorescence spectroscopy. A batochromic shifting of the UV and photoluminescence maxima was observed with the increase of the acceptor group number. The electrochemical behavior was studied by cyclic voltammetry. The cyclic voltammograms have evidenced that triphenylamine-phenylacetylene compounds undergo only oxidation processes while compounds modified with tetracyanoethylene show both oxidation and reduction peaks associated with donor and acceptor groups, respectively. The donor–acceptor compounds coordinate metal ions (i.e., Hg{sup 2+} and Sn{sup 2+}) by cyano groups resulting in the decreasing of charge transfer band intensity, and they can be used as chemosensors. - Highlights: • Three triphenylamine-based ethynylene compounds were prepared by Sonogashira reaction. • Post-modification of ethynylene linkages by tetracyanethylene cycloaddition and retroconversion led to donor–acceptor compounds. • Photophysical properties of donor–acceptor oligomers were studied in different solvents.

Electrochemical, spectroscopic, and photophysical properties of structurally diverse polyazine-bridged Ru(II),Pt(II) and Os(II),Ru(II),Pt(II) supramolecular motifs.

Science.gov (United States)

Knoll, Jessica D; Arachchige, Shamindri M; Wang, Guangbin; Rangan, Krishnan; Miao, Ran; Higgins, Samantha L H; Okyere, Benjamin; Zhao, Meihua; Croasdale, Paul; Magruder, Katherine; Sinclair, Brian; Wall, Candace; Brewer, Karen J

2011-09-19

Five new tetrametallic supramolecules of the motif [{(TL)(2)M(dpp)}(2)Ru(BL)PtCl(2)](6+) and three new trimetallic light absorbers [{(TL)(2)M(dpp)}(2)Ru(BL)](6+) (TL = bpy = 2,2'-bipyridine or phen = 1,10-phenanthroline; M = Ru(II) or Os(II); BL = dpp = 2,3-bis(2-pyridyl)pyrazine, dpq = 2,3-bis(2-pyridyl)quinoxaline, or bpm = 2,2'-bipyrimidine) were synthesized and their redox, spectroscopic, and photophysical properties investigated. The tetrametallic complexes couple a Pt(II)-based reactive metal center to Ru and/or Os light absorbers through two different polyazine BL to provide structural diversity and interesting resultant properties. The redox potential of the M(II/III) couple is modulated by M variation, with the terminal Ru(II/III) occurring at 1.58-1.61 V and terminal Os(II/III) couples at 1.07-1.18 V versus Ag/AgCl. [{(TL)(2)M(dpp)}(2)Ru(BL)](PF(6))(6) display terminal M(dπ)-based highest occupied molecular orbitals (HOMOs) with the dpp(π*)-based lowest unoccupied molecular orbital (LUMO) energy relatively unaffected by the nature of BL. The coupling of Pt to the BL results in orbital inversion with localization of the LUMO on the remote BL in the tetrametallic complexes, providing a lowest energy charge separated (CS) state with an oxidized terminal Ru or Os and spatially separated reduced BL. The complexes [{(TL)(2)M(dpp)}(2)Ru(BL)](6+) and [{(TL)(2)M(dpp)}(2)Ru(BL)PtCl(2)](6+) efficiently absorb light throughout the UV and visible regions with intense metal-to-ligand charge transfer (MLCT) transitions in the visible at about 540 nm (M = Ru) and 560 nm (M = Os) (ε ≈ 33,000-42,000 M(-1) cm(-1)) and direct excitation to the spin-forbidden (3)MLCT excited state in the Os complexes about 720 nm. All the trimetallic and tetrametallic Ru-based supramolecular systems emit from the terminal Ru(dπ)→dpp(π*) (3)MLCT state, λ(max)(em) ≈ 750 nm. The tetrametallic systems display complex excited state dynamics with quenching of the (3)MLCT emission at

Synthesis and properties of regenerated cellulose-based hydrogels with high strength and transparency for potential use as an ocular bandage

International Nuclear Information System (INIS)

Patchan, M.; Graham, J.L.; Xia, Z.; Maranchi, J.P.; McCally, R.; Schein, O.; Elisseeff, J.H.; Trexler, M.M.

2013-01-01

Cellulose is a biologically derived material with excellent wound-healing properties. The high strength of cellulose fibers and the ability to synthesize gels with high optical transparency make these materials suitable for ocular applications. In this study, cellulose materials derived from wood pulp, cotton, and bacterial sources were dissolved in lithium chloride/N,N-dimethylacetamide to form regenerated cellulose hydrogels. Material properties of the resulting hydrogels, including water content, optical transparency, and tensile and tear strengths, were evaluated. Synthesis parameters, including activation time, dissolution time, relative humidity, and cellulose concentration, were found to impact the material properties of the resulting hydrogels. Overnight activation time improves the optical transparency of the hydrogels from 77% to 97% at 550 nm, whereas controlling cellulose concentration improves their tear strength by as much as 200%. On the basis of the measured transmittance and strength values of the regenerated hydrogels prepared via the optimized synthesis parameters, Avicel PH 101, Sigma-Aldrich microcrystalline cellulose 435236, and bacterial cellulose types were prioritized for future biocompatibility testing and potential clinical investigation. - Highlights: • Hydrogels were prepared (via LiCl/DMAc) from 7 different types of cellulose. • Synthesis parameters (activation, gelation, and concentration) were optimized. • Impact of synthesis parameters on transparency and strength was explored

Synthesis and properties of regenerated cellulose-based hydrogels with high strength and transparency for potential use as an ocular bandage

Energy Technology Data Exchange (ETDEWEB)

Patchan, M. [Research and Exploratory Development Department, The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Graham, J.L. [Department of Biomedical Engineering, Johns Hopkins University, School of Medicine, 720 Rutland Avenue/Ross 720, Baltimore, MD 21205 (United States); Xia, Z.; Maranchi, J.P. [Research and Exploratory Development Department, The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); McCally, R. [Research and Exploratory Development Department, The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Wilmer Eye Institute, Johns Hopkins Medical Institutions, 600 N. Wolfe Street, Baltimore, MD 21287 (United States); Schein, O. [Wilmer Eye Institute, Johns Hopkins Medical Institutions, 600 N. Wolfe Street, Baltimore, MD 21287 (United States); Elisseeff, J.H. [Department of Biomedical Engineering, Johns Hopkins University, School of Medicine, 720 Rutland Avenue/Ross 720, Baltimore, MD 21205 (United States); Trexler, M.M., E-mail: morgana.trexler@jhuapl.edu [Research and Exploratory Development Department, The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States)

2013-07-01

Cellulose is a biologically derived material with excellent wound-healing properties. The high strength of cellulose fibers and the ability to synthesize gels with high optical transparency make these materials suitable for ocular applications. In this study, cellulose materials derived from wood pulp, cotton, and bacterial sources were dissolved in lithium chloride/N,N-dimethylacetamide to form regenerated cellulose hydrogels. Material properties of the resulting hydrogels, including water content, optical transparency, and tensile and tear strengths, were evaluated. Synthesis parameters, including activation time, dissolution time, relative humidity, and cellulose concentration, were found to impact the material properties of the resulting hydrogels. Overnight activation time improves the optical transparency of the hydrogels from 77% to 97% at 550 nm, whereas controlling cellulose concentration improves their tear strength by as much as 200%. On the basis of the measured transmittance and strength values of the regenerated hydrogels prepared via the optimized synthesis parameters, Avicel PH 101, Sigma-Aldrich microcrystalline cellulose 435236, and bacterial cellulose types were prioritized for future biocompatibility testing and potential clinical investigation. - Highlights: • Hydrogels were prepared (via LiCl/DMAc) from 7 different types of cellulose. • Synthesis parameters (activation, gelation, and concentration) were optimized. • Impact of synthesis parameters on transparency and strength was explored.

Lipid and carotenoid synthesis by Rhodosporidium diobovatum, grown on glucose versus glycerol, and its biodiesel properties.

Science.gov (United States)

Nasirian, Nima; Mirzaie, Maryam; Cicek, Nazim; Levin, David B

2018-04-01

Relationships between lipid and carotenoid synthesis by Rhodosporidium diobovatum were investigated for cell cultures in nitrogen-limited medium (GMY) containing equimolar amounts of carbon of glucose or glycerol. The cultures were also supplemented with additional substrate at 120 h postinoculation (pi) and during a fed-batch experiment. Growth of R. diobovatum on glucose resulted in higher yields of triacyglycerides (TAGs) and carotenoid than when grown on glycerol, even though the cultures contained equimolar amounts of carbon. After the addition of fresh substrate at 120 h pi, total carotenoid concentrations were significantly different from the concentrations measured at 120 h pi in both glucose and glycerol cultures, with no concomitant increase in lipid concentrations, suggesting that carotenoid synthesis is linked to exponential-phase growth, while lipid synthesis is linked to stationary phase. We also compared the calculated properties of biodiesel that could be made with TAGs derived from R. diobovatum with properties of biodiesel made from TAGs of other oleaginous yeasts, microalgae, vegetable oils, and animal fats. This study shows that R. diobovatum can be an effective strain for production of neutral lipids containing high percentages of oleic acid, palmitic acid, and linoleic acid, as well as carotenoids.

Analogues of uracil nucleosides with intrinsic fluorescence (NIF-analogues): synthesis and photophysical properties.

Science.gov (United States)

Segal, Meirav; Fischer, Bilha

2012-02-28

Uridine cannot be utilized as fluorescent probe due to its extremely low quantum yield. For improving the uracil fluorescence characteristics we extended the natural chromophore at the C5 position by coupling substituted aromatic rings directly or via an alkenyl or alkynyl linker to create fluorophores. Extension of the uracil base was achieved by treating 5-I-uridine with the appropriate boronic acid under the Suzuki coupling conditions. Analogues containing an alkynyl linker were obtained from 5-I-uridine and the suitable boronic acid in a Sonogashira coupling reaction. The uracil fluorescent analogues proposed here were designed to satisfy the following requirements: a minimal chemical modification at a position not involved in base-pairing, resulting in relatively long absorption and emission wavelengths and high quantum yield. 5-((4-Methoxy-phenyl)-trans-vinyl)-2'-deoxy-uridine, 6b, was found to be a promising fluorescent probe. Probe 6b exhibits a quantum yield that is 3000-fold larger than that of the natural chromophore (Φ 0.12), maximum emission (478 nm) which is 170 nm red shifted as compared to uridine, and a Stokes shift of 143 nm. In addition, since probe 6b adopts the anti conformation and S sugar puckering favored by B-DNA, it makes a promising nucleoside analogue to be incorporated in an oligonucleotide probe for detection of genetic material.

Synthesis of Silica Nanoparticles by Sol-Gel: Size-Dependent Properties, Surface Modification, and Applications in Silica-Polymer Nano composites-A Review

International Nuclear Information System (INIS)

Ismail, A.R.; Vejayakumaran, P.

2012-01-01

Application of silica nanoparticles as fillers in the preparation of nano composite of polymers has drawn much attention, due to the increased demand for new materials with improved thermal, mechanical, physical, and chemical properties. Recent developments in the synthesis of monodispersed, narrow-size distribution of nanoparticles by sol-gel method provide significant boost to development of silica-polymer nano composites. This paper is written by emphasizing on the synthesis of silica nanoparticles, characterization on size-dependent properties, and surface modification for the preparation of homogeneous nano composites, generally by sol-gel technique. The effect of nano silica on the properties of various types of silica-polymer composites is also summarized.

Thin film properties of triphenylamine-cored dendrimers: A molecular approach to control aggregation

International Nuclear Information System (INIS)

Vamvounis, George; Pivrikas, Almantas; Shaw, Paul E.; Burn, Paul L.

2013-01-01

The solid-state photophysical and charge transport properties of two first-generation dendrimers are presented. The dendrimers are comprised of a triphenylamine core, dendrons containing a phenyl branching unit with thiophene (Dendrimer 1) or bithiophene (Dendrimer 2) moieties, and dodecyl surface groups. For Dendrimer 1, the excited state is located within the center of the dendrimer giving rise to a moderate solid-state photoluminescence quantum yield (Φ pl ) (0.13) and significant charge trapping, with both observations due to the degree of overlap of the main electroactive chromophores on adjacent dendrimers. For Dendrimer 2, the excited state is located within the dendron and in the solid-state this leads to a strongly red-shifted and weakened emission (Φ pl ∼ 0.02) due to strong intermolecular chromophore interactions. For films of Dendrimer 2 the charge mobility was higher than Dendrimer 1 but was still limited by a low density of strongly interacting electroactive chromophores. The pronounced difference between the solid-state properties of the two dendrimers is simply engineered by the addition of an extra thiophene in each of the dendrons. - Highlights: • Photophysical and charge-transport properties of two dendrimers are investigated. • Excited-state is on the center for Dendrimer 1 and on the dendron for Dendrimer 2. • Film quantum yield of luminescence is higher for Dendrimer 1. • Dendrimer 1 displays greater charge trapping at high fields

Porphyrins intercalated in Zn/Al and Mg/Al layered double hydroxides: properties and structural arrangement

Czech Academy of Sciences Publication Activity Database

Káfuňková, Eva; Taviot-Guého, Ch.; Bezdička, Petr; Klementová, Mariana; Kovář, P.; Kubát, Pavel; Mosinger, Jiří; Pospíšil, M.; Lang, Kamil

2010-01-01

Roč. 22, č. 8 (2010), s. 2481-2490 ISSN 0897-4756 R&D Projects: GA ČR GA203/07/1424; GA ČR GAP207/10/1447 Institutional research plan: CEZ:AV0Z40320502; CEZ:AV0Z40400503 Keywords : hydrotalcite-like compounds * molecular-dynamic simulations * photophysical properties Subject RIV: CA - Inorganic Chemistry Impact factor: 6.400, year: 2010

Synthesis, crystal structure and photo physical properties of isomeric fluorinated s-shaped polyaromatic dibenzo[c,l]chrysene derivatives

Science.gov (United States)

Moriguchi, Tetsuji; Tabuchi, Daichi; Yakeya, Daisuke; Tsuge, Akihiko; Jalli, Venkataprasad; Yoza, Kenji

2018-01-01

Two s-shaped fluorinated isomeric polyaromatic dibenzo[c,l]chrysene derivatives have been synthesized by a two step process using the Wittig, Heck and iodine promoted cyclization reactions. These cyclized compounds were characterized by 1H NMR and EI-MS. Further, absolute configurations of isomeric 4a and 4b were determined by X-ray diffraction analysis. Compound 4a crystallized under monoclinic system with space group P21/c and compound 4b crystallized under monoclinic system with space group Cc. They have good solubility in common organic solvents such as dichloromethane, chloroform and THF. Photophysical properties of 4a and 4b were evaluated by using UV-Visible and Fluorescence spectrophotometer. Compounds 4a and 4b showed strong absorption maximum wavelength at 317 nm. The emission spectra of 4a and 4b displayed sharp peaks in the visible region from 417 to 441 nm. The shape of the UV-Visible and Fluorescence spectra of 4a and 4b looks almost identical. But compound 4a exhibited better fluorescence intensity than compound 4b. This difference may be due to the difference in the configuration of compounds 4a and 4b.

Greener synthesis of magnetite nanoparticles using green tea extract and their magnetic properties

Science.gov (United States)

Karade, V. C.; Waifalkar, P. P.; Dongle, T. D.; Sahoo, Subasa C.; Kollu, P.; Patil, P. S.; Patil, P. B.

2017-09-01

The facile green synthesis method has been employed for the synthesis of biocompatible Fe3O4 magnetic nanoparticles (MNPs) using green tea extract. The effective reduction of ferric ions (Fe3+) were done using an aqueous green tea extract where it acts as reducing as well as capping agent. The effect of iron precursor to green tea extract ratio and reaction temperature was studied. The MNPs were characterized by x-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, dynamic light scattering and vibrating sample magnetometer. It was observed that the reaction temperature strongly affects the magnetic and structural properties of MNPs. The magnetic measurements study showed that Fe3O4 MNPs are superparamagnetic at 300 K, while at 60 K have ferromagnetic as well as superparamagnetic contributions.

