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Sample records for goldi phosphinegoldi azides

  1. Azido, triazolyl, and alkynyl complexes of gold(I): syntheses, structures, and ligand effects.

    Science.gov (United States)

    Robilotto, Thomas J; Deligonul, Nihal; Updegraff, James B; Gray, Thomas G

    2013-08-19

    Gold(I) triazolyl complexes are prepared in [3 + 2] cycloaddition reactions of (tertiary phosphine)gold(I) azides with terminal alkynes. Seven such triazolyl complexes, not previously prepared, are described. Reducible functional groups are accommodated. In addition, two new (N-heterocyclic carbene)gold(I) azides and two new gold(I) alkynyls are described. Eight complexes are crystallographically authenticated; aurophilic interactions appear in one structure only. The packing diagrams of gold(I) triazolyls all show intermolecular hydrogen bonding between N-1 of one molecule and N-3 of a neighbor. This hydrogen bonding permeates the crystal lattice. Density-functional theory calculations of (triphenylphosphine)gold(I) triazolyls and the corresponding alkynyls indicate that the triazolyl is a stronger trans-influencer than is the alkynyl, but the alkynyl is more electron-releasing. These results suggest that trans-influences in two-coordinate gold(I) complexes can be more than a simple matter of ligand donicity.

  2. Sodium Azide

    Science.gov (United States)

    ... Exposure to a large amount of sodium azide by any route may cause these other health effects as well: Convulsions Low blood pressure Loss of consciousness Lung injury Respiratory failure leading to death Slow heart rate ...

  3. Thermochemistry of organic azides revisited

    International Nuclear Information System (INIS)

    Emel'yanenko, Vladimir N.; Algarra, Manuel; Esteves da Silva, Joaquim C.G.; Hierrezuelo, Jesús; López-Romero, Juan M.; Verevkin, Sergey P.

    2014-01-01

    Highlights: • Pure samples of 4-nitro-phenyl azide, 1-octyl- and 1-decyl-azides were prepared. • Vapour pressures, sublimation and vaporization enthalpies measured by transpiration. • Enthalpy of formation of 1-alkyl azides measured by combustion calorimetry. • Enthalpy of fusion of 4-nitro-phenyl azide measured by DSC. • Experimental gas enthalpies of formation were in agreement with calculated by G4. - Abstract: Highly pure samples of 4-nitro-phenyl azide, 1-octyl azide and 1 decyl-azide were prepared for thermochemical studies. Vapour pressures over the solid and the liquid sample of 4-nitro-phenyl azide have been determined by the transpiration method. The molar enthalpies of vaporization/sublimation for this compound were derived from the temperature dependencies of vapour pressures. The molar enthalpy of fusion of 4-nitro-phenyl azide was measured by DSC. The measured data set for 4-nitro-phenyl azide was successfully checked for internal consistency. Molar enthalpies of vaporization of 1-octyl azide and 1 decyl-azide were measured by transpiration. The molar enthalpies of formation of the liquid 1-octyl azide and 1 decyl-azides were derived from the combustion calorimetry. New experimental results for these organic azides have been used to derive their molar enthalpies of formation in the gas state and for comparison with results from quantum-chemical method G4

  4. Mutagenic azide metabolite is azidoalanine

    International Nuclear Information System (INIS)

    Owais, W.M.; Rosichan, J.L.; Ronald, R.C.; Kleinhofs, A.; Nilan, R.A.

    1981-01-01

    Sodium axide produces high mutation rates in a number of species. Azide mutagenicity is mediated through a metabolite in barley and bacteria. Many studies showed that azide affects the L-cysteine biosynthesis pathway. Cell-free extracts of Salmonella typhimurium convert azide and O-acetylserine to the mutagenic metabolite. O-acetylserine sulfhydrylase was identified as the enzyme responsible for the metabolite biosynthesis. To confirm the conclusion that the azide metabolite is formed through the β-substitution pathway of L-cysteine, we radioactively labeled the azide metabolite using 14 C-labeled precursors. Moreover, the mutagenic azide metabolite was purified and identified as azidoalanine based on mass spectroscopy and elemental analysis. 26 refs., 3 figs., 1 tab

  5. Siim Nestor soovitab : Goldie. Chris Simmonds / Siim Nestor

    Index Scriptorium Estoniae

    Nestor, Siim, 1974-

    2002-01-01

    Drum'n'bassi esimese superstaari Goldie esinemisest 16. nov. Circulation-sarja peol Lillepaviljonis Tallinnas. Londoni diskori Chris Simmondsi esinemistest 15. nov. Tartu klubis Tallinn ja 16. nov. Tallinnas kohvikus Moskva

  6. Thiophene-2-carbonyl azide

    Directory of Open Access Journals (Sweden)

    Michael Findlater

    2013-08-01

    Full Text Available The title compound, C5H3N3OS, is almost planar (r.m.s. deviation for the ten non-H atoms = 0.018 Å and forms an extended layer structure in the (100 plane, held together via hydrogen-bonding interactions between adjacent molecules. Of particular note is the occurrence of RC—H...N−=N+=NR interactions between an aromatic C—H group and an azide moiety which, in conjunction with a complementary C—H...O=C interaction, forms a nine-membered ring.

  7. Alkaline azide mutagenicity in cowpea

    Energy Technology Data Exchange (ETDEWEB)

    Mahna, S K; Bhargava, Anubha; Mohan, Lalit [Cytogenetics and Mycology Laboratory, Department of Botany, Government College, Ajmer (India)

    1990-07-01

    Sodium azide is known as a potent mutagen in cereals and legumes. It is very effective in acidic medium in barley. Here an attempt is made to measure the effectiveness of sodium azide in alkaline medium (pH 7.4) on cowpea (Vigna unguiculata (L.) Walp., variety FS-68). Seeds pre-soaked in distilled water for 5 hours were treated with different concentrations (10{sup -6}, 10{sup -5}, 10{sup -4} and 10{sup -3}M) of sodium azide (NaN{sub 3}) for 4 hours at 28{+-} 2 deg. C. Bottles were intermittently shaken, then the seeds were thoroughly washed in running tap water and subsequently planted in pots. The treatment caused significant biological damage such as reduction in seed germination, length of root and shoot, number of nodules and pods per plant and morphological leaf variations. Morphological, as well as chlorophyll mutants, were detected in M{sub 2}.

  8. Alkaline azide mutagenicity in cowpea

    International Nuclear Information System (INIS)

    Mahna, S.K.; Bhargava, Anubha; Mohan, Lalit

    1990-01-01

    Sodium azide is known as a potent mutagen in cereals and legumes. It is very effective in acidic medium in barley. Here an attempt is made to measure the effectiveness of sodium azide in alkaline medium (pH 7.4) on cowpea (Vigna unguiculata (L.) Walp., variety FS-68). Seeds pre-soaked in distilled water for 5 hours were treated with different concentrations (10 -6 , 10 -5 , 10 -4 and 10 -3 M) of sodium azide (NaN 3 ) for 4 hours at 28± 2 deg. C. Bottles were intermittently shaken, then the seeds were thoroughly washed in running tap water and subsequently planted in pots. The treatment caused significant biological damage such as reduction in seed germination, length of root and shoot, number of nodules and pods per plant and morphological leaf variations. Morphological, as well as chlorophyll mutants, were detected in M 2

  9. Beberapa Sifat dari Modul dan Gelanggang dengan Dimensi Goldie Berhingga (Suatu Kajian Pustaka

    Directory of Open Access Journals (Sweden)

    Amir Kamal Amir

    2012-11-01

    Full Text Available Suatu modul M dikatakan mempunyai demensi Goldie berhingga jika modul tersebuttidak memuat suatu jumlahan langsung dari takberhingga banyak submodul-submodultaknol. Sedangkan, suatu gelanggang R dikatakan mempunyai dimensi Goldie kanan berhinggajika gelanggang tersebut mempunyai dimensi Goldie berhingga sebagai suatu modul kanan.Tulisan ini akan menyajikan beberapa sifat dari modul dan gelanggang yang mempunyai dimensiGoldie berhingga. Sifat-sifat tersebut bukanlah merupakan sifat-sifat yang baru. Namundemikian, tulisan ini akan menyajikan pembuktian dari sifat-sifat tersebut dengan cara yanglebih terperinci dan lengkap sehingga lebih mudah dimengerti, terutama bagi pembaca pemuladalam bidang aljabar.

  10. Goldie Brangman Remembers the Operation to Save Dr King.

    Science.gov (United States)

    Koch, Evan; Brangman, Goldie

    2015-12-01

    In September 1958 the Rev Dr Martin Luther King Jr was stabbed and nearly assassinated. Surgeons at Harlem Hospital in New York City removed a 17.8-cm (7-in)-long letter opener from Dr King's chest. Certified Registered Nurse Anesthetist Goldie Brangman remembers this event because she participated in Dr King's anesthetic. This article correlates Brangman's memories with published accounts of the event. It also places the event within the context of the modern civil rights movement that Dr King led.

  11. Determination of insoluble azides by thermometric titrimetry.

    Science.gov (United States)

    Chagas, A P; Godinho, O E; Costa, J L

    1977-09-01

    A method for determination of azide, based on the thermometric titration of this anion with hydrochloric acid, is described. Although this reaction has a large enthalpy change (DeltaH = -3.6 kcal/ mole), sulphate is added as an endothermic thermometric indicator to improve the end-point. The application of the method to the analysis of insoluble azides has been studied.

  12. Optimal policies of non-cross-resistant chemotherapy on Goldie and Coldman's cancer model.

    Science.gov (United States)

    Chen, Jeng-Huei; Kuo, Ya-Hui; Luh, Hsing Paul

    2013-10-01

    Mathematical models can be used to study the chemotherapy on tumor cells. Especially, in 1979, Goldie and Coldman proposed the first mathematical model to relate the drug sensitivity of tumors to their mutation rates. Many scientists have since referred to this pioneering work because of its simplicity and elegance. Its original idea has also been extended and further investigated in massive follow-up studies of cancer modeling and optimal treatment. Goldie and Coldman, together with Guaduskas, later used their model to explain why an alternating non-cross-resistant chemotherapy is optimal with a simulation approach. Subsequently in 1983, Goldie and Coldman proposed an extended stochastic based model and provided a rigorous mathematical proof to their earlier simulation work when the extended model is approximated by its quasi-approximation. However, Goldie and Coldman's analytic study of optimal treatments majorly focused on a process with symmetrical parameter settings, and presented few theoretical results for asymmetrical settings. In this paper, we recast and restate Goldie, Coldman, and Guaduskas' model as a multi-stage optimization problem. Under an asymmetrical assumption, the conditions under which a treatment policy can be optimal are derived. The proposed framework enables us to consider some optimal policies on the model analytically. In addition, Goldie, Coldman and Guaduskas' work with symmetrical settings can be treated as a special case of our framework. Based on the derived conditions, this study provides an alternative proof to Goldie and Coldman's work. In addition to the theoretical derivation, numerical results are included to justify the correctness of our work. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Controlling hazardous chemicals in microreactors: Synthesis with iodine azide

    Directory of Open Access Journals (Sweden)

    Johan C. Brandt

    2009-06-01

    Full Text Available Aromatic aldehydes have been converted into the corresponding carbamoyl azides using iodine azide. These reactions have been performed safely under continuous flow reaction conditions in microreactors.

  14. AZIDE-ALKYNE CLICK POLYMERIZATION: AN UPDATE

    Institute of Scientific and Technical Information of China (English)

    Hong-kun Li; Jing-zhi Sun; An-jun Qin; Ben Zhong Tang

    2012-01-01

    The great achievements of click chemistry have encouraged polymer scientists to use this reaction in their field.This review assembles an update of the advances of using azide-alkyne click polymerization to prepare functional polytriazoles (PTAs) with linear and hyperbranched structures.The Cu(Ⅰ)-mediated click polymerization furnishes 1,4-regioregular PTAs,whereas,the metal-free click polymerization of propiolates and azides produces PTAs with 1,4-regioisomer contents up to 90%.The PTAs display advanced functions,such as aggregation-induced emission,thermal stability,biocompatibility and optical nonlinearity.

  15. New Gold(I) Organometallic Compounds with Biological Activity in Cancer Cells

    NARCIS (Netherlands)

    Bertrand, Benoit; de Almeida, Andreia; van der Burgt, Evelien P. M.; Picquet, Michel; Citta, Anna; Folda, Alessandra; Rigobello, Maria Pia; Le Gendre, Pierre; Bodio, Ewen; Casini, Angela

    N-Heterocyclic carbene gold(I) complexes bearing a fluorescent coumarin ligand were synthesized and characterized by various techniques. The compounds were examined for their antiproliferative effects in normal and tumor cells in vitro; they demonstrated moderate activity and a certain degree of

  16. Siim Nestor soovitab : Goldie. Kevin Saunderson. Nicole Willis. King Britt / Siim Nestor

    Index Scriptorium Estoniae

    Nestor, Siim, 1974-

    2005-01-01

    Popmuusikaüritustest: briti muusik Goldie esineb jungle-muusikaga Tallinnas 21. apr. klubis Privé, DJ Kevin Saunderson 22. apr. klubis Privé, laulja Nicole Willis 27. apr. BonBon Jazz Lounge'il klubis BonBon, Philadelphia muusik King Britt ja Eesti ansambel Broken Time Orchestra esitlevad oma heliplaate

  17. Thio-phene-2-carbonyl azide.

    Science.gov (United States)

    Hsu, Gene C; Singer, Laci M; Cordes, David B; Findlater, Michael

    2013-01-01

    The title compound, C5H3N3OS, is almost planar (r.m.s. deviation for the ten non-H atoms = 0.018 Å) and forms an extended layer structure in the (100) plane, held together via hydrogen-bonding inter-actions between adjacent mol-ecules. Of particular note is the occurrence of RC-H⋯N(-)=N(+)=NR inter-actions between an aromatic C-H group and an azide moiety which, in conjunction with a complementary C-H⋯O=C inter-action, forms a nine-membered ring.

  18. Cancer cell death induced by phosphine gold(I) compounds targeting thioredoxin reductase.

    Science.gov (United States)

    Gandin, Valentina; Fernandes, Aristi Potamitou; Rigobello, Maria Pia; Dani, Barbara; Sorrentino, Francesca; Tisato, Francesco; Björnstedt, Mikael; Bindoli, Alberto; Sturaro, Alberto; Rella, Rocco; Marzano, Cristina

    2010-01-15

    The thioredoxin system, composed of thioredoxin reductase (TrxR), thioredoxin (Trx), and NADPH (nicotinamide adenine dinucleotide phosphate), plays a central role in regulating cellular redox homeostasis and signaling pathways. TrxR, overexpressed in many tumor cells and contributing to drug resistance, has emerged as a new target for anticancer drugs. Gold complexes have been validated as potent TrxR inhibitors in vitro in the nanomolar range. In order to obtain potent and selective TrxR inhibitors, we have synthesized a series of linear, 'auranofin-like' gold(I) complexes all containing the [Au(PEt(3))](+) synthon and the ligands: Cl(-), Br(-), cyanate, thiocyanate, ethylxanthate, diethyldithiocarbamate and thiourea. Phosphine gold(I) complexes efficiently inhibited cytosolic and mitochondrial TrxR at concentrations that did not affect the two related oxidoreductases glutathione reductase (GR) and glutathione peroxidase (GPx). The inhibitory effect of the redox proteins was also observed intracellularly in cancer cells pretreated with gold(I) complexes. Gold(I) compounds were found to induce antiproliferative effects towards several human cancer cells some of which endowed with cisplatin or multidrug resistance. In addition, they were able to activate caspase-3 and induce apoptosis observed as nucleosome formation and sub-G1 cell accumulation. The complexes with thiocyanate and xanthate ligands were particularly effective in inhibiting thioredoxin reductase and inducing apoptosis. Pharmacodynamic studies in human ovarian cancer cells allowed for the correlation of intracellular drug accumulation with TrxR inhibition that leads to the induction of apoptosis via the mitochondrial pathway.

  19. Synthesis of fluoranthenes by hydroarylation of alkynes catalyzed by gold(I or gallium trichloride

    Directory of Open Access Journals (Sweden)

    Sergio Pascual

    2011-11-01

    Full Text Available Electrophilic gold(I catalyst 6 competes with GaCl3 as the catalyst of choice in the synthesis of fluoranthenes by intramolecular hydroarylation of alkynes. The potential of this catalyst for the preparation of polyarenes is illustrated by a synthesis of two functionalized decacyclenes in a one-pot transformation in which three C–C bonds are formed with high efficiency.

  20. Model AIDA: Pola Penggunaan Media Sosial dalam Meningkatkan Kepuasan Penjualan di Toko Online Goldies Hijab

    OpenAIRE

    Poetra, Reza Riesnanda; Christantyawati, Nevrettia

    2017-01-01

    This research would to answer the following research questions: how the patterns of use of social media in increasing sales satisfaction in the online store goldies hijab?      This research data overall obtained and collected through questionnaires, observation and documentation (written data) which was then analyzed using descriptive statistical methods then the conclusions drawn through quantitative techniques, with deductive mindset. The results of this study concluded:      First, when s...

  1. Goldie Roth unchained: risk and its management in Lian Tanner’s Museum of Thieves

    Directory of Open Access Journals (Sweden)

    Wood, Danielle

    2014-06-01

    Full Text Available In her children’s action adventure novel Museum of Thieves, Lian Tanner overtly critiques adult risk-aversion and the over-protection of children. The protagonist is Goldie, an unruly child who escapes the oppressive regime of the City of Jewel where children up to the age of 12 are chained, for their own safety, to adult companions. Goldie escapes Jewel’s power structures and enters a mysterious museum housing the city’s unwanted wildness and danger. In its opening chapter Museum of Thieves establishes a subversive schema that problematises concepts of safety and order and glorifies chaos and risk, but this paper argues that as the novel progresses the author finds the schema increasingly difficult to control. It is tempting to read the museum as a “time out” zone such as CS Lewis’s Narnia, L Frank Baum’s Oz, and Maurice Sendak’s “place where the wild things are”: a space in which child characters can gain self-knowledge and skills before returning to an adult-dominated order. However, because of the degree to which Jewel and its structures are pathologised, Tanner finds she cannot bring Goldie back from “time out”. But rather than being a transgressive text, Museum of Thieves ends in a much less subversive place than it sets out to reach; the museum is revealed as a tightly controlled space and Goldie is well-protected, both within the diegesis by the museum’s special features, and beyond the diegesis by the author and the author’s cognisance of contemporary publishing industry expectations about the depiction of risk in children’s fiction.

  2. Sodium Azide Associated Acute Hyperkalemia in a Swine Model of Sodium Azide Toxicity

    Science.gov (United States)

    2017-06-16

    Sodium Azide Toxicity presented at/published to SURF , San Antonio, TX, 16 June 2017 in accordance with MDWI 41-108, has been approved and assigned local...Surgical Center (WHASC) internship and residency programs. 3. Please know that if you are a Graduate Health Sciences Education student and your... waves on electrocardiogram and continued acidosis (lactate mean 6.7 mmo/L). Statistics: Repeated measures ANOVA was used to determine statistically

  3. Connections between Ethical Values, the Meaning of Human Life, and Human Communities, according to Vasile Goldiș

    Directory of Open Access Journals (Sweden)

    Iovan Marţian

    2017-06-01

    Full Text Available The author presents the views held by Vasile Goldiș – Transylvanian scholar, politician, and one of the masterminds of the Great Union of 1 December 1918 – regarding the role of universal human values in guiding individuals and human communities. Together with other Christian values, ethics guides individuals, communities, political and administrative elites, churches, and academia. This results in greater justice, community solidarity and cohesion, and a greater ability for society to shape and promote its internal moral order. Considering the diversity of moral profiles found among various nations, ethnicities and political elites, Goldiș highlights their common grounds – which facilitates a new moral order in inter-human, inter-community and international relations. The ethical testament promoted by Goldiș in his writings and throughout his life is still relevant today, and it also holds true for the next generations.

  4. Vapor pressures and enthalpies of vaporization of azides

    International Nuclear Information System (INIS)

    Verevkin, Sergey P.; Emel'yanenko, Vladimir N.; Algarra, Manuel; Manuel Lopez-Romero, J.; Aguiar, Fabio; Enrique Rodriguez-Borges, J.; Esteves da Silva, Joaquim C.G.

    2011-01-01

    Highlights: → We prepared and measured vapor pressures and vaporization enthalpies of 7 azides. → We examined consistency of new and available in the literature data. → Data for geminal azides and azido-alkanes selected for thermochemical calculations. - Abstract: Vapor pressures of some azides have been determined by the transpiration method. The molar enthalpies of vaporization Δ l g H m of these compounds were derived from the temperature dependencies of vapor pressures. The measured data sets were successfully checked for internal consistency by comparison with vaporization enthalpies of similarly structured compounds.

  5. Surviving a massive sodium azide poisoning with toxic cardiomyopathy

    Directory of Open Access Journals (Sweden)

    P. Overtchouk

    2015-01-01

    Full Text Available Sodium azide poisoning is rare (~50 case reports but can be quickly fatal. A systematic review reported the fatal dose in humans to be over 10 mg/kg1. A 69 year-old female was admitted to our hospital for voluntary sodium azide poisoning. She ingested a massive dose of a soup spoon (15 g of pure sodium azide powder with intention to commit suicide without any co-intoxication. Within minutes, she felt nauseous and had several vomiting. She was immediately brought to the hospital.

  6. Insights into the Halogen Oxidative Addition Reaction to Dinuclear Gold(I) Di(NHC) Complexes

    KAUST Repository

    Baron, Marco; Tubaro, Cristina; Basato, Marino; Isse, Abdirisak Ahmed; Gennaro, Armando; Cavallo, Luigi; Graiff, Claudia; Dolmella, Alessandro; Falivene, Laura; Caporaso, Lucia

    2016-01-01

    Gold(I) dicarbene complexes [Au2(MeIm-Y-ImMe)2](PF6)2(Y=CH2(1), (CH2)2(2), (CH2)4(4), MeIm=1-methylimidazol-2-ylidene) react with iodine to give the mixed-valence complex [Au(MeIm-CH2-ImMe)2AuI2](PF6)2(1 aI) and the gold(III) complexes [Au2I4(Me

  7. Effectiveness of sodium azide alone compared to sodium azide in combination with methyl nitrosurea for rice mutagenesis

    Science.gov (United States)

    Rice seeds of the temperate japonica cultivar Kitaake were mutagenized with sodium azide alone and in combination with methyl nitrosourea. Using the reduced representation sequencing method Restriction Enzyme Sequence Comparative Analysis (RESCAN), the mutation densities, types and local sequence co...

  8. Dual emission behavior of phenyleneethynylene gold(I) complexes dictated by intersystem crossing: a theoretical perspective.

    Science.gov (United States)

    Wang, Li; Li, Yuanyuan; Zhang, Yanxin; He, Hongqing; Zhang, Jinglai

    2015-02-25

    In commonly studied gold(I) complexes with oligo (o-, p-, or m-phenyleneethynylene) (PE) ligands, an intriguing photophysical behavior is dual emission composed of fluorescence from S1 and phosphorescence from T1 which is dictated by effective intersystem crossing (ISC) process. In order to explore the salient photodynamics of such oligo-PE gold(I) complexes effectively, we have deliberately chosen three model complexes, namely, Ph-C≡C-Au(PMe3) (1a') and Ph-C≡C-(1,m)C6H4-C≡C-Au(PMe3) (m=4, 2a'; m=3, 3a') in place of the real system. Firstly, electronic structure methods based on DFT and TD-DFT are utilized to perform optimization calculations for the ground- and lowest-lying excited states, respectively. Next, basic photophysical properties including absorption and emission spectra are investigated by TD-DFT under the optimized geometries. Besides, on the basis of the electronic spectra herein, we succeed in searching for surface intersections as the minima on the seam of singlet-triplet surface crossings (SCs) at the CASSCF level of theory. By integration of the results available, the process of delayed fluorescence of triplet-triplet annihilation (TTA) and phosphorescence was displayed in detail with SCs playing the lead in monitoring the ISC. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Determinants for Tight and Selective Binding of a Medicinal Dicarbene Gold(I) Complex to a Telomeric DNA G-Quadruplex: a Joint ESI MS and XRD Investigation.

    Science.gov (United States)

    Bazzicalupi, Carla; Ferraroni, Marta; Papi, Francesco; Massai, Lara; Bertrand, Benoît; Messori, Luigi; Gratteri, Paola; Casini, Angela

    2016-03-18

    The dicarbene gold(I) complex [Au(9-methylcaffein-8-ylidene)2 ]BF4 is an exceptional organometallic compound of profound interest as a prospective anticancer agent. This gold(I) complex was previously reported to be highly cytotoxic toward various cancer cell lines in vitro and behaves as a selective G-quadruplex stabilizer. Interactions of the gold complex with various telomeric DNA models have been analyzed by a combined ESI MS and X-ray diffraction (XRD) approach. ESI MS measurements confirmed formation of stable adducts between the intact gold(I) complex and Tel 23 DNA sequence. The crystal structure of the adduct formed between [Au(9-methylcaffein-8-ylidene)2 ](+) and Tel 23 DNA G-quadruplex was solved. Tel 23 maintains a characteristic propeller conformation while binding three gold(I) dicarbene moieties at two distinct sites. Stacking interactions appear to drive noncovalent binding of the gold(I) complex. The structural basis for tight gold(I) complex/G-quadruplex recognition and its selectivity are described. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Versatile lanthanide-azide complexes with azide/carboxylate/hydroxy mixed bridged chain exhibiting magnetic and luminescent properties

    International Nuclear Information System (INIS)

    Wang Haichao; Xue Min; Guo Qian; Zhao Jiongpeng; Liu Fuchen; Ribas, Joan

    2012-01-01

    Two new lanthanide-azide complexes, [Ln 2 (N 3 )(isonic) 2 (OH) 3 (Hisonic)(H 2 O)] n (Ln=Yb for 1 and Tb for 2, isonic=isonicotinate), were obtained in hydrothermal condition. X-ray diffraction analysis indicated the two complexes are isomorphic chain structure in which the Ln III ions are mixed bridged by the azide anions, hydroxyl anions and carboxylate groups of the isonicotinate ligands. Further studies indicated weak antiferromagnetic interactions between the Ln III ions in 1 and 2, and complex 2 exhibit green sensitized Luminescent character of Tb III ion. - Graphical abstract: Two new 1D lanthanide-azide complexes, [Ln 2 (N 3 )(isonic) 2 (OH) 3 (Hisonic)(H 2 O)] n (Ln=Yb III for 1 and Tb III for 2, isonic=isonicotinate), were synthesized by hydrothermal reaction and exhibit interesting magnetism and fluorescence properties. Highlights: ► The research provided a new method for synthesizing lanthanide-azide complexes. ► The complexes have an interesting azide/hydroxyl/carboxylate mixed bridged1D chain structure. ► The antiferromagnetic coupling between the complexes and 2 displays green luminescence.

  11. Applications of Azide-Based Bioorthogonal Click Chemistry in Glycobiology

    Directory of Open Access Journals (Sweden)

    Xiu Zhang

    2013-06-01

    Full Text Available Click chemistry is a powerful chemical reaction with excellent bioorthogonality features: biocompatible, rapid and highly specific in biological environments. For glycobiology, bioorthogonal click chemistry has created a new method for glycan non-invasive imaging in living systems, selective metabolic engineering, and offered an elite chemical handle for biological manipulation and glycomics studies. Especially the [3 + 2] dipolar cycloadditions of azides with strained alkynes and the Staudinger ligation of azides and triarylphosphines have been widely used among the extant click reactions. This review focuses on the azide-based bioorthogonal click chemistry, describing the characteristics and development of these reactions, introducing some recent applications in glycobiology research, especially in glycan metabolic engineering, including glycan non-invasive imaging, glycomics studies and viral surface manipulation for drug discovery as well as other applications like activity-based protein profiling and carbohydrate microarrays.

  12. Conversion of Azides into Diazo Compounds in Water

    Science.gov (United States)

    Chou, Ho-Hsuan; Raines, Ronald T.

    2013-01-01

    Diazo compounds are in widespread use in synthetic organic chemistry, but have untapped potential in chemical biology. We report on the design and optimization of a phosphinoester that mediates the efficient conversion of azides into diazo compounds in phosphate buffer at neutral pH and room temperature. High yields are maintained in the presence of common nucleophilic or electrophilic functional groups, and reaction progress can be monitored by colorimetry. As azido groups are easy to install and maintain in biopolymers or their ligands, this new mode of azide reactivity could have substantial utility in chemical biology. PMID:24053717

  13. The extraction of low-concentrations of gold(I) with 198Au as a radiotracer

    International Nuclear Information System (INIS)

    Jianzhun Jiang; Chunli Liu; Weijin Zhou; Hongcheng Gao

    2002-01-01

    The solvent extraction of gold from alkaline cyanide solution was studied by using 198 Au as a radiotracer. The influence of several variables on the gold extraction, including the concentration of gold, the molar ratio of extractants to gold(I), the volume percentage of cosolvent and the pH value of the aqueous phase, was investigated. The results indicated that the radioactive tracer technique is a quick, accurate, and convenient tool to investigate the extraction behavior of an element existing in low concentrations. The experimental results indicated that the studied amines, tetradecyldimethylbenzylammonium chloride, N1923 and tri-n-octylamine, could be used as extractants for the recovery of gold from aqueous alkaline cyanide solutions. (author)

  14. Ultrafast Infrared and UV-vis Studies of the Photochemistry of Methoxycarbonylphenyl Azides in Solution

    OpenAIRE

    Xue, Jiadan; Luk, Hoi Ling; Eswaran, S. V.; Hadad, Christopher M.; Platz, Matthew S.

    2012-01-01

    The photochemistry of 4-methoxycarbonylphenyl azide (2a), 2-methoxycarbonylphenyl azide (3a) and 2-methoxy-6-methoxycarbonylphenyl azide (4a) were studied by ultrafast time-resolved infrared (IR) and UV-vis spectroscopies in solution. Singlet nitrenes and ketenimines were observed and characterized for all three azides. Isoxazole species 3g and 4g are generated after photolysis of 3a and 4a, respectively, in acetonitrile. Triplet nitrene 4e formation correlated with the decay of singlet nitre...

  15. Synthesis, characterization and anticancer activity of gold(I) complexes that contain tri-tert-butylphosphine and dialkyl dithiocarbamate ligands

    KAUST Repository

    Altaf, Muhammad

    2015-03-10

    Two new gold(I) complexes that contain tri-ter-butylphosphine and dialkyl dithiocarbamate ligands were synthesized and characterized by FTIR, NMR spectroscopy, Cyclic voltammetry, elemental analysis and X-ray diffraction. The in vitro cytotoxicity of both complexes was examined against A549 (lung cancer), MCF7 (breast cancer), and HeLa (cervical cancer) human cancer cell lines. Both complexes exhibit very strong in vitro cytotoxic effects against A549, MCF7 and HeLa cell lines. The screening of the cytotoxic activity based on IC50 data against the A549, MCF7, and HeLa lines shows that the synthesized gold(I) complexes are highly effective, particularly against HeLa cancer cell line. Based on IC50 data, the cytotoxic activity of both complexes is better than well-known commercial anticancer drug cisplatin against all the three cancer lines tested.

  16. Morphogical effects of sodium azide on tomato ( Lycopersicon ...

    African Journals Online (AJOL)

    Dry seeds of tomato (Lycopersicon esculentun Mill), varieties T106, T244 and T420 obtained from the Institute of Agriculture Research, Ahmadu Bello University Zaria, Nigeria were treated with sodium azide at concentrations of 1.0, 2.0 and 4.0 mM aimed at determining the effects of the mutagen on the morphological ...

  17. Cyanogen Azide. Ionization Potentials and Ab Initio SCF MO Calculation

    DEFF Research Database (Denmark)

    Bak, Börge; Jansen, Peter; Stafast, Herbert

    1975-01-01

    The Ne(I) and He(I) photoelectron(PE) spectra of cyanogen azide, NCN3, have been recorded at high resolution. Their interpretation is achieved by comparison with the PE spectrum of HN3 and an ab initio LCGO SCF MO calculation. Deviations from Koopmans' theorem of quite different magnitudes...

  18. Azide- and alkyne-derivatised α-amino acids

    DEFF Research Database (Denmark)

    Johansson, Karl Henrik; Pedersen, D.S.

    2012-01-01

    With the emergence of the copper-catalysed Huisgen cycloaddition the use of azide- and alkyne-derivatised α-amino acids has found widespread use within most chemistry disciplines. Despite a growing interest in these building blocks researchers are struggling to identify the best way for their syn......With the emergence of the copper-catalysed Huisgen cycloaddition the use of azide- and alkyne-derivatised α-amino acids has found widespread use within most chemistry disciplines. Despite a growing interest in these building blocks researchers are struggling to identify the best way...... for their synthesis. In this review we have compiled available methods for synthesising optically active azide- and alkyne-derivatised α-amino acids that can be prepared from readily available α-amino acids. We highlight a number of commonly overlooked problems associated with existing methods and direct attention...... to unexplored possibilities. Azide- and alkyne-derivatised α-amino acids are finding widespread use within most chemistry disciplines. However, it is far from clear what the best way for the synthesis of these useful building blocks is. Herein we show the available methods for synthesis of optically active...

  19. Thermal Decompositon Studies Of Pre-Irradiated Nickel (II) Azides ...

    African Journals Online (AJOL)

    The effect of pre-irradiation on the thermal decomposition of three samples of nickel (II) azide was studied. It was found that the rates of thermal decomposition of Ni(OH)N3 increased substantially with increase in pre-irradiation dosage. The initial reaction rates change from time-dependant nucleation law for the unirradiated ...

  20. Effects of sodium azide on yield parameters of groundnut (Arachis ...

    African Journals Online (AJOL)

    GREGO

    2007-03-19

    Mar 19, 2007 ... Cowpea and mungbean improvement by mutation induction Mutation Breeding Newsletter, 21: 9. Gregory WC (1955). X-ray breeding of peanuts Arachis hypogaea L.,. Agron. J. 47: 394-399. Kleinhofs W, Sander C (1975). Azide mutagenesis in Barley. Third. Barley Genetics Symp. Garching. Proceedings of ...

  1. Synthesis, characterization, cytotoxic and antitubercular activities of new gold(I) and gold(III) complexes containing ligands derived from carbohydrates.

    Science.gov (United States)

    Chaves, Joana Darc Souza; Damasceno, Jaqueline Lopes; Paula, Marcela Cristina Ferreira; de Oliveira, Pollyanna Francielli; Azevedo, Gustavo Chevitarese; Matos, Renato Camargo; Lourenço, Maria Cristina S; Tavares, Denise Crispim; Silva, Heveline; Fontes, Ana Paula Soares; de Almeida, Mauro Vieira

    2015-10-01

    Novel gold(I) and gold(III) complexes containing derivatives of D-galactose, D-ribose and D-glucono-1,5-lactone as ligands were synthesized and characterized by IR, (1)H, and (13)C NMR, high resolution mass spectra and cyclic voltammetry. The compounds were evaluated in vitro for their cytotoxicity against three types of tumor cells: cervical carcinoma (HeLa) breast adenocarcinoma (MCF-7) and glioblastoma (MO59J) and one non-tumor cell line: human lung fibroblasts (GM07492A). Their antitubercular activity was evaluated as well expressed as the minimum inhibitory concentration (MIC90) in μg/mL. In general, the gold(I) complexes were more active than gold(III) complexes, for example, the gold(I) complex (1) was about 8.8 times and 7.6 times more cytotoxic than gold(III) complex (8) in MO59J and MCF-7 cells, respectively. Ribose and alkyl phosphine derivative complexes were more active than galactose and aryl phosphine complexes. The presence of a thiazolidine ring did not improve the cytotoxicity. The study of the cytotoxic activity revealed effective antitumor activities for the gold(I) complexes, being more active than cisplatin in all the tested tumor cell lines. Gold(I) compounds (1), (2), (3), (4) and (6) exhibited relevant antitubercular activity even when compared with first line drugs such as rifampicin.

  2. Insights into the Halogen Oxidative Addition Reaction to Dinuclear Gold(I) Di(NHC) Complexes

    KAUST Repository

    Baron, Marco

    2016-06-14

    Gold(I) dicarbene complexes [Au2(MeIm-Y-ImMe)2](PF6)2(Y=CH2(1), (CH2)2(2), (CH2)4(4), MeIm=1-methylimidazol-2-ylidene) react with iodine to give the mixed-valence complex [Au(MeIm-CH2-ImMe)2AuI2](PF6)2(1 aI) and the gold(III) complexes [Au2I4(MeIm-Y-ImMe)2](PF6)2(2 cIand 4 cI). Reaction of complexes 1 and 2 with an excess of ICl allows the isolation of the tetrachloro gold(III) complexes [Au2Cl4(MeIm-CH2-ImMe)2](PF6)2(1 cCl) and [Au2Cl4(MeIm-(CH2)2-ImMe)2](Cl)2(2 cCl-Cl) (as main product); remarkably in the case of complex 2, the X-ray molecular structure of the crystals also shows the presence of I-Au-Cl mixed-sphere coordination. The same type of coordination has been observed in the main product of the reaction of complexes 3 or 4 with ICl. The study of the reactivity towards the oxidative addition of halogens to a large series of dinuclear bis(dicarbene) gold(I) complexes has been extended and reviewed. The complexes react with Cl2, Br2and I2to give the successive formation of the mixed-valence gold(I)/gold(III) n aXand gold(III) n cX(excluding compound 1 cI) complexes. However, complex 3 affords with Cl2and Br2the gold(II) complex 3 bX[Au2X2(MeIm-(CH2)3-ImMe)2](PF6)2(X=Cl, Br), which is the predominant species over compound 3 cXeven in the presence of free halogen. The observed different relative stabilities of the oxidised complexes of compounds 1 and 3 have also been confirmed by DFT calculations. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. A Direct Comparison of Azide and Nitrile Vibrational Probes

    Science.gov (United States)

    Gai, Xin Sonia; Coutifaris, Basil A.; Brewer, Scott H.; Fenlon, Edward E.

    2011-01-01

    The synthesis of 2′-azido-5-cyano-2′-deoxyuridine, N3CNdU (1), from trityl-protected 2′-amino-2′-deoxyuridine was accomplished in four steps with a 12.5% overall yield. The IR absorption positions and profiles of the azide and nitrile group of N3CNdU were investigated in 14 different solvents and water/DMSO solvent mixtures. The azide probe was superior to the nitrile probe in terms of its extinction coefficient, which is 2–4 times larger. However, the nitrile IR absorbance profile is generally less complicated by accidental Fermi resonance. The IR frequencies of both probes undergo a substantial red shift upon going from water to aprotic solvents such as THF or DMSO. DFT calculations supported the hypothesis that the molecular origin of the higher observed frequency in water is primarily due to hydrogen bonds between the probes and water molecules. PMID:21336362

  4. Targeted Diazotransfer Reagents Enable Selective Modification of Proteins with Azides.

    Science.gov (United States)

    Lohse, Jonas; Swier, Lotteke J Y M; Oudshoorn, Ruben C; Médard, Guillaume; Kuster, Bernhard; Slotboom, Dirk-Jan; Witte, Martin D

    2017-04-19

    In chemical biology, azides are used to chemically manipulate target structures in a bioorthogonal manner for a plethora of applications ranging from target identification to the synthesis of homogeneously modified protein conjugates. While a variety of methods have been established to introduce the azido group into recombinant proteins, a method that directly converts specific amino groups in endogenous proteins is lacking. Here, we report the first biotin-tethered diazotransfer reagent DtBio and demonstrate that it selectively modifies the model proteins streptavidin and avidin and the membrane protein BioY on cell surface. The reagent converts amines in the proximity of the binding pocket to azides and leaves the remaining amino groups in streptavidin untouched. Reagents of this novel class will find use in target identification as well as the selective functionalization and bioorthogonal protection of proteins.

  5. INDUCED-GROWTH AND YIE BY SODIUM AZIDE IN TOMATO ...

    African Journals Online (AJOL)

    userpc

    ABSTRACT. The mutagenic effect of various concentra traits of three varieties of tomato was inve quantity of the traits of economic importa. Roma, UC and a Local variety were treated. (0.1mM, 1.0 mM, 2.0 mM and 0.0 mM as con seasons. The results obtained revealed high various concentrations of sodium azide on.

  6. Glycosyl azide-a novel substrate for enzymatic transgycosylations

    Czech Academy of Sciences Publication Activity Database

    Fialová, Pavla; Carmona, A. T.; Robina, I.; Ettrich, R.; Sedmera, Petr; Přikrylová, Věra; Hušáková, Lucie; Křen, Vladimír

    2005-01-01

    Roč. 46, - (2005), s. 8715-8718 ISSN 0040-4039 R&D Projects: GA ČR GA203/05/0172; GA MŠk OC D25.002 Grant - others:GA KONTAKT 1862/04 Institutional research plan: CEZ:AV0Z50200510 Keywords : enzyme catalysis * glycosyl azide * molecular modelling Subject RIV: EE - Microbiology, Virology Impact factor: 2.477, year: 2005

  7. Sodium azide mutagenesis in wheat: Mutants with golden glumes

    International Nuclear Information System (INIS)

    Siddiqui, K.A.; Jafri, K.A.; Arain, M.A.

    1989-01-01

    In bread wheat, Triticum aestivum L. (2n=6x=42, AABBDD), detection of induced mutations is hampered by the presence of duplicate and triplicate genes. Induced changes in spike characteristics are known, but mutants with changed glume colour do not seem to have been reported. Physical mutagens such as gamma rays, thermal neutrons and fast neutrons, and chemical mutagens like EMS, El, dES and NEH have been extensively used for induction of mutations in bread wheat but it seems as if these mutagens did not induce mutants with changed glume colour. We used sodium azide for inducing mutations in the widely adapted cultivar 'Sonalika', which is characterized by brown glume colour. Presoaked seeds were treated with 0.2M sodium azide for 3 hours. Three spikes were harvested from each M 1 plant. M 2 generation was space-planted as spike progeny. We were successful in identifying 3 mutants with golden glumes. The mutants resemble 'Sonalika' in other spike characteristics. The mutants glume colour was confirmed in M 3 . The mutants were also evaluated for agronomically important characteristics. Some characters were significantly different from the parent. Glume colours may be useful as genetic markers since such characters are less influenced by the environment. Our investigation confirms that also agronomically useful genetic variation may be readily induced in bread wheat through sodium azide

  8. Facile reactions of gold(i) complexes with tri(tert-butyl)azadiboriridine.

    Science.gov (United States)

    Shang, Rong; Saito, Souta; Jimenez-Halla, J Oscar C; Yamamoto, Yohsuke

    2018-04-17

    Direct structural evidence for group 11 metal-mediated B-B bond activation was obtained from reactions of tri(tert-butyl)azadiboriridine (1) with AuCl(L) complexes. The AuCl(SMe2) reaction afforded [η2-B,B-B(tBu)N(tBu)B(tBu)]AuCl (2) by ligand displacement. More donating phosphines as co-ligands led to B-B bond cleavage accompanied by either halide or L migration to form boron-gold complexes 3 (L = PPh3) and 4 (L = PMe3). A similar product 5, which is isostructural to 4, was obtained by the addition of dimethylaminopyridine (DMAP) to 2-4. Complexes 2-5 constitute rare examples of metal complexes bearing two Lewis acidic centres. The effect of the boryl ligand was demonstrated in the formation of a gold(i) complex 6 bearing a 5-membered heterocycle from 3 and tert-butylisonitrile. Plausible reaction mechanisms that led to these complexes and their bonding situation were explored computationally at the DFT level.

  9. Anti-trypanosomal activity of cationic N-heterocyclic carbene gold(I) complexes.

    Science.gov (United States)

    Winter, Isabel; Lockhauserbäumer, Julia; Lallinger-Kube, Gertrud; Schobert, Rainer; Ersfeld, Klaus; Biersack, Bernhard

    2017-06-01

    Two gold(I) N-heterocyclic carbene complexes 1a and 1b were tested for their anti-trypanosomal activity against Trypanosoma brucei parasites. Both gold compounds exhibited excellent anti-trypanosomal activity (IC 50 =0.9-3.0nM). The effects of the gold complexes 1a and 1b on the T. b. brucei cytoskeleton were evaluated. Rapid detachment of the flagellum from the cell body occurred after treatment with the gold complexes. In addition, a quick and complete degeneration of the parasitic cytoskeleton was induced by the gold complexes, only the microtubules of the detached flagellum remained intact. Both gold compounds 1a and 1b feature selective anti-trypanosomal agents and were distinctly more active against T. b. brucei cells than against human HeLa cells. Thus, the gold complexes 1a and 1b feature promising drug candidates for the treatment of trypanosome infections such as sleeping sickness (human African Trypanosomiasis caused by Trypanosoma brucei parasites). Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Alkynyl gold(I) complex triggers necroptosis via ROS generation in colorectal carcinoma cells.

    Science.gov (United States)

    Mármol, Inés; Virumbrales-Muñoz, María; Quero, Javier; Sánchez-de-Diego, Cristina; Fernández, Luis; Ochoa, Ignacio; Cerrada, Elena; Yoldi, Mª Jesús Rodríguez

    2017-11-01

    Given the rise of apoptosis-resistant tumors, there exist a growing interest in developing new drugs capable of inducing different types of cell death to reduce colorectal cancer-related death rates. As apoptosis and necroptosis do not share cellular machinery, necroptosis induction may have a great therapeutic potential on those apoptosis-resistant cancers, despite the inflammatory effects associated with it. We have synthesized an alkynyl gold(I) complex [Au(CC-2-NC 5 H 4 )(PTA)] whose anticancer effect was tested on the colorectal adenocarcinoma Caco-2 cell line. With regard to its mechanism of action, this gold complex enters the mitochondria and disrupts its normal function, leading to an increase in ROS production, which triggers necroptosis. Necroptosis induction has been found dependent of TNF-α (Tumor necrosisfactor α) and TNFR1(Tumor necrosisfactor receptor 1) binding, RIP1(Receptor-Interacting Protein 1) activation and NF-κB (Nuclear Factor Kappa-Light-Chain-Enhancer of Activated B Cells) signaling. Moreover, the antitumor potential of [Au(CC-2-NC 5 H 4 )(PTA)] has also been confirmed on the 3D cancer model spheroid. Overall, the obtained data show firstly that gold complexes might have the ability of inducing necroptosis, and secondarily that our compound [Au(CC-2-NC 5 H 4 )(PTA)] is an interesting alternative to current chemotherapy drugs in cases of apoptosis resistance. Copyright © 2017. Published by Elsevier Inc.

  11. An enzymatic method for determination of azide and cyanide in aqueous phase.

    Science.gov (United States)

    Wan, Nan-Wei; Liu, Zhi-Qiang; Xue, Feng; Zheng, Yu-Guo

    2015-11-20

    A halohydrin dehalogenase (HHDH-PL) from Parvibaculum lavamentivorans DS-1 was characterized and applied to determine azide and cyanide in the water. In this methodology, HHDH-PL catalysed azide and cyanide to react with butylene oxide and form corresponding β-substituted alcohols 1-azidobutan-2-ol (ABO) and 3-hydroxypentanenitrile (HPN) that could be quantitatively detected by gas chromatograph. The detection calibration curves for azide (R(2)=0.997) and cyanide (R(2)=0.995) were linear and the lower limits of detection for azide and cyanide were 0.1 and 0.3mM, respectively. Several other nucleophiles were identified having no effect on the analysis of azide and cyanide, excepting nitrite which influenced the detection of cyanide. This was the first report of a biological method to determine the inorganic azide and cyanide by converting them to the measurable organics. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. The SolemnAddress Uttered by Vasile Goldiş in Alba-Iulia on 1 December, 1918

    Directory of Open Access Journals (Sweden)

    Eugen GAGEA

    2011-01-01

    Full Text Available In the report he presented before the Great National Assembly of Alba-Iulia, Vasile Goldişunderlined some of the ideals for which humankind had fought and continued to fight in the postwarperiod: national freedom, social equality. The solemn address he uttered is an expression of hishumanism and confidence in human civilization, of the conviction that the organization of ademocratic state and the achievement of equality of rights for all citizens are and must be a “workof civilization”.

  13. Copper(I), silver(I) and gold(I) halide complexes with the dithioformamidinium dihalides

    Science.gov (United States)

    Peyronel, Giorgio; Malavasi, Wanda; Pignedoli, Anna

    Some copper(I), silver(I) and gold(I) halide complexes with the dithioformamidinium dihalides (Tu 2X 2) were prepared and studied by infrared spectroscopy and conductometry: 3CuX.2Tu 2X 2(XCl,I), CuBr.Tu 2Br 2, 4CuBr.3.5Tu 2Br 2.MeOH, 2CuBr.Tu 2Br 2.0.66EtOH, 3CuI.2Tu 2I 2, 2AgCl.2.5Tu 2Cl 2, 3AgCl.2Tu 2Cl 2.0.5EtOH, 3AgCl.Tu 2Cl 2, 2AgBr.2Tu 2Br 2.0.5Tu 2(NO 3) 2.H 2O, AgBr.Tu 2Br 2, 4AgBr.Tu 2Br 2, 4AgI.0.5Tu 2I 2.EtOH, AuCl.1.5Tu 2Cl 2, 4AuCl.3.5Tu 2Cl 2.2DMF, AuBr.4Tu 2Br 2, AuBr.2Tu 2Br 2.1.5DMF, AuI.5Tu 2I 2, AuI.Tu 2I 2. A decrease of the ν(NH), δ(NH 2) and ν(CN 2) frequencies and an increase of the ν(CS) frequencies indicate an N-coordination of the dithioformamidinium cation to the metal ions; ν(MN) and ν(MX) frequencies are tentatively assigned in the far-infrared spectra.

  14. 1,2,4-Triazole-based N-heterocyclic carbene complexes of gold(I): synthesis, characterization and biological activity

    Czech Academy of Sciences Publication Activity Database

    Turek, J.; Růžičková, Z.; Tloušťová, Eva; Mertlíková-Kaiserová, Helena; Günterová, Jana; Rulíšek, Lubomír; Růžička, A.

    2016-01-01

    Roč. 30, č. 5 (2016), s. 318-322 ISSN 0268-2605 R&D Projects: GA ČR(CZ) GA14-31419S; GA MŠk LO1302 Institutional support: RVO:61388963 Keywords : gold(I) complexes * N-heterocyclic carbenes * cytotoxicity * apoptosis Subject RIV: CC - Organic Chemistry Impact factor: 2.319, year: 2016

  15. Who Needs Empathy? A Response to Goldie's Arguments against Empathy and Suggestions for an Account of Mutual Perspective-Shifting in Contexts of Help and Care

    Science.gov (United States)

    Coeckelbergh, Mark

    2007-01-01

    According to an influential view, empathy has, and should have, a role in ethics, but it is by no means clear what is meant by "empathy", and why exactly it is supposed to be morally good. Recently, Peter Goldie has challenged that view. He shows how problematic empathy is, and argues that taking an external perspective is morally…

  16. Who needs empathy? A response to Goldie's arguments against empathy and suggestions for an account of mututal perspective-shifting in contexts of help and care.

    NARCIS (Netherlands)

    Coeckelbergh, Mark

    2007-01-01

    According to an influential view, empathy has, and should have, a role in ethics, but it is by no means clear what is meant by 'empathy', and why exactly it is supposed to be morally good. Recently, Peter Goldie has challenged that view. He shows how problematic empathy is, and argues that taking an

  17. The intriguing enhancement of chloroperoxidase mediated one-electron oxidations by azide, a known active-site ligand

    International Nuclear Information System (INIS)

    Andrew, Daniel; Hager, Lowell; Manoj, Kelath Murali

    2011-01-01

    Highlights: ► Azide is a well known heme–enzyme active site ligand and inhibitor. ► Herein, azide is reported to enhance a set of heme–enzyme mediated reactions. ► This effect is disconnected from native enzyme–azide binding. ► Azide could enhance heme–enzyme reactions via a newly proposed mechanism. ► Azide contained in reagents could impact reaction outcomes in redox biochemistry. -- Abstract: Azide is a well-known inhibitor of heme–enzymes. Herein, we report the counter-intuitive observation that at some concentration regimes, incorporation of azide in the reaction medium enhances chloroperoxidase (CPO, a heme–enzyme) mediated one-electron abstractions from several substrates. A diffusible azidyl radical based mechanism is proposed for explaining the phenomenon. Further, it is projected that the finding could have significant impact on routine in situ or in vitro biochemistry studies involving heme–enzyme systems and azide.

  18. Single-step azide introduction in proteins via an aqueous diazo transfer

    NARCIS (Netherlands)

    van Dongen, S.F.M.; Teeuwen, R.L.M.; Nallani, M.; van Berkel, S.S.; Cornelissen, J.J.L.M.; Nolte, R.J.M.; van Hest, J.C.M.

    The controlled introduction of azides in proteins provides targetable handles for selective protein manipulation. We present here an efficient diazo transfer protocol that can be applied in an aqueous solution, leading to the facile introduction of azides in the side chains of lysine residues and at

  19. Single-Step Azide Introduction in Proteins via an Aqueous Diazo Transfer

    NARCIS (Netherlands)

    van Dongen, Stijn; Teeuwen, R.L.M.; Nallani, Madhavan; van Berkel, S.S; Cornelissen, Jeroen Johannes Lambertus Maria; Nolte, Roeland; van Hest, Jan

    2009-01-01

    The controlled introduction of azides in proteins provides targetable handles for selective protein manipulation. We present here an efficient diazo transfer protocol that can be applied in an aqueous solution, leading to the facile introduction of azides in the side chains of lysine residues and at

  20. Polarographic studies about indium (III) behaviour in aqueous media of sodium azide

    International Nuclear Information System (INIS)

    Tokoro, R.

    1988-01-01

    The present study shows some polarographic behavior of indium (III) in azide media that is close those observed in a thiocyanate solution. The presence of azide ligand decreases the overpotential in the discharge of indium whose catalytic character can be explained by formation of an azide bridge between electrode and indium (III) increasing the speed of electron transfer. The discharge of indium in azide media is diffusion controlled. As the azide concentration is increased the half wave potential displaces in the cathodic direction. This displacement is due to complex formation. The number of electrons, n, involved in the total process was estimates by the reversible polarographic equation to be 2,7. The potentiostatic coulometry of indium in azide/hydrazoic acid buffer showed a catalytic process where the chemistry regeneration was performed by reaction of hydrazoic acid and indium amalgam. The electrochemistry evidence was the constancy of current as the electrolysis proceeded. The chemistry aspect was the presence of ammonium cation in electrolysed solution. The catalytic process with chemistry regeneration and the formation of a bridge by azide could explain the higher value of current in azide media compared to perchlorate solution. (author) [pt

  1. Polymerization of nitrogen in cesium azide under modest pressure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaoli, E-mail: use126126@126.com, E-mail: lijianfu@lyu.edu.cn [Institute of Condensed Matter Physics, Linyi University, Linyi 276005 (China); Beijing Computational Science Research Center, Beijing 100084 (China); State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China); Li, Jianfu, E-mail: use126126@126.com, E-mail: lijianfu@lyu.edu.cn [Institute of Condensed Matter Physics, Linyi University, Linyi 276005 (China); Department of Physics and Materials Science, City University of Hong Kong (Hong Kong); Zhu, Hongyang [State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China); Chen, Li [Institute of Condensed Matter Physics, Linyi University, Linyi 276005 (China); Lin, Haiqing [Beijing Computational Science Research Center, Beijing 100084 (China)

    2014-07-28

    Alkali metal azides can be used as starting materials in the synthesis of polymeric nitrogen, a potential high-energy-density material. The structural evolutionary behaviors of nitrogen in CsN{sub 3} have been studied up to 200 GPa using particle swarm optimization structure search combining with density functional theory. Three stable new phases with C2/m, P2{sub 1}/m, and P-1 structure at pressure of 6, 13, and 51 GPa are identified for the first time. The phase transition to chain like structure (P-1 phase) occurs at a modest pressure 51 GPa, the azide ions N{sub 3}{sup −} (linear chains of three N atoms with covalent bonds and interact weakly with each other) begin to show remarkable polymeric N properties in the CsN{sub 3} system. Throughout the stable pressure range, the structure is metallic and consists of N atoms in sp{sup 2} hybridizations. Our study completes the structural evolution of CsN{sub 3} under pressure and reveals that the introduced Cs atoms are responsible for the decreased synthesis pressure comparing to pure molecular nitrogen under compression.

  2. Evolving Structural Diversity and Metallicity in Compressed Lithium Azide

    KAUST Repository

    Prasad, Dasari L. V. K.

    2013-10-10

    In pursuit of new stable nitrogen-rich phases and of a possible insulator-metal transition, the ground-state electronic structure of lithium azide, LiN3, is investigated from 1 atm to 300 GPa (∼2-fold compression) using evolutionary crystal structure exploration methods coupled with density functional theoretical calculations. Two new LiN3 phases, containing slightly reduced and well-separated N2 units, are found to be enthalpically competitive with the known lithium azide crystal structure at 1 atm. At pressures above 36 GPa nitrogen-rich assemblies begin to evolve. These incorporate NN bond formation beyond that in N2 or N3 -. N6 rings and infinite one-dimensional linear nitrogen chains (structural analogues to polyacetylene) appear. Above 200 GPa quasi-one- and two-dimensional extended puckered hexagonal and decagonal nitrogen layers emerge. The high-pressure phase featuring linear chains may be quenchable to P = 1 atm. With increasing pressure the progression in electrical conductivity is from insulator to metal. © 2013 American Chemical Society.

  3. Taming tosyl azide: the development of a scalable continuous diazo transfer process.

    Science.gov (United States)

    Deadman, Benjamin J; O'Mahony, Rosella M; Lynch, Denis; Crowley, Daniel C; Collins, Stuart G; Maguire, Anita R

    2016-04-07

    Heat and shock sensitive tosyl azide was generated and used on demand in a telescoped diazo transfer process. Small quantities of tosyl azide were accessed in a 'one pot' batch procedure using shelf stable, readily available reagents. For large scale diazo transfer reactions tosyl azide was generated and used in a telescoped flow process, to mitigate the risks associated with handling potentially explosive reagents on scale. The in situ formed tosyl azide was used to rapidly perform diazo transfer to a range of acceptors, including β-ketoesters, β-ketoamides, malonate esters and β-ketosulfones. An effective in-line quench of sulfonyl azides was also developed, whereby a sacrificial acceptor molecule ensured complete consumption of any residual hazardous diazo transfer reagent. The telescoped diazo transfer process with in-line quenching was used to safely prepare over 21 g of an α-diazocarbonyl in >98% purity without any column chromatography.

  4. In Vitro Antitumor Active Gold(I Triphenylphosphane Complexes Containing 7-Azaindoles

    Directory of Open Access Journals (Sweden)

    Pavel Štarha

    2016-12-01

    Full Text Available A series of gold(I complexes of the general composition [Au(naza(PPh3] (1–8 was prepared and thoroughly characterized (e.g., electrospray ionization (ESI mass spectrometry and multinuclear nuclear magnetic resonance (NMR spectroscopy. The N1-deprotonated anions of 7-azaindole or its derivatives (naza are coordinated to the metal centre through the N1 atom of their pyrrole ring, as proved by a single crystal X-ray analysis of the complexes [Au(3I5Braza(PPh3] (7 and [Au(2Me4Claza(PPh3]·½H2O (8′. The in vitrocytotoxicity of the complexes 1–8 was studied against both the cisplatin-sensitive and -resistant variants of the A2780 human ovarian carcinoma cell line, as well as against the MRC-5 human normal fibroblast cell line. The complexes 4, 5, and 8, containing deprotonated 3-iodo-7-azaindole, 5-bromo-7-azaindole, and 2-methyl-4-chloro-7-azaindole (2Me4Claza, respectively, showed significantly higher potency (IC50 = 2.8–3.5 µM than cisplatin (IC50 = 20.3 µM against the A2780 cells and markedly lower effect towards the MRC-5 non-cancerous cells (IC50 = 26.0–29.2 µM, as compared with the mentioned A2780 cancer cells. The results of the flow cytometric studies of the A2780 cell cycle perturbations revealed a G2-cell cycle phase arrest of the cells treated by the representative complexes 1 and 5, which is indicative of a different mechanism of action from cisplatin (induced S-cell cycle phase arrest. The stability of the representative complex 8 in the water-containing solution as well as its ability to interact with the reduced glutathione, cysteine and bovine serum albumin was also studied using 1H and 31P-NMR spectroscopy (studied in the 50% DMF-d7/50% D2O mixture and ESI+ mass spectrometry (studied in the 50% DMF/50% H2O mixture; DMF = dimethylformamide. The obtained results are indicative for the release of the N-donor azaindole-based ligand in the presence of the used biomolecules.

  5. Effect of sodium azide addition and aging storage on casein micelle size

    Science.gov (United States)

    Sinaga, H.; Deeth, H.; Bhandari, B.

    2018-02-01

    Casein micelles affected most of milk properties, therefore the use sodium azide as milk preservation is not expected to alter milk properties during storage, including the casein micelle size. The aim of this study was to analyse casein micelle size after the addition of sodium azide during storage. The experiment was performed as a complete block randomised design with three replications. The addition of 0.02-0.10% Na-azide do not lead to any noticeable differences in average casein size at the same day and show similar trend after 14 day-storage. At concentration of 0.02% sodium azide (Na-azide), the size of pasteurised milk did not change up to 12 days, while the size of raw skim milk slightly increased by ageing time at day 5. The treated concentration did not affect the size distribution, except for milk with 0.02% Na-azide which had narrower distribution compared to other treated and control milk. The finding from this study suggests that the role of Na-azide in this experiments during storage at 4°C is only for preventing the microbial growth.

  6. Polarografic study about the complex formation between indium (III) and sodium azide, in aqueous media

    International Nuclear Information System (INIS)

    Tokoro, R.; Bertotti, M.

    1988-01-01

    The present work is a branch of the main work concerned with the complex formation between several metal cations and azide ligand in aqueous media. The polarographic behavior of indium in azide system showed the tendency of complexation. Using polarographic method to determine the half potential of indium at each analytical concentration afforded experimental data to evaluate the constants. The azide concentrations was modified from 1 m to 100 m , the ionic strength held at 2,0 M with sodium perchlorate, indium concentration 7.892 x 10 -4 M, and temperature kept constant at 25,0 0 C. (author) [pt

  7. Effects of sodium azide on the abundance of prokaryotes and viruses in marine samples.

    Directory of Open Access Journals (Sweden)

    Christian Winter

    Full Text Available Flow cytometry is set to become the standard method for enumerating prokaryotes and viruses in marine samples. However, the samples need to be flash-frozen in liquid nitrogen directly after aldehyde fixation. Because liquid nitrogen may not always be available, we tested the potential of sodium azide as a preservative for prokaryotes and viruses in marine samples as a possible alternative. For that we conducted incubation experiments with untreated and sodium azide treated marine water samples at 4°C and room temperature. The data indicate that sodium azide cannot be used to maintain marine samples used for the enumeration of prokaryotes and viruses.

  8. Chiral gold(I vs chiral silver complexes as catalysts for the enantioselective synthesis of the second generation GSK-hepatitis C virus inhibitor

    Directory of Open Access Journals (Sweden)

    María Martín-Rodríguez

    2011-07-01

    Full Text Available The synthesis of a GSK 2nd generation inhibitor of the hepatitis C virus, by enantioselective 1,3-dipolar cycloaddition between a leucine derived iminoester and tert-butyl acrylate, was studied. The comparison between silver(I and gold(I catalysts in this reaction was established by working with chiral phosphoramidites or with chiral BINAP. The best reaction conditions were used for the total synthesis of the hepatitis C virus inhibitor by a four step procedure affording this product in 99% ee and in 63% overall yield. The origin of the enantioselectivity of the chiral gold(I catalyst was justified according to DFT calculations, the stabilizing coulombic interaction between the nitrogen atom of the thiazole moiety and one of the gold atoms being crucial.

  9. Intramolecular Azide to Alkene Cycloadditions for the Construction of Pyrrolobenzodiazepines and Azetidino-Benzodiazepines

    Czech Academy of Sciences Publication Activity Database

    Hemming, K.; Chambers, Christopher S.; Jamshaid, F.; O´Gorman, Paul A.

    2014-01-01

    Roč. 19, č. 10 (2014), s. 16737-16756 ISSN 1420-3049 Institutional support: RVO:61388971 Keywords : azide * cycloadditions * benzodiazepines Subject RIV: CC - Organic Chemistry Impact factor: 2.416, year: 2014

  10. Mutagenic effects of sodium azide and γ-irradiation in Pisum

    International Nuclear Information System (INIS)

    Sander, C.; Muehlbauer, F.J.

    1977-01-01

    Sodium azide was an effective mutagen in Pisum when used at a concentration of 10 -3 M and at pH 3. Effects on dry, sound seeds of 'Juneau' so treated for 3 or 4 hr and for 3 hr in the presence of oxygen were compared with responses to 5, 10 and 20 kR of γ-rays for evaluating relative effectiveness in producing mutants. Leaf aberrations were observed on γ-irradiated plants but not on azide-treated plants, an indication that azide did not cause chromosome damage. At the treatment levels used, sodium azide was as effective in total yield of mutants but produced fewer stunted and variously deformed plants than γ-rays. (author)

  11. Catalytic Intermolecular Cross-Couplings of Azides and LUMO-Activated Unsaturated Acyl Azoliums

    KAUST Repository

    Li, Wenjun; Ajitha, Manjaly John; Lang, Ming; Huang, Kuo-Wei; Wang, Jian

    2017-01-01

    An example for the catalytic synthesis of densely functionalized 1,2,3-triazoles through a LUMO activation mode has been developed. The protocol is enabled by intermolecular cross coupling reactions of azides with in situ-generated alpha

  12. [3 + 2]-Cycloadditions of nitrile ylides after photoactivation of vinyl azides under flow conditions

    Directory of Open Access Journals (Sweden)

    Stephan Cludius-Brandt

    2013-08-01

    Full Text Available The photodenitrogenation of vinyl azides to 2H-azirines by using a photoflow reactor is reported and compared with thermal formation of 2H-azirines. Photochemically, the ring of the 2H-azirines was opened to yield the nitrile ylides, which underwent a [3 + 2]-cycloaddition with 1,3-dipolarophiles. When diisopropyl azodicarboxylate serves as the dipolarophile, 1,3,4-triazoles become directly accessible starting from the corresponding vinyl azide.

  13. Facile synthesis of 2,5-disubstituted thiazoles from terminal alkynes, sulfonyl azides, and thionoesters.

    Science.gov (United States)

    Miura, Tomoya; Funakoshi, Yuuta; Fujimoto, Yoshikazu; Nakahashi, Junki; Murakami, Masahiro

    2015-05-15

    A sequential procedure for the synthesis of 2,5-disubstituted thiazoles from terminal alkynes, sulfonyl azides, and thionoesters is reported. A copper(I)-catalyzed 1,3-dipolar cycloaddition of terminal alkynes with sulfonyl azides affords 1-sulfonyl-1,2,3-triazoles, which then react with thionoesters in the presence of a rhodium(II) catalyst. The resulting 3-sulfonyl-4-thiazolines subsequently aromatize into the corresponding 2,5-disubstituted thiazoles by elimination of the sulfonyl group.

  14. Structural Determinants of Alkyne Reactivity in Copper-Catalyzed Azide-Alkyne Cycloadditions

    Directory of Open Access Journals (Sweden)

    Xiaoguang Zhang

    2016-12-01

    Full Text Available This work represents our initial effort in identifying azide/alkyne pairs for optimal reactivity in copper-catalyzed azide-alkyne cycloaddition (CuAAC reactions. In previous works, we have identified chelating azides, in particular 2-picolyl azide, as “privileged” azide substrates with high CuAAC reactivity. In the current work, two types of alkynes are shown to undergo rapid CuAAC reactions under both copper(II- (via an induction period and copper(I-catalyzed conditions. The first type of the alkynes bears relatively acidic ethynyl C-H bonds, while the second type contains an N-(triazolylmethylpropargylic moiety that produces a self-accelerating effect. The rankings of reactivity under both copper(II- and copper(I-catalyzed conditions are provided. The observations on how other reaction parameters such as accelerating ligand, reducing agent, or identity of azide alter the relative reactivity of alkynes are described and, to the best of our ability, explained.

  15. Flash Vacuum Pyrolysis of Azides, Triazoles, and Tetrazoles.

    Science.gov (United States)

    Wentrup, Curt

    2017-03-08

    Flash vacuum pyrolysis (FVP) of azides is an extremely valuable method of generating nitrenes and studying their thermal rearrangements. The nitrenes can in many cases be isolated in low-temperature matrices and observed spectroscopically. NH and methyl, alkyl, aralkyl, vinyl, cyano, aryl and N-heteroaryl, acyl, carbamoyl, alkoxycarbonyl, imidoyl, boryl, silyl, phosphonyl, and sulfonyl nitrenes are included. FVP of triazoloazines generates diazomethylazines and azinylcarbenes, which often rearrange to the energetically more stable arylnitrenes. N 2 elimination from monocyclic 1,2,3-triazoles can generate iminocarbenes, 1H-azirines, ketenimines, and cyclization products, and 1,2,4-triazoles are precursors of nitrile ylides. Benzotriazoles are preparatively useful precursors of cyanocyclopentadienes, carbazoles, and aza-analogues. FVP of 5-aryltetrazoles can result in double N 2 elimination with formation of arylcarbenes or of heteroarylcarbenes, which again rearrange to arylnitrenes. Many 5-substituted and 2,5-disubstituted tetrazoles are excellent precursors of nitrile imines (propargylic, allenic, or carbenic), which are isolable at low temperatures in some cases (e.g., aryl- and silylnitrile imines) or rearrange to carbodiimides. 1,5-Disubstituted tetrazoles are precursors of imidoylnitrenes, which also rearrange to carbodiimides or add intramolecularly to aryl substituents to yield indazoles and related compounds. Where relevant for the mechanistic understanding, pyrolysis under flow conditions or in solution or the solid state will be mentioned. Results of photolysis reactions and computational chemistry complementing the FVP results will also be mentioned in several places.

  16. Copper-catalyzed azide alkyne cycloaddition polymer networks

    Science.gov (United States)

    Alzahrani, Abeer Ahmed

    The click reaction concept, introduced in 2001, has since spurred the rapid development and reexamination of efficient, high yield reactions which proceed rapidly under mild conditions. Prior to the discovery of facile copper catalysis in 2002, the thermally activated azide-alkyne or Huisgen cycloaddition reaction was largely ignored following its discovery in large part due to its slow kinetics, requirement for elevated temperature and limited selectivity. Now, arguably, the most prolific and capable of the click reactions, the copper-catalyzed azide alkyne cycloaddition (CuAAC) reaction is extremely efficient and affords exquisite control of the reaction. The orthogonally and chemoselectivity of this reaction enable its wide utility across varied scientific fields. Despite numerous inherent advantages and widespread use for small molecule synthesis and solution-based polymer chemistry, it has only recently and rarely been utilized to form polymer networks. This work focuses on the synthesis, mechanisms, and unique attributes of the CuAAC reaction for the fabrication of functional polymer networks. The photo-reduction of a series of copper(II)/amine complexes via ligand metal charge transfer was examined to determine their relative efficiency and selectivity in catalyzing the CuAAC reaction. The aliphatic amine ligands were used as an electron transfer species to reduce Cu(II) upon irradiation with 365 nm light while also functioning as an accelerating agent and as protecting ligands for the Cu(I) that was formed. Among the aliphatic amines studied, tertiary amines such as triethylamine (TEA), tetramethyldiamine (TMDA), N,N,N',N",N"-pentamethyldiethylenetriamine (PMDTA), and hexamethylenetetramine (HMTETA) were found to be the most effective. The reaction kinetics were accelerated by increasing the PMDETA : Cu(II) ratio with a ratio of ligand to Cu(II) of 4:1 yielding the maximum conversion in the shortest time. The sequential and orthogonal nature of the photo

  17. Efficiency and effectiveness of gamma rays and sodium azide in Sesbania cannabina Poir

    International Nuclear Information System (INIS)

    Kumar, G.; Srivastava, N.

    2013-01-01

    Mutagenic effectiveness and efficiency is an important factor for the selection of a mutagen for a mutation breeding program. Mutagenic effectiveness is a measure of the frequency of mutations induced by a unit mutagen dose, while mutagenic efficiency is a measure of the proportion of mutations in relation to undesirable changes such as lethality, sterility, meiotic aberrations etc. The present study envisages the mutagenic effectiveness and efficiency of individual and combined treatments of chemical and physical mutagens i.e. sodium azide (individual), gamma rays (individual) and sodium azide + gamma ray (combined). For the individual treatment of sodium azide, the seeds of the Sesbania cannabina variety ND-1 were treated with 0.5% solution of sodium azide (SA) for four different time durations, i.e. 3, 5, 7, and 9 h, and for the individual treatment of gamma rays, dry and healthy seeds were treated with 20, 40, 60, and 80 Kr doses of gamma rays. For the combined treatment, the seeds were exposed to four different doses of gamma rays (20, 40, 60, and 80 Kr) and after irradiation seeds were treated with 0.5% solution of sodium azide for 3 h. After treatment, seeds subjected to individual and combined treatment were sown in randomized block design to raise the M 1 generation and a study was conducted on germination percentage, survival percentage, pollen fertility percentage, and chromosomal aberrations at different doses of the individual and combined treatments. (author)

  18. Effects of mutagen application of sodium azide and gamma radiation in rice seeds

    International Nuclear Information System (INIS)

    Guimaraes, E.P.

    1980-01-01

    Effects of mutagen application of sodium azide and gamma radiation in rice seeds. Upland rice seeds, variety Dourado Precoce, were treated with gamma-rays and sodium azide(SA). Biological effects of these treatments were studied in the M 1 and M 2 generations. Survival number, seedling height, plant fertility and chlorophyill mutation frequencies based on mutations per 100 M 1 panicles and mutants per 100 M 2 seedlings were analysed. Among these characters, plant fertility was the most sensitive for mutagen treatments, and higher doses of gamma-rays or higher concentrations of sodium azide reduced significantly fertility of M 1 plants. The same effect as increase of concentration of sodium azide was observed when the acidity of buffer solution was increased, or when seeds were pre-treated in distilled water. The maximum chlorophyll mutation frequencies were obtained in sodium azide treatments: 40.74% in the M 1 panicles and 10.67% in the M 2 seedlings, in comparison with the maximum frequenies in gamma-irradiation of 10.39% in the M 1 panicles and 1.73% in the M 2 seedlings. (Author) [pt

  19. Reaction of Tris(cyclopentadienyl)uranium compounds with amines, azides, and related ligands

    International Nuclear Information System (INIS)

    Rosen, R.K.

    1989-12-01

    The trivalent uranium compound, (MeC 5 H 4 ) 3 U(thf), serves as a one- or two-electron reducing agent towards azides, RN 3 . These reactions produce either the uranium(IV) azide, (MeC 5 H 4 ) 3 UN 3 , or uranium(V) imides, (MeC 5 H 4 ) 3 UNR. The role of steric and electronic effects upon this reaction has been investigated using several series of azides. For Me 3 XN 3 , the imides are produced when X = C or Si, both products are formed when X = Ge, and the azide is produced when X = Sn. For Ph 3 XN 3 , the azide is produced when X = C or Sn. For Ph 3-x CH 3 N 3 , the imide is produced when x = 2 and both compounds are produced when x = 1. For substituted phenylazides, RC 6 H 4 N 3 , only the imides are produced. The magnetic properties of uranium diimides, [(MeC 5 H 4 ) 3 U] 2 (μ-NRN), were investigated. Several uranium(III) amines, (MeC 5 H 4 ) 3 U(NH 2 R), were produced from (MeC 5 H 4 ) 3 U(thf) and RNH 2 , and NH 3 was found to be a better ligand towards (MeC 5 H 4 ) 3 U than is PMe 3

  20. Blue-emitting dinuclear N-heterocyclic dicarbene gold(I) complex featuring a nearly unit quantum yield

    KAUST Repository

    Baron, Marco

    2012-02-06

    Dinuclear N-heterocyclic dicarbene gold(I) complexes of general formula [Au 2(RIm-Y-ImR) 2](PF 6) 2 (R = Me, Cy; Y = (CH 2) 1-4, o-xylylene, m-xylylene) have been synthesized and screened for their luminescence properties. All the complexes are weakly emissive in solution whereas in the solid state some of them show significant luminescence intensities. In particular, crystals or powders of the complex with R = Me, Y = (CH 2) 3 exhibit an intense blue emission (λ max = 450 nm) with a high quantum yield (Φ em = 0.96). The X-ray crystal structure of this complex is characterized by a rather short intramolecular Au•••Au distance (3.272 Ǻ). Time dependent density functional theory (TDDFT) calculations have been used to calculate the UV/vis properties of the ground state as well as of the first excited state of the complex, the latter featuring a significantly shorter Au•••Au distance. © 2012 American Chemical Society.