Carbon Nanotubes Advanced Topics in the Synthesis, Structure, Properties and Applications

CERN Document Server

Jorio, Ado; Dresselhaus, Mildred S

2008-01-01

The carbon nanotubes field has evolved substantially since the publication of the bestseller "Carbon Nanotubes: Synthesis, Structure, Properties and Applications". The present volume builds on the generic aspects of the aforementioned book, which emphasizes the fundamentals, with the new volume emphasizing areas that have grown rapidly since the first volume, guiding future directions where research is needed and highlighting applications. The volume also includes an emphasis on areas like graphene, other carbon-like and other tube-like materials because these fields are likely to affect and influence developments in nanotubes in the next 5 years.

Effect of Synthesis Parameters on the Structure and Magnetic Properties of Magnetic Manganese Ferrite/Silver Composite Nanoparticles Synthesized by Wet Chemistry Method

DEFF Research Database (Denmark)

Huy, L.T.; Tam, L.T.; Phan, V.N.

2016-01-01

In the present work, magnetic manganese ferrite/silver (MnFe2O4-Ag) composite nanoparticles were synthesized by wet chemistry method. This synthesis process consists of two steps: first, the seed of manganese ferrite nanoparticles (MnFe2O4 NPs) was prepared by a coprecipitationmethod; second......, growth of silver nanoparticles (AgNPs) on the MnFe2O4 seed by modified photochemical reaction. We have conducted systematically the effects of synthesis parameters such as pH value, synthesis time, precursor salts concentration, mass ratio and stabilizing agents on the structure and magnetic properties......-prepared MnFe2O4-Ag magnetic nanocomposites display excellent properties of high crystallinity, long-term aggregation stability in aqueous medium, large saturation magnetization in the range of 15-20 emu/g, and small sizes of Ag-NPs similar to 20 nm. These exhibited properties made the MnFe2O4-Ag...

Low Temperature Synthesis of Li2SiO3: Effect on Its Morphological and Textural Properties

Directory of Open Access Journals (Sweden)

Georgina Mondragón-Gutiérrez

2008-01-01

Full Text Available Synthesis, at low temperature, of Li2SiO3 was investigated using different Li : Si molar ratios and urea, which was used as template. This new synthesis was performed in order to look for different textural and morphological properties than those obtained usually by conventional methods in this kind of ceramics. XRD and SEM analyses showed that Li2SiO3 was obtained pure and with ceramic particle morphology of hollow spheres of 2–6 μm. TEM analysis showed that those spheres were composed by needle-like particles crosslinked among them. This morphology provided a high surface area, probed by N2 adsorption. Therefore, this method of synthesis may be used to obtain other similar ceramics and test them in different applications.

Synthesis of derivatives of tetronic acid and pulvinic acid. Total synthesis of norbadione A

International Nuclear Information System (INIS)

Mallinger, A.

2008-11-01

When vegetables like mushrooms are contaminated by radioactive caesium 137, this radioactive caesium is associated to norbadione A, a natural pigment present in two mushroom species and which can be used as a caesium decorporation agent or maybe as protection agent against ionizing radiations. Within this perspective, this research report describes the biosynthesis and the structure and properties of the norbadione A and of pulvinic acids (physicochemical properties, anti-oxidizing properties). Then, it presents the various tetronic acids (3-acyl-, 3-alkyl-, 3-alkoxy-, 3-aryl-tetronic acids and non 3-substituted tetronic acids), their synthesis path as they are described in the literature, and presents a new synthesis approach using a tandem reaction (with different esters or hydroxy esters) and the synthesis of tetronic acids. The author also proposes a new synthesis way for methyl pulvinates, and finally reports the work on the development of a total synthesis of the norbadione A

Novel metallomesogenic polyurethanes: Synthesis, characterization and properties

International Nuclear Information System (INIS)

Senthilkumar, Natarajan; Narasimhaswamy, Tanneru; Kim, Il-Jin

2012-01-01

A series of tetradentate Schiff base metallomesogenic diols were synthesized from two simple dihydroxy benzenes. The metallomesogenic diol was constructed from three ring containing mesogen linked through ester and azomethine with terminal hydroxy group. This upon complexation with copper(II) formed metallomesogenic diol with varying terminal chain length. A series of metallomesogenic polyurethanes were synthesized using these metallomesogenic diols as chain extenders for the prepolymers based on polytetramethylene glycol (PTMG) of varying molecular weight (M n = 650, 2000) and 2,4-toluene diisocyanate (TDI), or 4,4′-methylene bis(phenyl isocyanate) (MDI). The molar ratio of metallomesogenic diol and PTMG were varied in the polyurethane to find their role in liquid crystalline and mechanical properties. Extensive characterization of all metallomesogenic compounds and intermediates were carried out by FT-IR, 1 H and 13 C NMR, EPR, VSM, Mass (EI and FAB) and UV–visible spectroscopy. Hot stage polarizing microscope and differential scanning calorimetry were used to ensure the phase characteristics such as nature of phase, melting and clearing temperatures and phase range. The appearance of enantiotropic smectic A phases indicated high molecular polarizability of the core due to the metal ion. - Highlights: ► Design and synthesis of metallomesogenic diols. ► Metallomesogenic polyurethanes were prepared using these diols as chain extenders. ► Liquid crystalline and mechanical properties were studied. ► A square pyramidal structure for the copper(II) complexes have been proposed. ► Polyurethanes exhibited enantiotropic smectic A phases.

Combustion synthesis of TiC-based materials: Mechanisms, densification, and properties

International Nuclear Information System (INIS)

LaSalvia, J.C.; Meyers, M.A.

1995-01-01

The micromechanisms involved in the combustion synthesis of a Ti-C-Ni-Mo mixture resulting in the formation of a TiC-based composite were examined using the combustion wave quenching technique developed by Rogachev et al. At the micron level, the main reaction occurs at the interface between a Ti-Ni-C melt and C particles, resulting in the formation of a solid TiC x layer on the C particles. This layer undergoes a successive process of rapid growth and decomposition into TiC x spherules until all of the C particle is consumed. This mechanism is consistent with the apparent activation energy (E = 100 kJ/mol) for the process obtained from a macrokinetic investigation of the system. The apparent uniformity in size (d = 1 μm) of the TiC x spherules upon formation indicates a critical condition in the stability of the energetics involved in the process. These TiC x spherules undergo growth due to Ostwald ripening and coalescence mechanisms resulting in a final apparent size of 2.5 μm. For the compositions investigated, the addition of Mo did not affect either the micromechanisms or macrokinetics of the combustion synthesis process. Densification of the porous body after the combustion synthesis process can be carried out while it is still in a easily deformable state. The highly porous body is densified by a combination of fracture (communition), plastic deformation, and sintering. The mechanisms are identified for the case of combustion synthesized TiC. Mechanical properties and microstructures of a number of materials (e.g. TiC, TiB 2 , Al 2 O 3 -TiB 2 , TiB 2 -SiC, TiC-Ni-Mo) produced by combustion synthesis combined with a high-velocity forging step are reviewed

Synthesis and magnetic properties of size-selected CoPt nanoparticles

International Nuclear Information System (INIS)

Tournus, F.; Blanc, N.; Tamion, A.; Hillenkamp, M.; Dupuis, V.

2011-01-01

CoPt nanoparticles are widely studied, in particular for their potentially very high magnetic anisotropy. However, their magnetic properties can differ from the bulk ones and they are expected to vary with the particle size. In this paper, we report the synthesis and characterization of well-defined CoPt nanoparticle samples produced in ultrahigh vacuum conditions following a physical route: the mass-selected low energy cluster beam deposition technique. This approach relies on an electrostatic deviation of ionized clusters which allows us to easily adjust the particle size, independently from the deposited equivalent thickness (i.e. the surface or volume particle density in a sample). Diluted samples made of CoPt particles, with different diameters, embedded in amorphous carbon are studied by transmission electron microscopy and superconducting interference device magnetometry, which gives access to the magnetic anisotropy energy distribution. We then compare the magnetic properties of two different particle sizes. The results are found to be consistent with an anisotropy constant (including its distribution) which does not evolve with the particle size in the range considered. - Highlights: → Samples of mass-selected CoPt nanoparticles are synthesized by an original physical method. → The magnetic properties of two different particle sizes are compared. → The anisotropy constant (including its dispersion) does not evolve in the range considered. → These results illustrate some invariance properties of ZFC curves.

New materials graphyne, graphdiyne, graphone, and graphane: review of properties, synthesis, and application in nanotechnology

Directory of Open Access Journals (Sweden)

Peng Q

2014-04-01

Full Text Available Qing Peng,1 Albert K Dearden,2 Jared Crean,1 Liang Han,1 Sheng Liu,3 Xiaodong Wen,4,5 Suvranu De11Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA; 2Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY, USA; 3Institute for Microsystems, School of Mechanical Engineering, Huazhong University of Science and Technology, Wuhan, People's Republic of China; 4State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, People's Republic of China; 5Synfuels China Co, Ltd, Huairou, Beijing, People's Republic of ChinaAbstract: Plenty of new two-dimensional materials including graphyne, graphdiyne, graphone, and graphane have been proposed and unveiled after the discovery of the "wonder material" graphene. Graphyne and graphdiyne are two-dimensional carbon allotropes of graphene with honeycomb structures. Graphone and graphane are hydrogenated derivatives of graphene. The advanced and unique properties of these new materials make them highly promising for applications in next generation nanoelectronics. Here, we briefly review their properties, including structural, mechanical, physical, and chemical properties, as well as their synthesis and applications in nanotechnology. Graphyne is better than graphene in directional electronic properties and charge carriers. With a band gap and magnetism, graphone and graphane show important applications in nanoelectronics and spintronics. Because these materials are close to graphene and will play important roles in carbon-based electronic devices, they deserve further, careful, and thorough studies for nanotechnology applications.Keywords: two-dimensional materials, graphene-like structures, properties and synthesis, nanotechnology applications, graphyne, hydrogenation of grapheme

Fluorescent Rhodamines and Fluorogenic Carbopyronines for Super‐Resolution STED Microscopy in Living Cells

Science.gov (United States)

Mitronova, Gyuzel Yu.; Sidenstein, Sven C.; Klocke, Jessica L.; Kamin, Dirk; Meineke, Dirk N. H.; D'Este, Elisa; Kraemer, Philip‐Tobias; Danzl, Johann G.

2016-01-01

Abstract A range of bright and photostable rhodamines and carbopyronines with absorption maxima in the range of λ=500–630 nm were prepared, and enabled the specific labeling of cytoskeletal filaments using HaloTag technology followed by staining with 1 μm solutions of the dye–ligand conjugates. The synthesis, photophysical parameters, fluorogenic behavior, and structure–property relationships of the new dyes are discussed. Light microscopy with stimulated emission depletion (STED) provided one‐ and two‐color images of living cells with an optical resolution of 40–60 nm. PMID:26844929

Structural, thermal and photo-physical data of azo-aromatic TEMPO derivatives before and after their grafting to polyolefins

Directory of Open Access Journals (Sweden)

Francesca Cicogna

2016-03-01

Full Text Available The data reported in this paper are complementary to the characterization of 4-(phenylazo-benzoyl-2,2,6,6-tetramethylpiperidine-1-oxyl radical (AzO-TEMPO and of the 4-(2-thienylazo-benzoyl-2,2,6,6-tetramethylpiperidine-1-oxyl radical (ThiO-TEMPO before and after their grafting to two polyethylene matrices (a copolymer ethylene/α-olefin (co-EO and a high density polyethylene (HDPE. Particularly the data reported in this paper confirm the structure (FT-IR analysis, the thermal (TGA and EPR and the photo-physical (UV–vis properties of the RO-TEMPO derivatives before and after their grafting. Herein, the FT-IR spectrum and TGA thermogram of ThiO-TEMPO were compared with those of AzO-TEMPO. Moreover, the superimposition of UV–vis spectra collected during the irradiation under 366 or 254 nm emitting lamp of AzO-TEMPO and ThiO-TEMPO in acetonitrile solution are reported. Finally, a complete DSC characterization of the functionalized POs is shown.DOI of original article: 〈http://dx.doi.org/10.1016/j.polymer.2015.11.018〉 [1

Photophysical study of blue-light excitable ternary Eu(III) complexes and their encapsulation into polystyrene nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Räsänen, Markus, E-mail: mpvras@utu.fi [Department of Chemistry, University of Turku, FIN-20014 Turku (Finland); Takalo, Harri [DHR Finland Oy, Innotrac Diagnostics, Biolinja 12, FIN-20750 Turku (Finland); Soukka, Tero [Department of Biochemistry/Biotechnology, University of Turku, FIN-20014 Turku (Finland); Haapakka, Keijo; Kankare, Jouko [Department of Chemistry, University of Turku, FIN-20014 Turku (Finland)

2015-04-15

In this work, 14 ternary Eu(III) complexes were studied by means of spectroscopy. The studied Eu(III) complexes consisted of Lewis bases (4′-(4-diethylaminophenyl)-2,2′:6′,2″-terpyridine (L{sup 8}) or 1,10-phenanthroline (L{sup 9})) and differently substituted β-diketones. The ternary complexes with L{sup 8} show the excitation peak at 405 nm and the quantum yield even 76%. The brightest ternary complex at the 405 nm excitation was Eu(L{sup 3}){sub 3}L{sup 8} while Eu(L{sup 7}){sub 3}L{sup 8} (HL{sup 3}=4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione, HL{sup 7}=1-(9-ethyl-9H-carbazol-3-yl)-4,4,5,5,5-pentafluoro-1,3-pentanedione) was found to be the brightest at the ligand-centred excitation maximum. The ternary complexes were studied mainly in toluene as the model environment for the polystyrene nanoparticle cavities. The complexes were successfully loaded into the polystyrene nanoparticles enabling their bioanalytical application in aqueous environment. The encapsulation of the complexes preserved, or even enhanced, their good photophysical features. - Highlights: • Ternary Eu{sup 3+} complexes with some β-diketone and substituted terpyridine were studied. • Ternary complexes with substituted terpyridine showed blue-light excitability. • Ternary complexes were successfully loaded into the polystyrene nanoparticles. • Encapsulation of the complexes preserved their good photophysical features.

Synthesis of Silver Nanoparticles Using Buchu Plant Extracts and Their Analgesic Properties

Directory of Open Access Journals (Sweden)

Herbert Chiguvare

2016-06-01

Full Text Available We herein report for the first time the synthesis and analgesic properties of silver nanoparticles (Ag-NPs using buchu plant extract. The as-synthesised Ag-NPs at different temperatures were characterised by UV-Vis spectroscopy, Fourier transform infra-red spectroscopy (FTIR and transmission transform microscopy (TEM to confirm the formation of silver nanoparticles. Phytochemical screening of the ethanolic extract revealed the presence of glycosides, proteins, tannins, alkaloids, flavonoids and saponins. The absorption spectra showed that the synthesis is temperature and time dependent. The TEM analysis showed that the as-synthesised Ag-NPs are polydispersed and spherical in shape with average particle diameter of 19.95 ± 7.76 nm while the FTIR results confirmed the reduction and capping of the as-synthesised Ag-NPs by the phytochemicals present in the ethanolic extract. The analgesic study indicated that the combined effect of the plant extract and Ag-NPs is more effective in pain management than both the aspirin drug and the extract alone.