  1. Blue-emitting dinuclear N-heterocyclic dicarbene gold(I) complex featuring a nearly unit quantum yield

    KAUST Repository

    Baron, Marco; Tubaro, Cristina; Biffis, Andrea; Basato, Marino; Graiff, Claudia; Poater, Albert; Cavallo, Luigi; Armaroli, Nicola; Accorsi, Gianluca

    2012-01-01

    Dinuclear N-heterocyclic dicarbene gold(I) complexes of general formula [Au 2(RIm-Y-ImR) 2](PF 6) 2 (R = Me, Cy; Y = (CH 2) 1-4, o-xylylene, m-xylylene) have been synthesized and screened for their luminescence properties. All the complexes are weakly emissive in solution whereas in the solid state some of them show significant luminescence intensities. In particular, crystals or powders of the complex with R = Me, Y = (CH 2) 3 exhibit an intense blue emission (λ max = 450 nm) with a high quantum yield (Φ em = 0.96). The X-ray crystal structure of this complex is characterized by a rather short intramolecular Au•••Au distance (3.272 Ǻ). Time dependent density functional theory (TDDFT) calculations have been used to calculate the UV/vis properties of the ground state as well as of the first excited state of the complex, the latter featuring a significantly shorter Au•••Au distance. © 2012 American Chemical Society.

  2. Asymmetric Catalysis with Organic Azides and Diazo Compounds Initiated by Photoinduced Electron Transfer.

    Science.gov (United States)

    Huang, Xiaoqiang; Webster, Richard D; Harms, Klaus; Meggers, Eric

    2016-09-28

    Electron-acceptor-substituted aryl azides and α-diazo carboxylic esters are used as substrates for visible-light-activated asymmetric α-amination and α-alkylation, respectively, of 2-acyl imidazoles catalyzed by a chiral-at-metal rhodium-based Lewis acid in combination with a photoredox sensitizer. This novel proton- and redox-neutral method provides yields of up to 99% and excellent enantioselectivities of up to >99% ee with broad functional group compatibility. Mechanistic investigations suggest that an intermediate rhodium enolate complex acts as a reductive quencher to initiate a radical process with the aryl azides and α-diazo carboxylic esters serving as precursors for nitrogen and carbon-centered radicals, respectively. This is the first report on using aryl azides and α-diazo carboxylic esters as substrates for asymmetric catalysis under photoredox conditions. These reagents have the advantage that molecular nitrogen is the leaving group and sole byproduct in this reaction.

  3. Ionic conduction in sodium azide under high pressure: Experimental and theoretical approaches

    Science.gov (United States)

    Wang, Qinglin; Ma, Yanzhang; Sang, Dandan; Wang, Xiaoli; Liu, Cailong; Hu, Haiquan; Wang, Wenjun; Zhang, Bingyuan; Fan, Quli; Han, Yonghao; Gao, Chunxiao

    2018-04-01

    Alkali metal azides can be used as starting materials for the synthesis of polymeric nitrogen, a potential material of high energy density. In this letter, we report the ionic transport behavior in sodium azide under high pressure by in situ impedance spectroscopy and density functional theory calculations. The ionic transportation consists of ion transfer and Warburg diffusion processes. The ionic migration channels and barrier energy were given for the high-pressure phases. The enhanced ionic conductivity of the γ phase with pressure is because of the formation of space charge regions in the grain boundaries. This ionic conduction and grain boundary effect in NaN3 under pressures could shed light on the better understanding of the conduction mechanism of alkali azides and open up an area of research for polymeric nitrogen in these compounds and other high-energy-density polynitrides.

  4. Synthesis of radiolabelled aryl azides from diazonium salts: experimental and computational results permit the identification of the preferred mechanism.

    Science.gov (United States)

    Joshi, Sameer M; de Cózar, Abel; Gómez-Vallejo, Vanessa; Koziorowski, Jacek; Llop, Jordi; Cossío, Fernando P

    2015-05-28

    Experimental and computational studies on the formation of aryl azides from the corresponding diazonium salts support a stepwise mechanism via acyclic zwitterionic intermediates. The low energy barriers associated with both transition structures are compatible with very fast and efficient processes, thus making this method suitable for the chemical synthesis of radiolabelled aryl azides.

  5. Synthesis of positron labeled photoactive compounds: 18F labeled aryl azides for positron labeling of biochemical molecules

    International Nuclear Information System (INIS)

    Hashizume, Kazunari; Hashimoto, Naota; Miyake, Yoshihiro

    1995-01-01

    The authors have prepared various [ 18 F] fluorine labeled aryl azides as a novel photoactive compounds suitable for positron labeling of biochemical molecules. The introduction of fluorine substituents to aryl azides can be expected to have dramatic effects on their nature and reactivity toward photolysis. Positron labeled reagents for labeling proteins or peptides have recently attracted considerable attention due to their wide applicability in biochemistry and positron emission tomography (PET). Various labeled azide compounds are often used in biochemistry for radiolabeling biological molecules by photolysis, but there have been no reports on the preparation or use of fluorine-18 labeled azides. The authors now report a novel synthesis of 18 F-labeled aryl azides which will have wide application in the biochemistry and nuclear medicine as a means for 18 F-fluorine labeling for proteins, peptides, and nucleic acids. 2 tabs

  6. Alkylating efficiency of sodium azide on pod yield, nut size and ...

    African Journals Online (AJOL)

    Mutation has been utilised to improve growth and yield of many food crops, but only little effort has been made to ascertain the nutritional advantages in such improved crops. The present study evaluates the alkylating efficiency of sodium azide of different concentrations on pod yield, nut size and nutritional composition of ...

  7. Surface modification of GC and HOPG with diazonium, amine, azide, and olefin derivatives.

    Science.gov (United States)

    Tanaka, Mutsuo; Sawaguchi, Takahiro; Sato, Yukari; Yoshioka, Kyoko; Niwa, Osamu

    2011-01-04

    Surface modification of glassy carbon (GC) and highly oriented pyrolytic graphite (HOPG) was carried out with diazonium, amine, azide, and olefin derivatives bearing ferrocene as an electroactive moiety. Features of the modified surfaces were evaluated by surface concentrations of immobilized molecule, blocking effect of the modified surface against redox reaction, and surface observation using cyclic voltammetry and electrochemical scanning tunneling microscope (EC-STM). The measurement of surface concentrations of immobilized molecule revealed the following three aspects: (i) Diazonium and olefin derivatives could modify substrates with the dense-monolayer concentration. (ii) The surface concentration of immobilized amine derivative did not reach to the dense-monolayer concentration reflecting their low reactivity. (iii) The surface modification with the dense-monolayer concentration was also possible with azide derivative, but the modified surface contained some oligomers produced by the photoreaction of azides. Besides, the blocking effect against redox reaction was observed for GC modified with diazonium derivative and for HOPG modified with diazonium and azide derivatives, suggesting fabrication of a densely modified surface. Finally, the surface observation for HOPG modified with diazonium derivative by EC-STM showed a typical monolayer structure, in which the ferrocene moieties were packed densely at random. On the basis of those results, it was demonstrated that surface modification of carbon substrates with diazonium could afford a dense monolayer similar to the self-assembled monolayer (SAM) formation.

  8. Catalytic Intermolecular Cross-Couplings of Azides and LUMO-Activated Unsaturated Acyl Azoliums

    KAUST Repository

    Li, Wenjun

    2017-02-15

    An example for the catalytic synthesis of densely functionalized 1,2,3-triazoles through a LUMO activation mode has been developed. The protocol is enabled by intermolecular cross coupling reactions of azides with in situ-generated alpha,beta-unsaturated acyl azoliums. High yields and broad scope as well as the investigation of reaction mechanism are reported.

  9. Biological and genetic effects of combined treatments of sodium azide, gamma rays and EMS in barley

    International Nuclear Information System (INIS)

    Cheng, X.Y.; Gao, M.W.

    1988-01-01

    Dry seeds of diploid barley were subjected to mutagenic treatments of sodium azide, gamma rays and EMS alone or in combination. Damage (reduction in seedling height, plant height and fertility), the frequency of chimeras in the M1 generation, and the frequency of chlorophyll-deficient mutations as well as morphological mutations in the M2 generation induced by combined treatments were greater than those by either of the single treatments. Synergistic increase in the frequency of chimeras, chlorphyll-deficient mutations and morphological mutations were observed in both sodium azide post-irradiation treatments and pre-EMS treatments; interaction among the mutagens in the treatment combinations on M1 damage was generally subtractive. An 8- to 16-hr soaking period of irradiated seeds in distilled water prior to sodium azide treatment significantly increased chlorophyll mutation frequency, as compared to that from the non-soaking treatment. Damage and frequency of chimeras, chlorophyll mutations and morphological mutations were consistently reduced by the soaking treatment in sodium azide plus EMS treatments. (author)

  10. Continuous flow photolysis of aryl azides: Preparation of 3H-azepinones

    Directory of Open Access Journals (Sweden)

    Farhan R. Bou-Hamdan

    2011-08-01

    Full Text Available Photolysis of aryl azides to give nitrenes, and their subsequent rearrangement in the presence of water to give 3H-azepinones, is performed in continuous flow in a photoreactor constructed of fluorinated ethylene polymer (FEP tubing. Fine tuning of the reaction conditions using the flow reactor allowed minimization of secondary photochemical reactions.

  11. Azidoperfluoroalkanes: Synthesis and Application in Copper(I)-Catalyzed Azide-Alkyne Cycloaddition

    Czech Academy of Sciences Publication Activity Database

    Blastik, Zsófia E.; Voltrová, Svatava; Matoušek, V.; Jurásek, Bronislav; Manley, David W.; Klepetářová, Blanka; Beier, Petr

    2017-01-01

    Roč. 56, č. 1 (2017), s. 346-349 ISSN 1433-7851 EU Projects: European Commission(XE) 607787 - FLUOR21 Institutional support: RVO:61388963 Keywords : azides * click reactions * fluorine * perfluoroalkanes * triazoles Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 11.994, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/anie.201609715/full

  12. Phosphoramidite accelerated copper(I)-catalyzed [3+2] cycloadditions of azides and alkynes

    NARCIS (Netherlands)

    Campbell-Verduyn, Lachlan S.; Mirfeizi, Leila; Dierckx, Rudi A.; Elsinga, Philip H.; Feringa, Ben L.

    2009-01-01

    Monodentate phosphoramidite ligands are used to accelerate the copper(I)-catalyzed 1,3-dipolar cycloaddition of azides and alkynes (CuAAC) rapidly yielding a wide variety of functionalized 1,4-disubstituted-1,2,3-triazoles; Cu(I) and Cu(II) salts both function as the copper source in aqueous

  13. In situ generation of the Ohira-Bestmann Reagent from stable sulfonyl azide

    DEFF Research Database (Denmark)

    Jepsen, Tue Heesgaard; Kristensen, Jesper Langgaard

    2014-01-01

    We report an improved method for in situ generation of the Ohira-Bestmann reagent. Using the recently reported bench stable imidazole-1-sulfonyl azide as diazotransfer reagent, this new method represents a safe and scalable approach for the transformation of aldehydes into terminal alkynes...

  14. Continuous flow hydrogenation of nitroarenes, azides and alkenes using maghemite-Pd nanocomposites

    Science.gov (United States)

    Maghemite-supported ultra-fine Pd (1-2 nm) nanoparticles, prepared by a simple co-precipitation method, find application in the catalytic continuous flow hydrogenation of nitroarenes, azides, and alkenes wherein they play an important role in reduction of various functional group...

  15. Copper on Chitosan: A Recyclable Heterogeneous Catalyst for Azide-alkyne Cycloaddition Reactions in Water

    Science.gov (United States)

    Copper sulfate is immobilized over chitosan by simply stirring an aqueous suspension of chitosan in water with copper sulfate; the ensuing catalyst has been utilized for the azide-alkyne cycloaddition in aqueous media and it can be recycled and reused many time without loosing it...

  16. 49 CFR 173.182 - Barium azide-50 percent or more water wet.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Barium azide-50 percent or more water wet. 173.182 Section 173.182 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS... Class 1 and Class 7 § 173.182 Barium azide—50 percent or more water wet. Barium azide—50 percent or more...

  17. C,N-Chelated Organotin(IV) Azides: Synthesis, Structure and Use within the Click Chemistry.

    Czech Academy of Sciences Publication Activity Database

    Švec, P.; Bartoš, K.; Růžičková, Z.; Cuřínová, Petra; Dušek, L.; Turek, J.; de Proft, F.; Růžička, A.

    2016-01-01

    Roč. 40, č. 7 (2016), s. 5808-5817 ISSN 1144-0546 Grant - others:FWO(BE) 12T6615N Institutional support: RVO:67985858 Keywords : organotin(IV)azides * click chemistry * chelation Subject RIV: CC - Organic Chemistry Impact factor: 3.269, year: 2016

  18. In vitro and in vivo studies of gold(I) azolate/phosphane complexes for the treatment of basal like breast cancer.

    Science.gov (United States)

    Gambini, Valentina; Tilio, Martina; Maina, Eunice Wairimu; Andreani, Cristina; Bartolacci, Caterina; Wang, Junbiao; Iezzi, Manuela; Ferraro, Stefano; Ramadori, Anna Teresa; Simon, Oumarou Camille; Pucciarelli, Stefania; Wu, Guojun; Dou, Q Ping; Marchini, Cristina; Galassi, Rossana; Amici, Augusto

    2018-06-02

    Basal like breast cancer (BLBC) is a very aggressive subtype of breast cancer giving few chances of survival, against which cisplatin based therapy is a compromise among the anticancer activity, the resistance development and the severe side effects. With the aim of finding new anticancer agents alternative to cisplatin, seven gold(I) azolate/phosphane compounds were evaluated in vitro by MTT tests in human MDA-MB-231, human mammary epithelial HMLE cells overexpressing FoxQ1, and murine A17 cells as models of BLBC. Two compounds, (4,5-dichloro-1H-imidazolate-1-yl)-(triphenylphosphane)-gold(I) 1 and (4,5-dicyano-1H-imidazolate-1-yl)-(triphenylphosphane)-gold(I) 2 were found very active and chosen for an in vivo study in A17 tumors transplanted in syngeneic mice. The compounds resulted to be more active than cisplatin, less nephrotoxic and generally more tolerated by the mice. This study also provides evidence that both gold(I) complexes inhibited the 19 S proteasome-associated deubiquitinase USP14 and induced apoptosis, while compound 1's mechanism of action depends also on its ability to down-regulate key molecules governing cancer growth and progression, such as STAT3 and Cox-2. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  19. Reaction of Tris(cyclopentadienyl)uranium compounds with amines, azides, and related ligands

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, R.K.

    1989-12-01

    The trivalent uranium compound, (MeC{sub 5}H{sub 4}){sub 3}U(thf), serves as a one- or two-electron reducing agent towards azides, RN{sub 3}. These reactions produce either the uranium(IV) azide, (MeC{sub 5}H{sub 4}){sub 3}UN{sub 3}, or uranium(V) imides, (MeC{sub 5}H{sub 4}){sub 3}UNR. The role of steric and electronic effects upon this reaction has been investigated using several series of azides. For Me{sub 3}XN{sub 3}, the imides are produced when X = C or Si, both products are formed when X = Ge, and the azide is produced when X = Sn. For Ph{sub 3}XN{sub 3}, the azide is produced when X = C or Sn. For Ph{sub 3-x}CH{sub 3}N{sub 3}, the imide is produced when x = 2 and both compounds are produced when x = 1. For substituted phenylazides, RC{sub 6}H{sub 4}N{sub 3}, only the imides are produced. The magnetic properties of uranium diimides, ((MeC{sub 5}H{sub 4}){sub 3}U){sub 2}({mu}-NRN), were investigated. Several uranium(III) amines, (MeC{sub 5}H{sub 4}){sub 3}U(NH{sub 2}R), were produced from (MeC{sub 5}H{sub 4}){sub 3}U(thf) and RNH{sub 2}, and NH{sub 3} was found to be a better ligand towards (MeC{sub 5}H{sub 4}){sub 3}U than is PMe{sub 3}.

  20. Comparison of physiological and genetic effects of gamma radiation and sodium azide on two rice (Oryza sativa, L.) genotypes

    International Nuclear Information System (INIS)

    Faracco, A.L.A.

    1990-01-01

    The sensitivity of both genotypes (Oryzica 1 and Strain 30036) to gamma rays and sodium azide is studied. Doses of gamma-rays and concentrations of sodium azide were chosen so as to produce around 20%-25% height reduction in these genotypes. Emergence, survival and fertility were the physiological effects on M 1 generation analysed after the final treatment. The number of chlorophyll mutations and the number of seedling mutants were counted in M 2 generation. Taking into consideration, specially M 1 generation sterility, it was concluded that for the two genotypes studied, sodium azide presented a greater mutagen effect. (M.A.C.)

  1. Sequential One-Pot Ruthenium-Catalyzed Azide−Alkyne Cycloaddition from Primary Alkyl Halides and Sodium Azide

    KAUST Repository

    Johansson, Johan R.

    2011-04-01

    An experimentally simple sequential one-pot RuAAC reaction, affording 1,5-disubstituted 1H-1,2,3-triazoles in good to excellent yields starting from an alkyl halide, sodium azide, and an alkyne, is reported. The organic azide is formed in situ by treating the primary alkyl halide with sodium azide in DMA under microwave heating. Subsequent addition of [RuClCp*(PPh 3) 2] and the alkyne yielded the desired cycloaddition product after further microwave irradiation. © 2011 American Chemical Society.

  2. Environmental Friendly Azide-Alkyne Cycloaddition Reaction of Azides, Alkynes, and Organic Halides or Epoxides in Water: Efficient "Click" Synthesis of 1,2,3-Triazole Derivatives by Cu Catalyst

    Institute of Scientific and Technical Information of China (English)

    刘建明; 刘慕文; 岳园园; 姚美焕; 卓克垒

    2012-01-01

    An efficient click synthesis of 1,2,3-triazole derivatives from benzyl halides or alkyl halides, epoxides, terminal alkynes, and sodium azides in the presence of copper salts and relative benzimidazole salts have been developed. This procedure eliminates the need to handle potentially organic azides, which are generated in situ. A broad spec- trum of substrates can participate in the process effectively to produce the desired products in good yields.

  3. Direct C–H Azidation of Calix[4]arene as a Novel Method to Access Meta Substituted Derivatives

    Czech Academy of Sciences Publication Activity Database

    Stejskal, F.; Eigner, V.; Dvořáková, H.; Cuřínová, Petra; Lhoták, P.

    2015-01-01

    Roč. 56, č. 39 (2015), s. 5357-5361 ISSN 0040-4039 Institutional support: RVO:67985858 Keywords : calixarene * azidation * regionselectivity Subject RIV: CC - Organic Chemistry Impact factor: 2.347, year: 2015

  4. Synthesis of novel bis(perfluorophenyl azides) coupling agents: Evaluation of their performance by crosslinking of poly(ethylene oxide)

    KAUST Repository

    Mehenni, Hakim; Bakr, Osman

    2011-01-01

    Novel bis(perfluorophenyl azides) coupling agents, containing spacer arms from ethylene or ethylene glycol subunits, were successfully synthesized. Nitrenes photogenerated from these novel bis(PFPA) coupling agents were applied successfully

  5. Consecutive hydrazino-Ugi-azide reactions: synthesis of acylhydrazines bearing 1,5-disubstituted tetrazoles

    Directory of Open Access Journals (Sweden)

    Angélica de Fátima S. Barreto

    2017-12-01

    Full Text Available Isocyanide-based multicomponent reactions (IMCRs allow the construction of relatively complex molecules through a one-pot synthesis. The combination of IMCRs in a consecutive or sequential fashion further extends the complexity of the molecules obtained. Herein, we report the efficient application of this approach to the synthesis of acylhydrazines bearing 1,5-disubstituted tetrazoles. Our strategy was accomplished in only three steps: first, a one-pot hydrazino-Ugi-azide four-component reaction; second a hydrazinolysis and finally an additional hydrazino-Ugi-azide reaction. This sequence provides the title compounds in moderate to excellent yields. The products synthesized herein contain functional groups within their structures that can be easily modified to obtain new acylhydrazino 1,5-disubstituted tetrazoles.

  6. Experimental evidence for the involvement of dinuclear alkynylcopper(I) complexes in alkyne-azide chemistry.

    Science.gov (United States)

    Buckley, Benjamin R; Dann, Sandra E; Heaney, Harry

    2010-06-01

    Dinuclear alkynylcopper(I) ladderane complexes are prepared by a robust and simple protocol involving the reduction of Cu(2)(OH)(3)OAc or Cu(OAc)(2) by easily oxidised alcohols in the presence of terminal alkynes; they function as efficient catalysts in copper-catalysed alkyne-azide cycloaddition reactions as predicted by the Ahlquist-Fokin calculations. The same copper(I) catalysts are formed during reactions by using the Sharpless-Fokin protocol. The experimental results also provide evidence that sodium ascorbate functions as a base to deprotonate terminal alkynes and additionally give a convincing alternative explanation for the fact that the Cu(I)-catalysed reactions of certain 1,3-diazides with phenylacetylene give bis(triazoles) as the major products. The same dinuclear alkynylcopper(I) complexes also function as catalysts in cycloaddition reactions of azides with 1-iodoalkynes.

  7. Ultrafast infrared and UV-vis studies of the photochemistry of methoxycarbonylphenyl azides in solution.

    Science.gov (United States)

    Xue, Jiadan; Luk, Hoi Ling; Eswaran, S V; Hadad, Christopher M; Platz, Matthew S

    2012-06-07

    The photochemistry of 4-methoxycarbonylphenyl azide (2a), 2-methoxycarbonylphenyl azide (3a), and 2-methoxy-6-methoxycarbonylphenyl azide (4a) were studied by ultrafast time-resolved infrared (IR) and UV-vis spectroscopies in solution. Singlet nitrenes and ketenimines were observed and characterized for all three azides. Isoxazole species 3g and 4g are generated after photolysis of 3a and 4a, respectively, in acetonitrile. Triplet nitrene 4e formation correlated with the decay of singlet nitrene 4b. The presence of water does not change the chemistry or kinetics of singlet nitrenes 2b and 3b, but leads to protonation of 4b to produce nitrenium ion 4f. Singlet nitrenes 2b and 3b have lifetimes of 2 ns and 400 ps, respectively, in solution at ambient temperature. The singlet nitrene 4b in acetonitrile has a lifetime of about 800 ps, and reacts with water with a rate constant of 1.9 × 10(8) L·mol(-1)·s(-1) at room temperature. These results indicate that a methoxycarbonyl group at either the para or ortho positions has little influence on the ISC rate, but that the presence of a 2-methoxy group dramatically accelerates the ISC rate relative to the unsubstituted phenylnitrene. An ortho-methoxy group highly stabilizes the corresponding nitrenium ion and favors its formation in aqueous solvents. This substituent has little influence on the ring-expansion rate. These results are consistent with theoretical calculations for the various intermediates and their transition states. Cyclization from the nitrene to the azirine intermediate is favored to proceed toward the electron-deficient ester group; however, the higher energy barrier is the ring-opening process, that is, azirine to ketenimine formation, rendering the formation of the ester-ketenimine (4d') to be less favorable than the isomeric MeO-ketenimine (4d).

  8. Gamma ray and sodium azide induced heterophylly of Bhindi and Clusterbean

    International Nuclear Information System (INIS)

    Khaleel Basha, S.; Gopala Rao, P.

    1988-01-01

    Gamma rays (35, 45 Krad) and sodium azide (100, 200 ppm) and their combinations caused heterophylly in Bhindi (Hibiscus esculentus) and Clusterbean (Cyamopsis tetragonoloba). Changes like notching of leaf at the tip region, reduction of secondary and tertiary veins, formation of 2,4 leaflets, reduction of leaf lobes and change of shape were noticed. More changes were observed at higher doses of the mutagens. (author). 12 refs

  9. Functionalization of Graphene Nanoplatelets Using Sugar Azide for Graphene/Epoxy Nanocomposites

    Science.gov (United States)

    2014-06-20

    supercapacitor electrode . Nanotechnology, 22, 295202(2011). doi:10.1088/0957-4484/22/29/295202 20. Leinonen H, Pettersson M, Lajunen M, Water-soluble...Azide for Graphene/Epoxy Nanocomposites Saswata Bose1, Lawrence T. Drzal 1* Dept of Chemical Engineering and Materials Science Composite Materials ...ORGANIZATION NAME(S) AND ADDRESS(ES) Dept of Chemical Engineering and Materials Science,Composite Materials and Structures Center,2100 Engineering

  10. Synthesis of polynorbornene with pendant moiety bearing azide and terminal alkyne groups

    Institute of Scientific and Technical Information of China (English)

    Ze Zhang; Zhi Wei Peng; Kun Zeng Fan

    2011-01-01

    A powerful approach to the synthesis of an unprecedented polynorbornene with pendant moiety bearing azide and terminal alkyne groups is developed. Two key intermediates, namely, 3-azido-5-(2-(trimethylsilyl)ethynyl) benzyl alcohol and 4-(4-aza-tricyclo [5.2.1.02.6]dec-8-en-4-yl) benzoic acid, were optimally synthesized for convergent synthesis of the corresponding monomer.

  11. Intramolecular Azide to Alkene Cycloadditions for the Construction of Pyrrolobenzodiazepines and Azetidino-Benzodiazepines

    Directory of Open Access Journals (Sweden)

    Karl Hemming

    2014-10-01

    Full Text Available The coupling of proline- and azetidinone-substituted alkenes to 2-azidobenzoic and 2-azidobenzenesulfonic acid gives precursors that undergo intramolecular azide to alkene 1,3-dipolar cycloadditions to give imine-, triazoline- or aziridine-containing pyrrolo[1,4]benzodiazepines (PBDs, pyrrolo[1,2,5]benzothiadiazepines (PBTDs, and azetidino[1,4]benzodiazepines. The imines and aziridines are formed after loss of nitrogen from a triazoline cycloadduct. The PBDs are a potent class of antitumour antibiotics.

  12. A practical and azide-free synthetic approach to oseltamivir from diethyl D-tartrate.

    Science.gov (United States)

    Weng, Jiang; Li, Yong-Bo; Wang, Rui-Bin; Li, Feng-Quan; Liu, Can; Chan, Albert S C; Lu, Gui

    2010-05-07

    A short and practical synthesis of oseltamivir was accomplished in 11 steps from inexpensive and abundant diethyl D-tartrate starting material. This azide-free route featured an asymmetric aza-Henry reaction and a domino nitro-Michael/Horner-Wadsworth-Emmons (HWE) reaction as the key steps to construct the relevant cyclohexene ring of the product, which provided an economical and practical alternative for the synthesis of oseltamivir.

  13. Pressure-accelerated azide-alkyne cycloaddition: micro capillary versus autoclave reactor performance.

    Science.gov (United States)

    Borukhova, Svetlana; Seeger, Andreas D; Noël, Timothy; Wang, Qi; Busch, Markus; Hessel, Volker

    2015-02-01

    Pressure effects on regioselectivity and yield of cycloaddition reactions have been shown to exist. Nevertheless, high pressure synthetic applications with subsequent benefits in the production of natural products are limited by the general availability of the equipment. In addition, the virtues and limitations of microflow equipment under standard conditions are well established. Herein, we apply novel-process-window (NPWs) principles, such as intensification of intrinsic kinetics of a reaction using high temperature, pressure, and concentration, on azide-alkyne cycloaddition towards synthesis of Rufinamide precursor. We applied three main activation methods (i.e., uncatalyzed batch, uncatalyzed flow, and catalyzed flow) on uncatalyzed and catalyzed azide-alkyne cycloaddition. We compare the performance of two reactors, a specialized autoclave batch reactor for high-pressure operation up to 1800 bar and a capillary flow reactor (up to 400 bar). A differentiated and comprehensive picture is given for the two reactors and the three methods of activation. Reaction speedup and consequent increases in space-time yields is achieved, while the process window for favorable operation to selectively produce Rufinamide precursor in good yields is widened. The best conditions thus determined are applied to several azide-alkyne cycloadditions to widen the scope of the presented methodology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Click functionalization of phenyl-capped bithiophene on azide-terminated self-assembled monolayers

    International Nuclear Information System (INIS)

    Zheng, Yijun; Cui, Jiaxi; Ikeda, Taichi

    2015-01-01

    Graphical abstract: - Highlights: • Electrochemically-active self-assembled monolayers with phenyl-capped bithiophene were prepared. • Post-functionalization method based on click chemistry solved the solubility issue of phenyl-capped thiophene alkanethiol. • The capture and release of the counter anions during the redox reaction were detectable by E-QCM. - Abstract: We immobilized tetra(ethylene glycol)-substituted phenyl-capped bithiophene with alkyne terminals (Ph2TPh-alkyne) on azide-terminated self-assembled monolayers (N 3 -SAMs) by Cu-catalyzed azide-alkyne cycloaddition reaction. Ph2TPh-functionalized SAMs on a gold substrate showed reversible electrochemical response. The surface densities of the azide groups in N 3 -SAMs and Ph2TPh units in Ph2TPh-functionalized SAMs were estimated to be 7.3 ± 0.3 × 10 −10 mol cm −2 and 4.6 ± 0.3 × 10 −10 mol cm −2 , respectively, by quartz crystal microbalance (QCM). Most of Ph2TPh-alkynes are considered to be anchored on N 3 -SAMs via both terminal groups. Ph2TPh-functionalized SAMs exhibited reversible redox peaks in cyclic voltammetry (CV). In redox reaction, reversible capture and release of the counter anion could be monitored by electrochemical QCM (E-QCM).

  15. Click functionalization of phenyl-capped bithiophene on azide-terminated self-assembled monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yijun; Cui, Jiaxi [Max Planck Institute for Polymer Research (MPIP), Ackermannweg 10, Mainz 55128 (Germany); Ikeda, Taichi, E-mail: IKEDA.Taichi@nims.go.jp [Max Planck Institute for Polymer Research (MPIP), Ackermannweg 10, Mainz 55128 (Germany); Polymer Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan)

    2015-11-15

    Graphical abstract: - Highlights: • Electrochemically-active self-assembled monolayers with phenyl-capped bithiophene were prepared. • Post-functionalization method based on click chemistry solved the solubility issue of phenyl-capped thiophene alkanethiol. • The capture and release of the counter anions during the redox reaction were detectable by E-QCM. - Abstract: We immobilized tetra(ethylene glycol)-substituted phenyl-capped bithiophene with alkyne terminals (Ph2TPh-alkyne) on azide-terminated self-assembled monolayers (N{sub 3}-SAMs) by Cu-catalyzed azide-alkyne cycloaddition reaction. Ph2TPh-functionalized SAMs on a gold substrate showed reversible electrochemical response. The surface densities of the azide groups in N{sub 3}-SAMs and Ph2TPh units in Ph2TPh-functionalized SAMs were estimated to be 7.3 ± 0.3 × 10{sup −10} mol cm{sup −2} and 4.6 ± 0.3 × 10{sup −10} mol cm{sup −2}, respectively, by quartz crystal microbalance (QCM). Most of Ph2TPh-alkynes are considered to be anchored on N{sub 3}-SAMs via both terminal groups. Ph2TPh-functionalized SAMs exhibited reversible redox peaks in cyclic voltammetry (CV). In redox reaction, reversible capture and release of the counter anion could be monitored by electrochemical QCM (E-QCM).

  16. A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

    Directory of Open Access Journals (Sweden)

    Stefanie Wolfram

    2014-10-01

    Full Text Available Molecular probes are widely used tools in chemical biology that allow tracing of bioactive metabolites and selective labeling of proteins and other biomacromolecules. A common structural motif for such probes consists of a reporter that can be attached by copper(I-catalyzed 1,2,3-triazole formation between terminal alkynes and azides to a reactive headgroup. Here we introduce the synthesis and application of the new thiazole-based, azide-tagged reporter 4-(3-azidopropoxy-5-(4-bromophenyl-2-(pyridin-2-ylthiazole for fluorescence, UV and mass spectrometry (MS detection. This small fluorescent reporter bears a bromine functionalization facilitating the automated data mining of electrospray ionization MS runs by monitoring for its characteristic isotope signature. We demonstrate the universal utility of the reporter for the detection of an alkyne-modified small molecule by LC–MS and for the visualization of a model protein by in-gel fluorescence. The novel probe advantageously compares with commercially available azide-modified fluorophores and a brominated one. The ease of synthesis, small size, stability, and the universal detection possibilities make it an ideal reporter for activity-based protein profiling and functional metabolic profiling.

  17. 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.

  18. Introduction of sample tubes with sodium azide as a preservative for ethyl glucuronide in urine.

    Science.gov (United States)

    Luginbühl, Marc; Weinmann, Wolfgang; Al-Ahmad, Ali

    2017-09-01

    Ethyl glucuronide (EtG) is a direct alcohol marker, which is widely used for clinical and forensic applications, mainly for abstinence control. However, the instability of EtG in urine against bacterial degradation or the post-collectional synthesis of EtG in contaminated samples may cause false interpretation of EtG results in urine samples. This study evaluates the potential of sodium azide in tubes used for urine collection to hinder degradation of ethyl glucuronide by bacterial metabolism taking place during growth of bacterial colonies. The tubes are part of a commercial oral fluid collection device. The sampling system was tested with different gram-positive and gram-negative bacterial species previously observed in urinary tract infections, such as Escherichia coli, Staphylococcus aureus, Enterecoccus faecalis, Staphylococcus epidermidis, Klebsiella pneumoniae, Enterobacter cloacae, and Pseudomonas aeruginosa. Inhibition of bacterial growth by sodium azide, resulting in lower numbers of colony forming units compared to control samples, was observed for all tested bacterial species. To test the prevention of EtG degradation by the predominant pathogen in urinary tract infection, sterile-filtered urine and deficient medium were spiked with EtG, and inoculated with E. coli prior to incubation for 4 days at 37 °C in tubes with and without sodium azide. Samples were collected every 24 hours, during four consecutive days, whereby the colony forming units (CFU) were counted on Columbia blood agar plates, and EtG was analyzed by LC-MS/MS. As expected, EtG degradation was observed when standard polypropylene tubes were used for the storage of contaminated samples. However, urine specimens collected in sodium azide tubes showed no or very limited bacterial growth and no EtG degradation. As a conclusion, sodium azide is useful to reduce bacterial growth of gram-negative and gram-positive bacteria. It inhibits the degradation of EtG by E. coli and can be used for

  19. Synthesis, solid-state structure, and bonding analysis of a homoleptic beryllium azide

    International Nuclear Information System (INIS)

    Naglav, Dominik; Tobey, Briac; Lyhs, Benjamin; Roemer, Beate; Blaeser, Dieter; Woelper, Christoph; Jansen, Georg; Schulz, Stephan

    2017-01-01

    [Ph 4 P] 2 [Be(N 3 ) 4 ] (1) and [PNP] 2 [Be(N 3 ) 4 ] (2; PNP=Ph 3 PNPPh 3 ) were synthesized by reacting Be(N 3 ) 2 with [Ph 4 P]N 3 and [PNP]N 3 . Compound 1 represents the first structurally characterized homoleptic beryllium azide. The electronic structure and bonding situation in the tetraazidoberyllate dianion [Be(N 3 ) 4 ] 2- were investigated by quantum-chemical calculations (NPA, ELF, LOL). (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Azide- and Alkyne-Functionalised α- and β3-Amino Acids

    DEFF Research Database (Denmark)

    Sminia, T.J.; Pedersen, Daniel Sejer

    2012-01-01

    The synthesis and full characterisation of bifunctional β -amino acids that have side chains functionalised with terminal azides (S)-4 and (R)-4 or acetylenes 5 and 6 is reported for the first time. The building blocks incorporate a turn-inducing β -segment and a side chain that can...... be functionalised further, for example, through copper-catalysed Huisgen cycloaddition. Moreover, the corresponding α-amino acids 1 and 3 have been synthesised and characterised. All amino acid building blocks were of high optical purity as demonstrated by derivatisation and subsequent NMR analysis....

  1. Synthesis, Solid-State Structure, and Bonding Analysis of a Homoleptic Beryllium Azide.

    Science.gov (United States)

    Naglav, Dominik; Tobey, Briac; Lyhs, Benjamin; Römer, Beate; Bläser, Dieter; Wölper, Christoph; Jansen, Georg; Schulz, Stephan

    2017-07-10

    [Ph 4 P] 2 [Be(N 3 ) 4 ] (1) and [PNP] 2 [Be(N 3 ) 4 ] (2; PNP=Ph 3 PNPPh 3 ) were synthesized by reacting Be(N 3 ) 2 with [Ph 4 P]N 3 and [PNP]N 3 . Compound 1 represents the first structurally characterized homoleptic beryllium azide. The electronic structure and bonding situation in the tetraazidoberyllate dianion [Be(N 3 ) 4 ] 2- were investigated by quantum-chemical calculations (NPA, ELF, LOL). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Allylic azides as potential building blocks for the synthesis of nitrogenated compounds

    Directory of Open Access Journals (Sweden)

    Sá Marcus M.

    2003-01-01

    Full Text Available The synthetic potential of multifunctional allylic azides and imines in attempted intramolecular cyclizations to nitrogen-containing heterocycles was investigated. Tandem Staudinger/aza-Wittig reaction of (E-3-aryl-2-(azidomethylpropenoates with triphenylphosphine and aldehydes yielded N-allylic imines in good yield. The (E-stereochemistry of C=C and C=N bonds was assigned based on NOESY experiments. AlCl3 mediated formation of 3-carbomethoxyquinoline from methyl (E-2-(azidomethyl-3-phenylpropenoate is also described.

  3. Copper-Catalyzed Sulfonyl Azide-Alkyne Cycloaddition Reactions: Simultaneous Generation and Trapping of Copper-Triazoles and -Ketenimines for the Synthesis of Triazolopyrimidines.

    Science.gov (United States)

    Nallagangula, Madhu; Namitharan, Kayambu

    2017-07-07

    First simultaneous generation and utilization of both copper-triazole and -ketenimine intermediates in copper-catalyzed sulfonyl azide-alkyne cycloaddition reactions is achieved for the one-pot synthesis of triazolopyrimidines via a novel copper-catalyzed multicomponent cascade of sulfonyl azides, alkynes, and azirines. Significantly, the reaction proceeds under very mild conditions in good yields.

  4. Fourier transform infrared spectroscopy of azide and cyanate ion pairs in AOT reverse micelles

    Science.gov (United States)

    Owrutsky, Jeffrey C.; Pomfret, Michael B.; Barton, David J.; Kidwell, David A.

    2008-07-01

    Evidence for ion pair formation in aqueous bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles (RMs) was obtained from infrared spectra of azide and cyanate with Li+, Na+, K+, and NH4+ counterions. The anions' antisymmetric stretching bands near 2000 cm-1 are shifted to higher frequency (blueshifted) in LiAOT and to a lesser extent in NaAOT, but they are very similar to those in bulk water with K+ and NH4+ as the counterions. The shifts are largest for low values of wo=[water]/[AOT] and approach the bulk value with increasing wo. The blueshifts are attributed to ion pairing between the anions and the counterions. This interpretation is reinforced by the similar trend (Li+>Na+>K+) for producing contact ion pairs with the metal cations in bulk dimethyl sulfoxide (DMSO) solutions. We find no evidence of ion pairs being formed in NH4AOT RMs, whereas ammonium does form ion pairs with azide and cyanate in bulk DMSO. Studies are also reported for the anions in formamide-containing AOT RMs, in which blueshifts and ion pair formation are observed more than in the aqueous RMs. Ion pairs are preferentially formed in confined RM systems, consistent with the well established ideas that RMs exhibit reduced polarity and a disrupted hydrogen bonding network compared to bulk water and that ion-specific effects are involved in mediating the structure of species at interfaces.

  5. Theoretical investigation of some high-performance novel amine azide propellants

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, Debasis [Computational Fluid Dynamics Research Corp., Huntsville, AL 35805 (United States); Raman, Sumathi [Department of Chemistry, Oakwood College, 2000 Adventist Blvd., Huntsville, AL 35896 (United States)

    2007-08-15

    Monomethylhydrazine (MMH) is currently the most widely used hypergolic propellant, due to its high performance and low ignition delay. However, its toxicity is a major concern. The present work aims at developing high-performance hypergolic fuels that are based on tertiary amine azide functionality. A number of potential amine azide candidates have been proposed, and some of their physical and chemical properties have been computed using state-of-the-art molecular modeling techniques. Gas-phase heats of formation have been calculated using the CBS-QB3 method, and the first-principle COSMO-RS method has been used to compute heats of vaporization and vapor pressures. A density correlation, based on molecular-volume calculation, has been established to predict the densities of the candidate molecules. Finally, the liquid-phase heats of formation and densities have been used to predict the specific and density impulses of the proposed candidate molecules. The results show that many of the molecules proposed here have much higher density impulse than that of MMH, and may be considered for experimental studies. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  6. Rice mutants obtained through sodium azide (NaN3) treatment

    International Nuclear Information System (INIS)

    Silva, E.F.; Ando, A.; Tulmann Neto, A.

    2001-01-01

    The successful utilization of sodium azide to generate genetic variability in plant breeding has been reported in barley, rice, and other crops. Rice seeds of 'Dourado Precoce', Brazilian upland cultivar, were treated with 5x10 -3 M of sodium azide, prepared in buffer solution of pH 3,0, for 8 hours at laboratory temperature. Ten short culm mutant lines were selected in the M 2 , M 3 and M 4 generations. In the M 5 generation, the mutant lines were evaluated for flowering and maturing cycles, tiller number per plant, plant height, panicle number per m 2 , panicle length, fertility of panicle, weight of 1.000 grains, productivity, percentage of intact grains after milling, width and thickness of peeled and polished grains and length/width grain ratio. The experiment was conducted in the Centro Experimental of Instituto Agronomico, Campinas, Sao Paulo, Brazil, during the period of 1993/94, utilizing randomized block design with four replications. Each experimental plot consisted of five rows of four meters in length, 50 cm between rows, with 75 seeds sown per meter. The cultivar 'IAC 201' and the original Dourado Precoce were planted as checks. All observations were made on the three central rows of each experimental plot. The data was analysed by the SANEST statistical program and the mean values were discriminated by the Tukey's test at the level 5% of probability

  7. Ratiometric Fluorescence Azide-Alkyne Cycloaddition for Live Mammalian Cell Imaging.

    Science.gov (United States)

    Fu, Hongxia; Li, Yanru; Sun, Lingbo; He, Pan; Duan, Xinrui

    2015-11-17

    Click chemistry with metabolic labeling has been widely used for selectively imaging biomacromolecules in cells. The first example of azide-alkyne cycloaddition for ratiometric fluorescent imaging of live cells is reported. The precursor of the azido fluorophore (cresyl violet) has a fluorescence emission peak at 620 nm. The electron-rich nitrogen of the azido group blue-shifts the emission peak to 566 nm. When the click reaction occurs, an emission peak appears at 620 nm due to the lower electronic density of the newly formed triazole ring, which allows us to ratiometrically record fluorescence signals. This emission shift was applied to ratiometric imaging of propargylcholine- and dibenzocyclooctyne-labeled human breast cancer cells MCF-7 under laser confocal microscopy. Two typical triazole compounds were isolated for photophysical parameter measurements. The emission spectra presented a fluorescence emission peak around 620 nm for both click products. The results further confirmed the emission wavelength change was the result of azide-alkyne cycloaddition reaction. Since nearly all biomolecules can be metabolically labeled by reported alkyne-functionalized derivatives of native metabolites, our method can be readily applied to image these biomacromolecules.

  8. Rational Design in Catalysis: A Mechanistic Study of β-Hydride Eliminations in Gold(I) and Gold(III) Complexes Based on Features of the Reaction Valley.

    Science.gov (United States)

    Castiñeira Reis, Marta; López, Carlos Silva; Kraka, Elfi; Cremer, Dieter; Faza, Olalla Nieto

    2016-09-06

    β-Hydride eliminations for ethylgold(III) dichloride complexes are identified as reactions with an unusually long prechemical stage corresponding to the conformational preparation of the reaction complex and spanning six phases. The prechemical process is characterized by a geared rotation of the L-Au-L group (L = Cl) driving methyl group rotation and causing a repositioning of the ligands. This requires more than 28 kcal/mol of the total barrier of 34.0 kcal/mol, according to the unified reaction valley approach, which also determines that the energy requirements of the actual chemical process leading to the β-elimination product are only about 5.5 kcal/mol. A detailed mechanistic analysis was used as a basis for a rational design of substrates (via substituents on the ethyl group) and/or ligands, which can significantly reduce the reaction barrier. This strategy takes advantage of either a higher trans activity of the ligands or a tuned electronic demand of the ethyl group. The β-hydride elimination of gold(I) was found to suffer from strong Coulomb and exchange repulsion when a positively charged hydrogen atom enforces a coordination position in a d(10)-configured gold atom, thus triggering an unassisted σ-π Au(I)-C conversion.

  9. Development of a general methodology for labelling peptide-morpholino oligonucleotide conjugates using alkyne-azide click chemistry.

    Science.gov (United States)

    Shabanpoor, Fazel; Gait, Michael J

    2013-11-11

    We describe a general methodology for fluorescent labelling of peptide conjugates of phosphorodiamidate morpholino oligonucleotides (PMOs) by alkyne functionalization of peptides, subsequent conjugation to PMOs and labelling with a fluorescent compound (Cy5-azide). Two peptide-PMO (PPMO) examples are shown. No detrimental effect of such labelled PMOs was seen in a biological assay.

  10. Solid-phase synthesis of NH-1,2,3-triazoles using 4,4′- bismethoxybenzhydryl azide

    DEFF Research Database (Denmark)

    Cohrt, Anders Emil O'Hanlon; Le Quement, Sebastian Thordal; Nielsen, Thomas Eiland

    2014-01-01

    Readily available 4,4′-bismethoxybenzhydryl azide was found to be a useful building block for the synthesis of NH-1,2,3-triazoles through copper(I)-catalyzed cycloaddition reactions with solid-supported terminal alkynes, followed by acid-mediated deprotection. Peptide-containing NH-1,2,3-triazole...

  11. Target and identify: triazene linker helps identify azidation sites of labelled proteins via click and cleave strategy.

    Science.gov (United States)

    Lohse, Jonas; Schindl, Alexandra; Danda, Natasha; Williams, Chris P; Kramer, Karl; Kuster, Bernhard; Witte, Martin D; Médard, Guillaume

    2017-10-31

    A method for identifying probe modification of proteins via tandem mass spectrometry was developed. Azide bearing molecules are immobilized on functionalised sepharose beads via copper catalysed Huisgen-type click chemistry and selectively released under acidic conditions by chemical cleavage of the triazene linkage. We applied this method to identify the modification site of targeted-diazotransfer on BirA.

  12. Determination of gold osmium and ruthenium through iodine-azide reaction in presence of 2- or 6- mercaptopurine

    International Nuclear Information System (INIS)

    Matusiewicz, H.; Kurzawa, Z.

    1978-01-01

    The composition of osmium and ruthenium complexes with 6-mercaptopurine has been determined. The sensitivity of the method was enhanced due to a proper choice of the optimal time of the formation of these complexes and the time of equilibrium attainment in the presence of excess of azide. Also the gold complex with 2-mercaptopurine was investigated. (author)

  13. Azide-Alkyne Huisgen [3+2] Cycloaddition Using CuO Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hyunjoon Song

    2012-11-01

    Full Text Available Recent developments in the synthesis of CuO nanoparticles (NPs and their application to the [3+2] cycloaddition of azides with terminal alkynes are reviewed. With respect to the importance of click chemistry, CuO hollow NPs, CuO hollow NPs on acetylene black, water-soluble double-hydrophilic block copolymer (DHBC nanoreactors and ZnO–CuO hybrid NPs were synthesized. Non-conventional energy sources such as microwaves and ultrasound were also applied to these click reactions, and good catalytic activity with high regioselectivity was observed. CuO hollow NPs on acetylene black can be recycled nine times without any loss of activity, and water-soluble DHBC nanoreactors have been developed for an environmentally friendly process.

  14. Relative Performance of Alkynes in Copper-Catalyzed Azide-Alkyne Cycloaddition

    Science.gov (United States)

    Kislukhin, Alexander A.; Hong, Vu P.; Breitenkamp, Kurt E.; Finn, M.G.

    2013-01-01

    Copper-catalyzed azide–alkyne cycloaddition (CuAAC) has found numerous applications in a variety of fields. We report here only modest differences in the reactivity of various classes of terminal alkynes under typical bioconjugative and preparative organic conditions. Propargyl compounds represent an excellent combination of azide reactivity, ease of installation, and cost. Electronically activated propiolamides are slightly more reactive, at the expense of increased propensity for Michael addition. Certain alkynes, including tertiary propargyl carbamates, are not suitable for bioconjugation due to copper-induced fragmentation. A fluorogenic probe based on such reactivity is available in one step from rhodamine 110 and can be useful for optimization of CuAAC conditions. PMID:23566039

  15. Synthesis, solid-state structure, and bonding analysis of a homoleptic beryllium azide

    Energy Technology Data Exchange (ETDEWEB)

    Naglav, Dominik; Tobey, Briac; Lyhs, Benjamin; Roemer, Beate; Blaeser, Dieter; Woelper, Christoph; Jansen, Georg; Schulz, Stephan [Faculty of Chemistry and Center for Nanointegration Duisburg-Essen (Cenide), Duisburg-Essen Univ., Essen (Germany)

    2017-07-10

    [Ph{sub 4}P]{sub 2}[Be(N{sub 3}){sub 4}] (1) and [PNP]{sub 2}[Be(N{sub 3}){sub 4}] (2; PNP=Ph{sub 3}PNPPh{sub 3}) were synthesized by reacting Be(N{sub 3}){sub 2} with [Ph{sub 4}P]N{sub 3} and [PNP]N{sub 3}. Compound 1 represents the first structurally characterized homoleptic beryllium azide. The electronic structure and bonding situation in the tetraazidoberyllate dianion [Be(N{sub 3}){sub 4}]{sup 2-} were investigated by quantum-chemical calculations (NPA, ELF, LOL). (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Lithium Azide as an Electrolyte Additive for All-Solid-State Lithium-Sulfur Batteries.

    Science.gov (United States)

    Eshetu, Gebrekidan Gebresilassie; Judez, Xabier; Li, Chunmei; Bondarchuk, Oleksandr; Rodriguez-Martinez, Lide M; Zhang, Heng; Armand, Michel

    2017-11-27

    Of the various beyond-lithium-ion battery technologies, lithium-sulfur (Li-S) batteries have an appealing theoretical energy density and are being intensely investigated as next-generation rechargeable lithium-metal batteries. However, the stability of the lithium-metal (Li°) anode is among the most urgent challenges that need to be addressed to ensure the long-term stability of Li-S batteries. Herein, we report lithium azide (LiN 3 ) as a novel electrolyte additive for all-solid-state Li-S batteries (ASSLSBs). It results in the formation of a thin, compact and highly conductive passivation layer on the Li° anode, thereby avoiding dendrite formation, and polysulfide shuttling. It greatly enhances the cycling performance, Coulombic and energy efficiencies of ASSLSBs, outperforming the state-of-the-art additive lithium nitrate (LiNO 3 ). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Electronic effects of ruthenium-catalyzed [3+2]-cycloaddition of alkynes and azides

    KAUST Repository

    Hou, Duenren

    2010-11-01

    A combined experimental and theoretical study of ruthenium-catalyzed azide-alkyne cycloaddition (RuAAC) reactions is presented and various electronic analyses were conducted to provide a basis in understanding the observed regioselectivity of the 1,2,3-triazole products. Computational studies using density functional theory (DFT) and atoms in molecules quantum theory (AIM) further yield fresh details on the electronic factors that determine the regioselectivity in the RuAAC. It is found that the formation of 1,2,3-triazole products is irreversible and from the Hammett study, the pathway involving a vinyl cationic intermediate is ruled out. The electronic effect favors the formation of 5-electron-donating-group substituted-1,2,3-trizoles. © 2010 Elsevier Ltd. All rights reserved.

  18. Electronic effects of ruthenium-catalyzed [3+2]-cycloaddition of alkynes and azides

    KAUST Repository

    Hou, Duenren; Kuan, Tingchun; Li, YuKai; Lee, Richmond; Huang, Kuo-Wei

    2010-01-01

    A combined experimental and theoretical study of ruthenium-catalyzed azide-alkyne cycloaddition (RuAAC) reactions is presented and various electronic analyses were conducted to provide a basis in understanding the observed regioselectivity of the 1,2,3-triazole products. Computational studies using density functional theory (DFT) and atoms in molecules quantum theory (AIM) further yield fresh details on the electronic factors that determine the regioselectivity in the RuAAC. It is found that the formation of 1,2,3-triazole products is irreversible and from the Hammett study, the pathway involving a vinyl cationic intermediate is ruled out. The electronic effect favors the formation of 5-electron-donating-group substituted-1,2,3-trizoles. © 2010 Elsevier Ltd. All rights reserved.

  19. Exploring the flexible chemistry of 4-fluoro-3-nitrophenyl azide for biomolecule immobilization and bioconjugation.

    Science.gov (United States)

    Kumar, Saroj; Kumar, Dileep; Ahirwar, Rajesh; Nahar, Pradip

    2016-10-01

    Bioconjugation and functionalization of polymer surfaces are two major tasks in materials chemistry which are accomplished using a variety of coupling agents. Immobilization of biomolecules onto polymer surfaces and the construction of bioconjugates are essential requirements of many biochemical assays and chemical syntheses. Different linkers with a variety of functional groups are used for these purposes. Among them, the benzophenones, aryldiazirines, and arylazides represent the most commonly used photolinker to produce the desired chemical linkage upon their photo-irradiation. In this review, we describe the versatile applications of 4-fluoro-3-nitrophenyl azide, one of the oldest photolinkers used for photoaffinity labeling in the late 1960s. Surprisingly, this photolinker, historically known as 1-fluoro-2-nitro-4-azidobenzene (FNAB), has remained unexplored for a long time because of apprehension that FNAB forms ring-expanded dehydroazepine as a major product and hence cannot activate an inert polymer. The first evidence of photochemical activation of an inert surface by FNAB through nitrene insertion reaction was reported in 2001, and the FNAB-activated surface was found to conjugate a biomolecule without any catalyst, reagent, or modification. FNAB has distinct advantages over perfluorophenyl azide derivatives, which are contemporary nitrene-generating photolinkers, because of its simple, single-step preparation and ease of thermochemical and photochemical reactions with versatile polymers and biomolecules. Covering these aspects, the present review highlights the flexible chemistry of FNAB and its applications in the field of surface engineering, immobilization of biomolecules such as antibodies, enzymes, cells, carbohydrates, oligonucleotides, and DNA aptamers, and rapid diagnostics. Graphical Abstract An overview of the FNAB-engineered activated polymer surfaces for covalent ligation of versatile biomolecules.

  20. The orbital ground state of the azide-substrate complex of human heme oxygenase is an indicator of distal H-bonding: Implications for the enzyme mechanism‡

    Science.gov (United States)

    Ogura, Hiroshi; Evans, John P.; Peng, Dungeng; Satterlee, James D.; de Montellano, Paul R. Ortiz; Mar, Gerd N. La

    2009-01-01

    The active site electronic structure of the azide complex of substrate-bound human heme oxygenase-1, (hHO) has been investigated by 1H NMR spectroscopy to shed light on the orbital/spin ground state as an indicator of the unique distal pocket environment of the enzyme. 2D 1H NMR assignments of the substrate and substrate-contact residue signals reveal a pattern of substrate methyl contact shifts, that places the lone iron π-spin in the dxz orbital, rather than the dyz orbital found in the cyanide complex. Comparison of iron spin relaxivity, magnetic anisotropy and magnetic susceptibilities argues for a low-spin, (dxy)2(dyz,dxz)3, ground state in both azide and cyanide complexes. The switch from singly-occupied dyz for the cyanide to dxz for the azide complex of hHO is shown to be consistent with the orbital hole determined by the azide π-plane in the latter complex, which is ∼90° in-plane rotated from that of the imidazole π-plane. The induction of the altered orbital ground state in the azide relative to the cyanide hHO complex, as well as the mean low-field bias of methyl hyperfine shifts and their paramagnetic relaxivity relative to those in globins, indicate that azide exerts a stronger ligand field in hHO than in the globins, or that the distal H-bonding to azide is weaker in hHO than in globins. The Asp140 → Ala hHO mutant that abolishes activity retains the unusual WT azide complex spin/orbital ground state. The relevance of our findings for other HO complexes and the HO mechanism is discussed. PMID:19243105

  1. The orbital ground state of the azide-substrate complex of human heme oxygenase is an indicator of distal H-bonding: implications for the enzyme mechanism.

    Science.gov (United States)

    Ogura, Hiroshi; Evans, John P; Peng, Dungeng; Satterlee, James D; Ortiz de Montellano, Paul R; La Mar, Gerd N

    2009-04-14

    The active site electronic structure of the azide complex of substrate-bound human heme oxygenase 1 (hHO) has been investigated by (1)H NMR spectroscopy to shed light on the orbital/spin ground state as an indicator of the unique distal pocket environment of the enzyme. Two-dimensional (1)H NMR assignments of the substrate and substrate-contact residue signals reveal a pattern of substrate methyl contact shifts that places the lone iron pi-spin in the d(xz) orbital, rather than the d(yz) orbital found in the cyanide complex. Comparison of iron spin relaxivity, magnetic anisotropy, and magnetic susceptibilities argues for a low-spin, (d(xy))(2)(d(yz),d(xz))(3), ground state in both azide and cyanide complexes. The switch from singly occupied d(yz) for the cyanide to d(xz) for the azide complex of hHO is shown to be consistent with the orbital hole determined by the azide pi-plane in the latter complex, which is approximately 90 degrees in-plane rotated from that of the imidazole pi-plane. The induction of the altered orbital ground state in the azide relative to the cyanide hHO complex, as well as the mean low-field bias of methyl hyperfine shifts and their paramagnetic relaxivity relative to those in globins, indicates that azide exerts a stronger ligand field in hHO than in the globins, or that the distal H-bonding to azide is weaker in hHO than in globins. The Asp140 --> Ala hHO mutant that abolishes activity retains the unusual WT azide complex spin/orbital ground state. The relevance of our findings for other HO complexes and the HO mechanism is discussed.

  2. Gamma ray, EMS and sodium azide induced effectiveness and efficiency of chlorophyll mutations in basmati rice (Oryza sativa L.)

    International Nuclear Information System (INIS)

    Singh, Sanjeev; Singh, J.; Singh, R.K.

    2001-01-01

    The effectiveness and efficiency of gamma ray, EMS, sodium azide alone or in combination in relation to chlorophyll mutations in two varieties of Basmati rice (Oryza sativa L.) in M 2 generation were studied. The chlorophyll mutations were induced by all the doses of mutagens alone or in combination relatively at a fair frequency in both the varieties in M 2 generation. In general, it was found that combination treatments of gamma rays and EMS were observed to be more efficient in Taraori Basmati, while EMS alone and combination treatment of gamma rays and EMS were more efficient in Pusa Basmati 1 on sterility and growth injury basis both. Sodium azide at 0.5 mM was found as the most effective dose in both Taraori Basmati and Pusa Basmati 1 cultivars. (author)

  3. Detection of Alkynes via Click Chemistry with a Brominated Coumarin Azide by Simultaneous Fluorescence and Isotopic Signatures in Mass Spectrometry.

    Science.gov (United States)

    Yang, Lihua; Chumsae, Chris; Kaplan, Jenifer B; Moulton, Kevin Ryan; Wang, Dongdong; Lee, David H; Zhou, Zhaohui Sunny

    2017-09-20

    Alkynes are a key component of click chemistry and used for a wide variety of applications including bioconjugation, selective tagging of protein modifications, and labeling of metabolites and drug targets. However, challenges still exist for detecting alkynes because most 1,2,3-triazole products from alkynes and azides do not possess distinct intrinsic properties that can be used for their facile detection by either fluorescence or mass spectrometry. To address this critical need, a novel brominated coumarin azide was used to tag alkynes and detect alkyne-conjugated biomolecules. This tag has several useful properties: first, it is fluorogenic and the click-chemistry products are highly fluorescent and quantifiable; second, its distinct isotopic pattern facilitates identification by mass spectrometry; and third, its click-chemistry products form a unique pair of reporter ions upon fragmentation that can be used for the quick screening of data. Using a monoclonal antibody conjugated with alkynes, a general workflow has been developed and examined comprehensively.

  4. [1+1+3] Annulation of Diazoenals and Vinyl Azides: Direct Synthesis of Functionalized 1-Pyrrolines through Olefination.

    Science.gov (United States)

    Kanchupalli, Vinaykumar; Katukojvala, Sreenivas

    2018-05-04

    A dirhodium carboxylate catalyzed [1+1+3] annulation reaction of diazoenals and vinyl azides that gives synthetically important enal-functionalized 1-pyrroline derivatives was developed. The reaction involves a novel rhodium-catalyzed olefination of diazoenals with vinyl azides via electrophilic enal carbenoids, resulting in a new class of enal acrylates. The annulation reaction was used for the direct synthesis of valuable deuterated 1-pyrrolines. Structural diversification of the enal-functionalized 1-pyrrolines resulted in the biologically important pyrrolidine-fused oxaziridine, amino acid derivatives, and a 6-azabicyclo[3.2.1]octane motif present in polycyclic alkaloids. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. The effects of sodium azide on seed germination and seedling growth of chili pepper (Capsicum annum L. cv. Landung)

    Science.gov (United States)

    Yafizham; Herwibawa, B.

    2018-01-01

    This study was aimed to determine the effects of sodium azide on the performance of chili pepper. Dry seeds from pure lines of chili pepper cv. Landung were used in this experiment. Each set containing 50 seeds was placed in nylon fishner bags, washed in flowing water and soaked in distilled water for four hours. After soaking, four sets of seeds were dabbed dry with tissue paper and were treated for two hours at 30 0C in appropriate solution of 0, 0.10, 0.20, 0.40, 0.80, 1.60 mM sodium azide with phosphate buffer at pH 3. After treatment, the seeds were germinated in plastic boxes containing sterilized sand and kept under laboratory condition by supplied with water everyday. The seeds for M1 germination percentage, seedling height, plant height and number of leaves were recorded 30 days and 60 days after treatment, respectively. Seeds which radicle emerged were considered germinated, the seedling and plant height were measured from the tip of primary root to the base of the first leaf pair, and the number of leaves were counted for only fully expanded leaves. A completely randomized block design in four replicates was used throughout the experiment. Data obtained were analysed for range, mean, standard of deviation, and percent of control using Microsoft Office Excel 2007 software. It was concluded that different doses of sodium azide influenced the performances of chili pepper cv. Landung. Very low doses of sodium azide (0-1.60 mM) might be used to study the improvement of chili pepper diversity.

  6. Recent Advances in Recoverable Systems for the Copper-Catalyzed Azide-Alkyne Cycloaddition Reaction (CuAAC

    Directory of Open Access Journals (Sweden)

    Alessandro Mandoli

    2016-09-01

    Full Text Available The explosively-growing applications of the Cu-catalyzed Huisgen 1,3-dipolar cycloaddition reaction between organic azides and alkynes (CuAAC have stimulated an impressive number of reports, in the last years, focusing on recoverable variants of the homogeneous or quasi-homogeneous catalysts. Recent advances in the field are reviewed, with particular emphasis on systems immobilized onto polymeric organic or inorganic supports.

  7. Alkyne-Azide Cycloaddition Catalyzed by Silver Chloride and “Abnormal” Silver N-Heterocyclic Carbene Complex

    Directory of Open Access Journals (Sweden)

    Aldo I. Ortega-Arizmendi

    2013-01-01

    Full Text Available A library of 1,2,3-triazoles was synthesized from diverse alkynes and azides using catalytic amounts of silver chloride instead of copper compounds. In addition, a novel “abnormal” silver N-heterocyclic carbene complex was tested as catalyst in this process. The results suggest that the reaction requires only 0.5% of silver complex, affording 1,2,3-triazoles in good yields.

  8. In situ generation of the Ohira-Bestmann reagent from stable sulfonyl azide: scalable synthesis of alkynes from aldehydes.

    Science.gov (United States)

    Jepsen, Tue Heesgaard; Kristensen, Jesper Langgaard

    2014-10-03

    We report an improved method for in situ generation of the Ohira-Bestmann reagent. Using the recently reported bench-stable imidazole-1-sulfonyl azide as diazotransfer reagent, this new method represents a scalable and convenient approach for the transformation of aldehydes into terminal alkynes. The method features an easier workup compared to the existing in situ protocol due to increased aqueous solubility of waste products.

  9. Synthesis of novel bis(perfluorophenyl azides) coupling agents: Evaluation of their performance by crosslinking of poly(ethylene oxide)

    KAUST Repository

    Mehenni, Hakim

    2011-11-01

    Novel bis(perfluorophenyl azides) coupling agents, containing spacer arms from ethylene or ethylene glycol subunits, were successfully synthesized. Nitrenes photogenerated from these novel bis(PFPA) coupling agents were applied successfully to the cross-linking of poly(ethylene oxide) (PEO10,000) in either aqueous medium or at the solid state, thus, we demonstrated the potential of these bis(PFPA) molecules as promising coupling agents in surface engineering. © 2011 Elsevier Ltd. All rights reserved.

  10. Sequential continuous flow processes for the oxidation of amines and azides by using HOF·MeCN.

    Science.gov (United States)

    McPake, Christopher B; Murray, Christopher B; Sandford, Graham

    2012-02-13

    The generation and use of the highly potent oxidising agent HOF·MeCN in a controlled single continuous flow process is described. Oxidations of amines and azides to corresponding nitrated systems by using fluorine gas, water and acetonitrile by sequential gas-liquid/liquid-liquid continuous flow procedures are reported. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Direct Functionalization of an Acid-Terminated Nanodiamond with Azide: Enabling Access to 4-Substituted-1,2,3-Triazole-Functionalized Particles

    International Nuclear Information System (INIS)

    Kennedy, Zachary C.; Barrett, Christopher A.; Warner, Marvin G.

    2017-01-01

    Azides on the periphery of nanodiamond materials (ND) are of great utility because they have been shown to undergo Cu-catalyzed and Cu-free cycloaddition reactions with structurally diverse alkynes, affording particles tailored for applications in biology and materials science. However, current methods employed to access ND featuring azide groups typically require either harsh pretreatment procedures or multiple synthesis steps and use surface linking groups that may be susceptible to undesirable cleavage. Here in this paper we demonstrate an alternative single-step approach to producing linker-free, azide-functionalized ND. Our method was applied to low-cost, detonation-derived ND powders where surface carbonyl groups undergo silver-mediated decarboxylation and radical substitution with azide. ND with directly grafted azide groups were then treated with a variety of aliphatic, aromatic, and fluorescent alkynes to afford 1-(ND)-4-substituted-1,2,3-triazole materials under standard copper-catalyzed cycloaddition conditions. Surface modification steps were verified by characteristic infrared absorptions and elemental analyses. High loadings of triazole surface groups (up to 0.85 mmol g –1 ) were obtained as determined from thermogravimetric analysis. The azidation procedure disclosed is envisioned to become a valuable initial transformation in numerous future applications of ND.

  12. Direct Functionalization of an Acid-Terminated Nanodiamond with Azide: Enabling Access to 4-Substituted-1,2,3-Triazole-Functionalized Particles.

    Science.gov (United States)

    Kennedy, Zachary C; Barrett, Christopher A; Warner, Marvin G

    2017-03-21

    Azides on the periphery of nanodiamond materials (ND) are of great utility because they have been shown to undergo Cu-catalyzed and Cu-free cycloaddition reactions with structurally diverse alkynes, affording particles tailored for applications in biology and materials science. However, current methods employed to access ND featuring azide groups typically require either harsh pretreatment procedures or multiple synthesis steps and use surface linking groups that may be susceptible to undesirable cleavage. Here we demonstrate an alternative single-step approach to producing linker-free, azide-functionalized ND. Our method was applied to low-cost, detonation-derived ND powders where surface carbonyl groups undergo silver-mediated decarboxylation and radical substitution with azide. ND with directly grafted azide groups were then treated with a variety of aliphatic, aromatic, and fluorescent alkynes to afford 1-(ND)-4-substituted-1,2,3-triazole materials under standard copper-catalyzed cycloaddition conditions. Surface modification steps were verified by characteristic infrared absorptions and elemental analyses. High loadings of triazole surface groups (up to 0.85 mmol g -1 ) were obtained as determined from thermogravimetric analysis. The azidation procedure disclosed is envisioned to become a valuable initial transformation in numerous future applications of ND.

  13. Improved metal-adhesive polymers from copper(I)-catalyzed azide-alkyne cycloaddition.

    Science.gov (United States)

    Accurso, Adrian A; Delaney, Mac; O'Brien, Jeff; Kim, Hyonny; Iovine, Peter M; Díaz Díaz, David; Finn, M G

    2014-08-18

    Electrically conductive adhesive polymers offer many potential advantages relative to Sn-Pb solders, including reduced toxicity, low cost, low processing temperatures, and the ability to make application-specific formulations. Polymers generated from the copper(I)-catalyzed cycloaddition (CuAAC) reaction between multivalent azides and alkynes have previously been identified as strong metal-binding adhesives. Herein we demonstrate that the performance of these materials can be remarkably improved by the incorporation of a flexibility-inducing difunctionalized component and a tertiary amine additive in optimized concentrations. The best formulations were identified by means of rapid adhesion testing of a library of potential candidates by using a custom-built instrument and validated in an American Society for Testing and Materials (ASTM)-standard lap-shear test. Characteristic phase transitions were identified by differential scanning calorimetry (DSC) for adhesives with and without the additives as a function of curing temperature. The incorporation of flexible components was found to more than double the strength of the adhesive. Moreover, the adhesive was made electrically conductive by the inclusion of 20 wt% silver-coated copper flakes and further improved in this regard by the incorporation of multiwalled carbon nanotubes in the formulation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Azide-based cross-linking of polymers of intrinsic microporosity (PIMs) for condensable gas separation

    KAUST Repository

    Du, Naiying; Dal-Cin, Mauro M D; Pinnau, Ingo; Nicalek, Andrzej; Robertson, Gilles P.; Guiver, Michael D.

    2011-01-01

    Cross-linked polymers of intrinsic microporosity (PIM)s for gas separation membranes, were prepared by a nitrene reaction from a representative PIM in the presence of two different diazide cross-linkers. The reaction temperature was optimized using TGA. The homogenous membranes were cast from THF solutions of different ratios of PIM to azides. The resulting cross-linked structures of the PIMs membranes were formed at 175 °C after 7.5 h and confirmed by TGA, XPS, FT-IR spectroscopy and gel content analysis. These resulting cross-linked polymeric membranes showed excellent gas separation performance and can be used for O 2/N 2 and CO 2/N 2 gas pairs, as well as for condensable gases, such as CO 2/CH 4, propylene/propane separation. Most importantly, and differently from typical gas separation membranes derived from glassy polymers, the crosslinked PIMs showed no obvious CO 2 plasticization up to 20 atm pressure of pure CO 2 and CO 2/CH 4 mixtures. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Azide-based cross-linking of polymers of intrinsic microporosity (PIMs) for condensable gas separation

    KAUST Repository

    Du, Naiying

    2011-03-11

    Cross-linked polymers of intrinsic microporosity (PIM)s for gas separation membranes, were prepared by a nitrene reaction from a representative PIM in the presence of two different diazide cross-linkers. The reaction temperature was optimized using TGA. The homogenous membranes were cast from THF solutions of different ratios of PIM to azides. The resulting cross-linked structures of the PIMs membranes were formed at 175 °C after 7.5 h and confirmed by TGA, XPS, FT-IR spectroscopy and gel content analysis. These resulting cross-linked polymeric membranes showed excellent gas separation performance and can be used for O 2/N 2 and CO 2/N 2 gas pairs, as well as for condensable gases, such as CO 2/CH 4, propylene/propane separation. Most importantly, and differently from typical gas separation membranes derived from glassy polymers, the crosslinked PIMs showed no obvious CO 2 plasticization up to 20 atm pressure of pure CO 2 and CO 2/CH 4 mixtures. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Determination of azide in biological fluids by use of electron paramagnetic resonance

    International Nuclear Information System (INIS)

    Minakata, Kayoko; Suzuki, Osamu

    2005-01-01

    A simple and sensitive method has been developed for the determination of azide ion (N 3 - ) in biological fluids and beverages. The procedure was based on the formation of a ternary complex Cu(N 3 ) 2 (4-methylpyridine) x in benzene, followed by its detection by electron paramagnetic resonance. The complex in benzene showed a characteristic four-peak hyperfine structure with a g-value of 2.115 at room temperature. Cu 2+ reacted with N 3 - most strongly among common metals found in biological fluids. Several anions and metal ions in biological fluids did not interfere with the determination of N 3 - in the presence of large amounts of Cu 2+ and oxidants. In the present method, N 3 - at the concentration from 5 μM to 2 mM in 100 μl solution could be determined with the detection limit of 20 ng. The recoveries were more than 95% for N 3 - added to 100 μl of blood, urine, milk and beverages at 200 μM. Our method is recommendable because it takes less than 10 min to determine N 3 - and the produced complex is quite stable

  17. Mutagenic effectiveness and efficiency of EMS, sodium azide and gamma radiation in chickpea (Cicer arietinum L.)

    International Nuclear Information System (INIS)

    Barshile, J.D.; Apparao, B.J.

    2006-01-01

    Mutagenic effectiveness and efficiency of Ethyl Methane Sulphonate (EMS), Sodium Azide (SA) and gamma radiation on two cultivars of chickpea (Cicer arietinum L), Vijay and Vishwas were evaluated by the biological damages caused by them in M 1 generation and on the basis of frequency of chlorophyll mutations produced in the M 2 generation. All mutagenic treatments of EMS, SA and gamma radiation decreased germination, seedling height, plant survival and pollen fertility in both the cultivars. The extent of effect was dose dependent. LD 50 values of mutagen were found to be helpful for planning experimental mutagenesis in chickpea. Frequency of chlorophyll mutations in M 2 generation was less in Vijay as compared to Vishwas. Mutagenic effectiveness is inversely proportional to the increasing concentrations/doses of mutagens in both the cultivars, except for gamma radiation treatments in the cultivar Vishwas. All three mutagens (except EMS in the Vijay and gamma radiation in the cultivar Vishwas) exhibited gradual decrease in mutagenic efficiency, with an increase in their concentration/dose. (author)

  18. Biosensor Technology Reveals the Disruption of the Endothelial Barrier Function and the Subsequent Death of Blood Brain Barrier Endothelial Cells to Sodium Azide and Its Gaseous Products.

    Science.gov (United States)

    Kho, Dan T; Johnson, Rebecca H; O'Carroll, Simon J; Angel, Catherine E; Graham, E Scott

    2017-09-21

    Herein we demonstrate the sensitive nature of human blood-brain barrier (BBB) endothelial cells to sodium azide and its gaseous product. Sodium azide is known to be acutely cytotoxic at low millimolar concentrations, hence its use as a biological preservative (e.g., in antibodies). Loss of barrier integrity was noticed in experiments using Electric Cell-substrate Impedance Sensing (ECIS) biosensor technology, to measure endothelial barrier integrity continuously in real-time. Initially the effect of sodium azide was observed as an artefact where it was present in antibodies being employed in neutralisation experiments. This was confirmed where antibody clones that were azide-free did not mediate loss of barrier function. A delayed loss of barrier function in neighbouring wells implied the influence of a liberated gaseous product. ECIS technology demonstrated that the BBB endothelial cells had a lower level of direct sensitivity to sodium azide of ~3 µM. Evidence of gaseous toxicity was consistently observed at 30 µM and above, with disrupted barrier function and cell death in neighbouring wells. We highlight the ability of this cellular biosensor technology to reveal both the direct and gaseous toxicity mediated by sodium azide. The sensitivity and temporal dimension of ECIS technology was instrumental in these observations. These findings have substantial implications for the wide use of sodium azide in biological reagents, raising issues of their application in live-cell assays and with regard to the protection of the user. This research also has wider relevance highlighting the sensitivity of brain endothelial cells to a known mitochondrial disruptor. It is logical to hypothesise that BBB endothelial dysfunction due to mitochondrial dys-regulation could have an important but underappreciated role in a range of neurological diseases.