Synthesis and optical properties of novel organic-inorganic hybrid nanolayer structure semiconductors

Energy Technology Data Exchange (ETDEWEB)

Zhang Sanjun; Lanty, Gaetan; Lauret, Jean-Sebastien [Laboratoire de Photonique Quantique et Moleculaire de l' Ecole Normale Superieure de Cachan, 61 avenue du President Wilson, 94235 Cachan (France); Deleporte, Emmanuelle, E-mail: Emmanuelle.Deleporte@lpqm.ens-cachan.fr [Laboratoire de Photonique Quantique et Moleculaire de l' Ecole Normale Superieure de Cachan, 61 avenue du President Wilson, 94235 Cachan (France); Audebert, Pierre; Galmiche, Laurent [Laboratoire de Photophysique et Photochimie Supramoleculaires et Macromoleculaires de l' Ecole Normale Superieure de Cachan, 61 avenue du President Wilson, 94235 Cachan (France)

2009-06-15

We report on the synthesis of some novel organic-inorganic hybrid 2D perovskite semiconductors (R-(CH{sub 2}){sub n}NH{sub 3}){sub 2}PbX{sub 4}. These semiconductors are self-assembled intercalation nanolayers and have a multi-quantum-well energy level structure. We systematically vary the characteristic of organic groups (R-(CH{sub 2}){sub n}NH{sub 3}{sup +}) to study the relationship between their structures and the optical properties of (R-(CH{sub 2}){sub n}NH{sub 3}){sub 2}PbX{sub 4}. From optical absorption and photoluminescence spectroscopy experiments performed on series of samples, we find some trends of choosing the organic groups to improve the optical performance of (R-(CH{sub 2}){sub n}NH{sub 3}){sub 2}PbX{sub 4}. A new organic group, which allows synthesis of nanolayer perovskite semiconductors with quite high photoluminescence efficiency and better long-term stability, has been found.

Photocatalytic Properties of Nb/MCM-41 Molecular Sieves: Effect of the Synthesis Conditions

Directory of Open Access Journals (Sweden)

Caterine Daza Gomez

2015-08-01

Full Text Available The effect of synthesis conditions and niobium incorporation levels on the photocatalytic properties of Nb/MCM-41 molecular sieves was assessed. Niobium pentoxide supported on MCM-41 mesoporous silica was obtained using two methods: sol-gel and incipient impregnation, in each case also varying the percentage of niobium incorporation. The synthesized Nb-MCM-41 ceramic powders were characterized using the spectroscopic techniques of infrared spectroscopy (IR, Raman spectroscopy, X-ray diffraction (XRD, and transmission electron microscopy (TEM. The photodegradation capacity of the powders was studied using the organic molecule, methylene blue. The effect of both the method of synthesis and the percentage of niobium present in the sample on the photodegradation action of the solids was determined. The mesoporous Nb-MCM-41 that produced the greatest photodegradation response was obtained using the sol-gel method and 20% niobium incorporation.

Combustion synthesis of CoCrMo orthopedic implant alloys: microstructure and properties

International Nuclear Information System (INIS)

Li, Bingyun; Mukasyan, Alexander; Varma, Arvind

2003-01-01

Because of their excellent properties, such as corrosion resistance, fatigue strength and biocompatibility, cobalt-based alloys are widely used in total hip and knee replacements, dental devices and support structures for heart valves. In this work, CoCrMo alloys were synthesized using a novel method based on combustion synthesis (CS), an advanced technique to produce a wide variety of materials including alloys and near-net shape articles. This method possesses several advantages over conventional processes, such as low energy requirements, short processing times and simple equipment. The evaluated material properties included density and yield measurements, composition and microstructure analysis, hardness, friction and tensile tests. It was shown that microstructure of CS-material is finer and more uniform as compared to the conventional standard. It was also found that among various additives, Cr 3 C 2 is the most effective one for increasing material hardness. In addition, synthesized CoCrMo alloys exhibited good friction and mechanical properties. (orig.)

PFE: ZnO hybrid nanocomposites for OLED applications: Fabrication and photophysical properties

Energy Technology Data Exchange (ETDEWEB)

Belhaj, M. [Université de Monastir, Faculté des sciences de Monastir, Département de physique, Laboratoire des Interfaces et des Matériaux Avancés, 5019 Monastir (Tunisia); Dridi, C., E-mail: cherif.Dridi@issatso.rnu.tn [Université de Monastir, Faculté des sciences de Monastir, Département de physique, Laboratoire des Interfaces et des Matériaux Avancés, 5019 Monastir (Tunisia); Université de Sousse, Institut Supérieur des Sciences Appliquées et de Technologie de Sousse, Cité Ettafala, 4003 Ibn Khaldoun Sousse (Tunisia); Elhouichet, H. [Centre National de Recherches en Sciences des Matériaux, Laboratoire de physico-Chimie des Matériaux Minéreaux et leurs applications, B.P. 95 Hammam-Lif 2050 (Tunisia)

2015-01-15

In this work, ZnO nanoparticles (n-ZnO) and poly (9, 9-dioctyl-fluorenyl-2, 7-yleneethynylene) (PFE): n-ZnO based thin films were spin-coated onto glass substrates. Structural, morphological and optical properties of ZnO, PFE and the PFE: n-ZnO hybrid films with different n-ZnO mass ratios were investigated. n-ZnO films obtained by sol–gel technique are polycrystalline with a hexagonal wurtzite structure. They are also homogenous with an average grain size of about 35 nm. For polymer nanocomposite, the optical properties are closely related to the ZnO content in the mixture. Among the tested active layers, the best performance is observed for that containing 2 wt% of ZnO nanoparticles. - Highlights: • We have analyzed the optical properties of PFE: ZnO nanocomposites . • We have optimized the best PFE: ZnO nanocomposite for the OLED application. • We have demonstrated the feasibility of white OLED devices.

PFE: ZnO hybrid nanocomposites for OLED applications: Fabrication and photophysical properties

International Nuclear Information System (INIS)

Belhaj, M.; Dridi, C.; Elhouichet, H.

2015-01-01

In this work, ZnO nanoparticles (n-ZnO) and poly (9, 9-dioctyl-fluorenyl-2, 7-yleneethynylene) (PFE): n-ZnO based thin films were spin-coated onto glass substrates. Structural, morphological and optical properties of ZnO, PFE and the PFE: n-ZnO hybrid films with different n-ZnO mass ratios were investigated. n-ZnO films obtained by sol–gel technique are polycrystalline with a hexagonal wurtzite structure. They are also homogenous with an average grain size of about 35 nm. For polymer nanocomposite, the optical properties are closely related to the ZnO content in the mixture. Among the tested active layers, the best performance is observed for that containing 2 wt% of ZnO nanoparticles. - Highlights: • We have analyzed the optical properties of PFE: ZnO nanocomposites . • We have optimized the best PFE: ZnO nanocomposite for the OLED application. • We have demonstrated the feasibility of white OLED devices

Synthesis and properties of scandium ortho-phosphate

International Nuclear Information System (INIS)

Eshchenko, L.S.; Pechkovskij, V.V.; Dvoskina, R.N.

1979-01-01

With the aim to elucidate the influence of synthesis conditions on the chemical composition and properties of orthophosphates of scandium, the interaction of orthophosphoric acid and scandium-containing component (oxide or salt) was studied under various conditions. In the interaction of scandium salt, phosphoric acid and ammonia at room temperature and pH 3.0; 5.0; 7.0 and 9.0 amorphous scandium phosphates have been obtained with the composition of x Sc 2 O 3 xY P 2 O 5 xz NH 3 xn H 2 O. After prolonged staying in mother liquor, roentgenoamorphous precipitates of phosphates transform into the crystalline state. The dependences are studied of the specific surface of amorphous phosphates on pH of precipitation and temperature of the heat treatment (200-800 deg C). Precipitates obtained in a neutral medium at 400 deg C temperature of thermal treatment, show a maximum specific surface. At a temperature of 820-840 deg C the crystallization of amorphous phase occurs followed by the recrystallization and formation of anhydrous SePO 4 of zircon type

NIR dual luminescence from an extended porphyrin. Spectroscopy, photophysics and theory.

Science.gov (United States)

Gourlaouen, Christophe; Daniel, Chantal; Durola, Fabien; Frey, Julien; Heitz, Valérie; Sauvage, Jean-Pierre; Ventura, Barbara; Flamigni, Lucia

2014-05-22

Spectroscopic and photophysical properties of an extended Zn porphyrin with fused bis(tetraazaanthracene) arms including a 2,9-diphenyl-1,10-phenanthroline incorporated in a polyether macrocycle are investigated in solvents of different polarity pointing to the presence of two emitting singlet excited states. The absorption and emission features are identified and ascribed, on the basis of solvent polarity dependence, to a π-π* and to a charge transfer (CT) state, respectively. Whereas the intraligand π-π* transition is assigned to the intense absorption observed at 442-455 nm, the CT states contribute to the bands at 521-525 nm and 472-481 nm. The theoretical analysis of the absorption spectrum confirms the presence of two strong bands centered at 536 and 437 nm corresponding to CT and π-π* states, respectively. Weak CT transitions are calculated at 657 and 486 nm. Two emission maxima are observed in toluene at 724 nm from a (1)π-π* state and at 800 nm from a (1)CT state, respectively. (1)CT bands shift bathochromically by increasing the solvent polarity whereas the energy of the (1)π-π band is less affected. Likewise, the emission yield and lifetime associated with the low energy (1)CT band are strongly affected by solvent polarity. This is rationalized by a (1)π-π* → (1)CT internal conversion driven by solvent polarity, this process being competitive with the (1)π-π* to ground state deactivation channel. Time resolved absorption spectra indicate the presence of two triplet states, a short-lived one (nanoseconds range) and a longer lived one (hundreds of microsecond range) ascribed to a (3)π-π* and a (3)CT, respectively. For them, a conversion mechanism similar to that of the singlet excited states is suggested.

Synthesis and crystalline properties of CdS incorporated polyvinylidene fluoride (PVDF) composite film

Science.gov (United States)

Patel, Arunendra Kumar; Sunder, Aishwarya; Mishra, Shweta; Bajpai, Rakesh

2018-05-01

This paper gives an insight on the synthesis and crystalline properties of Polyvinylidene Fluoride (PVDF) (host matrix) composites impregnated with Cadmium Sulphide (CdS) using Dimethyl formamide (DMF) as the base, prepared by the well known solvent casting technique. The effect of doping concentration of CdS in to the PVDF matrix was studied using X-ray diffraction technique. The structural properties like crystallinity Cr, interplanar distance d, average size of the crystalline region (D), and average inter crystalline separation (R) have been estimated for the developed composite. The crystallinity index, crystallite size and inter crystalline separation is increasing with increase in the concentration of CdS in to the PVDF matrix while the interplanar distance d is decreasing.

Fluorinated Poly(p-phenylenevinylenes: Synthesis and Optical Properties of an Intriguing Class of Luminescent Polymers

Directory of Open Access Journals (Sweden)

Gianluca M. Farinola

2010-05-01

Full Text Available This review is an overview of our previous work on the synthesis and properties of poly(p-phenylenevinylenes (PPVs selectively fluorinated in different positions of the conjugated backbone. Both the synthetic challenges and the effects of functionalization with fluorine atoms on the optical behavior are discussed, highlighting the peculiarities and the interest of this class of conjugated polymers. A general polymerization protocol for PPVs, that is based on the Pd-catalyzed Stille cross-coupling reaction of bis-stannylated vinylene monomers with aromatic bis-halides, has been successfully extended to the synthesis of selectively fluorinated poly(p-phenylenevinylenes. The properties of a series of these PPVs differing in the number and positions of the fluorine atoms on the conjugated backbone have been studied, even in comparison with the non-fluorinated counterparts. The intriguing optical features of the resulting materials are discussed considering not only the role of the electronic and steric effects induced by the fluorine substituents, but also the impact of the fluorination on the solid state organization and intermolecular interactions.

The synthesis, characterization and optical properties of novel 1,3,4-oxadiazole-containing imidazo[1,5-a]pyridine derivatives

International Nuclear Information System (INIS)

Ge Yanqing; Hao Benqian; Duan Guiyun; Wang Jianwu

2011-01-01

A series of novel substituted 1,3,4-oxadiazole derivatives were synthesized by the reaction of 3-butyl-1-chloroimidazo[1,5-a]pyridine-7-carbohydrazide with propionyl chloride and substituted benzoic chloride in the presence of phosphorus oxychloride. The compounds were characterized using IR, 1 H NMR, 13 C NMR and HRMS. Absorption and fluorescence spectra were measured in dichloromethane; an intense absorption maxima was noted at ca. 290 nm and emission maxima was noted at ca. 470 nm. The absorption spectra of the 1,3,4-oxadiazole derivatives reveal that a phenyl and an ethyl group attached to the 1,3,4-oxadiazole ring markedly influenced the maximum absorption. The structures based on density function theory (DFT) calculation show planar configurations for the compounds. The calculated molecular orbital correlates well with their absorption. - Research highlights: → Novel imidazo[1,5-a]pyridine derivatives were synthesized. → The structures were determined by IR, 1 H NMR, 13 C NMR and HRMS spectra. → We investigated the absorption and fluorescence spectral characteristics of the compounds. → The side group in 1,3,4-oxadiazole ring can affect its photophysical properties markedly. → Quantum calculation correlates well with their absorption.

Bis-pyrene-modified unlocked nucleic acids: synthesis, hybridization studies, and fluorescent properties

DEFF Research Database (Denmark)

Perlíková, Pavla; Ejlersen, Maria; Langkjaer, Niels

2014-01-01

Efficient synthesis of a building block for the incorporation of a bis-pyrene-modified unlocked nucleic acid (UNA) into oligonucleotides (DNA*) was developed. The presence of bis-pyrene-modified UNA within a duplex leads to duplex destabilization that is more profound in DNA*/RNA and less distinc......)uracil:pyrene exciplex emission in the single-stranded form. Such fluorescent properties enable the application of bis-pyrene-modified UNA in the development of fluorescence probes for DNA/RNA detection and for detection of deletions at specific positions....

Poly(ferrocenyldimethylsilanes) at the interface of chemistry and materials science: synthesis, structure-properties and thin film applications

NARCIS (Netherlands)

Lammertink, Rob G.H.

2000-01-01

The work described in this thesis concerns the synthesis, characterization, and properties study of ferrocenyldimethylsilane homopolymers and block copolymers. Due to the presence of iron and silicon in the polymer main chain, these macromolecules possess characteristics that are very distinctive

Synthesis, Optical Properties and Applications for New Trianguleniums Derivatives

DEFF Research Database (Denmark)

Santella, Marco

The development of new types of emissive organic dyes is an exciting area of research due to the applicability of these compounds in a wide range of disciplines. Cationic triangulenium salts are highly stable carbenium ions with a planar conformation. The convenient and versatile synthetic proced...... focused on the synthesis of thioether para substituted dyes, where the reactivity of various para-methoxy substituted propeller shaped cations towards different alkyl thiols was examined. Furthermore, ringclosure reactions of these thioether bearing propellers in order to obtain trioxa...... structures. These dyes possess excellent emissive properties with possible applications as cell staining agents or as fluorescent probes. Lastly, I focused on the use of triangulenes as binding group for molecular electronics. It has been shown that TATA can form self-assembled monolayers (SAMs) on a gold...

SnSe Nanocrystals: Synthesis, Structure, Optical Properties, and Surface Chemistry

KAUST Repository

Baumgardner, William J.; Choi, Joshua J.; Lim, Yee-Fun; Hanrath, Tobias

2010-01-01

The colloidal synthesis of SnSe nanoparticles is accomplished through the injection of bis[bis(trimethylsilyl)amino]tin(II) into hot trioctylphosphine: selenium in the presence of oleylamine. Through the manipulation of reaction temperature particles are grown with the average diameter reliably tuned to 4-10 nm. Quantum confinement is examined by establishing a relationship between particle size and band gap while the in depth growth dynamics are illuminated through UV-vis-NIR spectroscopy. Surface chemistry effects are explored, including the demonstration of useful ligand exchanges and the development of routes toward anisotropic particle growth. Finally, transient current-voltage properties of SnSe nanocrystal films in the dark and light are examined. © 2010 American Chemical Society.

SnSe Nanocrystals: Synthesis, Structure, Optical Properties, and Surface Chemistry

KAUST Repository

Baumgardner, William J.

2010-07-21

The colloidal synthesis of SnSe nanoparticles is accomplished through the injection of bis[bis(trimethylsilyl)amino]tin(II) into hot trioctylphosphine: selenium in the presence of oleylamine. Through the manipulation of reaction temperature particles are grown with the average diameter reliably tuned to 4-10 nm. Quantum confinement is examined by establishing a relationship between particle size and band gap while the in depth growth dynamics are illuminated through UV-vis-NIR spectroscopy. Surface chemistry effects are explored, including the demonstration of useful ligand exchanges and the development of routes toward anisotropic particle growth. Finally, transient current-voltage properties of SnSe nanocrystal films in the dark and light are examined. © 2010 American Chemical Society.

A photophysical study of two fluorogen-activating proteins bound to their cognate fluorogens

Energy Technology Data Exchange (ETDEWEB)

Gaiotto, Tiziano [Los Alamos National Laboratory; Nguyen, Hau B [Los Alamos National Laboratory; Jung, Jaemyeong [Los Alamos National Laboratory; Bradbury, Andrew M [Los Alamos National Laboratory; Gnanakaran, S. [Los Alamos National Laboratory; Schmidt, Jurgen G [Los Alamos National Laboratory; Waldo, Geoffrey S [Los Alamos National Laboratory; Goodwin, Peter M [Los Alamos National Laboratory

2010-12-14

We are exploring the feasibility of using recently developed flu orogen-activating proteins (FAPs) as reporters for single-molecule imaging. FAPs are single-chain antibodies choosen to specifically bind small chromophoric molecules termed f1uorogens. Upon binding to its cognate FAP the fluorescence quantum yield of the fluorogen can increase substantially giving rise to a fluorescent complex. Based on the seminal work of Szent-Gyorgyi et al. (Nature Biotechnology, Volume 26, Number 2, pp 235-240, 2008) we have chosen to study two fluorogen-activating single-chain antibodies, HL 1.0.1-TOI and H6-MG bound to their cognate fluorogens, thiazole orange and malachite green derivatives, respectively. Here we use fluorescence correlation spectroscopy study the photophysics of these fluorescent complexes.

Synthesis and Study of Chemical and Photo-physical Properties of Quinolinate Aluminum and Zinc Complexes in Organic Light Emitting Diodes (OLEDs)

Science.gov (United States)

Rawat, Madhu; Prakash, Sattey; Singh, C.; Anand, R. S.

2011-10-01

Two well known electroluminescent (EL) compounds, aluminum and zinc metallo-8-hydroxyquinolates have been synthesized. Their chemical and physical properties like NMR, FTIR, Cyclic Voltammetry, absorption and EL are studied. Organic LEDs are fabricated using both the material as emissive layers. Electroluminescence spectra of the complexes are measured. 2Alq3 and Znq2 give peak emission in yellow-green region at wavelengths 527nm and 540nm respectively. Znq2 is slightly red shifted compared to Alq3 because metal to ligand charge transfer is more in Znq2. A study of ON voltage, luminance efficiency and stability of OLEDs using both materials is made.

Thermodynamic properties of the amorphous and crystalline modifications of carbon and the metastable synthesis of diamond

Energy Technology Data Exchange (ETDEWEB)

Guencheva, V.; Grantscharova, E.; Gutzow, I. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Physical Chemistry

2001-07-01

The temperature dependencies of the thermodynamic properties of the little known (or even hypothetical) undercooled carbon melt and of the glasses that could be obtained from it at appropriate cooling rates are constructed. This is done using both a general thermodynamic formalism to estimate equilibrium properties of undercooled glass-forming melts and the expected analogy in properties of Fourth Group Elements. A comparison of the hypothetical carbon glasses with amorphous materials, obtained by the pyrolisis of organic resins, usually called vitreous (or glassy) carbon, is made. It turns out that from a thermodynamic point of view existing vitreous carbon materials, although characterized by an amorphous, frozen-in structure, differ significantly from the carbon glasses, which could be obtained by a splat-cool-quench of the carbon melt. It is shown also that the hypothetical carbon glasses should have at any temperature a thermodynamic potential, significantly higher than that of diamond. Thus they could be used as a source of constant supersaturation in metastable diamond synthesis. Existing amorphous carbon materials, although showing considerably lower thermodynamic potentials than the hypothetical carbon glasses, could also be used as sources of constant supersaturation in a process of isothermal diamond synthesis if their thermodynamic potential is additionally increased (e.g. by mechano-chemical treatment or by dispersion into nano-size scale). Theoretical estimates made in terms of Ostwald's Rule of Stages indicate that in processes of metastable isothermal diamond synthesis additional kinetic factors (e.g. influencing the formation of sp{sup 3} - carbon structures in the ambient phase) and the introduction of active substrates (e.g. diamond powder) are to be of significance in the realization of this thermodynamic possibility. (orig.)

Large influence of the synthesis conditions on the physico-chemical properties of nanostructured Fe3O4

International Nuclear Information System (INIS)

Franger, S.; Berthet, P.; Dragos, O.; Baddour-Hadjean, R.; Bonville, P.; Berthon, J.

2007-01-01

Magnetite synthesized via three different synthesis routes (coprecipitation process in aqueous media, electrochemical synthesis in presence of complexing agents and solid state reaction at high temperature) has been characterized by X-Ray diffraction, scanning electron microscopy, thermal analysis (TGA), FT-IR and Moessbauer spectroscopies. Although each procedure gave homogeneous magnetite powders, many differences could be seen in the physico-chemical properties of the samples mostly depending on the synthesis conditions. For instance, at least two factors seem to have a huge impact onto the Fe 3 O 4 behaviour: the presence of hydration water molecules and the particle size of the powders since a superparamagnetic behaviour was observed with the thinnest particles, at room temperature, on the Moessbauer spectra via the appearance of line broadening and a pronounced central doublet

Synthesis, characterization, spectroscopic properties and DFT study of a new pyridazinone family

Science.gov (United States)

Arrue, Lily; Rey, Marina; Rubilar-Hernandez, Carlos; Correa, Sebastian; Molins, Elies; Norambuena, Lorena; Zarate, Ximena; Schott, Eduardo

2017-11-01

Nitrogen compounds are widely investigated due to their pharmacological properties such as antihypertensive, antinociceptive, antibacterial, antifungal, analgesic, anticancer and inhibition activities and lately even as pesticide. In this context, we present the synthesis of new compounds: (E)-6-(3,4-dimethoxyphenyl)-3-(3-(3,4-dimethoxyphenyl)acryloyl)-1-(4-R-phenyl)- 5,6-dihydropyridazin-4(1H)-one (with R = sbnd H(1), -Cl(2), -Br(3), sbnd I(4) and sbnd COOH(5)) that was carried out by reaction of (1E, 6E)-1,7-bis(3,4-dimethoxyphenyl)hepta-1,6-diene-3,5-dione with a substituted phenylamine with general formula p-R-C6H4sbnd NH2 (R = sbnd H (1), sbnd Cl (2), -Br(3), sbnd I(4) and sbnd COOH(5)). This is the first synthesis report of a pyridazinone using as precursors a curcuminoid derivative and a diazonium salt formed in situ. All compounds were characterized by EA, FT-IR, UV-Vis, Emission,1H- and13C-NMR spectroscopy and the crystalline and molecular structure of 4 was solved by X-rays diffraction method. DFT and TD-DFT quantum chemical calculations were also employed to characterize the compounds and provide a rational explanation to the spectroscopic properties. To assess the biological activity of the systems, we focused on pesticide tests on compound 2, which showed an inhibitory effect in plant growth of Agrostis tenuis Higland.

Evaluation of magnetic properties of NI-ZN ferrites obtained by different synthesis methods

International Nuclear Information System (INIS)

Simoes, A.N.; Neiva, L.S.; Simoes, V.N.; Gama, L.; Gomes Filho, A.C.; Oliveira, J.B.L.

2012-01-01

Ceramic oxides that exhibit ferromagnetic behavior represent important commercial products for the electronics industry and are commonly known as ferrites. The Ni-Zn ferrites are considered to be one of the most versatile and soft due to its high electrical resistivity and low eddy current losses. Thus, this study aims to evaluate the magnetic properties of Ni-Zn ferrite obtained by the Pechini and combustion reaction. After synthesis the powders were characterized by XRD, SEM, BET and magnetic measurements. The results showed that for both methods of synthesis used was the formation of the spinel phase of Ni-Zn ferrite. The micrographs show that the powders obtained by both methods have regular shapes and spherical. Were determined by BET surface area is 26 m 2 /g by the Pechini and 13 m 2 /g by combustion. And the samples synthesized by Pechini method obtained the best magnetic characteristics (author)

Thin film properties of triphenylamine-cored dendrimers: A molecular approach to control aggregation

Energy Technology Data Exchange (ETDEWEB)

Vamvounis, George, E-mail: g.vamvounis@uq.edu.au; Pivrikas, Almantas; Shaw, Paul E.; Burn, Paul L.

2013-12-02

The solid-state photophysical and charge transport properties of two first-generation dendrimers are presented. The dendrimers are comprised of a triphenylamine core, dendrons containing a phenyl branching unit with thiophene (Dendrimer 1) or bithiophene (Dendrimer 2) moieties, and dodecyl surface groups. For Dendrimer 1, the excited state is located within the center of the dendrimer giving rise to a moderate solid-state photoluminescence quantum yield (Φ{sub pl}) (0.13) and significant charge trapping, with both observations due to the degree of overlap of the main electroactive chromophores on adjacent dendrimers. For Dendrimer 2, the excited state is located within the dendron and in the solid-state this leads to a strongly red-shifted and weakened emission (Φ{sub pl} ∼ 0.02) due to strong intermolecular chromophore interactions. For films of Dendrimer 2 the charge mobility was higher than Dendrimer 1 but was still limited by a low density of strongly interacting electroactive chromophores. The pronounced difference between the solid-state properties of the two dendrimers is simply engineered by the addition of an extra thiophene in each of the dendrons. - Highlights: • Photophysical and charge-transport properties of two dendrimers are investigated. • Excited-state is on the center for Dendrimer 1 and on the dendron for Dendrimer 2. • Film quantum yield of luminescence is higher for Dendrimer 1. • Dendrimer 1 displays greater charge trapping at high fields.

Effect of quencher, denaturants, temperature and pH on the fluorescent properties of BSA protected gold nanoclusters

Energy Technology Data Exchange (ETDEWEB)

Chib, Rahul, E-mail: Rahul.chib@live.unthsc.edu [Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States); Butler, Susan [Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States); Raut, Sangram [Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States); Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129 (United States); Shah, Sunil; Borejdo, Julian [Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States); Gryczynski, Zygmunt [Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States); Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129 (United States); Gryczynski, Ignacy, E-mail: ignacy.gryczynski@unthsc.edu [Department of Cell Biology and Immunology, Center for Fluorescence Technologies and Nanomedicine, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States)

2015-12-15

In this paper, we have synthesized BSA protected gold nanoclusters (BSA Au nanocluster) and studied the effect of quencher, protein denaturant, pH and temperature on the fluorescence properties of the tryptophan molecule of the BSA Au nanocluster and native BSA. We have also studied their effect on the peak emission of BSA Au nanoclusters (650 nm). The photophysical characterization of a newly developed fluorophore in different environments is absolutely necessary to futher develop their biomedical and analytical applications. It was observed from our experiments that the tryptophan in BSA Au nanoclusters is better shielded from the polar environment. Tryptophan in native BSA showed a red shift in its peak emission wavelength position. Tryptophan is a highly polarity sensitive dye and a minimal change in its microenvironment can be easily observed in its photophysical properties. - Highlights: • Tryptophan is easily accessible in native BSA compared to BSA Au nanoclusters. • Guanidine HCL denatures native BSA more compared to BSA Au nanoclusters. • High temperature decreases the quantum yield of tryptophan and BSA Au nanocluster. • Emission wavelength of BSA Au nanoclusters remains constant with increasing pH. • BSA Au nanoclusters are robust to the changes in their environments.

Effect of quencher, denaturants, temperature and pH on the fluorescent properties of BSA protected gold nanoclusters

International Nuclear Information System (INIS)

Chib, Rahul; Butler, Susan; Raut, Sangram; Shah, Sunil; Borejdo, Julian; Gryczynski, Zygmunt; Gryczynski, Ignacy

2015-01-01

In this paper, we have synthesized BSA protected gold nanoclusters (BSA Au nanocluster) and studied the effect of quencher, protein denaturant, pH and temperature on the fluorescence properties of the tryptophan molecule of the BSA Au nanocluster and native BSA. We have also studied their effect on the peak emission of BSA Au nanoclusters (650 nm). The photophysical characterization of a newly developed fluorophore in different environments is absolutely necessary to futher develop their biomedical and analytical applications. It was observed from our experiments that the tryptophan in BSA Au nanoclusters is better shielded from the polar environment. Tryptophan in native BSA showed a red shift in its peak emission wavelength position. Tryptophan is a highly polarity sensitive dye and a minimal change in its microenvironment can be easily observed in its photophysical properties. - Highlights: • Tryptophan is easily accessible in native BSA compared to BSA Au nanoclusters. • Guanidine HCL denatures native BSA more compared to BSA Au nanoclusters. • High temperature decreases the quantum yield of tryptophan and BSA Au nanocluster. • Emission wavelength of BSA Au nanoclusters remains constant with increasing pH. • BSA Au nanoclusters are robust to the changes in their environments.

V2O5 xerogel-poly(ethylene oxide) hybrid material: Synthesis, characterization, and electrochemical properties

International Nuclear Information System (INIS)

Guerra, Elidia M.; Ciuffi, Katia J.; Oliveira, Herenilton P.

2006-01-01

In this work, we report the synthesis, characterization, and electrochemical properties of vanadium pentoxide xerogel-poly(ethylene oxide) (PEO) hybrid materials obtained by varying the average molecular weight of the organic component as well as the components' ratios. The materials were characterized by X-ray diffraction, ultraviolet/visible and infrared spectroscopies, thermogravimetric analysis, scanning electron microscopy, electron paramagnetic resonance, and cyclic voltammetry. Despite the presence of broad and low intensity peaks, the X-ray diffractograms indicate that the lamellar structure of the vanadium pentoxide xerogel is preserved, with increase in the interplanar spacing, giving evidence of a low-crystalline structure. We found that the electrochemical behaviour of the hybrid materials is quite similar to that found for the V 2 O 5 xerogel alone, and we verified that PEO leads to stabilization and reproducibility of the Li + electrochemical insertion/de-insertion into the V 2 O 5 xerogel structure, which makes these materials potential components of lithium ion batteries. - Graphical abstract: The synthesis, structural and electrochemical properties of vanadium pentoxide xerogel-poly(ethylene oxide) hybrid materials have been described. Despite the presence of broad and low intensity peaks, the X-ray diffractograms indicate that the lamellar structure of the vanadium pentoxide xerogel is preserved. The cyclic voltammetry technique demonstrated that PEO intercalation provides an improvement in the electrochemical properties, mainly with respect to the lithium electroinsertion process into the oxide matrix

Mechanical properties of calcium phosphate cements obtained by solution combustion synthesis

Energy Technology Data Exchange (ETDEWEB)

Volkmer, Tiago M.; Barreiro, Oscar; Souza, Vania Caldas; Santos, Luis Alberto dos, E-mail: tiagovolkmer@gmail.com, E-mail: oscarbafer@hotmail.com, E-mail: vania.souza@ufrgs.br, E-mail: luis.santos@ufrgs.br [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Laboratorio de Biomateriais

2009-07-01

Bioceramics based on calcium phosphates, especially hydroxyapatite and tricalcium phosphates (TCP) are the most used biomaterials as bone substitutes. The objective of this work is to evaluate the mechanical properties of α-tricalcium phosphate (α-TCP) synthesized by the solution combustion method. The solution combustion synthesis (SCS) can be considered as faster and simpler as other methods, furthermore it allows the obtainment of high purity α-TCP. In the calcium phosphates (CPC), α-TCP reacts with water forming needle like HA, which restrain the movement of grains, increasing mechanical resistance. In the present paper the influence of particle size on mechanical properties of α-TCP cements were evaluated. The α-TCP powder were characterized by XRD, TEM, BET and laser diffraction to asses particle size while the CPC bodies by SEM, Arquimedes method and compression tests. Increasing the milling time, the particle size decreases, resulting in samples with less porosity and consequently with higher compression resistance. (author)

Preparation and fluorescent recognition properties for fluoride of a nanostructured covalently bonded europium hybrid material

Institute of Scientific and Technical Information of China (English)

余旭东; 李景印; 李亚娟; 耿丽君; 甄小丽; 于涛

2015-01-01

A novel covalently bonded Eu3+-based silica hybrid material was designed and its spectrophotometric anion sensing prop-erty was studied. The fluorescent receptor (europium complex) was covalently grafted to the silica matrix via a sol-gel approach. FTIR, UV-vis spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and photoluminescent spectra were characterized, and the results revealed that the hybrid material with nanosphere structure displayed excellent photophysical property. In addition, the selective anion sensing property of the hybrid material was studied by UV-vis and fluorescence spectra. The results showed that the hybrid material exhibited a smart response with fluoride anions.