  19. Stereoselective Synthesis of(Z)-4-(2-Bromovinyl)benzenesulfonyl Azide and Its Synthetic Utility for the Transformation to(2)-N-[4-(2-Bromovinyl)benzenesulfonyl]imidates

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wensheng; KUANG Chunxiang; YANG Qing

    2009-01-01

    A novel method for the stereoselective synthesis of(Z)-4-(2-bromovinyl)benzenesulfonyl azide by simultaneous azidation and debrorninative decarboxylation of anti-2,3-dibromo-3-(4-chlorosulfonylphenyl)propanoic acid using NaN3 only was developed.Facile transformation of(Z)-4-(2-bromovinyl)benzenesulfonyl azide to(Z)-N-[4(2-bromovinyl)benzenesulfonyl]imidates was also achieved by Cu-catalyzed three-component coulping of (Z)-4-(2-bromovinyi)benzenesulfonyl azide,terminal alkynes and alcohols/phenols.

  20. Pressure induced polymorphism in ammonium azide (NH{sub 4}N{sub 3})

    Energy Technology Data Exchange (ETDEWEB)

    Medvedev, S.A., E-mail: s.medvedev@mpic.de [Max-Planck-Institute for Chemistry, Postfach 3060, D-55020 Mainz (Germany); Institute fuer Anorganische und Analytische Chemie, Johannes Gutenberg-Universitaet, D-55099 Mainz (Germany); Eremets, M.I. [Max-Planck-Institute for Chemistry, Postfach 3060, D-55020 Mainz (Germany); Evers, J.; Klapoetke, T.M. [Energetic Materials Research, Ludwig-Maximilian University Munich (LMU), Butenandtstrasse 5-13(D), D-81377 Munich (Germany); Palasyuk, T. [Max-Planck-Institute for Chemistry, Postfach 3060, D-55020 Mainz (Germany); Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw (Poland); Trojan, I.A. [Max-Planck-Institute for Chemistry, Postfach 3060, D-55020 Mainz (Germany)

    2011-07-28

    Graphical abstract: Polymorph phase transition is observed in NH{sub 4}N{sub 3} at {approx}3 GPa by pressure dependent Raman studies. The strength of hydrogen bond appears to be modified at the phase transition as illustrated by dependence of N-H stretching frequency on pressure shown on figure. Highlights: {yields} Ammonium azide (NH{sub 4}N{sub 3}) studied at high pressures by Raman spectroscopy. {yields} Phase transition is observed at pressure {approx}3 GPa. {yields} Strength of hydrogen bond appears to be modified at the phase transition. {yields} NH{sub 4}N{sub 3} remain in molecular form up to pressures above 50 GPa. - Abstract: Pressure-dependent Raman spectroscopy studies reveal polymorph phase transition in simple molecular ionic crystal NH{sub 4}N{sub 3} at pressure {approx}3 GPa unobserved by recent abinitio evolutionary structure searches. Hydrogen bonding is spectroscopically evident in both low- and high-pressure phases. The strength of hydrogen bond appears to be modified at the phase transition: in the low-pressure phase NH{sub 4}N{sub 3} behaves as system with very strong hydrogen bonding whereas changes of spectra with pressure in the high-pressure phase are indicative of weak or medium-strength hydrogen bonds. The high pressure phase is most likely thermodynamically stable at least up to pressure {approx}55 GPa contradicting the abinitio studies predicting transformation of NH{sub 4}N{sub 3} to nonmolecular hydronitrogen solid at 36 GPa.

  1. Photografting of perfluoroalkanes onto polyethylene surfaces via azide/nitrene chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Siegmann, Konstantin, E-mail: konstantin.siegmann@zhaw.ch [Institute of Materials and Process Engineering (IMPE), School of Engineering (SoE), Zurich University of Applied Sciences - ZHAW, Technikumstrasse 9, CH-8401 Winterthur (Switzerland); Inauen, Jan, E-mail: jan.inauen@zhaw.ch [Institute of Materials and Process Engineering (IMPE), School of Engineering (SoE), Zurich University of Applied Sciences - ZHAW, Technikumstrasse 9, CH-8401 Winterthur (Switzerland); Villamaina, Diego, E-mail: diego.villamaina@gmail.com [Visiting scientist at IMPE, Permanent address: Rapidplatz 3, CH-8953 Dietikon (Switzerland); Winkler, Martin, E-mail: martin.winkler@zhaw.ch [Institute of Materials and Process Engineering (IMPE), School of Engineering (SoE), Zurich University of Applied Sciences - ZHAW, Technikumstrasse 9, CH-8401 Winterthur (Switzerland)

    2017-02-28

    The purpose of this study is to render polyethylene surfaces strongly and permanently hydrophobic. Polyethylene is a common plastic and, because of its inertness, difficult to graft. We chose polyethylene as example because of its ubiquity and model character. As graft chains linear perfluoroalkyl residues (−C{sub 4}F{sub 9}, −C{sub 6}F{sub 13}, −C{sub 8}F{sub 17} and −C{sub 10}F{sub 21}) were chosen, and photografting was selected as grafting method. Photolytically generated nitrenes can insert into carbon–hydrogen bonds and are therefore suited for binding to polyethylene. Hydrophobic photo reactive surface modifiers based on azide/nitrene chemistry are designed, synthesized in high yield and characterized. Four new molecules are described. Water contact angles exceeding 110° were achieved on grafted polyethylene. One problem is to demonstrate that the photografted surface modifiers are bound covalently to the polyethylene. Abrasion tests show that all new molecules, when photografted to polyethylene, have a higher abrasion resistance than a polyethylene surface coated with a long-chain perfluoroalkane. Relative abrasion resitances of 1.4, 2.0, 2.1 and 2.5 compared to the fluoroalkane coating were obtained for the four compounds. An abrasion model using ice is developed. Although all four compounds have the same λ{sub max} of 266 nm in acetonitrile solution, their molar extincition coefficients increase from 1.6·10{sup 4} to 2.2·10{sup 4} with increasing length of the fluorotelomer chain. Exitonic coupling of the chromophores of the surface modifiers is observed for specific molecules in the neat state. A linear correlation of water contact angle with fluorine surface content, as measured by photoelectron spectroscopy, in grafted polyethylene surfaces is established.

  2. Metal-Free Poly-Cycloaddition of Activated Azide and Alkynes toward Multifunctional Polytriazoles: Aggregation-Induced Emission, Explosive Detection, Fluorescent Patterning, and Light Refraction.

    Science.gov (United States)

    Wu, Yongwei; He, Benzhao; Quan, Changyun; Zheng, Chao; Deng, Haiqin; Hu, Rongrong; Zhao, Zujin; Huang, Fei; Qin, Anjun; Tang, Ben Zhong

    2017-09-01

    The metal-free click polymerization (MFCP) of activated alkynes and azides or activated azide and alkynes have been developed into powerful techniques for the construction of polytriazoles without the obsession of metallic catalyst residues problem. However, the MFCP of activated azides and alkynes is rarely applied in preparation of functional polytriazoles. In this paper, soluble multifunctional polytriazoles (PIa and PIb) with high weight-average molecular weights (M w up to 32 000) are prepared via the developed metal-free poly-cycloaddition of activated azide and alkynes in high yields (up to 90%). The resultant PIa and PIb are thermally stable, and show aggregation-induced emission characteristics, enabling their aggregates to detect explosives with superamplification effect. Moreover, thanks to their containing aromatic rings and polar moieties, PIa and PIb exhibit high refractive indices. In addition, they can also be cross-linked upon UV irradiation to generate 2D fluorescent patterning due to their remaining azide groups and containing ester groups. Thus, these multifunctional polytriazoles are potentially applicable in the optoelectronic and sensing fields. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. AuBr3-catalyzed azidation of per-O-acetylated and per-O-benzoylated sugars.

    Science.gov (United States)

    Rajput, Jayashree; Hotha, Srinivas; Vangala, Madhuri

    2018-01-01

    Herein we report, for the first time, the successful anomeric azidation of per- O -acetylated and per- O -benzoylated sugars by catalytic amounts of oxophilic AuBr 3 in good to excellent yields. The method is applicable to a wide range of easily accessible per- O -acetylated and per- O -benzoylated sugars. While reaction with per- O -acetylated and per- O -benzoylated monosaccharides was complete within 1-3 h at room temperature, the per- O -benzoylated disaccharides needed 2-3 h of heating at 55 °C.

  4. Hydrothermal synthesis, characterization, and thermal properties of alumino silicate azide sodalite, Na8[AlSiO4]6(N3)2

    Science.gov (United States)

    Borhade, A. V.; Wakchaure, S. G.; Dholi, A. G.; Kshirsagar, T. A.

    2017-07-01

    First time we report the synthesis, structural characterization and thermal behavior of an unusual N3 - containing alumino-silicate sodalite mineral. Azide sodalite, Na8[AlSiO4]6(N3)2 has been synthesized under hydrothermal conditions at 433 K in steel lined Teflon autoclave. The structural and microstructural properties of azide sodalite mineral was characterized by various methods including FT-IR, XRD, SEM, TGA, and MAS NMR. Crystal structure have been refined by Rietveld method in P\\bar 43n space group, indicating that the N3 - sodalite has cubic in lattice. High temperature study was carried out to see the effect of thermal expansion on cell dimension ( a o) of azide sodalite. Thermal behavior of sodalite was also assessed by thermogravimetric method.

  5. Nonafluorobutanesulfonyl azide as a shelf-stable highly reactive oxidant for the copper-catalyzed synthesis of 1,3-diynes from terminal alkynes.

    Science.gov (United States)

    Suárez, José Ramón; Collado-Sanz, Daniel; Cárdenas, Diego J; Chiara, Jose Luis

    2015-01-16

    Nonafluorobutanesulfonyl azide is a highly efficient reagent for the copper-catalyzed coupling of terminal alkynes to give symmetrical and unsymmetrical 1,3-diynes in good to excellent yields and with good functional group compatibility. The reaction is extremely fast (<10 min), even at low temperature (−78 °C), and requires substoichiometric amounts of a simple copper(I) or copper(II) salt (2–5 mol %) and an organic base (0.6 mol %). A possible mechanistic pathway is briefly discussed on the basis of model DFT theoretical calculations. The quantitative assessment of the safety of use and shelf stability of nonafluorobutanesulfonyl azide has confirmed that this reagent is a superior and safe alternative to other electrophilic azide reagents in use today.

  6. Design and Synthesis of New Chacones Substituted with Azide/Triazole Groups and Analysis of Their Cytotoxicity Towards HeLa Cells

    Directory of Open Access Journals (Sweden)

    José A. F. P. Villar

    2012-08-01

    Full Text Available A series of new chalcones substituted with azide/triazole groups were designed and synthesized, and their cytotoxic activity was evaluated in vitro against the HeLa cell line. O-Alkylation, Claisen-Schmidt condensation and Cu(I-catalyzed cycloaddition of azides with terminal alkynes were applied in key steps. Fifteen compounds were tested against HeLa cells. Compound 8c was the most active molecule, with an IC50 value of 13.03 µM, similar to the value of cisplatin (7.37 µM.

  7. One-pot synthesis of 2,5-dihydropyrroles from terminal alkynes, azides, and propargylic alcohols by relay actions of copper, rhodium, and gold.

    Science.gov (United States)

    Miura, Tomoya; Tanaka, Takamasa; Matsumoto, Kohei; Murakami, Masahiro

    2014-12-01

    Relay actions of copper, rhodium, and gold formulate a one-pot multistep pathway, which directly gives 2,5-dihydropyrroles starting from terminal alkynes, sulfonyl azides, and propargylic alcohols. Initially, copper-catalyzed 1,3-dipolar cycloaddition of terminal alkynes with sulfonyl azides affords 1-sulfonyl-1,2,3-triazoles, which then react with propargylic alcohols under the catalysis of rhodium. The resulting alkenyl propargyl ethers subsequently undergo the thermal Claisen rearrangement to give α-allenyl-α-amino ketones. Finally, a gold catalyst prompts 5-endo cyclization to produce 2,5-dihydropyrroles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Rhodium/Silver-Cocatalyzed Transannulation of N-Sulfonyl-1,2,3-triazoles with Vinyl Azides: Divergent Synthesis of Pyrroles and 2 H-Pyrazines.

    Science.gov (United States)

    Zhang, Lin; Sun, Ge; Bi, Xihe

    2016-11-07

    The first cyclization reaction between vinyl azides and N-sulfonyl-1,2,3-triazoles is reported. A Rh/Ag binary metal catalyst system proved to be necessary for the successful cyclization. By varying the structure of vinyl azides, such reaction allows the divergent synthesis of pyrroles and 2H-pyrazines. The cyclization reactions feature a broad substrate scope, good functional group tolerance, high reaction efficiency, and good to high product yields. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Effect of gamma radiations, ethyl methane sulfonate and sodium azide on the sennoside content in Cassia angustifolia

    International Nuclear Information System (INIS)

    Khalatkar, A.S.; Bhargava, Y.R.

    1987-01-01

    Cassia angustifolia commonly known as Tinnevelly Senna is an excellent source of sennosides. The leaflets of this plant constitute the principal raw material. To investigate the effect(s) of mutagenic treatments on phytochemical characteristics, the sand treated dry seeds of Senna were treated with different doses of gamma radiations, ethyl methane sulfonate and sodium azide for 18 hours duration at 24 ± 2°C. The treated population in M1 generation exhibited different degree of stimulation in growth. Other parameters were also affected by all the three mutagenic treatments. Seeds collected from M1 generation were sown and M2 plant progenies were raised. Morphological mutations with desirable characters were further investigated. Biochemical estimation of sennoside from the leaflets in vegetative and blooming phases was carried out. Of the three mutagens, 0.006% sodium azide yielded maximum sennoside in the vegetative phase; while, in the blooming phase, it was highest with 20 kR of gamma radiations. Seeds of these plant types hold promise for enhancing the sennoside yields per gram of tissue

  10. Development of an improved and early sowing potential variety of jute - binadeshipat-2 using chemical mutagen sodium azide

    International Nuclear Information System (INIS)

    Shamsuzzaman, K.M.; Saha, C.S.; Azad, M.A.K.

    2001-01-01

    Jute is the important agricultural and industrial resource of Bangladesh for earning foreign currency. Seeds of the widely cultivated variety, CVL-1 were treated with 4 mM to 20mM of sodium azide (NaN3). The treated seeds were grown in M1 to M10 generations. A single plant (selection number C-278) was selected from M2 segregating population on the basis of early sowing potential and late flowering. Ten fiber quality characters were tested and it was found that the fiber quality of the mutant had been improved. Hence, the mutagen sodium azide showed extra potentiality to induce fiber quality characters of jute. The strain C-278 was also tested through Preliminary, Advanced, Zonal Yield Trial and Farmers field trial at different locations of the jute growing area in Bangladesh. The field evaluation team of the National Seed Board (NSB) visited most of the trials and reported that at early sowing and overall performance of the strain C-278 was found best than that of the mother variety. Besides these the strain produced 7.5% and 20% higher fiber yield than the mother variety CVL-1 and a local cultivar, D-154, respectively. After evaluation of the Technical Committee of NSB recommended that the strain C-278 may be released as a variety. The National Seed Board released the strain C-278 as a National jute variety under the name Binadeshipat-2 for cultivation in Bangladesh

  11. Magnetic resonance studies on the copper site of dopamine β-monooxygenase in the presence of cyanide and azide anions

    International Nuclear Information System (INIS)

    Obata, A.; Tanaka, H.; Kawazura, H.

    1987-01-01

    In order to elucidate the coordination state of water molecules in the Cu(II) site of dopamine [(3,4-dihydroxyphenyl)ethylamine] β-monooxygenase, measurements of the paramagnetic 1 H nuclear magnetic relaxation rate of solvent water in the enzyme solution containing cyanide or azide as an exogenous ligand were carried out to obtain the values of intrinsic paramagnetic relaxation rate decrements R/sub p/ 1 and R/sub p/ 2 for the ligand-enzyme 1:1 and 2:1 complexes, respectively. R/sub p/ 1 (percent) values were 53 (pH 5.5) and 52 (pH 7.0) for cyanide and 38 (pH 5.5) and 32 (pH 7.0) for azide, while R/sub p/ 2 (percent) values were 98 (pH 5.5) and 96 (pH 7.0) for azide. Although no R/sub p/ 2 values for cyanide were obtained because of its reducing power at the Cu(II) site, the R/sub p/ 1 and R/sub p/ 2 values obtained above prove that the Cu(II) center has two coordinated water molecules that are exchangeable for exogenous ligands at either pH. Supporting evidence was provided by electron paramagnetic resonance (EPR) titration, in which the enzyme solution containing cyanide-enzyme (1:1) complex in an equal proportion to uncomplexed enzyme gave an observed paramagnetic relaxation rate decrement, R/sub p/, of 23%. Another characteristic of the R/sub p/ 1 and R/sub p/ 2 values was their invariability with respect to pH, indicating that the three-dimensional structure of the Cu(II) site is pH-invariant within the range examined. Binding constants of ligand to enzyme K/sub b/ 1 and K/sub b/ 2 for 1:1 and 2:1 complex formation, respectively, were also determined through an analysis of the R/sub p/ values; it was found that K/sub b/ 1 was larger than K/sub b/ 2 irrespective of pH. On the basis of these results, together with the axial-symmetric EPR parameters of the 1:1 complexes, a possible coordination geometry of the two water molecules in the Cu(II) site of the enzyme is suggested

  12. Topological ferrimagnetic behaviours of coordination polymers containing manganese(II) chains with mixed azide and carboxylate bridges and alternating F/AF/AF'/AF'/AF interactions.

    Science.gov (United States)

    Wang, Yan-Qin; Liu, Hou-Ting; Qi, Yan; Gao, En-Qing

    2014-08-21

    Two Mn(ii) complexes with azide and a new zwitterionic tetracarboxylate ligand 1,2,4,5-tetrakis(4-carboxylatopyridinium-1-methylene)benzene (L(1)), {[Mn5(L(1))2(N3)8(OH)2]·12H2O}n () and {[Mn5(L(1))2(N3)8(H2O)2](ClO4)2·6H2O}n (), have been synthesized and characterized crystallographically and magnetically. and contain similar alternating chains constructed by azide and carboxylate bridges. The independent sets of bridges alternate in an ABCCB sequence between adjacent Mn(ii) ions: (EO-N3)2 double bridges (EO = end-on) (denoted as A), [(EO-N3)(OCO)2] triple bridges (denoted as B) and [(EO-N3)(OCO)] double bridges (denoted as C). The alternating chains are interlinked into 2D coordination networks by the tetrapyridinium spacers. Magnetic studies demonstrate that the magnetic coupling through the double EO azide bridges is ferromagnetic and that through mixed azide/carboxylate bridges is antiferromagnetic. The unprecedented F/AF/AF'/AF'/AF coupling sequence along the chain dictates an uncompensated ground spin state (S = 5/2 per Mn5 unit) and leads to one-dimensional topological ferrimagnetism, which features a minimum in the χT versus T plot.

  13. Determination of microgramme amounts of osmium and ruthenium based on inhibition of the iodine-azide reaction by their complexes with 6-mercaptopurine

    International Nuclear Information System (INIS)

    Matusiewicz, H.; Kurzawa, Z.

    1976-01-01

    A new kinetic method of the determination of microamounts of osmium and ruthenium has been developed. The reaction between sodum azide and iodine induced by 6-mercaptopurine (6-MP) was used for this purpose. Under suitable experimental conditions the induction coefficient of 6-MP amounts to 1750+-40. The formed complexes of the metals are stable in the medium containing an excess of azide ions and do not induce the iodine-azide reaction. The method consists in the determination of the 6-MP not bound to the metal. The amount of osmium or ruthenium is then determined from linear relations. Before the determination osmium and ruthenium must be separated from other cations and from each other by distillation as volatile tetroxides. The iodine-azide method is simple, sensitive and does not require any apparatus. The range of the determination is 0.1-5.0 μg in 5 cm 3 of the solution of Os(8) and 0.5-5.0 μg for Ru(8). The error of the determination is +-6.4% and +- 6.1% for osmium and ruthenium, respectively. The time of the determination is 30 minutes not taking into account 2-hour waiting time necessary for the formation of the complexes. (author)

  14. Traceless Azido Linker for the Solid-Phase Synthesis of NH-1,2,3-Triazoles via Cu-Catalyzed Azide-Alkyne Cycloaddition Reactions

    DEFF Research Database (Denmark)

    Cohrt, Anders Emil; Jensen, Jakob Feldthusen; Nielsen, Thomas Eiland

    2010-01-01

    A broadly useful acid-labile traceless azido linker for the solid-phase synthesis of NH-1,2,3-triazoles is presented. A variety of alkynes were efficiently immobilized on a range of polymeric supports by Cu(I)-mediated azide-alkyne cycloadditions. Supported triazoles showed excellent compatibility...

  15. Techniques in gas-phase thermolyses - Part 7. Direct surface participation in gas-phase Curie-point pyrolysis: The pyrolysis of phenyl azide

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Carlsen, Lars

    1986-01-01

    The possible direct participation of the hot reactor surface in the formation of pyrolysis products was elucidated through the pyrolytic decomposition of phenyl azide. It is demonstrated that the intermediate phenyl nitrene generated reacts with elemental carbon at the filament surface, leading...

  16. Solution NMR characterization of magnetic/electronic properties of azide and cyanide-inhibited substrate complexes of human heme oxygenase: implications for steric ligand tilt.

    Science.gov (United States)

    Peng, Dungeng; Ogura, Hiroshi; Ma, Li-Hua; Evans, John P; de Montellano, Paul R Ortiz; La Mar, Gerd N

    2013-04-01

    Solution 2D (1)H NMR was carried out on the azide-ligated substrate complex of human heme oxygenase, hHO, to provide information on the active site molecular structure, chromophore electronic/magnetic properties, and the distal H-bond network linked to the exogenous ligand by catalytically relevant oriented water molecules. While 2D NMR exhibited very similar patterns of two-dimensional nuclear Overhauser spectroscopy cross peaks of residues with substrate and among residues as the previously characterized cyanide complex, significant, broadly distributed chemical shift differences were observed for both labile and non-labile protons. The anisotropy and orientation of the paramagnetic susceptibility tensor, χ, were determined for both the azide and cyanide complexes. The most significant difference observed is the tilt of the major magnetic axes from the heme normal, which is only half as large for the azide than cyanide ligand, with each ligand tilted toward the catalytically cleaved α-meso position. The difference in chemical shifts is quantitatively correlated with differences in dipolar shifts in the respective complexes for all but the distal helix. The necessity of considering dipolar shifts, and hence determination of the orientation/anisotropy of χ, in comparing chemical shifts involving paramagnetic complexes, is emphasized. The analysis shows that the H-bond network cannot detect significant differences in H-bond acceptor properties of cyanide versus azide ligands. Lastly, significant retardation of distal helix labile proton exchange upon replacing cyanide with azide indicates that the dynamic stability of the distal helix is increased upon decreasing the steric interaction of the ligand with the distal helix. Copyright © 2013. Published by Elsevier Inc.

  17. Two-Dimensional Infrared Study of Vibrational Coupling between Azide and Nitrile Reporters in a RNA Nucleoside.

    Science.gov (United States)

    Schmitz, Andrew J; Hogle, David G; Gai, Xin Sonia; Fenlon, Edward E; Brewer, Scott H; Tucker, Matthew J

    2016-09-08

    The vibrations in the azide, N3, asymmetric stretching region and nitrile, CN, symmetric stretching region of 2'-azido-5-cyano-2'-deoxyuridine (N3CNdU) are examined by two-dimensional infrared (2D IR) spectroscopy. At earlier waiting times, the 2D IR spectrum shows the presence of both vibrational transitions along the diagonal and off-diagonal cross peaks indicating vibrational coupling. The coupling strength is determined from the off-diagonal anharmonicity to be 66 cm(-1) for the intramolecular distance of ∼7.9 Å, based on a structural map generated for this model system. In addition, the frequency-frequency correlation decay is detected, monitoring the solvent dynamics around each individual probe position. Overall, these vibrational reporters can be utilized in tandem to simultaneously track global structural information and fast structural fluctuations.

  18. Structural, (197)Au Mössbauer and solid state (31)P CP/MAS NMR studies on bis (cis-bis(diphenylphosphino)ethylene) gold(I) complexes [Au(dppey)(2)]X for X = PF(6), I.

    Science.gov (United States)

    Healy, Peter C; Loughrey, Bradley T; Bowmaker, Graham A; Hanna, John V

    2008-07-28

    (197)Au Mössbauer spectra for the d(10) gold(i) phosphine complexes, [Au(dppey)(2)]X (X = PF(6), I; dppey = (cis-bis(diphenylphosphino)ethylene), and the single crystal X-ray structure and solid state (31)P CPMAS NMR spectrum of [Au(dppey)(2)]I are reported here. In [Au(dppey)(2)]I the AuP(4) coordination geometry is distorted from the approximately D(2) symmetry observed for the PF(6)(-) complex with Au-P bond lengths 2.380(2)-2.426(2) A and inter-ligand P-Au-P angles 110.63(5)-137.71(8) degrees . Quadrupole splitting parameters derived from the Mössbauer spectra are consistent with the increased distortion of the AuP(4) coordination sphere with values of 1.22 and 1.46 mm s(-1) for the PF(6)(-) and I(-) complexes respectively. In the solid state (31)P CP MAS NMR spectrum of [Au(dppey)(2)]I, signals for each of the four crystallographically independent phosphorus nuclei are observed, with the magnitude of the (197)Au quadrupole coupling being sufficiently large to produce a collapse of (1)J(Au-P) splitting from quartets to doublets. The results highlight the important role played by the counter anion in the determination of the structural and spectroscopic properties of these sterically crowded d(10) complexes.

  19. Effect of 2-chloro-substitution of adenine moiety in mixed-ligand gold(I triphenylphosphine complexes on anti-inflammatory activity: the discrepancy between the in vivo and in vitro models.

    Directory of Open Access Journals (Sweden)

    Jan Hošek

    Full Text Available A series of gold(I triphenylphosphine (PPh3 complexes (1-9 involving 2-chloro-N6-(substituted-benzyladenine derivatives as N-donor ligands was synthesized and thoroughly characterized by relevant methods, including electrospray-ionization (ESI mass spectrometry and multinuclear NMR spectroscopy. The anti-inflammatory and antiedematous effects of three representatives 1, 5 and 9 were evaluated by means of in vitro model based on the expression of pro- and anti-inflammatory cytokines and influence of the complexes on selected forms of matrix metalloproteinases secreted by LPS-activated THP-1 monocytes and in vivo model evaluating the antiedematous effect of the complexes in the carrageenan-induced rat hind-paw edema model. In addition to the pharmacological observations, the affected hind paws were post mortem subjected to histological and immunohistochemical evaluations. The results of both in vivo and ex vivo methods revealed low antiedematous and anti-inflammatory effects of the complexes, even though the in vitro model identified them as promising anti-inflammatory acting compounds. The reason for this discrepancy lies probably in low stability of the studied complexes in biological environment, as demonstrated by the solution interaction studies with sulfur-containing biomolecules (cysteine and reduced glutathione using the ESI mass spectrometry.

  20. Carboxymethyl glycoside lactone(CMGL) synthons:Scope of the method and preliminary results on step growth polymerization of α-azide-ω-alkyne glycomonomers

    Institute of Scientific and Technical Information of China (English)

    CHAMBERT; Stéphane; BERNARD; Julien; FLEURY; Etienne; QUENEAU; Yves

    2010-01-01

    Carboxymethyl glycoside lactones(CMGLs) are bicyclic synthons which open readily for accessing new types of pseudo-glycoconjugates,such as sugar-amino acid hybrids,neoglycolipids,pseudodisaccharides,and membrane imaging systems.After lactone opening,free OH-2 is available for further functionalization,leading to 1,2-bisfunctionalized derivatives.This strategy is illustrated herein with new polymerizable systems of the AB type bearing both azide and alkyne functions prepared from α or β gluco-CMGL synthons.After the reaction of lactones with propargylamine,an azido group was introduced by two different sequences leading to either the 2-manno-azido or the 6-gluco-azido products.The capability of these AB monomers to undergo step growth polymerization through copper(I) catalyzed alkyne-azide cycloaddition(CuAAC) and generate glycopolytriazoles was evidenced.

  1. Facile solid-phase ruthenium assisted azide-alkyne cycloaddition (RuAAC) utilizing the Cp*RuCl(COD)-catalyst

    DEFF Research Database (Denmark)

    Engholm, Ebbe; sgz228, sgz228; Blixt, Klas Ola

    2017-01-01

    The ruthenium assisted azide-alkyne cycloaddition (RuAAC) reaction is a well-established method for the generation of 1,5- and 1,4,5-substituted 1,2,3-triazoles, which we have extended to the solid-phase synthesis of 1,2,3-triazole-peptides. The 1,2,3-triazole moieties were formed upon the reacti...

  2. Solvent effect on copper-catalyzed azide-alkyne cycloaddition (CuAAC): synthesis of novel triazolyl substituted quinolines as potential anticancer agents.

    Science.gov (United States)

    Ellanki, Amarender Reddy; Islam, Aminul; Rama, Veera Swamy; Pulipati, Ranga Prasad; Rambabu, D; Krishna, G Rama; Reddy, C Malla; Mukkanti, K; Vanaja, G R; Kalle, Arunasree M; Kumar, K Shiva; Pal, Manojit

    2012-05-15

    A regioselective route to novel mono triazolyl substituted quinolines has been developed via copper-catalyzed azide-alkyne cycloaddition (CuAAC) of 2,4-diazidoquinoline with terminal alkynes in DMF. The reaction provided bis triazolyl substituted quinolines when performed in water in the presence of Et(3)N. A number of the compounds synthesized showed promising anti-proliferative properties when tested in vitro especially against breast cancer cells. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Facile synthesis of linear-dendritic cholesteryl-poly(epsilon-caprolactone)-b-(L-lysine)(G2) by thiol-ene and azide-alkyne "click" reactions

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Binder, W.H.; Tanner, S.

    2010-01-01

    The construction of a linear-dendritic block copolymer consisting of terminal cholesteryl moiety, poly(epsilon-caprolactone), and a second generation L-lysine dendron has been accomplished by the combination of copper(I) catalyzed azide-alkyne and UV-triggered thiol-ene "click" reactions. Ring-op...... and thiocholesterol. Near to quantitative functionalization of the intermediate and final products has been attained as confirmed by NMR spectroscopy and MALDI-TOF spectrometry....

  4. Synthesis, crystal structure, antimicrobial activity and electrochemistry study of chromium(III) and copper(II) complexes based on semicarbazone Schiff base and azide ligands

    Czech Academy of Sciences Publication Activity Database

    Shaabani, B.; Khandar, A.A.; Dušek, Michal; Pojarová, Michaela; Mahmoudi, F.

    2013-01-01

    Roč. 394, JAN (2013), s. 563-568 ISSN 0020-1693 Grant - others:AV ČR(CZ) AP0701 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:68378271 Keywords : antimicrobial activity * azide ligand * metal complex * Schiff base ligand * X-ray structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.041, year: 2013

  5. Well-defined polyethylene-based graft terpolymers by combining nitroxide-mediated radical polymerization, polyhomologation and azide/alkyne “click” chemistry†

    KAUST Repository

    Alkayal, Nazeeha

    2016-03-30

    Novel well–defined polyethylene–based graft terpolymers were synthesized via the “grafting onto” strategy by combining nitroxide-mediated radical polymerization (NMP), polyhomologation and copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) “click” chemistry. Three steps were involved in this approach: (i) synthesis of alkyne-terminated polyethylene-b-poly(ε-caprolactone) (PE-b-PCL-alkyne) block copolymers (branches) by esterification of PE-b-PCL-OH with 4-pentynoic acid; the PE-b-PCL-OH was obtained by polyhomologation of dimethylsulfoxonium methylide to afford PE-OH, followed by ring opening polymerization of ε-caprolactone using the PE-OH as macroinitiator, (ii) synthesis of random copolymers of styrene (St) and 4-chloromethylstyrene (4-CMS) with various CMS contents, by nitroxide-mediated radical copolymerization (NMP), and conversion of chloride to azide groups by reaction with sodium azide (NaN3) (backbone) and (iii) “click” linking reaction to afford the PE-based graft terpolymers. All intermediates and final products were characterized by high-temperature size exclusion chromatography (HT-SEC), Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR) and differential scanning calorimetry (DSC).

  6. Site-Specific Antibody Labeling by Covalent Photoconjugation of Z Domains Functionalized for Alkyne-Azide Cycloaddition Reactions.

    Science.gov (United States)

    Perols, Anna; Arcos Famme, Melina; Eriksson Karlström, Amelie

    2015-11-01

    Antibodies are extensively used in research, diagnostics, and therapy, and for many applications the antibodies need to be labeled. Labeling is typically performed by using amine-reactive probes that target surface-exposed lysine residues, resulting in heterogeneously labeled antibodies. An alternative labeling strategy is based on the immunoglobulin G (IgG)-binding protein domain Z, which binds to the Fc region of IgG. Introducing the photoactivable amino acid benzoylphenylalanine (BPA) into the Z domain makes it possible for a covalent bond to be be formed between the Z domain and the antibody on UV irradiation, to produce a site-specifically labeled product. Z32 BPA was synthesized by solid-phase peptide synthesis and further functionalized to give alkyne-Z32 BPA and azide-Z32 BPA for Cu(I) -catalyzed cycloaddition, as well as DBCO-Z32 BPA for Cu-free strain-promoted cycloaddition. The Z32 BPA variants were conjugated to the human IgG1 antibody trastuzumab and site-specifically labeled with biotin or fluorescein. The fluorescently labeled trastuzumab showed specific staining of the membranes of HER2-expressing cells in immunofluorescence microscopy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Azide photochemistry for facile modification of graphitic surfaces: preparation of DNA-coated carbon nanotubes for biosensing

    International Nuclear Information System (INIS)

    Moghaddam, Minoo J; Yang Wenrong; Bojarski, Barbara; Gengenbach, Thomas R; Gao Mei; Zareie, Hadi; McCall, Maxine J

    2012-01-01

    A facile, two-step method for chemically attaching single-stranded DNA to graphitic surfaces, represented here by carbon nanotubes, is reported. In the first step, an azide-containing compound, N-5-azido-nitrobenzoyloxy succinimide (ANB-NOS), is used to form photo-adducts on the graphitic surfaces in a solid-state photochemical reaction, resulting in active ester groups being oriented for the subsequent reactions. In the second step, pre-synthesized DNA strands bearing a terminal amine group are coupled in an aqueous solution with the active esters on the photo-adducts. The versatility of the method is demonstrated by attaching pre-synthesized DNA to surfaces of carbon nanotubes in two platforms—as vertically-aligned multi-walled carbon nanotubes on a solid support and as tangled single-walled carbon nanotubes in mats. The reaction products at various stages were characterized by x-ray photoelectron spectroscopy. Two different assays were used to check that the DNA strands attached to the carbon nanotubes were able to bind their partner strands with complementary base sequences. The first assay, using partner DNA strands tethered to gold nanoparticles, enabled the sites of DNA attachment to the carbon nanotubes to be identified in TEM images. The second assay, using radioactively labelled partner DNA strands, quantified the density of functional DNA strands attached to the carbon nanotubes. The diversity of potential applications for these DNA-modified carbon-nanotube platforms is exemplified here by the successful use of a DNA-modified single-walled carbon-nanotube mat as an electrode for the specific detection of metal ions. (paper)

  8. In vivo click reaction between Tc-99m-labeled azadibenzocyclooctyne-MAMA and 2-nitroimidazole-azide for tumor hypoxia targeting.

    Science.gov (United States)

    Sun, Wenjing; Chu, Taiwei

    2015-10-15

    The bioactivity of nitroimidazole in Tc-99m-labeled 2-nitroimidazole, a traditional solid tumor hypoxia-imaging agent for single photon emission computed tomography (SPECT), is reduced by the presence of large ligand and metallic radionuclide, exhibiting lower tumor-to-nontumor ratios. In an effort to solve this general problem, a pretargeting strategy based on click chemistry (strain-promoted cyclooctyne-azide cycloaddition) was applied. The functional click synthons were synthesized as pretargeting components: an azide group linked to 2-nitroimidazole (2NIM-Az) serves for tumor hypoxia-targeting and azadibenzocyclooctyne conjugated with monoamine monoamide dithiol ligand (AM) functions as radiolabeling and binding group to azides in vivo. 2NIM-triazole-MAMA was obtained from in vitro click reaction with a reaction rate constant of 0.98M(-1)s(-1). AM and 2NIM-triazole-MAMA were radiolabeled with Tc-99m. The hypoxia-pretargeting biodistribution was studied in Kunming mice bearing S180 tumor; (99m)Tc-AM and (99m)Tc-triazole-2NIM were used as blank control and conventional control. Compared to the control groups, the pretargeting experiment exhibits the best radio-uptake and retention in tumor, with higher tumor-to-muscle and tumor-to-blood ratios (up to 8.55 and 1.44 at 8h post-(99m)Tc-complex-injection, respectively). To some extent, the pretargeting strategy protects the bioactivity of nitroimidazole and therefore provides an innovative approach for the development of tumor hypoxia-SPECT imaging agents. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Site-specific bioconjugation of a murine dihydrofolate reductase enzyme by copper(I-catalyzed azide-alkyne cycloaddition with retained activity.