Electrospun V2O5 composite fibers: Synthesis, characterization and ammonia sensing properties

International Nuclear Information System (INIS)

Modafferi, V.; Trocino, S.; Donato, A.; Panzera, G.; Neri, G.

2013-01-01

In the present work, vanadium oxide (V 2 O 5 ) fibers have been investigated for monitoring ammonia (NH 3 ) at ppb levels in air. A simple sol gel-based electrospinning process has been applied for the synthesis of vanadium oxide/polyvinyl acetate (PVAc) and vanadium oxide/polyvinylpyrrolidone (PVP) composite fibers. Composite fibers doped with platinum (Pt) have been also prepared. The pure and Pt-doped metal oxide phase has been subsequently obtained by removing the polymer binder at high temperature in air. The samples have been widely studied to characterize their morphological and microstructural properties by X-Ray Diffraction, Fourier Transform InfraRed spectroscopy, X-ray Photoelectron Spectroscopy, and Scanning Electron Microscopy investigations. The application of the produced fibers in highly sensitive ammonia resistive sensors has been demonstrated. The influence of the nature of polymer binder and platinum addition on the sensing performances of the V 2 O 5 fibers has been investigated and discussed.V 2 O 5 fibers produced by using PVP as a polymer binder have shown higher sensitivity toward ammonia at ppb concentrations than fibers obtained with PVAc. Pt-doped samples have shown a lower response compared to un-doped samples. - Highlights: • Synthesis of vanadium oxide composite fibers by electrospinning • Physical and chemical characterization of prepared samples • Investigation of the sensing properties to ppb concentrations of ammonia in air

Synthesis and Magnetic Properties of Maghemite (γ-Fe2O3 Short-Nanotubes

Directory of Open Access Journals (Sweden)

Xiao XH

2010-01-01

Full Text Available Abstract We report a rational synthesis of maghemite (γ-Fe2O3 short-nanotubes (SNTs by a convenient hydrothermal method and subsequent annealing process. The structure, shape, and magnetic properties of the SNTs were investigated. Room-temperature and low-temperature magnetic measurements show that the as-fabricated γ-Fe2O3 SNTs are ferromagnetic, and its coercivity is nonzero when the temperature above blocking temperature (TB. The hysteresis loop was operated to show that the magnetic properties of γ-Fe2O3 SNTs are strongly influenced by the morphology of the crystal. The unique magnetic behaviors were interpreted by the competition of the demagnetization energy of quasi-one-dimensional nanostructures and the magnetocrystalline anisotropy energy of particles in SNTs.

Synthesis and ion-exchange properties of cerium(IV) molybdate

Energy Technology Data Exchange (ETDEWEB)

Srivastava, S K; Singh, Raj Pal; Agrawal, Sushma; Kumar, Satish [Roorkee Univ. (India). Dept. of Chemistry

1977-01-01

The synthesis, ion exchange properties, and the separation of a number of cation pairs on the columns of cerium (IV) molybdate is discussed. In order to obtain the product in gel form showing a high exchange capacity and suitable for column operation, preliminary experiments were performed to determine the optimum conditions of precipitation, i.e., the concentration of ceric and molybdate solutions, mixing ratio, pH of precipitation and the order of mixing. Cerium (IV) molybdate, prepared under the optimum conditions of concentration, acidity etc., shows exchange capacity of 0.96 meg per g of exchanger. The sorption of a large number of metal ions has been investigated and the compound shows promising behaviour as cation exchanger. Numerous separations of analytical and radiochemical interest have been performed on the column of this exchanger with great efficiency.

Synthesis and ion-exchange properties of cerium(IV) molybdate

International Nuclear Information System (INIS)

Srivastava, S.K.; Raj Pal Singh; Sushma Agrawal; Satish Kumar

1977-01-01

The synthesis, ion exchange properties, and the separation of a number of cation pairs on the columns of cerium (IV) molybdate is discussed. In order to obtain the product in gel form showing a high exchange capacity and suitable for column operation, preliminary experiments were performed to determine the optimum conditions of precipitation, i.e., the concentration of ceric and molybdate solutions, mixing ratio, pH of precipitation and the order of mixing. Cerium (IV) molybdate, prepared under the optimum conditions of concentration, acidity etc., shows exchange capacity of 0.96 meg per g of exchanger. The sorption of a large number of metal ions has been investigated and the compound shows promising behaviour as cation exchanger. Numerous separations of analytical and radiochemical interest have been performed on the column of this exchanger with great efficiency. (T.G.)

Properties and synthesis of D2EHPA and of alkylphosphoric acid

International Nuclear Information System (INIS)

Elias, Abdelhamid

1996-07-01

A great interest has been devoted to alkylphosphates which are used in various field of chemical industry as: agents for extracting metals (uranium, actinides and lanthanides), flame-retardant solid plasticizers for cellulose acetate,cellulose ethers and vinyls,ignition control agents for gasoline, lubricant additive,antifoam agents for water-based paints and in inks and paper manufacture. In this context, the present work is achieved in order to supply a selected bibliography and the main theoretical aspects concerning physical and chemical properties, analysis techniques, synthesis and purification processes and some applications of D2EHPA (di(2-ethylhexyl)phosphoric acid or di(2-ethylhexyl)phosphate) and of alkylphosphates in general

Graphene oxide-modified ZnO particles: synthesis, characterization, and antibacterial properties

Directory of Open Access Journals (Sweden)

Zhong LL

2015-08-01

Full Text Available Linlin Zhong, Kyusik Yun Department of Bionanotechnology, Gachon University, Gyeonggi-do, Republic of Korea Abstract: Nanosized ZnO particles with diameters of 15 nm were prepared with a solution precipitation method at low cost and high yield. The synthesis of the particles was functionalized by the organic solvent dimethylformamide, and the particles were covalently bonded to the surface of graphene oxide. The morphology of the graphene oxide sheets and ZnO particles was confirmed with field emission scanning electron microscopy and biological atomic force microscopy. Fourier transform infrared spectroscopy and X-ray diffraction were used to analyze the physical and chemical properties of the ZnO/graphene oxide composites that differed from those of the individual components. Enhanced electrochemical properties were detected with cyclic voltammetry, with a redox peak of the composites at 0.025 mV. Excellent antibacterial activity of ZnO/graphene oxide composites was observed with a microdilution method in which minimum inhibitory concentrations of 6.25 µg/mL for Escherichia coli and Salmonella typhimurium, 12.5 µg/mL for Bacillus subtilis, and 25 µg/mL for Enterococcus faecalis. After further study of the antibacterial mechanism, we concluded that a vast number of reactive oxygen species formed on the surface of composites, improving antibacterial properties. Keywords: graphene oxide, ZnO, characterization, antibacterial property

Single-step gas phase synthesis of stable iron aluminide nanoparticles with soft magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Vernieres, Jerome, E-mail: Jerome.vernieres@oist.jp; Benelmekki, Maria; Kim, Jeong-Hwan; Grammatikopoulos, Panagiotis; Diaz, Rosa E. [Nanoparticles by Design Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, 1919-1 Tancha, Onna Son, Okinawa 904-0495 (Japan); Bobo, Jean-François [Centre d’Elaboration de Materiaux et d’Etudes Structurales (CEMES), 29 rue Jeanne Marvig, 31055 Toulouse Cedex 4 (France); Sowwan, Mukhles, E-mail: Mukhles@oist.jp [Nanoparticles by Design Unit, Okinawa Institute of Science and Technology (OIST) Graduate University, 1919-1 Tancha, Onna Son, Okinawa 904-0495 (Japan); Nanotechnology Research Laboratory, Al-Quds University, P.O. Box 51000, East Jerusalem, Palestine (Country Unknown)

2014-11-01

Soft magnetic alloys at the nanoscale level have long generated a vivid interest as candidate materials for technological and biomedical purposes. Consequently, controlling the structure of bimetallic nanoparticles in order to optimize their magnetic properties, such as high magnetization and low coercivity, can significantly boost their potential for related applications. However, traditional synthesis methods stumble upon the long standing challenge of developing true nanoalloys with effective control over morphology and stability against oxidation. Herein, we report on a single-step approach to the gas phase synthesis of soft magnetic bimetallic iron aluminide nanoparticles, using a versatile co-sputter inert gas condensation technique. This method allowed for precise morphological control of the particles; they consisted of an alloy iron aluminide crystalline core (DO{sub 3} phase) and an alumina shell, which reduced inter-particle interactions and also prevented further oxidation and segregation of the bimetallic core. Remarkably, the as-deposited alloy nanoparticles show interesting soft magnetic properties, in that they combine a high saturation magnetization (170 emu/g) and low coercivity (less than 20 Oe) at room temperature. Additional functionality is tenable by modifying the surface of the particles with a polymer, to ensure their good colloidal dispersion in aqueous environments.

A New Star-shaped Carbazole Derivative with Polyhedral Oligomeric Silsesquioxane Core: Crystal Structure and Unique Photoluminescence Property.

Science.gov (United States)

Xu, Zixuan; Yu, Tianzhi; Zhao, Yuling; Zhang, Hui; Zhao, Guoyun; Li, Jianfeng; Chai, Lanqin

2016-01-01

A new inorganic–organic hybrid material based on polyhedral oligomeric silsesquioxane (POSS) capped with carbazolyl substituents, octakis[3-(carbazol-9-yl)propyldimethylsiloxy]-silsesquioxane (POSS-8Cz), was successfully synthesized and characterized. The X-ray crystal structure of POSS-8Cz were described. The photophysical properties of POSS-8Cz were investigated by using UV–vis,photoluminescence spectroscopic analysis. The hybrid material exhibits blue emission in the solution and the solid film.The morphology and thermal stablity properties were measured by X-ray diffraction (XRD) and TG-DTA analysis.

Synthesis and properties of Tl endash Ba endash Ca endash Cu endash O superconductors

International Nuclear Information System (INIS)

Siegal, M.P.; Venturini, E.L.; Morosin, B.; Aselage, T.L.

1997-01-01

We review the synthesis methods and properties of single crystal, powder and thin film TlBaCaCuO high-temperature superconducting (Tl-HTS) materials. With transition temperatures ≥100K for several compounds, Tl-HTS materials present real opportunities for applications above 77 K. Experiments using (1) single crystals: determined precise structural parameters and identified the complex Tl 1+ -Tl 3+ equilibrium model; (2) powders: studied the complex thermodynamic phase diagram; and (3) epitaxial films: have studied fundamental properties such as electron pair symmetry and the effect of controlled extrinsic defects on flux pinning strength, as well as providing the large-area surfaces required for device applications. copyright 1997 Materials Research Society

Mirror boxes and mirror mounts for photophysics beamline

International Nuclear Information System (INIS)

Raja Rao, P.M.; Raja Sekhar, B.N.; Das, N.C.; Khan, H.A.; Bhattacharya, S.S.; Roy, A.P.

1996-01-01

Photophysics beamline makes use of one metre Seya-Namioka monochromator and two toroidal mirrors in its fore optics. The first toroidal mirror (pre mirror) focuses light originating from the tangent point of the storage ring onto the entrance slit of the monochromator and second toroidal mirror (post mirror) collects light from the exit slit of the monochromator and focuses light onto the sample placed at a distance of about one metre away from the 2nd mirror. To steer light through monochromator and to focus it on the sample of 1mm x 1mm size require precision rotational and translational motion of the mirrors and this has been achieved with the help of precision mirror mounts. Since Indus-1 operates at pressures less than 10 -9 m.bar, the mirror mounts should be manipulated under similar ultra high vacuum conditions. Considering these requirements, two mirror boxes and two mirror mounts have been designed and fabricated. The coarse movements to the mirrors are imparted from outside the mirror chamber with the help of x-y tables and precision movements to the mirrors are achieved with the help of mirror mounts. The UHV compatibility and performance of the mirror mounts connected to mirror boxes under ultra high vacuum condition is evaluated. The details of the design, fabrication and performance evaluation are discussed in this report. 5 refs., 9 figs., 1 tab

Study on photophysical and aggregation induced emission recognition of 1,8-naphthalimide probe for casein by spectroscopic method

Science.gov (United States)

Sun, Yang; Liu, Zhen; Liang, Xuhua; Fan, Jun; Han, Quan

2013-05-01

A novel water-soluble 1,8-naphthalimide derivative 1, bearing two acetic carboxylic groups, exhibited fluorescent turn-on recognition for casein based on the aggregation induced emission (AIE) character. The photophysical properties of 1 consisting of donor and acceptor units were investigated in different solutions. The fluorescence intensity decreased through taking advantage of twisted intramolecular charge transfer (TICT) and self-association emission with increasing solvent polarity. Moreover, the spectral red-shift and intensity quench in protic solvents were caused by the excited-state hydrogen bond strengthening effect. Density Functional Theory (DFT) calculations revealed that 1 exhibited a strong TICT character. The AIE mechanism of 1 with casein was due to 1 docked in the hydrophobic cavity between sub-micelles and bound with Tyr and Trp residues, resulting in the aggregation of 1 on the casein surface and emission enhancement. Based on this, a novel casein assay method was developed. The proposed exhibited a good linear range from 0.1 to 22 μg mL-1, with the detection limit of 2.8 ng mL-1. Satisfactory reproducibility, reversibility and a short response time were realized. This method was applied to the determination of casein in milk powder samples and the results were in good agreement with the result of Biuret method.

Defective TiO2 with oxygen vacancies: synthesis, properties and photocatalytic applications

Science.gov (United States)

Pan, Xiaoyang; Yang, Min-Quan; Fu, Xianzhi; Zhang, Nan; Xu, Yi-Jun

2013-04-01

Titanium dioxide (TiO2), as an important semiconductor metal oxide, has been widely investigated in the field of photocatalysis. The properties of TiO2, including its light absorption, charge transport and surface adsorption, are closely related to its defect disorder, which in turn plays a significant role in the photocatalytic performance of TiO2. Among all the defects identified in TiO2, oxygen vacancy is one of the most important and is supposed to be the prevalent defect in many metal oxides, which has been widely investigated both by theoretical calculations and experimental characterizations. Here, we give a short review on the existing strategies for the synthesis of defective TiO2 with oxygen vacancies, and the defect related properties of TiO2 including structural, electronic, optical, dissociative adsorption and reductive properties, which are intimately related to the photocatalytic performance of TiO2. In particular, photocatalytic applications with regard to defective TiO2 are outlined. In addition, we offer some perspectives on the challenge and new direction for future research in this field. We hope that this tutorial minireview would provide some useful contribution to the future design and fabrication of defective semiconductor-based nanomaterials for diverse photocatalytic applications.Titanium dioxide (TiO2), as an important semiconductor metal oxide, has been widely investigated in the field of photocatalysis. The properties of TiO2, including its light absorption, charge transport and surface adsorption, are closely related to its defect disorder, which in turn plays a significant role in the photocatalytic performance of TiO2. Among all the defects identified in TiO2, oxygen vacancy is one of the most important and is supposed to be the prevalent defect in many metal oxides, which has been widely investigated both by theoretical calculations and experimental characterizations. Here, we give a short review on the existing strategies for the

Simple synthesis, photophysics, and electroluminescent properties of poly[2,7-bis(4-tert-butylstyryl)fluorene-9,9-diyl-alt-alkane-.alpha.,.omega.-diyl

Czech Academy of Sciences Publication Activity Database

Mikroyannidis, J. A.; Barberis, V. P.; Výprachtický, Drahomír; Cimrová, Věra

2007-01-01

Roč. 45, č. 5 (2007), s. 809-821 ISSN 0887-624X R&D Projects: GA MŠk(CZ) 1M06031; GA AV ČR IAA4050409; GA ČR GA203/04/1372 Institutional research plan: CEZ:AV0Z40500505 Keywords : distyrylfluorene * electrochemical properties * electroluminescence Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.529, year: 2007

Linear and nonlinear photophysics and bioimaging of an integrin-targeting water-soluble fluorenyl probe.