    Directory of Open Access Journals (Sweden)

    Sung In Lim

    Full Text Available Cu(I-catalyzed azide-alkyne cycloaddition (CuAAC is an efficient reaction linking an azido and an alkynyl group in the presence of copper catalyst. Incorporation of a non-natural amino acid (NAA containing either an azido or an alkynyl group into a protein allows site-specific bioconjugation in mild conditions via CuAAC. Despite its great potential, bioconjugation of an enzyme has been hampered by several issues including low yield, poor solubility of a ligand, and protein structural/functional perturbation by CuAAC components. In the present study, we incorporated an alkyne-bearing NAA into an enzyme, murine dihydrofolate reductase (mDHFR, in high cell density cultivation of Escherichia coli, and performed CuAAC conjugation with fluorescent azide dyes to evaluate enzyme compatibility of various CuAAC conditions comprising combination of commercially available Cu(I-chelating ligands and reductants. The condensed culture improves the protein yield 19-fold based on the same amount of non-natural amino acid, and the enzyme incubation under the optimized reaction condition did not lead to any activity loss but allowed a fast and high-yield bioconjugation. Using the established conditions, a biotin-azide spacer was efficiently conjugated to mDHFR with retained activity leading to the site-specific immobilization of the biotin-conjugated mDHFR on a streptavidin-coated plate. These results demonstrate that the combination of reactive non-natural amino acid incorporation and the optimized CuAAC can be used to bioconjugate enzymes with retained enzymatic activity.

  10. Novel Synthesis of 1,2,3-Triazoles via 1,3-Dipolar Cycloadditions of Alkynes to Azides in Ionic Liquid

    Institute of Scientific and Technical Information of China (English)

    ZHONG,Ping(钟平); GUO,Sheng-Rong(郭圣荣)

    2004-01-01

    2-Azido-3,5-dichloropyridine and 2-azido-5-chloro-3-fluoropyridine were given by reaction of sodium azide with 2,3,5-trichloropyridine, 3,5-dichloro-2-fluoropyridine or 5-chloro-2,3-difiuoropyridine in ionic liquids.1,3-Dipolar cycloaddition of 2-azido-3,5-dichloropyridine or 2-azido-5-chloro-3-fluoropyridine to alkynes in ionic liquids afforded the corresponding 1,4,5-trisubstituted [1,2,3]-triazoles in good yields and regioselectivities.

  11. Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanylphenyl-1H-1,2,3-triazol-4-ylketones

    Directory of Open Access Journals (Sweden)

    Gabriel P. Costa

    2017-04-01

    Full Text Available The use of sonochemistry is described in the organocatalytic enamine–azide [3 + 2] cycloaddition between 1,3-diketones and aryl azidophenyl selenides. These sonochemically promoted reactions were found to be amenable to a range of 1,3-diketones or aryl azidophenyl selenides, providing an efficient access to new ((arylselanylphenyl-1H-1,2,3-triazol-4-ylketones in good to excellent yields and short reaction times. In addition, this protocol was extended to β-keto esters, β-keto amides and α-cyano ketones. Selanyltriazoyl carboxylates, carboxamides and carbonitriles were synthesized in high yields at short times of reaction under very mild reaction conditions.

  12. The orbital ground state of the azide-substrate complex of human heme oxygenase is an indicator of distal H-bonding: Implications for the enzyme mechanism‡

    OpenAIRE

    Ogura, Hiroshi; Evans, John P.; Peng, Dungeng; Satterlee, James D.; de Montellano, Paul R. Ortiz; Mar, Gerd N. La

    2009-01-01

    The active site electronic structure of the azide complex of substrate-bound human heme oxygenase-1, (hHO) has been investigated by 1H NMR spectroscopy to shed light on the orbital/spin ground state as an indicator of the unique distal pocket environment of the enzyme. 2D 1H NMR assignments of the substrate and substrate-contact residue signals reveal a pattern of substrate methyl contact shifts, that places the lone iron π-spin in the dxz orbital, rather than the dyz orbital found in the cya...

  13. 2D and 3D surface photopatterning via laser-promoted homopolymerization of a perfluorophenyl azide-substituted BODIPY.

    Science.gov (United States)

    Raffy, Guillaume; Bofinger, Robin; Tron, Arnaud; Guerzo, André Del; McClenaghan, Nathan D; Vincent, Jean-Marc

    2017-11-09

    An innovative photopatterning process is described that allows, in a single laser-promoted operation, the covalent attachment of a molecule on a surface (2D patterning - xy dimensions) and its photopolymerization to grow micro-/nanostructures with spatial control in a third z-dimension. The surface patterning process, based on nitrene reactivity, was harnessed using the highly fluorescent azide-substituted boron difluoride dipyrromethene (BODIPY) 1 that was prepared in a single synthetic step from the parent pentafluorophenyl BODIPY on reacting with NaN 3 . Using the laser of a fluorescence microscope (375 nm or 532 nm) 1 could be grafted on adapted surfaces and then homopolymerised. In this study we show that using glass coverslips coated with PEG/high density alkyne groups (density of ∼1 × 10 14 per cm 2 ), the patterning process was much more spatially confined than when using PEG only coating. Varying the irradiation time (1 to 15 s) or laser power (0.14-3.53 μW) allowed variation of the amount of deposited BODIPY to afford, in the extreme case, pillars of a height up to 800 nm. AFM and MS studies revealed that the nano/microstructures were formed of particles of photopolymerized 1 having a mean diameter of ca. 30 nm. The emission spectra and fluorescence lifetimes for the patterned structures were measured, revealing a red-shift (from ∼560 nm up to 620 nm) of the maximum emission and a shortening (from ∼6 ns to 0.8 ns) of the fluorescence lifetimes in areas where the density of BODIPY is high. As an application of the patterning process, a figure formed of 136 dots/pillars was prepared. The confocal hyperspectral fluorescence image revealed that the figure is clearly resolved and constituted by highly photoluminescent red dots whose fluorescence intensities and emission color proved to be highly reproducible. SEM and AFM studies showed that the luminescent dots were pillars with a conical shape, an average height of 710 ± 28 nm and a FWHM of 400 ± 20

  14. A Theoretical Study of the Relationship between the Electrophilicity ω Index and Hammett Constant σp in [3+2] Cycloaddition Reactions of Aryl Azide/Alkyne Derivatives

    Directory of Open Access Journals (Sweden)

    Hicham Ben El Ayouchia

    2016-10-01

    Full Text Available The relationship between the electrophilicity ω index and the Hammett constant σp has been studied for the [2+3] cycloaddition reactions of a series of para-substituted phenyl azides towards para-substituted phenyl alkynes. The electrophilicity ω index—a reactivity density functional theory (DFT descriptor evaluated at the ground state of the molecules—shows a good linear relationship with the Hammett substituent constants σp. The theoretical scale of reactivity correctly explains the electrophilic activation/deactivation effects promoted by electron-withdrawing and electron-releasing substituents in both azide and alkyne components.

  15. The concern of emergence of multi-station reaction pathways that might make stepwise the mechanism of the 1,3-dipolar cycloadditions of azides and alkynes

    Science.gov (United States)

    Mohtat, Bita; Siadati, Seyyed Amir; Khalilzadeh, Mohammad Ali; Zareyee, Daryoush

    2018-03-01

    After hot debates on the concerted or stepwise nature of the mechanism of the catalyst-free 1,3-dipolar cycloadditions (DC)s, nowadays, it is being believed that for the reaction of each dipole and dipolarophile, there is a possibility that the reaction mechanism becomes stepwise, intermediates emerge, and the reaction becomes non-stereospecific. Yield of even minimal amounts of unwanted side products or stereoisomers as impurities could bring many troubles like difficult purification steps. In this project, we have made attempts to study all probable reaction channels of the azide cycloadditions with two functionalized alkynes, in order to answer this question: "is there any possibility that intermediates evolve in the catalyst-free click 1,3-DC reaction of azide-alkynes?". During the calculations, several multi-station reaction pathways supporting the stepwise and concerted mechanisms were detected. Also, the born-oppenheimer molecular dynamic (BOMD) simulation was used to find trustable geometries which could be emerged during the reaction coordinate.

  16. Electron-transporting layer doped with cesium azide for high-performance phosphorescent and tandem white organic light-emitting devices

    Science.gov (United States)

    Yu, Yaoyao; Chen, Xingming; Jin, Yu; Wu, Zhijun; Yu, Ye; Lin, Wenyan; Yang, Huishan

    2017-07-01

    Cesium azide was employed as an effective n-dopant in the electron-transporting layer (ETL) of organic light-emitting devices (OLEDs) owing to its low deposition temperature and high ambient stability. By doping cesium azide onto 4,7-diphenyl-1,10-phenanthroline, a green phosphorescent OLED having best efficiencies of 66.25 cd A-1, 81.22 lm W-1 and 18.82% was realized. Moreover, the efficiency roll-off from 1000 cd m-2 to 10 000 cd m-2 is only 12.9%, which is comparable with or even lower than that of devices utilizing the co-host system. Physical mechanisms for the improvement of device performance were studied in depth by analyzing the current density-voltage (J-V) characteristics of the electron-only devices. In particular, by comparing the J-V characteristics of the electron-only devices instead of applying the complicated ultraviolet photoelectron spectrometer measurements, we deduced the decrease in barrier height for electron injection at the ETL/cathode contact. Finally, an efficient tandem white OLED utilizing the n-doped layer in the charge generation unit (CGU) was constructed. As far as we know, this is the first report on the application of this CGU for fabricating tandem white OLEDs. The emissions of the tandem device are all in the warm white region from 1213 cd m-2 to 10870 cd m-2, as is beneficial to the lighting application.

  17. Poli (metil azoteto de glicidila - GAP. I: síntese e caracterização Glycidyl azide polymer (GAP. I: syntheses and characterization

    Directory of Open Access Journals (Sweden)

    Sandro P. Ribeiro

    2012-01-01

    Full Text Available O poli (metil azoteto de glicidila - GAP - é um material energético que pode ser utilizado como aglutinante (binder e como plastificante energético em compostos explosivos e propulsores de foguetes. Neste trabalho, foi abordada a síntese do (GAP através da conversão direta da epicloridrina (ECH a GAP. Os reagentes utilizados foram azida de sódio, epicloridrina e vários álcoois extensores de cadeias, o etanodiol, o 1,4-butanodiol, o dietilenoglicol e o glicerol. Alguns parâmetros de operação foram avaliados, como o tempo de reação, a proporção entre os reagentes, dois tipos de solvente e a ordem de adição dos reagentes. A variável observada para a análise foi a massa molecular do GAP. Todos os materiais sintetizados também foram caracterizados por análises de FTIR, UV, RMN, DSC, análise elementar e TGA. Uma maior massa molecular, maior rendimento e uma melhor conversão do grupo azida a GAP foram obtidos com a adição de epicloridrina sobre a azida de sódio e usando DMF como solvente.GAP is an aliphatic polyether that includes hydroxyl groups and highly energetic azide groups. Thus, it is an energetic material that can be used as binder or plasticizing agent in propellants and explosive mixtures. The glycidyl azide polymer (GAP was synthesized and characterized by direct conversion of epichlorohydrin. GAP was synthesized by reaction of sodium azide, epichlorohydrin, and some extensor alcohols. The investigation focused on the effects of some key reaction parameters including reagent proportions, reaction time and two different solvents. The product was characterized by FTIR, UV, NMR, DSC, elemental analysis, TGA and GPC. The species were also evaluated through molecular weight (GPC, glass transition temperature (DSC, ignition time and sensitivity.

  18. Rational design of azide-bridged bimetallic complexes. Crystal structure and magnetic properties of Fe(III)MFe(III) (M = Ni(II) and Cu(II)) trinuclear species.

    Science.gov (United States)

    Colacio, Enrique; Costes, Jean-Pierre; Domínguez-Vera, José M; Maimoun, Ikram Ben; Suárez-Varela, José

    2005-01-28

    The first examples of azide-bridged bimetallic trinuclear complexes ([M(cyclam)][FeL(N3)(mu1,5-N3)]2) (H2L = 4,5-dichloro-1,2-bis(pyridine-2-carboxamido) benzene) have been structurally and magnetically characterized.

  19. Solvent-resistant small molecule solar cells by roll-to-roll fabrication via introduction of azide cross-linkable group

    DEFF Research Database (Denmark)

    Chen, Mei-Rong; Fan, Cong-Cheng; Andersen, Thomas Rieks

    2014-01-01

    A novel cross-linkable azide-functionalized diketopyrrolopyrrole based compound DPP(BT-N-3)(2) was designed and synthesized via Stille coupling. Cross-linking of such molecule could help us fabricate insoluble film which could be used to fabricate heterostructures through solution processing......, without dissolving the pre-patterned layers. In order to investigate the photovoltaic performances of the newly synthesized compound, large area solar cells were produced by roll coating technique. Two set of devices were fabricated by employing DPP(BT-N-3)(2) as either an electron donor or acceptor....... A best power conversion efficiency of 0.067%, combined with an open circuit voltage of 0.53 V, and a fill factor of 37.6% were obtained for the device with DPP(BT-N-3)(2) as an electron acceptor. In addition, we could prove that the large area small molecule based organic solar cells could be fabricated...

  20. The effects of duration of pre-soaking treatments on the frequency and spectrum of mutations induced by sodium azide in CES 14 Mungbean variety

    International Nuclear Information System (INIS)

    Asencion, A.B.

    1982-04-01

    Seeds of mungbean variety CES 14 were treated with 10 - 3 sodium azide for 2 hours buffered at pH 3 after various pre-soaking treatment durations of 0, 4, 6, 8, 10, 12, 14 and 16 hours. The biological parameters that were significantly affected by the treatments in the M 1 were germination, seedling height and survival. The chlorophyll and other morphological mutations in the M 2 gradually increased with increasing pre-soaking time. The treatment that had the lowest mutation rate was the 16-hour pre-soaked seeds. No chlorophyll mutation was noted in both the water and buffer control. One variant was noted, however, in the buffer control. (author)

  1. 'Clicking' on the nanoscale: 1,3-dipolar cycloaddition of terminal acetylenes on azide functionalized, nanometric surface templates with nanometer resolution

    International Nuclear Information System (INIS)

    Haensch, Claudia; Hoeppener, Stephanie; Schubert, Ulrich S

    2009-01-01

    Electro-oxidative lithography is used as a tool to create chemical nanostructures on an n-octadecyltrichlorosilane (OTS) monolayer self-assembled on silicon. The use of a bromine precursor molecule, which is exclusively assembled on these chemical templates, can be used to further functionalize the nanostructures by the site-selective generation of azide functions and performing the highly effective 1,3-dipolar cycloaddition reaction with acetylene functionalized molecules. The versatility of this reaction scheme provides the potential to integrate a large variety of functional molecules, to tailor the surface properties of the nanostructures or to anchor molecular building blocks or particles in confined, pre-defined surface areas. The results demonstrated in the present study introduce a conceivable route towards the functionalization of chemically active surface templates with high fidelity and reliability. It is demonstrated that surface features with a lateral resolution of 50 nm functionalized with propargyl alcohol can be fabricated.

  2. Effects of UVA irradiation, aryl azides, and reactive oxygen species on the orthogonal inactivation of the human immunodeficiency virus (HIV-1)

    International Nuclear Information System (INIS)

    Belanger, Julie M.; Raviv, Yossef; Viard, Mathias; Cruz, M. Jason de la; Nagashima, Kunio; Blumenthal, Robert

    2011-01-01

    Previously we reported that hydrophobic aryl azides partition into hydrophobic regions of the viral membrane of enveloped viruses and inactivate the virus upon UVA irradiation for 2 min. Prolonged irradiation (15 min) resulted in viral protein aggregation as visualized via Western blot analysis, due to reactive oxygen species (ROS) formation, with preservation of the surface antigenic epitopes. Herein, we demonstrate that these aggregates show detergent resistance and that this property may be useful towards the creation of a novel orthogonal virus inactivation strategy for use in preparing experimental vaccines. When ROS-modified HIV virus preparations were treated with 1% Triton X-100, there was an increase in the percent of viral proteins (gp41, p24) in the viral pellet after ultracentrifugation through sucrose. Transmission electron microscopy (TEM) of these detergent-resistant pellets shows some recognizable virus fragments, and immunoprecipitation studies of the gp41 aggregates suggest the aggregation is covalent in nature, involving short-range interactions.

  3. Evaluation Of GAMMA And Sodium Azide Radiation Looking For Resistance To MACROPHOMINA Phaseoli T. In Three Promissory Lines Of Benne Sesamum Indicum L

    International Nuclear Information System (INIS)

    Lopez R, Liliana V.; Melo O, Mario E.; Reina C, Yasmin

    1993-01-01

    The Benne in Colombia is a cultivation relegated to small properties and its main problem is the withering (Macrophomina phaseoli T.) which may cause losses of the cent per cent. Situation that generated the interest to carry out a study on induction of mutations in this species, using Gamma Rays and Sodium Azide with the purpose of obtaining possible resistant mutants to the mushroom. The initial stage of the work, determination of good dose, was developed in the INEA in Bogota and the field evaluation in the ICA Nataima in Espinal. A rehearsal was mounted to evaluate germination and plants height in the lines Cycle 0 - PlO, ENA 841-3 and ENA 841-5 tried with the doses (OR, 25, 50, 75 and 100) krad of gamma rays and (OR, 5, 10, 15 and 20) mm of Sodium Azide, the obtained information was processed using a Complete Blocks design at random with Factorial arrangement 3x5 and test of Duncan, based on the obtained data the Curves of Radio and chemical sensitivity were determined. Then the massive treatment of the seed was made with the optimum mutagenic dose and it was taken to field (Ml), giving it good conditions for the development of the cultivation. The test of chlorophyll ian mutants was applied to the seed harvested M2 to select the treatment with which the program of improvement should continue, it was sowed in a lot with high pressure of selection of the mushroom and an inter and intra family selection was made

  4. Comparison Of The Caused Physiologic Effects For The GAMMA Radiations And The Sodium Azide (NAN3) In Four Genotypes Of Wheat

    International Nuclear Information System (INIS)

    Quevedo C, Luis A.

    1994-01-01

    As it happens in many countries of the world. The wheat occupies an important line in the feeding of the Colombian town, what demands the continuous obtaining of new cultivations to assist the necessities of the farmers and consumers. The induction of mutations is a tool by means of which excellent results have been obtained in the improvement of cereals, especially in wheat, rice and barley, where mutants have been obtained that have been used directly by the farming ones and indirectly for the programs of improvement. Keeping in mind that in Colombia it is sought to use the induction of mutations in the programs of wheat improvement, and that it doesn't have deep investigations in this respect, it was solved to carry out the present work, where the main objective was to compare the tired physiologic effects after the treatment with different dose and concentrations of gamma rays and sodium azide in four genotypes of wheat of national interest. The work was carried out in two phases, the first one (generation M1) in the one that the seeds of the four genotypes were sowed (ICA-Tenza, Pav -76, Bonza-63 and Creole Pelao) tried with dose of 0, 10, 20, 30 and 40 krad of gamma rays and concentrations of 0, 0.1, 0.2, 0.3 and 0.4 m Molar of sodium azide. The data have more than enough emergency, plant height, longitude of the spike, grains/tassel number and weight of 100 grains, they were tabulated, processed and drawing for each one of the treatments being obtained this way, the radio curves and chemical- sensitivity. The second phase denominated generation M2, makes reference to the seeds coming from the plants M1, which were collected in form singular, taking 2 tassel/plant of the total of plants survivors planted in field

  5. Kinetics and mechanics of photo-polymerized triazole-containing thermosetting composites via the copper(I)-catalyzed azide-alkyne cycloaddition.

    Science.gov (United States)

    Song, Han Byul; Wang, Xiance; Patton, James R; Stansbury, Jeffrey W; Bowman, Christopher N

    2017-06-01

    Several features necessary for polymer composite materials in practical applications such as dental restorative materials were investigated in photo-curable CuAAC (copper(I)-catalyzed azide-alkyne cycloaddition) thermosetting resin-based composites with varying filler loadings and compared to a conventional BisGMA/TEGDMA based composite. Tri-functional alkyne and di-functional azide monomers were synthesized for CuAAC resins and incorporated with alkyne-functionalized glass microfillers for CuAAC composites. Polymerization kinetics, in situ temperature change, and shrinkage stress were monitored simultaneously with a tensometer coupled with FTIR spectroscopy and a data-logging thermocouple. The glass transition temperature was analyzed by dynamic mechanical analysis. Flexural modulus/strength and flexural toughness were characterized in three-point bending on a universal testing machine. The photo-CuAAC polymerization of composites containing between 0 and 60wt% microfiller achieved ∼99% conversion with a dramatic reduction in the maximum heat of reaction (∼20°C decrease) for the 60wt% filled CuAAC composites as compared with the unfilled CuAAC resin. CuAAC composites with 60wt% microfiller generated more than twice lower shrinkage stress of 0.43±0.01MPa, equivalent flexural modulus of 6.1±0.7GPa, equivalent flexural strength of 107±9MPa, and more than 10 times higher energy absorption of 10±1MJm -3 when strained to 11% relative to BisGMA-based composites at equivalent filler loadings. Mechanically robust and highly tough, photo-polymerized CuAAC composites with reduced shrinkage stress and a modest reaction exotherm were generated and resulted in essentially complete conversion. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  6. Electron-transporting layer doped with cesium azide for high-performance phosphorescent and tandem white organic light-emitting devices

    International Nuclear Information System (INIS)

    Yu, Yaoyao; Chen, Xingming; Jin, Yu; Wu, Zhijun; Yu, Ye; Lin, Wenyan; Yang, Huishan

    2017-01-01

    Cesium azide was employed as an effective n-dopant in the electron-transporting layer (ETL) of organic light-emitting devices (OLEDs) owing to its low deposition temperature and high ambient stability. By doping cesium azide onto 4,7-diphenyl-1,10-phenanthroline, a green phosphorescent OLED having best efficiencies of 66.25 cd A −1 , 81.22 lm W −1 and 18.82% was realized. Moreover, the efficiency roll-off from 1000 cd m −2 to 10 000 cd m −2 is only 12.9%, which is comparable with or even lower than that of devices utilizing the co-host system. Physical mechanisms for the improvement of device performance were studied in depth by analyzing the current density–voltage ( J – V ) characteristics of the electron-only devices. In particular, by comparing the J – V characteristics of the electron-only devices instead of applying the complicated ultraviolet photoelectron spectrometer measurements, we deduced the decrease in barrier height for electron injection at the ETL/cathode contact. Finally, an efficient tandem white OLED utilizing the n-doped layer in the charge generation unit (CGU) was constructed. As far as we know, this is the first report on the application of this CGU for fabricating tandem white OLEDs. The emissions of the tandem device are all in the warm white region from 1213 cd m −2 to 10870 cd m −2 , as is beneficial to the lighting application. (paper)

  7. Manganese(II), iron(II), and mixed-metal metal-organic frameworks based on chains with mixed carboxylate and azide bridges: magnetic coupling and slow relaxation.

    Science.gov (United States)

    Wang, Yan-Qin; Yue, Qi; Qi, Yan; Wang, Kun; Sun, Qian; Gao, En-Qing

    2013-04-15

    Mn(II) and Fe(II) compounds derived from azide and the zwitterionic 1-carboxylatomethylpyridinium-4-carboxylate ligand are isomorphous three-dimensional metal-organic frameworks (MOFs) with the sra net, in which the metal ions are connected into anionic chains by mixed (μ-1,1-azide)bis(μ-carboxylate) triple bridges and the chains are cross-linked by the cationic backbones of the zwitterionic ligands. The Mn(II) MOFs display typical one-dimensional antiferromagnetic behavior. In contrast, with one more d electron per metal center, the Fe(II) counterpart shows intrachain ferromagnetic interactions and slow relaxation of magnetization attributable to the single-chain components. The activation energies for magnetization reversal in the infinite- and finite-chain regimes are Δτ1 = 154 K and Δτ2 = 124 K, respectively. Taking advantage of the isomorphism between the Mn(II) and Fe(II) MOFs, we have prepared a series of mixed-metal Mn(II)(1-x)Fe(II)(x) MOFs with x = 0.41, 0.63, and 0.76, which intrinsically feature random isotropic/anisotropic sites and competing antiferromagnetic-ferromagnetic interactions. The materials show a gradual antiferromagnetic-to-ferromagnetic evolution in overall behaviors as the Fe(II) content increases, and the Fe-rich materials show complex relaxation processes that may arise for mixed SCM and spin-glass mechanisms. A general trend is that the activation energy and the blocking temperature increase with the Fe(II) content, emphasizing the importance of anisotropy for slow relaxation of magnetization.

  8. GoldiRunx and Remembering Cytotoxic Memory.

    Science.gov (United States)

    Mikami, Yohei; Kanno, Yuka

    2018-04-17

    The molecular basis for T cell memory differentiation remains elusive. Wang et al. (2018) identify Runx3 as an initiating transcription factor that specifies regulatory regions required for cytotoxic T cell (CTL) memory differentiation early after TCR signaling and constrains the ability of T-bet to drive terminal effector generation. Published by Elsevier Inc.

  9. One-pot synthesis of novel 1-(1H-tetrazol-5-yl)-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine derivatives via an Ugi-azide 4CR process.

    Science.gov (United States)

    Ghandi, Mehdi; Salahi, Saleh; Taheri, Abuzar; Abbasi, Alireza

    2018-05-01

    A facile one-pot method has been developed for the synthesis of novel pyrrolo[2,1-a]pyrazine scaffolds. A variety of 1-(1H-tetrazol-5-yl)-1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazine derivatives were obtained in moderate to high yields in methanol using a one-pot four-component condensation of 1-(2-bromoethyl)-1H-pyrrole-2-carbaldehyde, amine, isocyanide and sodium azide at room temperature. These reactions presumably proceed via a domino imine formation, intramolecular annulation and Ugi-azide reaction. Unambiguous assignment of the molecular structures was carried out by single-crystal X-ray diffraction.

  10. Iodide, azide, and cyanide complexes of (N,C), (N,N), and (N,O) metallacycles of tetra- and pentavalent uranium

    International Nuclear Information System (INIS)

    Benaud, Olivier; Berthet, Jean-Claude; Thuery, Pierre; Ephritikhine, Michel

    2011-01-01

    In contrast to the neutral macrocycle [UN* 2 (N,C)] (1) [N* = N(SiMe 3 ) 3 ; N,C = CH 2 SiMe 2 N-(SiMe 3 )] which was quite inert toward I 2 , the anionic bismetallacycle [NaUN*(N,C) 2 ] (2) was readily transformed into the enlarged monometallacycle [UN*(N,N)I] (4) [N,N = (Me 3 Si)NSiMe 2 CH 2 CH 2 SiMe 2 N(SiMe 3 )] resulting from C-C coupling of the two CH 2 groups, and [NaUN*(N,O) 2 ] (3) [N,O = OC(=CH 2 )SiMe 2 N(SiMe 3 )], which is devoid of any U-C bond, was oxidized into the UV bismetallacycle [Na{UN*(N,O) 2 }2(μ-I)] (5). Sodium amalgam reduction of 4 gave the U(III) compound [UN*(N,N)] (6). Addition of MN 3 or MCN to the (N,C), (N,N), and (N,O) metallacycles 1, 4, and 5 led to the formation of the anionic azide or cyanide derivatives M[UN* 2 (N,C)(N 3 )] [M = Na, 7a or Na(15-crown-5), 7b], M[UN* 2 (N,C)(CN)] [M = NEt 4 , 8a or Na(15-crown-5), 8b or K(18-crown-6), 8c], M[UN*(N,N)(N 3 ) 2 ] [M = Na, 9a or Na(THF)4, 9b], [NEt 4 ][UN*(N,N)(CN) 2 ] (10), M[UN*(N,O) 2 (N 3 )] [M = Na, 11a or Na(15-crown-5), 11b], M[UN*(N,O) 2 (CN)] [M = NEt 4 , 12a or Na(15-crown-5), 12b]. In the presence of excess iodine in THF, the cyanide 12a was converted back into the iodide 5, while the azide 11a was transformed into the neutral UV complex [U(N{SiMe 3 }-SiMe 2 C{CHI}O) 2 I(THF)] (13). The X-ray crystal structures of 4, 7b, 8a-c, 9b, 10, 12b, and 13 were determined. (authors)

  11. Regioselective Sequential Modification of Chitosan via Azide-Alkyne Click Reaction: Synthesis, Characterization, and Antimicrobial Activity of Chitosan Derivatives and Nanoparticles

    Science.gov (United States)

    Sarwar, Atif; Katas, Haliza; Samsudin, Siti Noradila; Zin, Noraziah Mohamad

    2015-01-01

    Recently, the attention of researchers has been drawn toward the synthesis of chitosan derivatives and their nanoparticles with enhanced antimicrobial activities. In this study, chitosan derivatives with different azides and alkyne groups were synthesized using click chemistry, and these were further transformed into nanoparticles by using the ionotropic gelation method. A series of chitosan derivatives was successfully synthesized by regioselective modification of chitosan via an azide-alkyne click reaction. The amino moieties of chitosan were protected during derivatization by pthaloylation and subsequently unblocked at the end to restore their functionality. Nanoparticles of synthesized derivatives were fabricated by ionic gelation to form complexes of polyanionic penta-sodium tripolyphosphate (TPP) and cationic chitosan derivatives. Particle size analysis showed that nanoparticle size ranged from 181.03 ± 12.73 nm to 236.50 ± 14.32 nm and had narrow polydispersity index and positive surface charge. The derivatives and corresponding nanoparticles were evaluated in vitro for antibacterial and antifungal activities against three gram-positive and gram-negative bacteria and three fungal strains, respectively. The minimum inhibitory concentration (MIC) of all derivatives ranged from 31.3 to 250 µg/mL for bacteria and 188 to1500 µg/mL for fungi and was lower than that of native chitosan. The nanoparticles with MIC ranging from 1.56 to 25 µg/mLfor bacteria and 94 to 750 µg/mL for fungi exhibited higher activity than the chitosan derivatives. Chitosan O-(1-methylbenzene) triazolyl carbamate and chitosan O-(1-methyl phenyl sulfide) triazolyl carbamate were the most active against the tested bacterial and fungal strains. The hemolytic assay on erythrocytes and cell viability test on two different cell lines (Chinese hamster lung fibroblast cells V79 and Human hepatic cell line WRL68) demonstrated the safety; suggesting that these derivatives could be used in future

  12. PH dependence of the spectral and anion binding properties of iron containing superoxide dismutase from E. coli B. An explanation for the azide inhibition of dismutase activity

    Energy Technology Data Exchange (ETDEWEB)

    Fee, J A; McClune, G J; Lees, A C [Michigan Univ., Ann Arbor (USA). Dept. of Biological Chemistry; Zidovetzki, R; Pecht, I [Weizmann Inst. of Science, Rehovoth (Israel). Dept. of Chemical Immunology

    1981-01-01

    Examination of the optical and EPR properties of the ferric form of the iron containing superoxide dismutase from E.coli B, at pH values ranging from 4.5 to 10.9, has revealed two reversible structural transitions affecting the Fe/sup 3 +/ ion. The apparent pKsub(a) values of these transitions are 5.1+-0.3 and 9.O+-0.3. The binding of azide has been studied over the pH range 4.5 to 10.7; the affinity of the Fe/sup 3 +/ for N/sub 3//sup -/ is independent of pH from 4.5 to approximately 7.5, after which the dissociation constant decreased by a factor of 10 per unit increase in pH. The apparent pKsub(a) which affects N/sub 3//sup -/ binding to the iron is 8.6+-0.2. The association of N/sub 3//sup -/ with the iron has been examined using the temperature-jump method at pH 7.4 and 9.3. The kinetics of ligand association were shown to conform to the minimal mechanism: P-Fe/sup 3 +/ + N/sub 3//sup -/reversible K/sub 1/N/sub 3//sup -/ - P-Fe/sup 3 +/reversible K/sub 2/P-Fe/sup 3 +/ - N/sub 3//sup -/. K/sub 1/ was found to be essentially unaffected by pH whereas K/sub 2/ was much lower at pH 9.3 than at 7.4. The value of K/sub 1/ at pH 7.4 (100 M/sup -1/) corresponds very closely to that obtained for the inhibition constant of azide, 10mM. A scheme is presented in which N/sub 3//sup -/ inhibits the iron containing dismutase by competing with O/sub 2//sup -/ for an anion binding site near, but not on the Fe/sup 3 +/.

  13. Reactive Energetic Plasticizers Utilizing Cu-Free Azide-Alkyne 1,3-Dipolar Cycloaddition for In-Situ Preparation of Poly(THF-co-GAP-Based Polyurethane Energetic Binders

    Directory of Open Access Journals (Sweden)

    Mingyang Ma

    2018-05-01

    Full Text Available Reactive energetic plasticizers (REPs coupled with hydroxy-telechelic poly(glycidyl azide-co-tetrahydrofuran (PGT-based energetic polyurethane (PU binders for use in solid propellants and plastic-bonded explosives (PBXs were investigated. The generation of gem-dinitro REPs along with a terminal alkyne stemmed from a series of finely designed approaches to not only satisfy common demands as conventional energetic plasticizers, but also to prevent the migration of plasticizers. The miscibility and rheological behavior of a binary mixture of PGT/REP with various REP fractions were quantitatively determined by differential scanning calorimetry (DSC and rheometer, respectively, highlighting the promising performance of REPs in the formulation process. The kinetics on the distinct reactivity of propargyl vs. 3-butynyl species of REPs towards the azide group of the PGT prepolymer in terms of Cu-free azide-alkyne 1,3-dipolar cycloaddition (1,3-DPCA was studied by monitoring 1H nuclear magnetic resonance spectroscopy and analyzing the activation energies (Ea obtained using DSC. The thermal stability of the finally cured energetic binders with the incorporation of REPs indicated that the thermal stability of the REP/PGT-based PUs was maintained independently of the REP content. The tensile strength and modulus of the PUs increased with an increase in the REP content. In addition, the energetic performance and sensitivity of REP and REP triazole species was predicted.

  14. A novel nanostructured composite formed by interaction of copper octa(3-aminopropyl)octasilsesquioxane with azide ligands: Preparation, characterization and a voltammetric application

    International Nuclear Information System (INIS)

    Ribeiro do Carmo, Devaney; Paim, Leonardo Lataro; Metzker, Gustavo; Dias Filho, Newton Luiz; Stradiotto, Nelson Ramos

    2010-01-01

    This study presents the preparation, characterization and application of copper octa(3-aminopropyl)octasilsesquioxane following its subsequent reaction with azide ions (ASCA). The precursor (AC) and the novel compound (ASCA) were characterized by Fourier transform infrared spectra (FTIR), nuclear magnetic resonance (NMR), electron paramagnetic resonance (EPR), scanning electronic microscopy (SEM), X-ray diffraction (XRD), Thermogravimetric analyses and voltammetric technique. The cyclic voltammogram of the modified graphite paste electrode with ASCA (GPE-ASCA), showed one redox couple with formal potential (E 1/2 ox ) = 0.30 V and an irreversible process at 1.1 V (vs. Ag/AgCl; NaCl 1.0 M; v=20mVs -1 ). The material is very sensitive to nitrite concentrations. The modified graphite paste electrode (GPE-ASCA) gives a linear range from 1.0 x 10 -4 to 4.0 x 10 -3 mol L -1 for the determination of nitrite, with a detection limit of 2.1 x 10 -4 mol L -1 and the amperometric sensitivity of 8.04 mA/mol L -1 .

  15. Studies on the rice seed (Oryza sativa) sensitivity to gama radiation, neutrons di-enthyl sulphate (DES) and sodium azide (SA)

    International Nuclear Information System (INIS)

    Guimaraes, E.P.

    1978-04-01

    Dry rice seeds of 'Dourado Precoce' variety were treated with gama-rays, thermal and fast neutrons, di-ethyl sulphate (DES) and sodium azide (SA). Biologial effects on survival, seedling height, plant fertility and chlorophy 11 mutation frequency were studied in the M 1 generation. The data obtained were analysed by 'independent test'. Survival was not affected by increased gama ray dosage, but by increased DES and SA dosages, as well as by SA treatments with increased solution acidity for seeds pretreated in distilled water. Seedling height was decreased with the increase of gama-ray dosage, DES concentration. SA acidity and concentration. Plant fertility was reduced drastically with higher gama-ray and neutron dosages and with high SA acidity and concentrations. The maximum chlorophy 11 mutation frequency was obtained in the SA treatment. Seeds pretreated with distilled water showed larger physiological damages in the SA treatments and higher mutation frequencies. Regarding chlorophyll mutation frequency, thermal neutrons were more efficient than gama-rays. SA was the most efficient mutagen used . DES showed lower physiological damages in the M 1 plants, but did not induce mutations in the used conditions [pt

  16. Chelator-Accelerated One-Pot ‘Click’ Labeling of Small Molecule Tracers with 2-[18F]Fluoroethyl Azide

    Directory of Open Access Journals (Sweden)

    Erik Årstad

    2013-05-01

    Full Text Available 2-[18F]Fluoroethyl azide ([18F]FEA can readily be obtained by nucleophilic substitution of 2-azidoethyl-4-toluenesulfonate with [18F]fluoride (half-life 110 min, and has become widely used as a reagent for ‘click’ labeling of PET tracers. However, distillation of [18F]FEA is typically required, which is time-consuming and unpractical for routine applications. In addition, copper(I-catalyzed cycloaddition of [18F]FEA with non-activated alkynes, and with substrates containing labile functional groups, can be challenging. Herein, we report a highly efficient and practical ligand-accelerated one-pot/two-step method for ‘click’ labeling of small molecule tracers with [18F]FEA. The method exploits the ability of the copper(I ligand bathophenanthrolinedisulfonate to accelerate the rate of the cycloaddition reaction. As a result, alkynes can be added directly to the crude reaction mixture containing [18F]FEA, and as cyclisation occurs almost immediately at room temperature, the reaction is tolerant to labile functional groups. The method was demonstrated by reacting [18F]FEA with a series of alkyne-functionalized 6-halopurines to give the corresponding triazoles in 55–76% analytical radiochemical yield.

  17. Divergent Pathways Involving 1,3-Dipolar Addition and N-N Bond Splitting of an Organic Azide across a Zirconium Methylidene.

    Science.gov (United States)

    Kurogi, Takashi; Mane, Manoj V; Zheng, Shuai; Carroll, Patrick J; Baik, Mu-Hyun; Mindiola, Daniel J

    2018-02-12

    The zirconium methylidene (PNP)Zr=CH 2 (OAr) (1) reacts with N 3 Ad to give two products (PNP)Zr=NAd(OAr) (2) and (PNP)Zr(η 2 -N=NAd)(N=CH 2 )(OAr) (3), both resulting from a common cycloaddition intermediate (PNP)Zr(CH 2 N 3 Ad)(OAr) (A). Using a series of control experiments in combination with DFT calculations, it was found that 2 results from a nitrene by a carbene metathesis reaction in which N 2 acts as a delivery vehicle and forms N 2 CH 2 as a side product. In the case of 3, N-N bond splitting of the azide at the α-position allowed the isolation of a rare example of a parent ketimide complex of zirconium. Isotopic labeling studies and solid-state X-ray analysis are presented for 2 and 3, in addition to an independent synthesis for the former. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Detection of sodium azide-induced mutagenicity in the regenerated shoots of artemisia annual L., using internal transcribed spacer (its) sequences of nrDNA

    International Nuclear Information System (INIS)

    Al-Qurainy, F.; Al-Hemaidi, F.M.; Khan, S.; Ali, M.A.; Tarroum, M.; Ashraf, M.