Science.gov (United States)

Morales, Alma R; Luchita, Gheorghe; Yanez, Ciceron O; Bondar, Mykhailo V; Przhonska, Olga V; Belfield, Kevin D

2010-06-07

Linear photophysical characterization and two-photon absorption (2PA) properties of a new water-soluble fluorene derivative, 3-(9-(2-(2-methoxyethoxy)ethyl)-2,7-bis{3-[2-(polyethyleneglycol-550-monomethylether-1-yl)]-4-(benzo[d]thiazol-2-yl)styryl}-9H-fluoren-9-yl)propanoic acid (1), were investigated in several organic solvents and water at room temperature. A comprehensive analysis of the steady-state absorption, emission and excitation anisotropy spectra revealed electronic structures of 1, including mutual orientation of the transition dipoles, relatively weak solvatochromic effects, high fluorescence quantum yield (approximately 0.5-1.0), and strong aggregation in water. The 2PA spectra of 1 were obtained in the 600-900 nm spectral range by two-photon induced fluorescence (2PF) and open aperture Z-scan methods using femtosecond laser sources. No discrete 2PA bands were apparent and values of the corresponding 2PA cross sections monotonically increased in the short wavelength range up to 3000 GM in organic solvents and approximately 6000 GM in aqueous solution, reflecting relatively high two-photon absorptivity. The 2PA efficiency of in water increased 2-3 times relative to aprotic solvents and can be explained by cooperative electronic effects of molecular aggregates of 1 produced in aqueous media. The carboxylic acid fluorenyl probe 1 was conjugated with the cyclic peptide RGDfK. Two-photon fluorescence microscopy (2PFM) imaging of U87MG cells (and MCF-7 as control), incubated with fluorene-RGD peptide conjugate 2, demonstrated high alpha(v)beta(3) integrin selectivity, making this probe particularly attractive for integrin imaging.

Synthesis and fluorosolvatochromism of 3-arylnaphtho[1,2-b]quinolizinium derivatives

Directory of Open Access Journals (Sweden)

Phil M. Pithan

2016-05-01

Full Text Available Cationic biaryl derivatives were synthesized by Suzuki–Miyaura coupling of 3-bromonaphtho[1,2-b]quinolizinium bromide with arylboronic acids. The resulting cationic biaryl derivatives exhibit pronounced fluorosolvatochromic properties. First photophysical studies in different solvents showed that the emission energy of the biaryl derivatives decreases with increasing solvent polarity. This red-shifted emission in polar solvents is explained by a charge shift (CS in the excited state and subsequent solvent relaxation. Furthermore, the polarity of protic polar and aprotic polar solvents affects the emission energy to different extent, which indicates a major influence of hydrogen bonding on the stabilization of the ground and excited states.

Blue-light emitting triazolopyridinium and triazoloquinolinium salts

KAUST Repository

Carboni, Valentina

2017-01-27

Compounds that emit blue light are of interest for applications that include optoelectronic devices and chemo/biosensing and imaging. The design and synthesis of small organic molecules that can act as high-efficiency deep-blue-light emitters in the solid state and can be easily processed from solutions represents a significant challenge. Herein we present the preparation and photophysical, photochemical and electrochemical properties of a series of triazolopyridinium and triazoloquinolinium compounds. The compounds are soluble in water or polar organic solvents and exhibit photoluminescence in the blue region of the spectrum in fluid solution, in the solid state and in a frozen matrix.

New materials graphyne, graphdiyne, graphone, and graphane: review of properties, synthesis, and application in nanotechnology

Science.gov (United States)

Peng, Qing; Dearden, Albert K; Crean, Jared; Han, Liang; Liu, Sheng; Wen, Xiaodong; De, Suvranu

2014-01-01

Plenty of new two-dimensional materials including graphyne, graphdiyne, graphone, and graphane have been proposed and unveiled after the discovery of the “wonder material” graphene. Graphyne and graphdiyne are two-dimensional carbon allotropes of graphene with honeycomb structures. Graphone and graphane are hydrogenated derivatives of graphene. The advanced and unique properties of these new materials make them highly promising for applications in next generation nanoelectronics. Here, we briefly review their properties, including structural, mechanical, physical, and chemical properties, as well as their synthesis and applications in nanotechnology. Graphyne is better than graphene in directional electronic properties and charge carriers. With a band gap and magnetism, graphone and graphane show important applications in nanoelectronics and spintronics. Because these materials are close to graphene and will play important roles in carbon-based electronic devices, they deserve further, careful, and thorough studies for nanotechnology applications. PMID:24808721

Population synthesis and x-ray properties of passively evolving galaxies

International Nuclear Information System (INIS)

Renzini, A.

1989-01-01

In this review some evolutionary processes in galaxies will be considered which may be less exciting than other phenomena such as starburst activities, galactic interactions, merging, or cannibalism. The discussion will rather be restricted to passively evolving stellar populations, i.e. to what may happen when all giant molecular clouds have blown away, when every shower of star formation has ceased, and stars just shine, age, and eventually die. Only this passive evolution is in fact subject to laws that - at least in principle - can be rigorously formulated, while star formation processes, because of the prominent role played by chaotic hydrodynamics, rather resemble meteorological events. In Section 2 some fundamental properties of simple stellar populations are introduced. These can be regarded as the basic laws controlling the evolution of stellar populations, once that they have condensed from the diffused medium. In Section 3 the primary requirements that acceptable evolutionary population synthesis should fulfil are then briefly recalled, and, finally, in Section 4 some of the basic laws are put at play in an attempt to discuss the evolution over cosmological times of the X-ray properties of elliptical galaxies. (author)

Synthesis and magnetic properties of tin spinel ferrites doped manganese

Science.gov (United States)

El Moussaoui, H.; Mahfoud, T.; Habouti, S.; El Maalam, K.; Ben Ali, M.; Hamedoun, M.; Mounkachi, O.; Masrour, R.; Hlil, E. K.; Benyoussef, A.

2016-05-01

In this work we report the synthesis, the microstructural characterization and the magnetic properties of tin spinel ferrites doped manganese (Sn1-xMnxFe2O4 with x=0.25, 0.5, 0.75, and 1) nanoparticles prepared by co-precipitation method. The effect of annealing temperature on the structure, morphology and magnetic properties of Sn0.5Mn0.5Fe2O4 has been investigated. The synthesized nanoparticle sizes have been controlled between 4 and 9 nm, with uniform spherical morphology as confirmed by transmission electron microscopy (TEM). All the samples prepared possess single domain magnetic. The nanoparticles of Sn0.5Mn0.5Fe2O4 with 4 nm in diameter have a blocking temperature close to 100 K. In addition, the cation distribution obtained from the X-ray diffraction of this sample was confirmed by magnetic measurement. For the Sn1-xMnxFe2O4; (0≤x≤1) samples, the magnetization and coercive fields increase when the augmentation of Mn content increases. For x=0.5, such parameters decrease when the calcination temperature increases.

Rational design of tetraphenylethylene-based luminescent down-shifting molecules: photophysical studies and photovoltaic applications in a CdTe solar cell from small to large units.

Science.gov (United States)

Li, Yilin; Li, Zhipeng; Ablekim, Tursunjan; Ren, Tianhui; Dong, Wen-Ji

2014-12-21

A rational design strategy of novel fluorophores for luminescent down-shifting (LDS) application was proposed and tested in this paper. Three new fluorophores (1a-c) with specific intramolecular charge transfer (ICT) and aggregation-induced emission (AIE) characteristics were synthesized as LDS molecules for increasing the output short circuit current density (Jsc) of a CdTe solar cell. Photophysical studies of their solution and solid states, and photovoltaic measurements of their PMMA solid films applied on a CdTe solar cell suggested that the specific spectroscopic properties and Jsc enhancement effects of these molecules were highly related to their chemical structures. The Jsc enhancement effects of these fluorophores were measured on both a CdTe small cell and a large panel. An increase in the output Jsc by as high as 5.69% for a small cell and 8.88% for a large panel was observed. Compared to a traditional LDS molecule, Y083, these fluorophores exhibited more superior capabilities of LDS.

Solid-state synthesis and electrical properties of polyaniline/Cu-montmorillonite nanocomposite

International Nuclear Information System (INIS)

Bekri-Abbes, Imene; Srasra, Ezzeddine

2010-01-01

In this paper, the solid-state synthesis of polyaniline/Cu-montmorillonite nanocomposite is reported. Mixture of anilinium chlorure and Cu exchanged montmorillonite was grinded at room temperature while we vary the molar rate of aniline to interlayer Cu 2+ cations (R) from 0.5 to 6. The properties of the hybrid compounds are characterized by X-ray diffraction, thermogravimetric analysis, SEM, FTIR and impedance spectroscopy. The results showed that the structure and the conductivity of PANI in hybrid materials depend on R. The ac conduction showed a regime of constant dc conductivity at low frequencies and a crossover to a frequency-dependent regime of the type A ω s at high frequencies.

Synthesis, characterization and antibacterial property of ZnO:Mg nanoparticles

Science.gov (United States)

Kompany, A.; Madahi, P.; Shahtahmasbi, N.; Mashreghi, M.

2012-09-01

Sol-gel method was successfully used for the synthesis of ZnO nanoparticles (NPs) doped with different concentrations of Mg and the structural, optical and antibacterial properties of the nanoparticles were studied. The synthesized ZnO:Mg powders were characterized using x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transformation Infrared (FTIR) and UV-Vis spectroscopy. It was revealed that the samples have hexagonal Wurtzite structure, and the phase segregation takes place for 15% Mg content. TEM images show that the average size of the particles is about 50 nm. Also, the antibacterial activities of the nanoparticles were tested against Escherichia coli (Gram negative) cultures. ZnO:Mg nanofluid showed good antibacterial activity which increases with the increase of NPs concentration, and decreases slightly with the amount of Mg.

Properties, synthesis, and growth mechanisms of carbon nanotubes with special focus on thermal chemical vapor deposition.

Science.gov (United States)

Nessim, Gilbert D

2010-08-01

Carbon nanotubes (CNTs) have been extensively investigated in the last decade because their superior properties could benefit many applications. However, CNTs have not yet made a major leap into industry, especially for electronic devices, because of fabrication challenges. This review provides an overview of state-of-the-art of CNT synthesis techniques and illustrates their major technical difficulties. It also charts possible in situ analyses and new reactor designs that might enable commercialization. After a brief description of the CNT properties and of the various techniques used to synthesize substrate-free CNTs, the bulk of this review analyzes chemical vapor deposition (CVD). This technique receives special attention since it allows CNTs to be grown in predefined locations, provides a certain degree of control of the types of CNTs grown, and may have the highest chance to succeed commercially. Understanding the primary growth mechanisms at play during CVD is critical for controlling the properties of the CNTs grown and remains the major hurdle to overcome. Various factors that influence CNT growth receive a special focus: choice of catalyst and substrate materials, source gases, and process parameters. This review illustrates important considerations for in situ characterization and new reactor designs that may enable researchers to better understand the physical growth mechanisms and to optimize the synthesis of CNTs, thus contributing to make carbon nanotubes a manufacturing reality.

Synthesis, Characterization, and Electrochemical Properties of Polyaniline Thin Films

Science.gov (United States)

Rami, Soukaina

Conjugated polymers have been used in various applications (battery, supercapacitor, electromagnetic shielding, chemical sensor, biosensor, nanocomposite, light-emitting-diode, electrochromic display etc.) due to their excellent conductivity, electrochemical and optical properties, and low cost. Polyaniline has attracted the researchers from all disciplines of science, engineering, and industry due to its redox properties, environmental stability, conductivity, and optical properties. Moreover, it is a polymer with fast electroactive switching and reversible properties displayed at low potential, which is an important feature in many applications. The thin oriented polyaniline films have been fabricated using self-assembly, Langmuir-Blodgett, in-situ self-assembly, layer-by-layer, and electrochemical technique. The focus of this thesis is to synthesize and characterize polyaniline thin films with and without dyes. Also, the purpose of this thesis is to find the fastest electroactive switching PANI electrode in different electrolytic medium by studying their electrochemical properties. These films were fabricated using two deposition techniques: in-situ self-assembly and electrochemical deposition. The characterization of these films was done using techniques such as Fourier Transform Infrared Spectroscopy (FTIR), UV-spectroscopy, Scanning Electron Microscope (SEM), and X-Ray Diffraction (XRD). FTIR and UV-spectroscopy showed similar results in the structure of the polyaniline films. However, for the dye incorporated films, since there was an addition in the synthesis of the material, peak locations shifted, and new peaks corresponding to these materials appeared. The 1 layer PANI showed compact film morphology, comparing to other PANI films, which displayed a fiber-like structure. Finally, the electrochemical properties of these thin films were studied using cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) in

SYNTHESIS AND PHYSICAL-CHEMICAL PROPERTIES OF WATER-SOLUBLE 3-BENZYLXANTHINE DERIVATIVES

Directory of Open Access Journals (Sweden)

K. V. Аleksandrova

2015-04-01

Full Text Available Introduction Nowadays, research of novel biological active compounds with low toxicity, are carried out among different classes of organic compounds of natural and synthetic genesis. One of the main ways of these studies is search of water-soluble compounds – convenient objects for pharmacological researches. In recent years researchers paid attention to xanthine derivatives, because of their high variativity of possible chemical modification and ability to form different salts with wide spectrum of biological action. Thus, among water-soluble xanthine derivatives were found compounds with pronounced antioxidant, diuretic and analeptic properties. Primary methods of obtaining water-soluble xanthine derivatives are direct interaction of bases with xanthine molecule or insertion basic or acidic residues in positions 7 or 8 of xanthine bicycle. According from the above, search of biologically active compounds among water-soluble substituted xanthines is prospective and actual. The aim of the study was development of synthetic ways of obtaining novel water-soluble derivatives of 3-benzyl-8-methylxanthine and studying their physical and chemical properties. Material and methods Melting points of obtained compounds were determined by capillary method on PTP (M device. ІR-spectra of synthesized compounds were recorded on the Bruker Alpha device (company «Bruker» – Germany on 4000-400 sm-1 with using console ATR (direct insertion of compound. 1Н NMR-spectra were recorded on the Varian Mercury VX-200 device (company «Varian» – USA solvent – (DMSO-d6, internal standart – ТМС. Elemental analysis was made on Elementar Vario L cube device. Chromatoraphic studies were made on the plates Sorbfil-AFV-UV (company «Sobrpolimer» –Russia. Systhems for chromatography: «acetone-propanol-2» in ratio 2:3, «propanol-2-benzene» in ratio 10:1 and exersized in UV-light in wave 200-300 nm. Results and discussion We developed methodic of synthesis

Novel vanillin derivatives: Synthesis, anti-oxidant, DNA and cellular protection properties.

Science.gov (United States)

Scipioni, Matteo; Kay, Graeme; Megson, Ian; Kong Thoo Lin, Paul

2018-01-01

Antioxidants have been the subject of intense research interest mainly due to their beneficial properties associated with human health and wellbeing. Phenolic molecules, such as naturally occurring Resveratrol and Vanillin, are well known for their anti-oxidant properties, providing a starting point for the development of new antioxidants. Here we report, for the first time, the synthesis of a number of new vanillin through the reductive amination reaction between vanillin and a selection of amines. All the compounds synthesised, exhibited strong antioxidant properties in DPPH, FRAP and ORAC assays, with compounds 1b and 2c being the most active. The latter also demonstrated the ability to protect plasmid DNA from oxidative damage in the presence of the radical initiator AAPH. At cellular level, neuroblastoma SH-SY5Y cells were protected from oxidative damage (H 2 O 2 , 400 μM) with both 1b and 2c. The presence of a tertiary amino group, along with the number of vanillin moieties in the molecule contribute for the antioxidant activity. Furthermore, the delocalization of the electron pair of the nitrogen and the presence of an electron donating substituent to enhance the antioxidant properties of this new class of compounds. In our opinion, vanillin derivatives 1b and 2c described in this work can provide a viable platform for the development of antioxidant based therapeutics. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

[Synthesis and physico-chemical properties of lonazolac-Ca, a new antiphlogistic/antirheumatic agent].

Science.gov (United States)

Rainer, G; Krüger, U; Klemm, K

1981-01-01

Calcium-[3-(p-chlorophenyl)-1-phenylpyrazole-4]-acetate (Lonazolac-Ca, active principle of Irritren) is a new antiinflammatory/antirheumatic agent whose synthesis and physico-chemical properties are described. The physical parameters measured (pKa, partition coefficient P, saturation concentration Cs, surface activity, protein binding) are held against the corresponding values of indomethacin, diclofenac, and phenylbutazone. The size of the permeability coefficient PM of the passive transport through artificial phospholipid collodion membranes as well as the invasion curves calculated from PM indicate a good absorption of lonazolac in man.

Synthesis and Properties of Sulfhydryl-Reactive Near-Infrared Cyanine Fluorochromes for Fluorescence Imaging

Directory of Open Access Journals (Sweden)

Yuhui Lin

2003-04-01

Full Text Available Near-infrared fluorochromes (NIRF are useful compounds for diverse biotechnology applications and for in vivo biomedical imaging. Such NIRF must have high quantum yield, be biocompatible, and be conjugatable to a wide variety of proteins, peptides, and other affinity ligands. Here, we describe the synthesis of four new nonsymmetrical sulfhydryl-reactive cyanine NIRF with excellent optical and chemical properties. Each fluorochrome was designed to contain an iodoacetamido group that reacts specifically with sulfhydryl-containing molecules. The synthesized fluorochromes were used to label model peptides and sulfhydryl-containing biomolecules.

Organic synthesis

Energy Technology Data Exchange (ETDEWEB)

Thomas, S.E.

1991-01-01

This paper reports on reactions of organoboranes. Organoboron routes to unsaturated hydrocarbons. Boronic ester homologation. Properties of organosilicon compounds. Alkene synthesis (Peterson olefination). Allylsilanes and acylsilanes.

Synthesis and photophysical characteristics of 2,7-fluorenevinylene-based trimers and their electroluminescence.

Science.gov (United States)

Mikroyannidis, John A; Fenenko, Larysa; Adachi, Chihaya

2006-10-19

Three new 2,7-fluorenevinylene-based trimers were synthesized and characterized. The synthesis was carried out by the Heck coupling reaction of 9,9-dihexyl-2,7-divinylfluorene with 2-(4-bromophenyl)-5-phenyl-1,3,4-oxadiazole, N,N-diphenyl-4-bromoaniline, or 3-bromopyrene to afford the trimers OXD, TPA, and PYR, respectively. All the trimers were readily soluble in common organic solvents such as tetrahydrofuran, dichloromethane, chloroform, and toluene. Their glass transition temperatures ranged from 33 to 60 degrees C. The UV-vis spectra showed an absorption maximum at lambda(a,max) = 379-417 nm with optical band gap of Eg = 2.47-2.66 eV. In solution, they emitted strong blue-green photoluminescence (PL) with PL maximum at lambda(f,max) = 455-565 nm and fluorescence quantum yield of Phi(f) = 0.65-0.74. On the other hand, in their spin-coated films, the PL efficiencies significantly decreased due to the presence of concentration quenching. All samples showed nanosecond transient lifetime containing two components, suggesting excimer formation. The organic light-emitting diodes (OLEDs) with OXD and TPA showed green emission with electroluminescence (EL) quantum efficiencies of eta(EL) approximately 10(-2)%, while very weak EL efficiency of eta(EL) approximately 10(-5)% was observed with PYR. The highest occupied molecular orbital (HOMO) levels of the films were found to be 5.05-5.75 eV.

Molecular Design of Bioinspired Nanostructures for Biomedical Applications: Synthesis, Self-Assembly and Functional Properties

Science.gov (United States)

Xu, Hesheng Victor; Zheng, Xin Ting; Mok, Beverly Yin Leng; Ibrahim, Salwa Ali; Yu, Yong; Tan, Yen Nee

2016-08-01

Biomolecules are the nanoscale building blocks of cells, which play multifaceted roles in the critical biological processes such as biomineralization in a living organism. In these processes, the biological molecules such as protein and nucleic acids use their exclusive biorecognition properties enabled from their unique chemical composition, shape and function to initiate a cascade of cellular events. The exceptional features of these biomolecules, coupled with the recent advancement in nanotechnology, have led to the emergence of a new research field that focuses on the molecular design of bioinspired nanostructures that inherit the extraordinary function of natural biomaterials. These “bioinspired” nanostructures could be formulated by biomimetic approaches through either self-assembling of biomolecules or acting as a biomolecular template/precursor to direct the synthesis of nanocomposite. In either situation, the resulting nanomaterials exhibit phenomenal biocompatibility, superb aqueous solubility and excellent colloidal stability, branding them exceptionally desirable for both in vitro and in vivo biomedical applications. In this review, we will present the recent developments in the preparation of “bioinspired” nanostructures through biomimetic self-assembly and biotemplating synthesis, as well as highlight their functional properties and potential applications in biomedical diagnostics and therapeutic delivery. Lastly, we will conclude this topic with some personal perspective on the challenges and future outlooks of the “bioinspired” nanostructures for nanomedicine.

Facile synthesis of improved room temperature gas sensing properties of TiO2 nanostructures: Effect of acid treatment

CSIR Research Space (South Africa)

Tshabalala, Zamaswazi P

2016-03-01

Full Text Available and Actuators B: Chemical Facile synthesis of improved room temperature gas sensing properties of TiO2 nanostructures: Effect of acid treatment Z.P. Tshabalalaa,b, D.E. Motaunga,∗, G.H. Mhlongoa,∗, O.M. Ntwaeaborwab,∗ a DST/CSIR, National Centre...

Synthesis and electrochemical properties of binary MgTi and ternary MgTiX (X=Ni, Si) hydrogen storage alloys

NARCIS (Netherlands)

Gobichettipalayam Manivasagam, T.; Iliksu, M.; Danilov, D.L.; Notten, P.H.L.

2017-01-01

Mg-based hydrogen storage alloys are promising candidate for many hydrogen storage applications because of the high gravimetric hydrogen storage capacity and favourable (de)hydrogenation kinetics. In the present study we have investigated the synthesis and electrochemical hydrogen storage properties

Influence of synthesis procedure on the formation and properties of zinc oxide

International Nuclear Information System (INIS)

Music, S.; Popovic, S.; Maljkovic, M.; Dragcevic, D.

2002-01-01

Formation and properties of zinc oxide were investigated in dependence on the synthesis procedure. Zinc oxide did not crystallize upon hydrothermal treatment of Zn(NO 3 ) 2 aqueous solutions containing urea, up to 160 deg. C. Hydrozincite was formed instead. Changes in the X-ray diffraction patterns and Fourier transform infrared (FT-IR) spectra were interpreted in terms of stacking disorder in hydrozincite crystals. Zinc oxide powder was obtained by thermal treatment in air of precipitated hydrozincite. The conditions for instantaneous synthesis of very fine zinc oxide particles were found. This procedure is based on addition of TMAH (tetramethylammonium hydroxide) solution to an ethanolic solution of zinc acetate dihydrate, up to pH∼14. On the other hand, addition of an equivalent volume of water to the ethanolic solution of zinc acetate dihydrate, prior to the addition of TMAH solution up to pH∼14, yielded ZnO flakes without any specific shape. All zinc oxide particles produced upon heating at 600 deg. C in air showed similar morphology and tendency to aggregation due to the sintering effect. The features of the FT-IR spectra of zinc oxide particles were related to their shapes

Water soluble {2-[3-(diethylamino)phenoxy]ethoxy} substituted zinc(II) phthalocyanine photosensitizers

Energy Technology Data Exchange (ETDEWEB)

Çakır, Dilek [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Göl, Cem [Gebze Institute of Technology, Department of Chemistry, PO Box 141, Gebze, 41400, Kocaeli (Turkey); Çakır, Volkan [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Durmuş, Mahmut [Gebze Institute of Technology, Department of Chemistry, PO Box 141, Gebze, 41400, Kocaeli (Turkey); Bıyıklıoğlu, Zekeriya, E-mail: zekeriya_61@yahoo.com [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey); Kantekin, Halit [Department of Chemistry, Faculty of Sciences, Karadeniz Technical University, 61080 Trabzon (Turkey)

2015-03-15

The new peripherally and non-peripherally tetra-{2-[3-(diethylamino)phenoxy] ethoxy} substituted zinc phthalocyanines (2a and 3a) were synthesized by cyclotetramerization of phthalonitrile derivatives (2 and 3). 2-[3-(diethylamino)phenoxy] ethoxy group was chosen as substituent because the quaternization of the diethylamino functionality on the structure of this group produced water soluble zinc phthalocyanines (2b and 3b). The water solubility is very important for many different applications such as photosensitizers in the photodynamic therapy of cancer because the water soluble photosensitizers can be injected directly to the body and they can transport to cancer cells through blood stream. The new compounds were characterized by using elemental analysis, UV–vis, IR, {sup 1}H NMR, {sup 13}C NMR and mass spectroscopies. The photophysical and photochemical properties of these novel photosensitizer compounds were examined in DMSO (both non-ionic and ionic complexes) and in PBS (for ionic complexes) solutions. The investigation of these properties is very important for the usage of the compounds as photosensitizers for PDT because determination of these properties is the first stage of potential of the compounds as photosensitizers. The bovine serum albumin (BSA) and DNA binding behaviour of the studied water soluble zinc (II) phthalocyanines were also investigated in PBS solutions for the determination of biological activity of these compounds. - Highlights: • Synthesis of water soluble zinc phthalocyanines. • Photophysical and photochemical properties for phthalocyanines. • Photodynamic therapy studies.

Water soluble {2-[3-(diethylamino)phenoxy]ethoxy} substituted zinc(II) phthalocyanine photosensitizers

International Nuclear Information System (INIS)

Çakır, Dilek; Göl, Cem; Çakır, Volkan; Durmuş, Mahmut; Bıyıklıoğlu, Zekeriya; Kantekin, Halit

2015-01-01

The new peripherally and non-peripherally tetra-{2-[3-(diethylamino)phenoxy] ethoxy} substituted zinc phthalocyanines (2a and 3a) were synthesized by cyclotetramerization of phthalonitrile derivatives (2 and 3). 2-[3-(diethylamino)phenoxy] ethoxy group was chosen as substituent because the quaternization of the diethylamino functionality on the structure of this group produced water soluble zinc phthalocyanines (2b and 3b). The water solubility is very important for many different applications such as photosensitizers in the photodynamic therapy of cancer because the water soluble photosensitizers can be injected directly to the body and they can transport to cancer cells through blood stream. The new compounds were characterized by using elemental analysis, UV–vis, IR, 1 H NMR, 13 C NMR and mass spectroscopies. The photophysical and photochemical properties of these novel photosensitizer compounds were examined in DMSO (both non-ionic and ionic complexes) and in PBS (for ionic complexes) solutions. The investigation of these properties is very important for the usage of the compounds as photosensitizers for PDT because determination of these properties is the first stage of potential of the compounds as photosensitizers. The bovine serum albumin (BSA) and DNA binding behaviour of the studied water soluble zinc (II) phthalocyanines were also investigated in PBS solutions for the determination of biological activity of these compounds. - Highlights: • Synthesis of water soluble zinc phthalocyanines. • Photophysical and photochemical properties for phthalocyanines. • Photodynamic therapy studies

Photo-physics study of an hydroxy-quinoline derivative as inhibitor of Pim-1 kinase: ultraviolet-visible linear dichroism spectroscopy and quantum chemical calculations.

Science.gov (United States)

Lamhasni, T; Ait Lyazidi, S; Hnach, M; Haddad, M; Desmaële, D; Spanget-Larsen, J; Nguyen, D D; Ducasse, L

2013-09-01

The photophysical properties of the antiviral 7-nicotinoyl-styrylquinoline (MB96) were investigated by means of UV-Vis linear dichroism (LD) spectroscopy on molecular samples aligned in stretched polyvinylalcohol (PVA), supported by time dependent density functional theory (TD-DFT) calculations. Experimentally, the directions of the transitions moments with respect to the long axis of the molecule were deduced from the orientation K factors, determined by means of "trial-and-error" procedure. The absorption spectrum presents two parts. The main transition in the lowest energy part, observed around 365 nm and showing the highest K value 0.8, is longitudinally in-plane polarized. The highest energy part which is extended between 230 and 320 nm, large, diffuse, and of weak intensity, shows estimated K values between 0.2 and 0.5. This complex structure is transversally polarized with some contamination by the longitudinal character of the first strong band. The TD-DFT results agree fairly well with the LD measurements. Copyright © 2013 Elsevier B.V. All rights reserved.

Synthesis and properties of Oxasmaragdyrins containing one Five ...

Indian Academy of Sciences (India)

pioneering synthesis of Vitamin B12.2a However, the first synthesis of .... 2.3b Compound 3: Yield 22% (135 mg); 1H NMR. (500 MHz, CDCl3, 25 .... (b). Figure 1. (a) 1H NMR and (b) 1H-1H COSY NMR spectrum of compound 4 recorded in CDCl3 at room temperature. The double crossed peak in (a) and an asterix marked ...

5-Bromo-4′,5′-bis(dimethylaminofluorescein: Synthesis and Photophysical Studies

Directory of Open Access Journals (Sweden)

Jun Yeon Hwang

2018-01-01

Full Text Available In this study, three new fluorescein derivatives—5-bromo-4′,5′-dinitrofluorescein (BDNF, 5-bromo-4′,5′-diaminofluorescein (BDAF, and 5-bromo-4′,5′-bis(dimethylaminofluorescein (BBDMAF—were synthesized and their pH-dependent protolytic equilibria were investigated. In particular, BBDMAF exhibited pH-dependent fluorescence, showing strong emission only at pH 3–6. BBDMAF bears a bromine moiety and thus, can be used in various cross-coupling reactions to prepare derivatives and take advantage of its unique emission properties. To confirm this, the Suzuki and Sonogashira reactions of BBDMAF with phenylboronic acid and phenylacetylene, respectively, were performed, and the desired products were successfully obtained.