    2011-01-01

    Sodium azide (NaN/sub 3/) is a well known chemical mutagen which can effectively cause point mutation in plant genome. The mutagenicity by this potential mutagen was assessed in the regenerated mutant shoots of Artemisia annua using internal transcribed spacer (ITS) sequences of n rDNA. Insertions and/or deletions were detected in n rDNA-ITS sequences of all mutant shoots and compared with control ones using the ClustalX program. The regenerated shoots TS1 and TS2 had deleted bases, whereas TS3, TS4 and TS5 had insertions, because NaN/sub 3/ replaced the cytosine (C) by thymine (T) (C - T) (shoots; TS1 and TS4) and thymine (T) replaced by guanine (G) (T - G) (shoot; TS5), respectively. Artemisinin content was also measured in the regenerated six-week-old shoots of A. annua. All regenerated shoots had enhanced level of this compound as compared to that in the controls, being highest in the regenerated shoot TS3. (author)

  19. Ultrasonically-enhanced preparation, characterization of CaFe-layered double hydroxides with various interlayer halide, azide and oxo anions (CO32-, NO3-, ClO4-).

    Science.gov (United States)

    Szabados, Márton; Varga, Gábor; Kónya, Zoltán; Kukovecz, Ákos; Carlson, Stefan; Sipos, Pál; Pálinkó, István

    2018-01-01

    An ultrasonically-enhanced mechanochemical method was developed to synthesize CaFe-layered double hydroxides (LDHs) with various interlayer anions (CO 3 2- , NO 3 - , ClO 4 - , N 3 - , F - , Cl - , Br - and I - ). The duration of pre-milling and ultrasonic irradiation and the variation of synthesis temperature in the wet chemical step were investigated to obtain the optimal parameters of preparation. The main method to characterize the products was X-ray diffractometry, but infrared and synchrotron-based X-ray absorption spectroscopies as well as thermogravimetric measurements were also used to learn about fine structural details. The synthesis method afforded successful intercalation of the anions, among others the azide anion, a rarely used counter ion providing a system, which enables safe handling the otherwise highly reactive anion. The X-ray absorption spectroscopic measurements revealed that the quality of the interlayered anions could modulate the spatial arrangement of the calcium ions around the iron(III) ions, but only in the second coordination sphere. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Detection of nearest neighbors to specific fluorescently tagged ligands in rod outer segment and lymphocyte plasma membranes by photosensitization of 5-iodonaphthyl 1-azide

    International Nuclear Information System (INIS)

    Raviv, Y.; Bercovici, T.; Gitler, C.; Salomon, Y.

    1989-01-01

    Lima bean agglutinin-fluorescein 5-isothiocyanate conjugate (FluNCS-lima bean lectin) interacts with specific receptor molecules on membranes both from the rod outer segment (ROS) of the frog retina and from S49 mouse lymphoma cells. When [125I]-5-iodonaphthyl 1-azide (125I-INA), which freely and randomly partitions into the lipid bilayer, is added to membranes and the suspension is irradiated at 480 nm, the FluNCS-conjugated lectin photosensitizes the [125I]INA but only at discrete sites. This results in the selective labeling of specific proteins: an 88-kDa protein on ROS membranes and a 56-kDa protein on S49 plasma membranes. Labeling is dependent upon the interaction of the FluNCS-lectin with glycosylated receptor sites, since N-acetylgalactosamine, but not methyl alpha-mannoside, blocked labeling of the 56-kDa protein on S49 membranes. In contrast, a random labeling pattern of membrane proteins was observed upon irradiation at 480 nm using other fluorescein conjugates, such as FluNCS-bovine serum albumin (FluNCS-BSA) or FluNCS-soybean trypsin inhibitor (FluNCS-STI), which interact with cell membranes in a nonselective manner, or with N-(fluorescein-5-thiocarbamoyl)-n-undecyclamine (FluNCS-NHC11), which is freely miscible in the membrane lipid. Random labeling was also obtained by direct photoexcitation of [125I]INA at 314 nm, with no distinct labeling of the 88- and 56-kDa proteins in the respective membranes. These results suggest that protein ligands can be used to guide sensitizers to discrete receptor sites and lead to their selective labeling by photosensitized activation of [125I]INA

  1. Purification, crystallization and preliminary X-ray crystallographic analysis of the ATPase domain of human TAP in nucleotide-free and ADP-, vanadate- and azide-complexed forms

    International Nuclear Information System (INIS)

    Meena, Sita R.; Gangwar, Shanti P.; Saxena, Ajay K.

    2012-01-01

    The ATPase domain of human TAP in nucleotide free, ADP, vanadate and azide complexed forms were purified and crystallized. The X-ray diffraction data sets were collected for all crystals in the resolution range of 2.8–3.0 Å. The human transporter associated with antigen processing (TAP) protein belongs to the ATP-binding cassette (ABC) transporter superfamily and is formed by the heterodimerization of TAP1 and TAP2 subunits. TAP selectively pumps cytosolic peptides into the lumen of the endoplasmic reticulum in an ATP-dependent manner. The catalytic cycle of the ATPase domain of TAP is not understood at the molecular level. The structures of catalytic intermediates of the ATPase domain of TAP will contribute to the understanding of the chemical mechanism of ATP hydrolysis. In order to understand this mechanism, the ATPase domain of human TAP1 (NBD1) was expressed and purified, crystallized in nucleotide-free and transition-state complex forms and X-ray crystallographic studies were performed. The NBD1 protein was crystallized (i) in the nucleotide-free apo form; (ii) in complex with ADP–Mg 2+ , mimicking the product-bound state; (iii) in complex with vanadate–ADP–Mg 2+ , mimicking the ATP-bound state; and (iv) in complex with azide–ADP–Mg 2+ , also mimicking the ATP-bound state. X-ray diffraction data sets were collected for apo and complexed NBD1 using an in-house X-ray diffraction facility at a wavelength of 1.5418 Å. The apo and complexed NBD1 crystals belonged to the primitive hexagonal space group P6 2 , with one monomer in the asymmetric unit. Here, the crystallization, data collection and preliminary crystallographic analysis of apo and complexed NBD1 are reported

  2. Fully recoverable rigid shape memory foam based on copper-catalyzed azide-alkyne cycloaddition (CuAAC) using a salt leaching technique.

    Science.gov (United States)

    Alzahrani, Abeer A; Saed, Mohand; Yakacki, Christopher M; Song, Han Byul; Sowan, Nancy; Walston, Joshua J; Shah, Parag K; McBride, Matthew K; Stansbury, Jeffrey W; Bowman, Christopher N

    2018-01-07

    This study is the first to employ the use of the copper-catalyzed azide-alkyne cycloaddition (CuAAC) polymerization to form a tough and stiff, porous material from a well-defined network possessing a high glass transition temperature. The effect of the network linkages formed as a product of the CuAAC reaction, i.e., the triazoles, on the mechanical behavior at high strain was evaluated by comparing the CuAAC foam to an epoxy-amine-based foam, which consisted of monomers with similar backbone structures and mechanical properties (i.e., T g of 115 °C and a rubbery modulus of 1.0 MPa for the CuAAC foam, T g of 125 °C and a rubbery modulus of 1.2 MPa for the epoxy-amine foam). When each foam was compressed uniformly to 80% strain at ambient temperature, the epoxy-amine foam was severely damaged after only reaching 70% strain in the first compression cycle with a toughness of 300 MJ/m 3 . In contrast, the CuAAC foam exhibited pronounced ductile behavior in the glassy state with three times higher toughness of 850 MJ/m 3 after the first cycle of compression to 80% strain. Additionally, when the CuAAC foam was heated above T g after each of five compression cycles to 80% strain at ambient temperature, the foam completely recovered its original shape while exhibiting a gradual decrease in mechanical performance over the multiple compression cycles. The foam demonstrated almost complete shape fixity and recovery ratios even through five successive cycles, indicative of "reversible plasticity", making it highly desirable as a glassy shape memory foams.

  3. Synthesis and characterization of cyclic polystyrene using copper-catalyzed alkyne-azide cycloaddition coupling - evaluation of physical properties and optimization of cyclization conditions

    Science.gov (United States)

    Elupula, Ravinder

    Polymers with a cyclic topology exhibit a range of unique and potentially useful physical properties, including reduced rates of degradation and increased rates of diffusion in bulk relative to linear analogs. However the synthesis of high purity cyclic polymers, and verification of their structural purity remains challenging. The copper-catalyzed azide-alkyne "click" cyclization route toward cyclic polymers has been used widely, due to its synthetic ease and its compatibility with diverse polymer backbones. Yet unoptimized click cyclization conditions have been observed to generate oligomeric byproducts. In order to optimize these cyclization conditions, and to better understand the structure of the higher molecular weight oligomers, these impurities have been isolated by size exclusion chromatography (SEC) and characterized by mass spectrometry (MS). Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-ToF) MS is a particularly valuable characterization tool and was used to determine that the high molecular weight impurities are predominantly cyclic oligomers. It should also be noted that the rapid analysis and small analyte requirements of this MS technique make it particularly attractive as a general tool for elucidating polymer architecture. Ability to tailor the physical properties of polymers by changing the architecture alone has garnered a lot of attention over the past few decades. Compared to their linear analogues, these novel polymer architectures behave completely different in nanoscale regime. Cyclic polymers are especially intriguing since we can compare the differences in the physical properties with that of the linear chains. One of the major physical property changes are T g-confinement effect. Using ATRP and "click chemistry" we have produced highly pure cyclic PS (c-PS) with number-average molecular weight (MW) of 3.4 kg/mol and 9.1 kg/mol. Bulk glass transition temperatures for c-PS were weakly depended on MWs

  4. Azid sodný a animální modely Alzheimerovy nemoci. Část I – chronická subkutánní aplikace mladým zvířatům, behaviorální testy a biochemická analýza mozku mladých zvířat

    Czech Academy of Sciences Publication Activity Database

    Krištofíková, Z.; Ort, Michael; Helešic, V.; Bureš, Jan; Řípová, D.

    2006-01-01

    Roč. 10, č. S3 (2006), s. 39-42 ISSN 1211-7579 R&D Projects: GA MŠk(CZ) 1M0517 Institutional research plan: CEZ:AV0Z50110509 Keywords : sodium azide * Alzheimer disease * animal model Subject RIV: FH - Neurology

  5. Rhodium(II-Catalysed Intramolecular O-H Insertion of a-Diazo-g-Azido-d-Hydroxy-b-Ketoesters: Evidence for a Novel Sigmatropic Rearrangement of an Allylic Azide Intermediate

    Directory of Open Access Journals (Sweden)

    Padwa Albert

    1999-01-01

    Full Text Available The Rh2(OAc4 catalyzed intramolecular O-H insertion reaction of delta-hydroxy-alpha-diazoesters affords 3(2H-furanone-2-carboxylates in good yield but with moderate selectivity (d.e. ca 60%. The initially formed 2,5-substituted cis-furanones were found to epimerize to the corresponding 2,5-trans isomers when subjected to silica gel chromatography. The Rh2(OAc4 catalyzed decomposition of gamma-azido-delta-hydroxy-alpha-diazoesters also furnished 3(2H-furanone-2-carboxylates. These compounds are derived by a sequential O-H insertion reaction followed by a concerted [3,3]-sigmatropic shift of the allylic azide intermediate.

  6. Novel 99mTc(III)-azide complexes [99mTc(N3)(CDO)(CDOH)2B-R] (CDOH2 = cyclohexanedione dioxime) as potential radiotracers for heart imaging

    International Nuclear Information System (INIS)

    Liu, Min; Zheng, Yumin; Avcibasi, Ugur; Liu, Shuang

    2016-01-01

    Introduction: In this study, novel 99m Tc(III)-azide complexes [ 99m Tc(N 3 )(CDO)(CDOH) 2 B-R] ( 99m Tc-ISboroxime-N 3 : R = IS; 99m Tc-MPboroxime-N 3 : R = MP; 99m Tc-PAboroxime-N 3 : R = PA; 99m Tc-PYboroxime-N 3 : R = PY; and 99m Tc-Uboroxime-N 3 : R = 5U) were evaluated as heart imaging agents. Methods: Complexes [ 99m Tc(N 3 )(CDO)(CDOH) 2 B-R] (R = IS, MP, PA, PY and 5U) were prepared by ligand exchange between NaN 3 and [ 99m TcCl(CDO)(CDOH) 2 B-R]. Biodistribution and imaging studies were carried out in Sprague–Dawley rats. Image quantification was performed to compare their initial heart uptake and myocardial retention. Results: 99m Tc-ISboroxime-N 3 , 99m Tc-PYboroxime-N 3 and 99m Tc-Uboroxime-N 3 were prepared with high RCP (93–98%) while the RCP of 99m Tc-MPboroxime-N 3 and 99m Tc-PAboroxime-N 3 was 80–85%. The myocardial retention curves of 99m Tc-ISboroxime-N 3 , 99m Tc-PYboroxime-N 3 and 99m Tc-Uboroxime-N 3 were best fitted to the bi-exponential decay function. The half-time of the fast component was 1.6 ± 0.4 min for 99m Tc-ISboroxime-N 3 , 0.7 ± 0.1 min for 99m Tc-PYboroxime-N 3 and 0.9 ± 0.4 min for 99m Tc-Uboroxime-N 3 . The 2-min heart uptake from biodistribution studies followed the ranking order of 99m Tc-ISboroxime-N 3 (3.60 ± 0.68%ID/g) > 99m Tc-PYboroxime-N 3 (2.35 ± 0.37%ID/g) ≫ 99m Tc-Uboroxime-N 3 (1.29 ± 0.06%ID/g). 99m Tc-ISboroxime-N 3 had the highest 2-min heart uptake among 99m Tc radiotracers revaluated in SD rats. High quality SPECT images were obtained with the right and left ventricular walls being clearly delineated. The best image acquisition window was 0–5 min for 99m Tc-ISboroxime-N 3 . Conclusion: Both azide coligand and boronate caps had significant impact on the heart uptake and myocardial retention of complexes [ 99m Tc(N 3 )(CDO)(CDOH) 2 B-R]. Among the radiotracers evaluated in SD rats, 99m Tc-ISboroxime-N 3 has the highest initial heart uptake with the heart retention comparable to that of 99m Tc

  7. Azid sodný a animální modely demence Alzheimerova typu. Část II – Chronická subkutánní aplikace mladým i starým zvířatům, shrnutí výsledků

    Czech Academy of Sciences Publication Activity Database

    Krištofíková, Z.; Ort, Michael; Helešic, V.; Vrbacký, Marek; Majer, E.; Bureš, Jan; Stuchlík, Aleš; Řípová, D.

    2007-01-01

    Roč. 11, Suppl.3 (2007), s. 30-33 ISSN 1211-7579. [Konference Centra neuropsychiatrických studií - Neurologie v klinické aplikaci /7./. Zdoňov, 03.10.2007-05.10.2007] R&D Projects: GA MŠk(CZ) 1M0517 Institutional research plan: CEZ:AV0Z50110509 Keywords : Sodium azide * Alzheimer’s dementia * memory Subject RIV: FH - Neurology

  8. Crystal structures and DFT calculations of mixed chloride-azide zinc(II) and chloride-isocyanate cadmium(II) complexes with the condensation product of 2-quinolinecarboxaldehyde and Girard's T reagent

    Science.gov (United States)

    Anđelković, Katarina; Pevec, Andrej; Grubišić, Sonja; Turel, Iztok; Čobeljić, Božidar; Milenković, Milica R.; Keškić, Tanja; Radanović, Dušanka

    2018-06-01

    The mixed chloride-azide [ZnL(N3)1.65Cl0.35] (1) and chloride-isocyanate [CdL(NCO)1.64Cl0.36] (2) complexes with the condensation product of 2-quinolinecarboxaldehyde and trimethylammonium acetohydrazide chloride (Girard's T reagent) (HLCl) have been prepared and characterized by X-ray crystallography. In complexes 1 and 2, Zn1 and Cd1 ions, respectively, are five-coordinated in a distorted square based pyramidal geometry with NNO set of donor atoms of deprotonated hydrazone ligand and two monodentate ligands N3- and/or N3- and Cl- in the case of 1 and OCN- and/or OCN- and Cl- in the case of 2. The structural parameters of 1 and 2 have been discussed in relation to those of previously reported M(II) complexes with the same hydrazone ligand. Density functional theory calculations have been employed to study the interaction between the Zn2+ and Cd2+ ions and ligands. High affinity of ligands towards the Zn2+ and Cd2+ ions are predicted for both complexes.

  9. Synthesis, Spectroscopy, Theoretical, and Electrochemical Studies of Zn(II, Cd(II, and Hg(II Azide and Thiocyanate Complexes of a New Symmetric Schiff-Base Ligand

    Directory of Open Access Journals (Sweden)

    Morteza Montazerozohori

    2013-01-01

    Full Text Available Synthesis of zinc(II/cadmium(II/mercury(II thiocyanate and azide complexes of a new bidentate Schiff-base ligand (L with general formula of MLX2 (M = Zn(II, Cd(II, and Hg(II in ethanol solution at room temperature is reported. The ligand and metal complexes were characterized by using ultraviolet-visible (UV-visible, Fourier transform infrared (FT-IR, 1H- and 13C-NMR spectroscopy and physical characterization, CHN analysis, and molar conductivity. 1H- and 13C-NMR spectra have been studied in DMSO-d6. The reasonable shifts of FT-IR and NMR spectral signals of the complexes with respect to the free ligand confirm well coordination of Schiff-base ligand and anions in an inner sphere coordination space. The conductivity measurements as well as spectral data indicated that the complexes are nonelectrolyte. Theoretical optimization on the structure of ligand and its complexes was performed at the Becke’s three-parameter hybrid functional (B3 with the nonlocal correlation of Lee-Yang-Parr (LYP level of theory with double-zeta valence (LANL2DZ basis set using GAUSSIAN 03 suite of program, and then some theoretical structural parameters such as bond lengths, bond angles, and torsion angles were obtained. Finally, electrochemical behavior of ligand and its complexes was investigated. Cyclic voltammograms of metal complexes showed considerable changes with respect to free ligand.

  10. Rare-earth doped phosphors: oldies or goldies?

    International Nuclear Information System (INIS)

    Moine, B.; Bizarri, G.

    2003-01-01

    The scientific research on phosphors has a long history starting more than 100 years ago. But recently the appearance of new kinds of displays and lighting devices (plasma display, fluorescent lamp without mercury, etc.) induced an increase of the research of new phosphors with better luminous efficiency than those available up to now. It has been shown that the behavior of 'classical' phosphors in a plasma display panel is quite different than in a cathode ray tube and that the vacuum ultraviolet (VUV) excitation process has to be studied with care in order to improve the phosphors efficiency. That is particularly true in PDPs. It is well established now that a good phosphor for electronic or ultraviolet excitation is not necessarily a good choice for excitation in VUV. This is probably due to the fact that the excitation process is very different in that case and also because the penetration depth of the VUV photons is extremely small inducing a large contribution of the surface of the phosphor. We will illustrate this with some examples. Methods to accelerate luminous intensity decrease under VUV excitation will be described. Low efficiency, fast aging process are both drawbacks that can be solved only in the framework of fundamental studies. Quantum cutting emission may be a solution for the first one but no satisfactory process was proposed for the moment to solve the second

  11. Kinetic study on alkaline hydrolysis of Y-substituted phenyl X-substituted benzenesulfonates: Effects of changing nucleophile from azide to hydroxide ion on reactivity and transition-state structure

    International Nuclear Information System (INIS)

    Moon, Ji Hyun; Kim, Min Young; Han, So Yeop; Um, Ik Hwan

    2015-01-01

    Second-order rate constants (math formula) for alkaline hydrolysis of 2,4-dinitrophenyl X-substituted benzenesulfonates (1a–1f) and Y-substituted phenyl 4-nitrobezenesulfonates (2a–2g) have been measured spectrophotometrically. Comparison of math formula with the math formula values reported previously for the corresponding reactions with math formula has revealed that OH [BOND] is only 10"3-fold more reactive than math formula, although the former is 11 pK _a units more basic than the latter. The Yukawa–Tsuno plot for the reactions of 1a–1f results in an excellent linear correlation with ρ_X = 2.09 and r = 0.41. The Brønsted-type plot for the reactions of 2a–2g is linear with β_l_g = −0.51, which is typical for reactions reported to proceed through a concerted mechanism. The Yukawa–Tsuno plot for the reactions of 2a–2g exhibits excellent linearity with ρ_Y = 1.85 and r = 0.25, indicating that a partial negative charge develops on the O atom of the leaving group in the transition state. Thus, the alkaline hydrolysis of 1a–1f and 2a–2g has been concluded to proceed through a concerted mechanism. Comparison of the ρ_X and β_l_g values for the reactions with math formula ions suggests that the reactions with hydroxide ion proceed through a tighter transition-state structure than those with azide ion

  12. Radiation-chemical decomposition of heavy metal azides - II. Silver azide radiolysis scheme

    International Nuclear Information System (INIS)

    Ryabykh, S.M.

    1987-01-01

    As a result of complex studies on the nature and properties of final products and intermediate particles using a wide number of experimental topography and radiolysis kinetics methods, we offer the AgN 3 radiolysis scheme including the following stages: homogeneous excitation of electron subsystem with 'hot' electrons and holes formed; 'hot' electron and hole thermalization with possible formation of N 4 - radical in volume on the point defects; electron localization on the immobile structural defects whose neighbourhood is rich in the mobile positively charged point defects; metal particle formation due to electrostatic attraction of the nearby mobile defect to the localized electron, with no thermal excitation; metal particle growth, according to both the diffusional mechanism of delivering the volume of corresponding positively charged point defect with consequent electron capture, and by decomposing anions on the interphase with the consequent border layer cation addition to the growing metal particle, interior space formation in the volume by disintegrating 'hot' excitons into ion defect pairs; nitrogen formation on the exterior and interior surfaces, as well as those formed by radiation, either by trapping the hole by surface cation vacancy or by removing the surface cation of the hole with the consequent addition of the second hole to the Vsub(F)-center, and by disintegrating the activated complex into three nitrogen molecules. For the above stages the characteristic parameters are determined by means of direct measurement and calculation. The kinetics and energy conditions of the process are also found. (author)

  13. Activation of 5-[125I]iodonaphthyl-1-azide via excitation of fluorescent (N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)) lipid analogs in living cells. A potential tool for identification of compartment-specific proteins and proteins involved in intracellular transport and metabolism of lipids

    International Nuclear Information System (INIS)

    Rosenwald, A.G.; Pagano, R.E.; Raviv, Y.

    1991-01-01

    We describe a new technique for analysis of proteins located near fluorescent lipid analogs in intact living cells using the membrane-permeant, photoactivatable probe, 5-[ 125 I]iodonaphthyl-1-azide ([ 125 I]INA). [ 125 I] INA can be activated directly with UV light or indirectly through excitation of adjacent fluorophores (photosensitizers) with visible light to modify nearby proteins covalently with 125 I. In this report we demonstrate that fluorescent phospholipids and sphingolipids containing N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)-6-aminocaproic acid serve as appropriate photosensitizers for [ 125 I]INA. Using Chinese hamster ovary fibroblasts, we optimized the labeling conditions with respect to lipid concentration and time of irradiation and then examined the profiles of cellular proteins that were labeled when fluorescent analogs of ceramide, sphingomyelin, and phosphatidic acid were used as photosensitizers in living cells. The use of different fluorescent lipids, which label different subcellular compartments of cells as determined by fluorescence microscopy, derivatized different sets of cellular proteins with 125 I. The labeled proteins were subsets of the total set of proteins available for derivatization as determined by direct activation of [ 125 I]INA. Most proteins labeled by this procedure were pelleted by centrifugation of cell lysates at high speed (260,000 x g), but several soluble proteins were also labeled under these conditions. The implications of using this technique for identification of compartment-specific proteins and proteins involved in lipid metabolism and transport are discussed

  14. New Acridine Thiourea Gold(I) Anticancer Agents: Targeting the Nucleus and Inhibiting Vasculogenic Mimicry

    Czech Academy of Sciences Publication Activity Database

    Perez, S.A.; de Haro, C.; Vicente, C.; Donaire, A.; Zamora, A.; Zajac, Juraj; Kostrhunová, Hana; Brabec, Viktor; Bautista, D.; Ruiz, J.

    2017-01-01

    Roč. 12, č. 6 (2017), s. 1524-1537 ISSN 1554-8929 R&D Projects: GA ČR(CZ) GA17-09436S Institutional support: RVO:68081707 Keywords : heterocyclic carbene complexes * inflammatory breast - cancer Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 4.995, year: 2016

  15. Extraction of gold(I) cyanide by the methyl tri-n-alkyl ammonium chloride

    International Nuclear Information System (INIS)

    Zhang Tianxi; Yan Wenfei; Wu Jinguang

    2000-01-01

    The solvent extraction of KAu(CN) 2 from alkaline solution by the tri-n-alkyl ammonium chloride (N263) using 198 Au tracer has been investigated. The effects of various parameters, such as gold (I) concentration in aqueous phase, cosolvent, phase ratio on the extraction of gold (I) are studied. The results demonstrate that almost all of gold (I) in aqueous phase can be extracted into the organic phase. Water concentration decreases significantly with the increase of gold (I) concentration in the organic phase. No water molecule could be involved in the extraction of gold (I)

  16. Azide-based mutagenesis suppresses Striga hermonthica seed ...

    African Journals Online (AJOL)

    GRACE

    2006-05-16

    May 16, 2006 ... the farmers' socio-economic conditions. ... The present paper reports on mutagenic conversion of ... flow rate of 0.4 ml/min. ... then transferred to circular plastic pots, which had several holes ... stimulant activity against S. hermonthica was observed in ... Longman Scientific and Technical, London. pp. 368-.

  17. Metal azides under pressure: An emerging class of high energy ...

    Indian Academy of Sciences (India)

    Advanced Centre of Research in High Energy Materials (ACRHEM), University of ... behaviour of LiN3 and KN3 by means of density functional calculations. ... and 4.08 eV (KN3) and as pressure increases the band gap decreases and show ...

  18. Azide functionalized poly(3-hexylthiophene) and methods of forming same

    Science.gov (United States)

    Qin, Yang; Grubbs, Robert B; Park, Young Suk

    2014-11-18

    This disclosure relates to a polymer having the formula: ##STR00001## wherein x is between 1 and about 100 an y is between about 99 and about 1, and x+Y=about 100. The disclosure also includes the use of the polymer in photovoltaic devices.

  19. Air quality modelling using chemometric techniques | Azid | Journal ...

    African Journals Online (AJOL)

    This study presents that the chemometric techniques and modelling become an excellent tool in API assessment, air pollution source identification, apportionment and can be setbacks in designing an API monitoring network for effective air pollution resources management. Keywords: air pollutant index; chemometric; ANN; ...

  20. Synthesis, characterization and anticancer activity of gold(I) complexes that contain tri-tert-butylphosphine and dialkyl dithiocarbamate ligands

    KAUST Repository

    Altaf, Muhammad; Monim-ul-Mehboob, M.; Seliman, Adam A.A.; Sohail, Manzar; Wazeer, Mohammed I.M.; Isab, Anvarhusein A.; Li, L.; Dhuna, V.; Bhatia, G.; Dhuna, K.

    2015-01-01

    of both complexes was examined against A549 (lung cancer), MCF7 (breast cancer), and HeLa (cervical cancer) human cancer cell lines. Both complexes exhibit very strong in vitro cytotoxic effects against A549, MCF7 and HeLa cell lines. The screening

  1. The Enzymatic and Structural Basis for Inhibition of Echinococcus granulosus Thioredoxin Glutathione Reductase by Gold(I).

    Science.gov (United States)

    Salinas, Gustavo; Gao, Wei; Wang, Yang; Bonilla, Mariana; Yu, Long; Novikov, Andrey; Virginio, Veridiana G; Ferreira, Henrique B; Vieites, Marisol; Gladyshev, Vadim N; Gambino, Dinorah; Dai, Shaodong

    2017-12-20

    New drugs are needed to treat flatworm infections that cause severe human diseases such as schistosomiasis. The unique flatworm enzyme thioredoxin glutathione reductase (TGR), structurally different from the human enzyme, is a key drug target. Structural studies of the flatworm Echinococcus granulosus TGR, free and complexed with Au I -MPO, a novel gold inhibitor, together with inhibition assays were performed. Au I -MPO is a potent TGR inhibitor that achieves 75% inhibition at a 1:1 TGR:Au ratio and efficiently kills E. granulosus in vitro. The structures revealed salient insights: (i) unique monomer-monomer interactions, (ii) distinct binding sites for thioredoxin and the glutaredoxin (Grx) domain, (iii) a single glutathione disulfide reduction site in the Grx domain, (iv) rotation of the Grx domain toward the Sec-containing redox active site, and (v) a single gold atom bound to Cys 519 and Cys 573 in the Au I -TGR complex. Structural modeling suggests that these residues are involved in the stabilization of the Sec-containing C-terminus. Consistently, Cys→Ser mutations in these residues decreased TGR activities. Mass spectroscopy confirmed these cysteines are the primary binding site. The identification of a primary site for gold binding and the structural model provide a basis for gold compound optimization through scaffold adjustments. The structural study revealed that TGR functions are achieved not only through a mobile Sec-containing redox center but also by rotation of the Grx domain and distinct binding sites for Grx domain and thioredoxin. The conserved Cys 519 and Cys 573 residues targeted by gold assist catalysis through stabilization of the Sec-containing redox center. Antioxid. Redox Signal. 27, 1491-1504.

  2. Anticancer Agents: Does a Phosphonium Behave Like a Gold(I) Phosphine Complex? Let a "Smart" Probe Answer!

    Science.gov (United States)

    Ali, Moussa; Dondaine, Lucile; Adolle, Anais; Sampaio, Carla; Chotard, Florian; Richard, Philippe; Denat, Franck; Bettaieb, Ali; Le Gendre, Pierre; Laurens, Véronique; Goze, Christine; Paul, Catherine; Bodio, Ewen

    2015-06-11

    Gold phosphine complexes, such as auranofin, have been recognized for decades as antirheumatic agents. Clinical trials are now underway to validate their use in anticancer or anti-HIV treatments. However, their mechanisms of action remain unclear. A challenging question is whether the gold phosphine complex is a prodrug that is administered in an inactive precursor form or rather that the gold atom remains attached to the phosphine ligand during treatment. In this study, we present two novel gold complexes, which we compared to auranofin and to their phosphonium analogue. The chosen ligand is a phosphine-based smart probe, whose strong fluorescence depends on the presence of the gold atom. The in vitro biological action of the gold complexes and the phosphonium derivative were investigated, and a preliminary in vivo study in healthy zebrafish larvae allowed us to evaluate gold complex biodistribution and toxicity. The different analyses carried out showed that these gold complexes were stable and behaved differently from phosphonium and auranofin, both in vitro and in vivo. Two-photon microscopy experiments demonstrated that the cellular targets of these gold complexes are not the same as those of the phosphonium analogue. Moreover, despite similar IC50 values in some cancer cell lines, gold complexes displayed a low toxicity in vivo, in contrast to the phosphonium salt. They are therefore suitable for future in vivo investigations.

  3. C-13 NMR Spectroscopy of N-Heterocyclic Carbenes Can Selectively Probe sigma Donation in Gold(I) Complexes

    NARCIS (Netherlands)

    Marchione, Demian; Izquierdo, Maria A.; Bistoni, Giovanni; Havenith, Remco W. A.; Macchioni, Alceo; Zuccaccia, Daniele; Tarantelli, Francesco; Belpassi, Leonardo

    The Dewar-Chatt-Duncanson (DCD) model provides a successful theoretical framework to describe the nature of the chemical bond in transition-metal compounds and is especially useful in structural chemistry and catalysis. However, how to actually measure its constituents (substrate- to-metal donation

  4. Effect of the porous structure of activated carbon on the adsorption kinetics of gold(I) cyanide complex

    Science.gov (United States)

    Ibragimova, P. I.; Grebennikov, S. F.; Gur'yanov, V. V.; Fedyukevich, V. A.; Vorob'ev-Desyatovskii, N. V.

    2014-06-01

    The effect the porous structure of activated carbons obtained from furfural and coconut shells has on the kinetics of [Au(CN)2]- ion adsorption is studied. Effective diffusion coefficients for [Au(CN)2]- anions in transport and adsorbing pores and mass transfer coefficients in a transport system of the pores and in microporous zones are calculated using the statistical moments of the kinetic curve.

  5. Sequential Functionalization of Alkynes and Alkenes Catalyzed by Gold(I) and Palladium(II) N-Heterocyclic Carbene Complexes

    KAUST Repository

    Gó mez-Herrera, Alberto; Nahra, Fady; Brill, Marcel; Nolan, Steven P.; Cazin, Catherine S. J.

    2016-01-01

    The iodination of terminal alkynes for the synthesis of 1-iodoalkynes using N-iodosuccinimide in the presence of a AuI-NHC (NHC=N-heterocyclic carbene) catalyst is reported. A series of aromatic alkynes was transformed successfully into the corresponding 1-iodoalkynes in good to excellent yields under mild reaction conditions. The further use of these compounds as organic building blocks and the advantageous choice of metal-NHC complexes as catalysts for alkyne functionalization were further demonstrated by performing selective AuI-catalyzed hydrofluorination to yield (Z)-2-fluoro-1-iodoalkenes, followed by a Suzuki–Miyaura cross-coupling with aryl boronic acids catalyzed by a PdII-NHC complex to access trisubstituted (Z)-fluoroalkenes. All methodologies can be performed sequentially with only minor variations in the optimized individual reaction conditions, maintaining high efficiency and selectivity in all cases, which therefore, provides straightforward access to valuable fluorinated alkenes from commercially available terminal alkynes.

  6. Lipophilic phosphorescent gold(I) clusters as selective probes for visualization of lipid droplets by two-photon microscopy

    Czech Academy of Sciences Publication Activity Database

    Koshel, E. I.; Cheluskin, P. S.; Melnikov, A. S.; Serdobintsev, P. Y.; Stolbovaia, A. Y.; Saifitdinova, A. F.; Scheslavskiy, V. I.; Chernyavskiy, Oleksandr; Gaginskaya, E. R.; Koshevoy, I. O.; Tunik, S. P.

    2017-01-01

    Roč. 332, Jan 1 (2017), s. 122-130 ISSN 1010-6030 R&D Projects: GA MŠk(CZ) LM2015062 Institutional support: RVO:67985823 Keywords : polynuclear gold-alkynyl cluster * lipophilic probe * phosphorescence * adipocyte * two-photon microscopy * PLIM Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Medical laboratory technology (including laboratory samples analysis Impact factor: 2.625, year: 2016

  7. Sequential Functionalization of Alkynes and Alkenes Catalyzed by Gold(I) and Palladium(II) N-Heterocyclic Carbene Complexes

    KAUST Repository

    Gómez-Herrera, Alberto

    2016-08-22

    The iodination of terminal alkynes for the synthesis of 1-iodoalkynes using N-iodosuccinimide in the presence of a AuI-NHC (NHC=N-heterocyclic carbene) catalyst is reported. A series of aromatic alkynes was transformed successfully into the corresponding 1-iodoalkynes in good to excellent yields under mild reaction conditions. The further use of these compounds as organic building blocks and the advantageous choice of metal-NHC complexes as catalysts for alkyne functionalization were further demonstrated by performing selective AuI-catalyzed hydrofluorination to yield (Z)-2-fluoro-1-iodoalkenes, followed by a Suzuki–Miyaura cross-coupling with aryl boronic acids catalyzed by a PdII-NHC complex to access trisubstituted (Z)-fluoroalkenes. All methodologies can be performed sequentially with only minor variations in the optimized individual reaction conditions, maintaining high efficiency and selectivity in all cases, which therefore, provides straightforward access to valuable fluorinated alkenes from commercially available terminal alkynes.

  8. 1,3-Dipolar Cycloadditions of Diazo Compounds in the Presence of Azides.

    Science.gov (United States)

    Aronoff, Matthew R; Gold, Brian; Raines, Ronald T

    2016-04-01

    The diazo group has untapped utility in chemical biology. The tolerance of stabilized diazo groups to cellular metabolism is comparable to that of azido groups. However, chemoselectivity has been elusive, as both groups undergo 1,3-dipolar cycloadditions with strained alkynes. Removing strain and tuning dipolarophile electronics yields diazo group selective 1,3-dipolar cycloadditions that can be performed in the presence of an azido group. For example, diazoacetamide but not its azido congener react with dehydroalanine residues, as in the natural product nisin.

  9. Molecular and electronic structure of chromium(V) nitrido complexes with azide and isothiocyanate ligands

    DEFF Research Database (Denmark)

    Bendix, Jesper; Birk, Torben; Weyhermüller, Thomas

    2005-01-01

    . This absorption provides the spectrochemical series for the equatorial ligands, which is found to be numerically almost identical to that determined for chromium(III). DFT calculations reproduce the observed structures and corroborate the ligand field picture of the electronic structure of these complexes....

  10. Synthesis of alpha-tetrasubstituted triazoles by copper-catalyzed silyl deprotection/azide cycloaddition

    Directory of Open Access Journals (Sweden)

    Zachary L. Palchak

    2015-08-01

    Full Text Available Propargylamines are popular substrates for triazole formation, but tetrasubstituted variants have required multistep syntheses involving stoichiometric amounts of metal. A recent cyclohexanone–amine–silylacetylene coupling forms silyl-protected tetrasubstituted propargylamines in a single copper-catalyzed step. The development of the tandem silyl deprotection–triazole formation reported herein offers rapid access to alpha-tetrasubstituted triazoles. A streamlined two-step approach to this uncommon class of hindered triazoles will accelerate exploration of their therapeutic potential. The superior activity of copper(II triflate in the formation of triazoles from sensitive alkyne substrates extends to simple terminal alkynes.