Photocatalytic Conversion of CO2 to CO using Rhenium Bipyridine Platforms Containing Ancillary Phenyl or BODIPY Moieties

Science.gov (United States)

Andrade, Gabriel A.; Pistner, Allen J.; Yap, Glenn P.A.; Lutterman, Daniel A.; Rosenthal, Joel

2013-01-01

Harnessing of solar energy to drive the reduction of carbon dioxide to fuels requires the development of efficient catalysts that absorb sunlight. In this work, we detail the synthesis, electrochemistry and photophysical properties of a set of homologous fac-ReI(CO)3 complexes containing either an ancillary phenyl (8) or BODIPY (12) substituent. These studies demonstrate that both the electronic properties of the rhenium center and BODIPY chromophore are maintained for these complexes. Photolysis studies demonstrate that both assemblies 8 and 12 are competent catalysts for the photochemical reduction of CO2 to CO in DMF using triethanolamine (TEOA) as a sacrificial reductant. Both compounds 8 and 12 display TOFs for photocatalytic CO production upon irradiation with light (λex ≥ 400 nm) of ~5 hr−1 with TON values of approximately 20. Although structural and photophysical measurements demonstrate that electronic coupling between the BODIPY and fac-ReI(CO)3 units is limited for complex 12, this work clearly shows that the photoactive BODIPY moiety is tolerated during catalysis and does not interfere with the observed photochemistry. When taken together, these results provide a clear roadmap for the development of advanced rhenium bipyridine complexes bearing ancillary BODIPY groups for the efficient photocatalytic reduction of CO2 using visible light. PMID:24015374

Photophysics of size-selected InP nanocrystals: Exciton recombination kinetics

International Nuclear Information System (INIS)

Kim, S.; Wolters, R.H.; Heath, J.R.

1996-01-01

We report here on the size-dependent kinetics of exciton recombination in a III endash V quantum dot system, InP. The measurements reported include various frequency dependent quantum yields as a function of temperature, frequency dependent luminescence decay curves, and time-gated emission spectra. This data is fit to a three-state quantum model which has been previously utilized to explain photophysical phenomena in II endash VI quantum dots. The initial photoexcitation is assumed to place an electron in a (delocalized) bulk conduction band state. Activation barriers for trapping and detrapping of the electron to surface states, as well as activation barriers for surface-state radiationless relaxation processes are measured as a function of particle size. The energy barrier to detrapping is found to be the major factor limiting room temperature band-edge luminescence. This barrier increases with decreasing particle size. For 30 A particles, this barrier is found to be greater than 6 kJ/mol emdash a barrier which is more than an order of magnitude larger than that previously found for 32 A CdS nanocrystals. copyright 1996 American Institute of Physics

Synthesis of Non-uniformly Pr-doped SrTiO3 Ceramics and Their Thermoelectric Properties

KAUST Repository

Mehdizadeh Dehkordi, Arash; Bhattacharya, Sriparna; Darroudi, Taghi; Zeng, Xiaoyu; Alshareef, Husam N.; Tritt, Terry M.

2015-01-01

We demonstrate a novel synthesis strategy for the preparation of Pr-doped SrTiO3 ceramics via a combination of solid state reaction and spark plasma sintering techniques. Polycrystalline ceramics possessing a unique morphology can be achieved by optimizing the process parameters, particularly spark plasma sintering heating rate. The phase and morphology of the synthesized ceramics were investigated in detail using X-ray diffraction, scanning electron microcopy and energy-dispersive X-ray spectroscopy It was observed that the grains of these bulk Pr-doped SrTiO3 ceramics were enhanced with Pr-rich grain boundaries. Electronic and thermal transport properties were also investigated as a function of temperature and doping concentration Such a microstructure was found to give rise to improved thermoelectric properties. Specifically, it resulted in a significant improvement in carrier mobility and the thermoelectric power factor. Simultaneously, it also led to a marked reduction in the thermal conductivity. As a result, a significant improvement (> 30%) in the thermoelectric figure of merit was achieved for the whole temperature range over all previously reported maximum values for SrTiO3-based ceramics. This synthesis demonstrates the steps for the preparation of bulk polycrystalline ceramics of non-uniformly Pr-doped SrTiO3.

Synthesis of Non-uniformly Pr-doped SrTiO3 Ceramics and Their Thermoelectric Properties

KAUST Repository

Mehdizadeh Dehkordi, Arash

2015-08-15

We demonstrate a novel synthesis strategy for the preparation of Pr-doped SrTiO3 ceramics via a combination of solid state reaction and spark plasma sintering techniques. Polycrystalline ceramics possessing a unique morphology can be achieved by optimizing the process parameters, particularly spark plasma sintering heating rate. The phase and morphology of the synthesized ceramics were investigated in detail using X-ray diffraction, scanning electron microcopy and energy-dispersive X-ray spectroscopy It was observed that the grains of these bulk Pr-doped SrTiO3 ceramics were enhanced with Pr-rich grain boundaries. Electronic and thermal transport properties were also investigated as a function of temperature and doping concentration Such a microstructure was found to give rise to improved thermoelectric properties. Specifically, it resulted in a significant improvement in carrier mobility and the thermoelectric power factor. Simultaneously, it also led to a marked reduction in the thermal conductivity. As a result, a significant improvement (> 30%) in the thermoelectric figure of merit was achieved for the whole temperature range over all previously reported maximum values for SrTiO3-based ceramics. This synthesis demonstrates the steps for the preparation of bulk polycrystalline ceramics of non-uniformly Pr-doped SrTiO3.

Synthesis, characterization and magnetic properties of Fe-Al nanopins

International Nuclear Information System (INIS)

Zhang, W.S.; Brueck, E.; Li, W.F.; Si, P.Z.; Geng, D.Y.; Zhang, Z.D.

2005-01-01

We report the synthesis of Fe-Al nanopins using arc discharge. The morphology and chemical composition of the Fe-Al nanopins were studied by means of X-ray diffraction, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), and high-resolution transmission electron microscopy (HRTEM). The nanopins are composed of a spherical base of about 20-100 nm and a needle-like tip of about several hundred nanometers. EDX and HRTEM studies indicate that the spherical base is mainly composed of α-Fe and FeAl core coated with a thin Al 2 O 3 layer, while the needle-like part contains only Al and O and corresponds to Al 2 O 3 . The formation mechanism of the nanopins is suggestive of a vapor-liquid-solid (VLS) growth process. The as-prepared Fe-Al nanopins show ferromagnetic properties. The temperature dependence of the magnetization at high temperatures indicates the existence of some phase transformations

Improvement of the luminescent properties of cadmium sulfide quantum dots by a post-synthesis modification

Energy Technology Data Exchange (ETDEWEB)

López, Israel; Gómez, Idalia, E-mail: maria.gomezd@uanl.edu.mx

2014-11-15

Here the improvement of the luminescent properties of CdS quantum dots by a post-synthesis modification with aqueous solutions of NaOH at different concentrations is presented. The CdS quantum dots were synthesized by a microwave-assisted method using citrate ions as stabilizer. The addition of the hydroxide ions increased the intensity of the orange-red emission by about 80%. Besides, a violet-blue emission was achieved by means of this post-synthesis modification. The hydroxide ions control the precipitation equilibria of the CdS and Cd(OH){sub 2}, dissolving and precipitating the surface of the quantum dots. The NaOH treatment increases the number of traps, which produces less band-edge and more deep-trap emission, which explains the decrease and increase in the intensity of the violet-blue and orange-red emissions, respectively.

Improvement of the luminescent properties of cadmium sulfide quantum dots by a post-synthesis modification

International Nuclear Information System (INIS)

López, Israel; Gómez, Idalia

2014-01-01

Here the improvement of the luminescent properties of CdS quantum dots by a post-synthesis modification with aqueous solutions of NaOH at different concentrations is presented. The CdS quantum dots were synthesized by a microwave-assisted method using citrate ions as stabilizer. The addition of the hydroxide ions increased the intensity of the orange-red emission by about 80%. Besides, a violet-blue emission was achieved by means of this post-synthesis modification. The hydroxide ions control the precipitation equilibria of the CdS and Cd(OH) 2 , dissolving and precipitating the surface of the quantum dots. The NaOH treatment increases the number of traps, which produces less band-edge and more deep-trap emission, which explains the decrease and increase in the intensity of the violet-blue and orange-red emissions, respectively

Synthesis, thermal behavior and thermoelectric properties of disordered tellurides with structures derived from the rocksalt type

Energy Technology Data Exchange (ETDEWEB)

Schroeder, Thorsten

2014-06-17

GeBi{sub 2}Te{sub 4} is proposed as phase-change material. Nanostructures in metastable GeBi{sub 2}Te{sub 4} were obtained by high-pressure synthesis and thermal quenching, - depending on temperature and pressure different modifications were found. The differences in the electrical characteristics can be attributed to the variation of grain boundary concentration and the grain size distribution. Two synthesis approaches were used to prepare Ag{sub 3.4}In{sub 3.7}Sb{sub 76.4}Te{sub 16.5} bulk samples and studied with respect to their transport and thermal properties. A high pressure route to prepare thermoelectrics with low thermal conductivity was developed for AgIn{sub x}Sb{sub 1-x}Te{sub 2}. Disorder and and transport studies on In{sub 3}SbTe{sub 2} were performed using X-ray, neutron and electron diffraction measurements. Nanostructures in Te/Sb/Ge/Ag (TAGS) thermoelectric materials were induced by phase transitions associated with vacancy ordering. Further studies concerned solid solution series (GeTe){sub x}(LiSbTe{sub 2}){sub 2} (1 smaller or equal x smaller or equal 11) and their thermoelectric properties.

Synthesis and physicochemical properties of 7,8-dicarba-nido-undecarborane(11) adducts with pyridine bases

International Nuclear Information System (INIS)

Volkov, O.V.; Il'inchik, E.A.; Volkov, V.V.; Voronina, G.S.; Yur'eva, O.P.; Polyanskaya, T.M.

1993-01-01

Synthesis of some 7,8-C 2 B 9 H 11 adducts in conducted via 7.8-C 2 B 9 H 12 ion interaction with iron (3) chloride at presence of pyridine derivatives and their study is carried out using IR, NMR 12 B, PMR, X-ray phase, UV spectroscopy techniques. Character of bond between heterocycle and carborane holyhedron is discussed. Luminescent properties of the prepared compounds under UV radiation are detected

Synthesis and electrochemical properties of {alpha}-MnO{sub 2} microspheres

Energy Technology Data Exchange (ETDEWEB)

Wang Hongen [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China); Zhengzhou Research Institute of CHALCO, Zhengzhou Research Institute of Light Metals, Zhengzhou 450041 (China); Qian Dong [College of Chemistry and Chemical Engineering, Central South University, Changsha 410083 (China)], E-mail: qiandong6@yahoo.com.cn

2008-06-15

We report the synthesis of {alpha}-MnO{sub 2} microspheres by a low-temperature hydrothermal method involving no templates or catalysts. The products were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-dispersive X-ray spectrum (EDX), transmission electron microscopy (TEM), Fourier transform infrared spectrum (FT-IR), and Brunauer-Emmett-Teller (BET). The results show that the as-synthesized products are mainly composed of large quantities of {alpha}-MnO{sub 2} microspheres having a sea-urchin shape and a few microspheres constructed of small nanorods. Electrochemical characterization indicates that the resulting {alpha}-MnO{sub 2} microspheres display promising discharge properties than the commercial electrolytic manganese dioxides (EMD) when used as cathodes in alkaline Zn-MnO{sub 2} batteries.

Nanoscale luminescent lanthanide-based metal–organic frameworks: properties, synthesis, and applications

Energy Technology Data Exchange (ETDEWEB)

Hu, Dongqin; Song, Yonghai; Wang, Li, E-mail: lwanggroup@aliyun.com [Jiangxi Normal University, Key Laboratory of Functional Small Organic Molecule, Ministry of Education, Key Laboratory of Chemical Biology, Jiangxi Province, College of Chemistry and Chemical Engineering (China)

2015-07-15

Nanoscale luminescent lanthanide-based metal–organic frameworks (NLLn-MOFs) possess superior optical and physical properties such as higher luminescent lifetime, quantum yield, high stability, high surface area, high agent loading, and intrinsic biodegradability, and therefore are regarded as a novel generation of luminescent material compared with bulk lanthanide-based metal–organic frameworks (Ln-MOFs). Traditional luminescent Ln-MOFs have been well studied; however, NLLn-MOFs taking the advantages of nanomaterials have attracted extensive investigations for applications in optical imaging in living cells, light-harvesting, and sensing. In this review, we provide a survey of the latest progresses made in developing NLLn-MOFs, which contains the fundamental optical features, synthesis, and their potential applications. Finally, the future prospects and challenges of the rapidly growing field are summarized.

The synthesis and adsorption properties of some carbohydrate-terminated dendrimer wedges

International Nuclear Information System (INIS)

Ainsworth, Richard L.

1997-01-01

A range of dendritic molecules that are designed to bind to a cotton surface has been synthesised. The architecture of the molecules allows the location of various functional, property modifying units at the focus and the attachment of recognition groups at the periphery of a dendritic molecule with wedge topology. The synthesis and characterisation of dendrimer wedges up to the second generation using a divergent approach has been performed. These wedges are readily built up using a simple and efficient stepwise pathway from the central core, and surface recognising species are subsequently attached to the molecule utilising procedures developed in conjunction with Unilever Research Laboratories. Work has been carried out to assess their adsorption onto a cotton surface and the postulated adsorption mechanism is discussed. (author)

Photoprotection and the photophysics of acylated anthocyanins.

Science.gov (United States)

da Silva, Palmira Ferreira; Paulo, Luísa; Barbafina, Adrianna; Eisei, Fausto; Quina, Frank H; Maçanita, António L

2012-03-19

The proposed role of anthocyanins in protecting plants against excess solar radiation is consistent with the occurrence of ultrafast (5-25 ps) excited-state proton transfer as the major de-excitation pathway of these molecules. However, because natural anthocyanins absorb mainly in the visible region of the spectra, with only a narrow absorption band in the UV-B region, this highly efficient deactivation mechanism would essentially only protect the plant from visible light. On the other hand, ground-state charge-transfer complexes of anthocyanins with naturally occurring electron-donor co-pigments, such as hydroxylated flavones, flavonoids, and hydroxycinnamic or benzoic acids, do exhibit high UV-B absorptivities that complement that of the anthocyanins. In this work, we report a comparative study of the photophysics of the naturally occurring anthocyanin cyanin, intermolecular cyanin-coumaric acid complexes, and an acylated anthocyanin, that is, cyanin with a pendant coumaric ester co-pigment. Both inter- and intramolecular anthocyanin-co-pigment complexes are shown to have ultrafast energy dissipation pathways comparable to those of model flavylium cation-co-pigment complexes. However, from the standpoint of photoprotection, the results indicate that the covalent attachment of co-pigment molecules to the anthocyanin represents a much more efficient strategy by providing the plant with significant UV-B absorption capacity and at the same time coupling this absorption to efficient energy dissipation pathways (ultrafast internal conversion of the complexed form and fast energy transfer from the excited co-pigment to the anthocyanin followed by adiabatic proton transfer) that avoid net photochemical damage. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation on the photophysical properties of tungsten trioxide and tungstate based nanocomposites

Science.gov (United States)

Palanisamy, G.; Pazhanivel, T.

2018-04-01

Tungsten trioxide (WO3), Metal tungstates (SrWO4, Cr2WO6), WO3/SrWO4 and WO3/Cr2WO6 nanocomposites were successfully prepared by microwave irradiation method at relatively low temperature (500 °C). The synthesized samples were subjected to different investigation techniques, to know the materials physical and chemical properties. The structural and phase change formation of nanoparticles were investigated through XRD analysis. It shows that, the nanoparticles have highly crystalline nature. The shape and composition of the prepared nanoparticles were investigated through SEM and EDAX analysis. The optical properties of the synthesized samples were verified by Ultraviolet-diffuse reflectance spectroscopy and photoluminescence spectrometer. The emission intensity maximum of WO3 nanoparticle was red shifted when compared to composites. It may be due to the effect of delocalized electrons in the parent material. Simultaneously, the emission intensity was decreased because of trap states occurred on the surface of the composite nanoparticles. The photoluminescence spectra of the synthesized samples exhibit different emission (violet and blue) behavior. Hence, it may be useful for light emitting diode (LED) applications.

Photo and biocatalytic activities along with UV protection properties on polyester fabric through green in-situ synthesis of cauliflower-like CuO nanoparticles.

Science.gov (United States)