  11. Electrocatalytic Azide Oxidation Mediated by a Rh(PNP) Pincer Complex

    NARCIS (Netherlands)

    Rebreyend, Christophe; Gloaguen, Yann; Lutz, Martin; Van Der Vlugt, Jarl Ivar; Siewert, Inke; Schneider, Sven; Bruin, Bas De

    2017-01-01

    One-electron oxidation of the rhodium(I) azido complex [Rh(N3)(PNP)] (5), bearing the neutral, pyridine-based PNP ligand 2,6-bis(di-tert-butylphosphinomethyl)pyridine, leads to instantaneous and selective formation of the mononuclear rhodium(I) dinitrogen complex [Rh(N2)(PNP)]+ (9+). Interestingly,

  12. Electrocatalytic Azide Oxidation Mediated by a Rh(PNP) Pincer Complex

    NARCIS (Netherlands)

    Rebreyend, C.; Gloaguen, Y.; Lutz, M.; van der Vlugt, J.I.; Siewert, I.; Schneider, S.; de Bruin, B.

    2017-01-01

    One-electron oxidation of the rhodium(I) azido complex [Rh(N3)(PNP)] ( 5 ), bearing the neutral, pyridine-based PNP ligand 2,6-bis(di-tert-butylphosphinomethyl)pyridine, leads to instantaneous and selective formation of the mononuclear rhodium(I) dinitrogen complex [Rh(N2)(PNP)]+ ( 9 +).

  13. Pressure-accelerated azide-alkyne cycloaddition : micro capillary versus autoclave reactor performance

    NARCIS (Netherlands)

    Borukhova, S.; Seeger, A.D.; Noël, T.; Wang, Q.; Busch, M.; Hessel, V.

    2015-01-01

    Pressure effects on regioselectivity and yield of cycloaddition reactions have been shown to exist. Nevertheless, high pressure synthetic applications with subsequent benefits in the production of natural products are limited by the general availability of the equipment. In addition, the virtues and

  14. Cross-linking and modification of saturated elastomers using functionalized azides

    NARCIS (Netherlands)

    Zielinska, A.J.

    2011-01-01

    The main advantage of saturated elastomers, such as EPM and EPDM over their unsaturated counter-parts is the absence of carbon-carbon unsaturation in the main polymer chain, resulting in excellent ozone and heat resistance. A consequent disadvantage of the absence of unsaturation is the lack of

  15. Sulfonyl azide-mediated norbornene aziridination for orthogonal peptide and protein labeling

    Czech Academy of Sciences Publication Activity Database

    Gattner, M. J.; Ehrlich, M.; Vrábel, Milan

    2014-01-01

    Roč. 50, č. 83 (2014), s. 12568-12571 ISSN 1359-7345 Institutional support: RVO:61388963 Keywords : Diels- Adler reactions * transfer RNA synthetase * free click chemistry Subject RIV: CC - Organic Chemistry Impact factor: 6.834, year: 2014

  16. A practical one-pot synthesis of azides directly from alcohols

    Indian Academy of Sciences (India)

    vity patterns make them one of the most sought-after functionalities in ... using easily available, yet efficient reagent systems is of immense ... without further purification. Most of the .... was quenched by adding to ice-cold water and extracted.

  17. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    selenolates are described. This study indicates that the nature of selenolate plays an important role in ligand exchange reactions in gold(I) selenolates. Furthermore, the reactivity of imidazole-based gold(I) selenolates toward nucleophiles such ...

  18. Creation of Optically Pure Crystals from a Meso-Type Gold(I) Metalloligand with d- and l-Amino Acids: A Coordination Trick.

    Science.gov (United States)

    Itai, Takuma; Kojima, Tatsuhiro; Kuwamura, Naoto; Konno, Takumi

    2017-11-21

    A unique example of a coordination system that creates optically pure crystals from a meso compound with d- and l-amino acids is reported. The 1:1 reaction of a newly prepared meso digold(I) complex, [Au 2 (dcpe)(d-Hpen)(l-Hpen)] ([H 2 1]), with Co(OAc) 2 under aerobic conditions yielded a cationic Au I 2 Co III trinuclear complex, [Au 2 Co(dcpe)(d-pen)(l-pen)] + [2] + , in which [1] 2- acts as a hexadentate-N 2 ,O 2 ,S 2 metalloligand to a Co III center. Similar reactions with M(OAc) 2 (M=Ni and Zn) produced analogous but neutral Au I 2 M II complexes, [Au 2 M(dcpe)(d-pen)(l-pen)] ([3 M ]). Complexes [2] + and [3 M ] are chiral (C vs. A) at the octahedral Co III and M II centers due to the arrangement of the N 2 ,O 2 ,S 2 donor set. In addition, through spontaneous resolution, [3 M ] gave optically pure C-[3 M ] and A-[3 M ] crystals, showing the creation of homochirality from meso-[1] 2- and achiral M 2+ through crystallization. Such a phenomenon was not observed for [2] + , which gave a racemic compound containing both C-[2] + and A-[2] + . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Gold(I) complex of 1,1'-bis(diphenylphosphino) ferrocene-quinoline conjugate: a virostatic agent against HIV-1.

    Science.gov (United States)

    Gama, Ntombenhle; Kumar, Kamlesh; Ekengard, Erik; Haukka, Matti; Darkwa, James; Nordlander, Ebbe; Meyer, Debra

    2016-06-01

    HIV infection is known for replicating in proliferating CD(+) T-cells. Treatment of these cells with cytostatic (anti-proliferation) compounds such as hydroxyurea interferes with the cells's ability support HIV replication. Combinations of such cytostatic compounds with proven anti-retroviral drugs (like ddI) are known as virostatic, and have been shown to aid in the control of the infection. The use of two different drugs in virostatic combinations however, carries the risk of adverse effects including drug-drug interactions, which could lead to augmented toxicities and reduced efficacy. Here, a novel digold(I) complex of ferrocene-quinoline (3) was investigated for cytostatic behaviour as well as anti-viral activity which if demonstrated would eliminate concerns of drug-drug interactions. The complex was synthesized and characterized by NMR, FT-IR and mass spectroscopy and the molecular structure was confirmed by X-ray crystallography. Bio-screening involved viability dyes, real time electronic sensing and whole virus assays. The complex showed significant (p = 0.0092) inhibition of virus infectivity (83 %) at 10 ug/mL. This same concentration caused cytostatic behaviour in TZM-bl cells with significant (p < 0.01) S and G2/M phase cell cycle arrest. These data supports 3 as a virostatic agent, possessing both anti-viral and cytostatic characteristics. In the absence of 3, TZM-bl cells were infected by a pseudovirus and this was demonstrated through luminescence in a luciferase assay. Pre-incubation of the virus with 3 decreased luminescence, indicating the anti-viral activity of 3. Complex 3 also showed cytostatic behavior with increased S-phase and G2/M phase cell cycle arrest.

  20. The Enzymatic and Structural Basis for Inhibition of Echinococcus granulosus Thioredoxin Glutathione Reductase by Gold(I)

    Energy Technology Data Exchange (ETDEWEB)

    Salinas, Gustavo [Worm Biology Lab, Institut Pasteur de Montevideo, Montevideo, Uruguay.; Cátedra de Inmunología, Facultad de Química, Instituto de Higiene, Universidad de la República, Montevideo, Uruguay.; Gao, Wei [Department of Biomedical Research, National Jewish Health, Denver, Colorado.; Department of Immunology and Microbiology, University of Colorado Denver, School of Medicine, Aurora, Colorado.; School of Science, Beijing Forestry University, Beijing, China.; Wang, Yang [Department of Biomedical Research, National Jewish Health, Denver, Colorado.; Department of Immunology and Microbiology, University of Colorado Denver, School of Medicine, Aurora, Colorado.; Bonilla, Mariana [Cátedra de Inmunología, Facultad de Química, Instituto de Higiene, Universidad de la República, Montevideo, Uruguay.; Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Uruguay.; Yu, Long [Department of Biomedical Research, National Jewish Health, Denver, Colorado.; Department of Immunology and Microbiology, University of Colorado Denver, School of Medicine, Aurora, Colorado.; Novikov, Andrey [Department of Biomedical Research, National Jewish Health, Denver, Colorado.; Department of Immunology and Microbiology, University of Colorado Denver, School of Medicine, Aurora, Colorado.; Virginio, Veridiana G. [Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.; Ferreira, Henrique B. [Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.; Vieites, Marisol [Cátedra de Química Inorgánica, Facultad de Química, Universidad de la República, Montevideo, Uruguay.; Gladyshev, Vadim N. [Brigham and Women' s Hospital, Harvard Medical School, Boston, Massachusetts.; Gambino, Dinorah [Cátedra de Química Inorgánica, Facultad de Química, Universidad de la República, Montevideo, Uruguay.; Dai, Shaodong [Department of Biomedical Research, National Jewish Health, Denver, Colorado.; Department of Immunology and Microbiology, University of Colorado Denver, School of Medicine, Aurora, Colorado.

    2017-12-20

    Aims: New drugs are needed to treat flatworm infections that cause severe human diseases such as schistosomiasis. The unique flatworm enzyme thioredoxin glutathione reductase (TGR), structurally different from the human enzyme, is a key drug target. Structural studies of the flatworm Echinococcus granulosus TGR, free and complexed with AuI-MPO, a novel gold inhibitor, together with inhibition assays were performed. Results: AuI-MPO is a potent TGR inhibitor that achieves 75% inhibition at a 1:1 TGR:Au ratio and efficiently kills E. granulosus in vitro. The structures revealed salient insights: (i) unique monomer–monomer interactions, (ii) distinct binding sites for thioredoxin and the glutaredoxin (Grx) domain, (iii) a single glutathione disulfide reduction site in the Grx domain, (iv) rotation of the Grx domain toward the Sec-containing redox active site, and (v) a single gold atom bound to Cys519 and Cys573 in the AuI-TGR complex. Structural modeling suggests that these residues are involved in the stabilization of the Sec-containing C-terminus. Consistently, Cys→Ser mutations in these residues decreased TGR activities. Mass spectroscopy confirmed these cysteines are the primary binding site. Innovation: The identification of a primary site for gold binding and the structural model provide a basis for gold compound optimization through scaffold adjustments. Conclusions: The structural study revealed that TGR functions are achieved not only through a mobile Sec-containing redox center but also by rotation of the Grx domain and distinct binding sites for Grx domain and thioredoxin. The conserved Cys519 and Cys573 residues targeted by gold assist catalysis through stabilization of the Sec-containing redox center. Antioxid. Redox Signal. 27, 1491–1504.

  1. Experimental and computational studies on the reactivity of a terminal thorium imidometallocene towards organic azides and diazoalkanes

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Wenshan [Beijing Normal Univ. (China). Dept. of Chemistry; Southwest Univ., Chongqing (China). College of Chemistry and Chemical Engineering; Zhou, Enwei; Fang, Bo; Hou, Guohua; Zi, Guofu; Fang, De-Cai [Beijing Normal Univ. (China). Dept. of Chemistry; Walter, Marc D. [Technische Univ. Braunschweig (Germany). Inst. fuer Anorganische und Analytische Chemie

    2014-10-13

    The reaction of the base-free terminal thorium imido complex [{η"5-1,2,4-(Me_3C)_3C_5H_2}{sub 2}Th=N(p-tolyl)] (1) with p-azidotoluene yielded irreversibly the tetraazametallacyclopentene [{η"5-1,2,4-(Me_3C)_3C_5H_2}{sub 2}Th{N(p-tolyl)N=N-N(p-tolyl)}] (2), whereas the bridging imido complex [{[η"5-1,2,4-(Me_3C)_3C_5H_2]Th(N_3)_2}{sub 2}{μ-N(p-tolyl)}{sub 2}][(n-C{sub 4}H{sub 9}){sub 4}N]{sub 2} (3) was isolated from the reaction of 1 with [(n-C{sub 4}H{sub 9}){sub 4}N]N{sub 3}. Unexpectedly, upon the treatment of 1 with 9-diazofluorene, the NN bond was cleaved, an N atom was transferred, and the η{sup 2}-diazenido iminato complex [{η"5-1,2,4-(Me_3C)_3C_5H_2}{sub 2}Th{η"2-[N=N(p-tolyl)]}{N=(9-C_1_3H_8)}] (4) was formed. In contrast, the reaction of 1 with Me{sub 3}SiCHN{sub 2} gave the nitrilimido complex [{η"5-1,2,4-(Me_3C)_3C_5H_2}{sub 2}Th{NH(p-tolyl)}{N_2CSiMe_3}] (5), which slowly converted into [{η"5-1,2,4-(Me_3C)_3C_5H_2}{η"5:κ-N-1,2-(Me_3C)_2-4-CMe_2(CH_2NN=CHSiMe_3)C_5H_2}Th{NH (p-tolyl)}] (6) by intramolecular C-H bond activation. The experimental results are complemented by density functional theory (DFT) studies.

  2. Spin-State-Controlled Photodissociation of Iron(III) Azide to an Iron(V) Nitride Complex

    Czech Academy of Sciences Publication Activity Database

    Andris, E.; Navrátil, R.; Jašík, J.; Sabenya, G.; Costas, M.; Srnec, Martin; Roithová, J.

    2017-01-01

    Roč. 56, č. 45 (2017), s. 14057-14060 ISSN 1521-3773 Institutional support: RVO:61388955 Keywords : Ion spectroscopy * Iron(V) nitride * Photodissociation Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry

  3. Reactivity studies of eta sup (6)-p-cymene ruthenium(II) carboxylato complexes towards azide some neutral ligands

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Kollipara, M.R.

    sub (2)O sub (4)(7) or C sub (2)CH sub (2)O sub (4)(10)] have been prepared by the reaction of [(p-cymene)RuCl sub (2)]sub (2) with the corresponding sodium salts of the carboxylic acids. Treatment of (eta sup (6)-p-cymene) ruthenium(II) carboxylato...

  4. 1,5 iodonaphthyl Azide Inactivated V3526 Protects against Aerosol Challenge with Virulent Venezuelan Equine Encephalitis Virus.

    Science.gov (United States)

    2016-06-02

    Ethics Statement: Animal experiments involving aerosol challenge with infectious VEEV-TrD were carried out in ABSL-3 containment facility at...furin-cleavage mutant of V3000 (full length clone of VEEV-TrD) and induces excellent immunogenicity, but caused adverse reaction in the vaccinees

  5. One pot 'click' reactions : tandem enantioselective biocatalytic epoxide ring opening and [3+2] azide alkyne cycloaddition

    NARCIS (Netherlands)

    Campbell-Verduyn, Lachlan S.; Szymanski, Wiktor; Postema, Christiaan P.; Dierckx, Rudi A.; Elsinga, Philip H.; Janssen, Dick B.; Feringa, Ben L.

    2010-01-01

    Halohydrin dehalogenase (HheC) can perform enantioselective azidolysis of aromatic epoxides to 1,2-azido alcohols which are subsequently ligated to alkynes producing chiral hydroxy triazoles in a one-pot procedure with excellent enantiomeric excess.

  6. Citrus Peel Additives for One-Pot Triazole Formation by Decarboxylation, Nucleophilic Substitution, and Azide-Alkyne Cycloaddition Reactions

    Science.gov (United States)

    Mendes, Desiree E.; Schoffstall, Allen M.

    2011-01-01

    This undergraduate organic laboratory experiment consists of three different reactions occurring in the same flask: a cycloaddition reaction, preceded by decarboxylation and nucleophilic substitution reactions. The decarboxylation and cycloaddition reactions occur using identical Cu(I) catalyst and conditions. Orange, lemon, and other citrus fruit…

  7. Non-Catalyzed Click Reactions of ADIBO Derivatives with 5-Methyluridine Azides and Conformational Study of the Resulting Triazoles

    Czech Academy of Sciences Publication Activity Database

    Smyslová, P.; Popa, I.; Lyčka, A.; Tejral, Gracian; Havlač, J.

    2015-01-01

    Roč. 10, č. 2 (2015), e0144613 E-ISSN 1932-6203 R&D Projects: GA TA ČR(CZ) TE01020028 Institutional support: RVO:68378041 Keywords : copper-free click * alkyne cycloaddition * chemistry Subject RIV: CC - Organic Chemistry Impact factor: 3.057, year: 2015

  8. Diversity-Oriented Peptide Stapling: A Third Generation Copper-Catalysed Azide-Alkyne Cycloaddition Stapling and Functionalisation Strategy

    Czech Academy of Sciences Publication Activity Database

    Tran, P. T.; Larsen, C. O.; Rondbjerg, T.; De Foresta, M.; Kunze, M. B. A.; Marek, Aleš; Loper, J. H.; Boyhus, L.-E.; Knuhtsen, A.; Lindorff-Larsen, K.; Pedersen, D. S.

    2017-01-01

    Roč. 23, č. 14 (2017), s. 3490-3495 ISSN 0947-6539 Institutional support: RVO:61388963 Keywords : bioconjugate chemistry * CuAAC * peptide chemistry * peptidomimetics * radiolabelling Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry Impact factor: 5.317, year: 2016

  9. 7-Chloroquinolinotriazoles: synthesis by the azide-alkyne cycloaddition click chemistry, antimalarial activity, cytotoxicity and SAR studies.

    Science.gov (United States)

    Pereira, Guilherme R; Brandão, Geraldo Célio; Arantes, Lucas M; de Oliveira, Háliton A; de Paula, Renata Cristina; do Nascimento, Maria Fernanda A; dos Santos, Fábio M; da Rocha, Ramon K; Lopes, Júlio César D; de Oliveira, Alaíde Braga

    2014-02-12

    Twenty-seven 7-chloroquinolinotriazole derivatives with different substituents in the triazole moiety were synthesized via copper-catalyzed cycloaddition (CuAAC) click chemistry between 4-azido-7-chloroquinoline and several alkynes. All the synthetic compounds were evaluated for their in vitro activity against Plasmodium falciparum (W2) and cytotoxicity to Hep G2A16 cells. All the products disclosed low cytotoxicity (CC50 > 100 μM) and five of them have shown moderate antimalarial activity (IC50 from 9.6 to 40.9 μM). As chloroquine analogs it was expected that these compounds might inhibit the heme polymerization and SAR studies were performed aiming to explain their antimalarial profile. New structural variations can be designed on the basis of the results obtained. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  10. Azide derivatized anticancer agents of Vitamin K 3: X-ray structural, DSC, resonance spectral and API studies

    Science.gov (United States)

    Badave, Kirti; Patil, Yogesh; Gonnade, Rajesh; Srinivas, Darbha; Dasgupta, Rajan; Khan, Ayesha; Rane, Sandhya

    2011-12-01

    Compound 1 [1-imino (acetyl hydrazino)-Vitamin K 3], displays valence tautomerically related electronic isomers as Form I and Form II. Form I exhibits 2D packing fragment with 1D ribbon chains of N-H⋯O hydrogen bonds and shows EPR silent features. While Form II is EPR active and exhibits biradical nature with double quantum transitions at g = 2.0040. 1H NMR of compound 2, [1-imino (hydrazino carboxylate)-Vitamin K 3] and Form II exhibit π delocalization via resonance assisted H-bonding [RAHB] effect compared to Form I. Molecular interactions in Form I and II are visualized by DSC. The electronic structures of compounds 1 and 2 have been correlated to their API values by measuring anticancer activities, mitochondrial potentials and DNA shearing patterns. Form II and compound 2 indicate mitochondria mediated apoptosis (˜75% cell death) while Form I causes 35% cell death.

  11. Two coordination polymers based on semicarbazone Schiff base and azide: synthesis, crystal structure, electrochemistry, magnetic properties and biological activity

    Czech Academy of Sciences Publication Activity Database

    Shaabani, B.; Khandar, A.A.; Dušek, Michal; Pojarová, Michaela; Mahmoudi, F.; Feher, A.; Kajňaková, M.

    2013-01-01

    Roč. 66, č. 5 (2013), s. 748-762 ISSN 0095-8972 Grant - others:AV ČR(CZ) AP0701 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:68378271 Keywords : Schiff bases * semicarbazone * coordination polymer * structure analyses Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 2.224, year: 2013

  12. Photoaffinity labeling of the human erythrocyte monosaccharide transporter with an aryl azide derivative of D-glucose

    International Nuclear Information System (INIS)

    Shanahan, M.F.; Wadzinski, B.E.; Lowndes, J.M.; Ruoho, A.E.

    1985-01-01

    A photoreactive, radioiodinated derivative of glucose, N-(4-iodoazidosalicyl)-6-amido-6-deoxyglucopyranose (IASA-glc), has been synthesized and used as a photoaffinity label for the human erythrocyte monosaccharide transporter. Photoinactivation and photoinsertion are both light-dependent and result in a marked decrease in the absorption spectra of the compound. When [ 125 I]IASA-glc was photolyzed with erythrocyte ghost membranes, photoinsertion of radiolabel was observed in three major regions, spectrin, band 3, and a protein of 58,000 daltons located in the zone 4.5 region. Of the three regions which were photolabeled, only labeling of polypeptides in the zone 4.5 region was partially blocked by D-glucose. In the non-iodinated form, N-(4-azidosalicyl)-6-amido-6-deoxy-glucopyranose inhibited the labeling of the transporter by [ 125 I]IASA-glc more effectively than D-glucose. The ability to synthesize this [ 125 I]containing photoprobe for the monosaccharide transporter at carrier-free levels offers several new advantages for investigating the structure of this transport protein in the erythrocyte

  13. Solvent Composition Directing Click-Functionalization at the Surface or in the Bulk of Azide-Modified PEDOT

    DEFF Research Database (Denmark)

    Lind, Johan Ulrik; Hansen, Thomas Steen; Daugaard, Anders Egede

    2011-01-01

    Thin films of the conducting polymer poly(3,4-(1-azidomethylethylene)dioxythiophene) tosylate (PEDOT−N3) can be functionalized by reaction with alkynated reagents in aqueous solutions. Reaction in pure water resulted in surface specific modification of PEDOT−N3 films, whereas both surface and bulk...... studies showed increasing film thickness with increasing DMSO content, with the measured thickness in pure DMSO being >250% of the thickness in pure water. A similar, but less pronounced, behavior was observed for unmodified poly(3,4-ethylenedioxythiophene) tosylate (PEDOT). High-density grafting...

  14. Continuous metal scavenging and coupling to one-pot copper-catalyzed azide-alkyne cycloaddition click reaction in flow

    NARCIS (Netherlands)

    Vural - Gursel, Dr. Iris; Aldiansyah, Ferry; Wang, Qi; Noël, Timothy; Hessel, Volker

    2015-01-01

    Increasing usage of catalytic chemistry calls for efficient removal of metal traces. This paper describes the development and optimization of a scavenger-based extraction in flow to remove metal catalysts. It enables liquid-liquid extraction with slug flow and phase separation with a porous

  15. Uusi heliplaate / Märt Milter

    Index Scriptorium Estoniae

    Milter, Märt

    1999-01-01

    Uute heliplaatide Ultrasound "Everything Picture", Texas "The Hush", Van " Classica", Electronic "Twisted Tenderness", Lamb "Fear Of Fours", "INCredible Sound Of Rdum"n"Bass: Mixed By Goldie" tutvustus

  16. Plaadid / Ants Tõnisson

    Index Scriptorium Estoniae

    Tõnisson, Ants

    2004-01-01

    Uutest heliplaatidest Erkki Hyva "Varjust rambini", Goldie Lookin Chain "Greatest Hits", Dynamo Productions "Get It Together", Shyne "Godfather Buried Alive", Kenny Dope "Brazilika", Soulwax "Any Minute Now"

  17. Phosphole complexes of Gold(I) halides: Comparison of solution and solid-state structures by a combination of solution and CP/MAS 31P NMR spectroscopy and x-ray crystallography

    International Nuclear Information System (INIS)

    Attar, S.; Nelson, J.H.; Bearden, W.H.; Alcock, N.W.; Alyea, E.C.

    1990-01-01

    A series of complexes of 1-phenyldibenzophosphole (DBP), 1-phenyl-3,4,-dimethylphosphole (DMPP), and triphenylphosphine of the type L n AuX (n = 1, L = DBP, DMPP, Ph 3 P, X = Cl, Br, I; n = 3, L = DBP, X = Cl, Br, I; n = 3, L = Ph 3 P, X = Cl; n = 4, L = DBP, DMPP, X = PF 6 ) have been prepared and characterized. The structures of (DBP)AuCl (1), (DBP) 3 AuCl (2), and (DMPP)AuCl (3) have been determined from three-dimensional x-ray data collected by counter methods. Crystal structure of the complexes is reported. The CP/MAS 31 P( 1 H) NMR spectrum of complex 1 shows two resonances in a 1:1 intensity ratio, and the CP/MAS 31 P( 1 H) NMR spectrum of complex 3 shows three resonances in a 1:1:1 intensity ratio for reasons that are not yet understood. Though the three phospholes are crystallographically inequivalent (d(AuP) = 2.359 (1), 2.382 (1), and 2.374 (2) angstrom) the molecule has effective C s symmetry as evidenced by the observation of two 31 P resonances in a 2:1 intensity ratio in its CP/MAS 31 P( 1 H) NMR spectrum. Variable-temperature 31 P( 1 H) NMR spectra obtained on solutions of LAuCl + L in various ratios were analyzed to determine the nature of the species present in solution and to gain information regarding their relative stabilities as a function of the nature of the phosphine. 79 refs., 8 figs., 9 tabs

  18. Comment on "Hydride, gold(i) and related derivatives of the unsaturated ditungsten anion [W2Cp2(μ-PCy2)(μ-CO)2]-" by M. A. Ruiz et al., Dalton Trans., 2014, 43, 16044.

    Science.gov (United States)

    Green, Malcolm L H

    2018-04-25

    Application of the covalent bond classification to the compounds [M2(η5-C5H5)2(μ-H)(μ-PCy2)(CO)2] (M = Mo, W) identifies the compounds as having two M-M bonds and a 2 electron 3 centre (2e-3c) bond incorporating the bridging hydrogen, in accord with density functional calculations, and assigns their class as ML4X4.

  19. Density functional theory-based prediction of the formation constants of complexes of ammonia in aqueous solution: indications of the role of relativistic effects in the solution chemistry of gold(I).

    Science.gov (United States)

    Hancock, Robert D; Bartolotti, Libero J

    2005-10-03

    A prediction of the formation constants (log K1) for complexes of metal ions with a single NH3 ligand in aqueous solution, using quantum mechanical calculations, is reported. DeltaG values at 298 K in the gas phase for eq 1 (DeltaG(DFT)) were calculated for 34 metal ions using density functional theory (DFT), with the expectation that these would correlate with the free energy of complex formation in aqueous solution (DeltaG(aq)). [M(H2O)6]n+(g) + NH(3)(g) = [M(H2O)5NH3]n+(g) + H2O(g) (eq 1). The DeltaG(aq) values include the effects of complex changes in solvation on complex formation, which are not included in eq 1. It was anticipated that such changes in solvation would be constant or vary systematically with changes in the log K(1) value for different metal ions; therefore, simple correlations between DeltaG(DFT) and DeltaG(aq) were sought. The bulk of the log K1(NH3) values used to calculate DeltaG(aq) were not experimental, but estimated previously (Hancock 1978, 1980) from a variety of empirical correlations. Separate linear correlations between DeltaG(DFT) and DeltaG(aq) for metal ions of different charges (M2+, M3+, and M4+) were found. In plots of DeltaG(DFT) versus DeltaG(aq), the slopes ranged from 2.201 for M2+ ions down to 1.076 for M4+ ions, with intercepts increasing from M2+ to M4+ ions. Two separate correlations occurred for the M3+ ions, which appeared to correspond to small metal ions with a coordination number (CN) of 6 and to large metal ions with a higher CN in the vicinity of 7-9. The good correlation coefficients (R) in the range of 0.97-0.99 for all these separate correlations suggest that the approach used here may be the basis for future predictions of aqueous phase chemistry that would otherwise be experimentally inaccessible. Thus, the log K1(NH3) value for the transuranic Lr3+, which has a half-life of 3.6 h in its most stable isotope, is predicted to be 1.46. These calculations should also lead to a greater insight into the factors governing complex formation in aqueous solution. All of the above DFT calculations involved corrections for scalar relativistic effects (RE). Au has been described (Koltsoyannis 1997) as a "relativistic element". The chief effect of RE for group 11 ions is to favor linear coordination geometry and greatly increase covalence in the M-L bond. The correlation for M+ ions (H+, Cu+, Ag+, Au+) involved the preferred linear coordination of the [M(H2O)2]+ complexes, so that the DFT calculations of DeltaG for the gas-phase reaction in eq 2 were carried out for M = H+, Cu+, Ag+, and Au+. [M(H2O)2]+(g) + NH3(g) = [M(H2O)NH3]+(g) + H2O(g) (eq 2). Additional DFT calculations for eq 2 were carried out omitting corrections for RE. These indicated, in the absence of RE, virtually no change in the log K1(NH3) value for H+, a small decrease for Cu+, and a larger decrease for Ag+. There would, however, be a very large decrease in the log K1(NH3) value for Au(I) from 9.8 (RE included) to 1.6 (RE omitted). These results suggest that much of "soft" acid behavior in aqueous solution in the hard and soft acid-base classification of Pearson may be the result of RE in the elements close to Au in the periodic table.

  20. Alkynyl gold(I) phosphane complexes: Evaluation of structure-activity -relationships for the phosphane ligands, effects on key signaling proteins and preliminary in-vivo studies with a nanoformulated complex

    Czech Academy of Sciences Publication Activity Database

    Andermark, V.; Göke, K.; Kokoschka, Malte; Abu el Maaty, M. A.; Lum, C. T.; Zou, T.; Sun, R. W. Y.; Aquiló, E.; Oehninger, L.; Rodríguez, L.; Bunjes, H.; Wölfl, S.; Che, C. M.; Ott, I.

    2016-01-01

    Roč. 160, Jul (2016), s. 140-148 ISSN 0162-0134 Institutional support: RVO:61388963 Keywords : alkyne * cancer * formulation * gold * microarray * xenograft Subject RIV: CE - Biochemistry Impact factor: 3.348, year: 2016

  1. The Content of Emotional Thoughts | Bloser | Philosophical Papers

    African Journals Online (AJOL)

    In this paper I examine Peter Goldie's theory of emotional thoughts and feelings, offered in his recent book The Emotions and subsequent articles. Goldie argues that emotional thoughts cannot be assimilated to belief or judgment, together with some added-on phenomenological component, and on this point I agree with ...

  2. Launch and Recovery System Literature Review

    Science.gov (United States)

    2010-12-01

    water. Goldie [21] suggests a sled or cart recovery system for use with UAV’s on the Littoral Combatant Ship (LCS) and other small deck navy ships...21. Goldie , J., “A Recovery System for Unmanned Aerial Vehicles (UAVs) Aboard LCS and other Small-Deck Navy Ships,” ASNE Launch and Recovery of

  3. Determination of the phospholipid precursor of anandamide and other N- acylethanolamine phospholipids before and after sodium azide-induced toxicity in cultured neocortical neurons

    DEFF Research Database (Denmark)

    Hansen, H.H.; Schousboe, A.; Hansen, Harald S.

    2000-01-01

    Phospholipase D-mediated hydrolysis of N-acylethanolamine phospholipids (NAPEs) releases anandamide and other N-acylethanolamines, resulting in different actions at cellular targets in the CNS. Recently, we have demonstrated that these N-acyl lipids accumulate in cultured neocortical neurons subj...... method, neuronal NAPE species can be identified and quantified with respect to N-acyl composition, including a trans-isomer of the anandamide precursor. The anandamide precursor is up-regulated to the same extent as other NAPEs upon neuronal injury....

  4. Site-SpecificCu Labeling of the Serine Protease, Active Site Inhibited Factor Seven Azide (FVIIai-N), Using Copper Free Click Chemistry

    DEFF Research Database (Denmark)

    Jeppesen, Troels E; Kristensen, Lotte K; Nielsen, Carsten H

    2018-01-01

    A method for site-specific radiolabeling of the serine protease active site inhibited factor seven (FVIIai) with64Cu has been applied using a biorthogonal click reaction. FVIIai binds to tissue factor (TF), a trans-membrane protein involved in hemostasis, angiogenesis, proliferation, cell migrati...

  5. Theoretical Study of 1,3-Dipolar Cycloadditions Regioselectivity of Benzyl Azide with Glycosyl-O Acetylene Using Density Functional Theory (DFT

    Directory of Open Access Journals (Sweden)

    Adib Ghaleb

    2017-12-01

    Full Text Available A theoretical study of 1,3-cycloaddition has been carried out using density functional theory (DFT methods at the B3LYP/6-31G* level. The regioselectivity of the reaction have been clarified through different theoretical approaches: Case of a Two-Center Process (Domingo approach, HSAB principle (Gazquez and Mendez approach, and the activation energy calculations. The analysis of results shows that the reaction takes place along concerted asynchronous mechanism and the isomer meta is favored, in agreement with the experiment results. DOI: http://dx.doi.org/10.17807/orbital.v9i5.1017 

  6. Synthesis, molecular structure, biological properties and molecular docking studies on Mn(II), Co(II) and Zn(II) complexes containing bipyridine-azide ligands.

    Science.gov (United States)

    Thamilarasan, Vijayan; Jayamani, Arumugam; Sengottuvelan, Nallathambi

    2015-01-07

    Metal complexes of the type Mn(bpy)2(N3)2 (1), Co(bpy)2(N3)2·3H2O (2) and Zn2(bpy)2(N3)4 (3) (Where bpy = 2,2-bipyridine) have been synthesized and characterized by elemental analysis and spectral (FT-IR, UV-vis) studies. The structure of complexes (1-3) have been determined by single crystal X-ray diffraction studies and the configuration of ligand-coordinated metal(II) ion was well described as distorted octahedral coordination geometry for Mn(II), Co(II) and distorted square pyramidal geometry for Zn(II) complexes. DNA binding interaction of these complexes (1-3) were investigated by UV-vis absorption, fluorescence circular dichroism spectral and molecular docking studies. The intrinsic binding constants Kb of complexes 1, 2 and 3 with CT-DNA obtained from UV-vis absorption studies were 8.37 × 10(4), 2.23 × 10(5) and 5.52 × 10(4) M(-1) respectively. The results indicated that the three complexes are able to bind to DNA with different binding affinity, in the order 2 > 1 > 3. Complexes (1-3) exhibit a good binding propensity to bovine serum albumin (BSA) proteins having relatively high binding constant values. Gel electrophoresis assay demonstrated the ability of the complexes 1-3 promote the cleavage ability of the pBR322 plasmid DNA in the presence of the reducing agent 3-mercaptopropionic acid (MPA) but with different cleavage mechanisms: the complex 3 cleaves DNA via hydrolytic pathway (T4 DNA ligase assay), while the DNA cleavage by complexes 1 and 2 follows oxidative pathway. The chemical nuclease activity follows the order: 2 > 1 > 3. The effects of various activators were also investigated and the nuclease activity efficacy followed the order MPA > GSH > H2O2 > Asc. The cytotoxicity studies of complexes 1-3 were tested in vitro on breast cancer cell line (MCF-7) and they found to be active. Copyright © 2014. Published by Elsevier Masson SAS.

  7. A long symmetric N· · ·H· · ·N hydrogen bond inbis(4-aminopyridinium)(1+) azide(1−): redetermination from the original data

    Czech Academy of Sciences Publication Activity Database

    Fábry, Jan

    2017-01-01

    Roč. 73, č. 9 (2017), s. 1344-1347 ISSN 2056-9890 R&D Projects: GA ČR(CZ) GA15-12653S Institutional support: RVO:68378271 Keywords : hydrogen bonding * symmetric hydrogen bonds * primary amine group Subject RIV: CC - Organic Chemistry OBOR OECD: Organic chemistry

  8. Interactions of DNA with a new platinum(IV) azide dipyridine complex activated by UVA and visible light: Relationship to toxicity in tumor cells

    Czech Academy of Sciences Publication Activity Database

    Prachařová, J.; Zerzánková, Lenka; Štěpánková, Jana; Nováková, Olga; Farrer, N.J.; Sadler, P.J.; Brabec, Viktor; Kašpárková, Jana

    2012-01-01

    Roč. 25, č. 5 (2012), s. 1099-1111 ISSN 0893-228X R&D Projects: GA ČR(CZ) GAP301/10/0598; GA ČR(CZ) GD301/09/H004 Institutional research plan: CEZ:AV0Z50040702 Keywords : antitumor platinum * photoactivation * DNA Subject RIV: BO - Biophysics Impact factor: 3.667, year: 2012

  9. Comparisons of protein, lipid, phenolics, γ-oryzanol, vitamin E, and mineral contents in bran layer of sodium azide-induced red rice mutants.

    Science.gov (United States)

    Jeng, Toong Long; Ho, Pei Tzu; Shih, Yi Ju; Lai, Chia Chi; Wu, Min Tze; Sung, Jih Min

    2011-06-01

    The bran part of red rice grain is concentrated with many phytochemicals, including proanthocyanidins, oryzanol and vitamin E, that exert beneficial effects on human health, but it contains low levels of essential minerals such as Fe and Zn. In the present study, the protein, lipid, phytochemicals and mineral contents in bran samples were compared among red rice SA-586 and its NaN₃-induced mutants. The plant heights of NaN₃-induced mutants were decreased. The contents of protein, lipid, total phenolics, total flavonoids, total anthocyanins, total proanthocyanidins, total γ-oryzanol, total tocopherols and total tocotrienols also varied among the tested mutants. The brans of mutants M-18, M-56 and M-50 contained more proanthocyanidins, γ-oryzanol, vitamin E than that of SA-586, respectively. M-54 accumulated more Fe content (588.7 mg kg⁻¹ bran dry weight) than SA-586 (100.1 mg kg⁻¹ bran dry weight). The brans of M-18, M-50 and M-56 are good sources of proanthocyanidins, vitamin E and γ-oryzanol, respectively, while the bran of M-54 is rich in Fe. Thus these mutants could be used to produce high-value phytochemicals or Fe byproducts from bran during rice grain milling or as genetic resources for rice improvement programs. Copyright © 2011 Society of Chemical Industry.

  10. Mono and dinuclear arene ruthenium(II) triazoles by 1,3-dipolar cycloadditions to a coordinated azide in ruthenium(II) compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Svitlyk, V.; Mozharivskyj, Y.

    = Me, 3 or Et, 4). In contrast, a similar 1,3-dipolar cycloaddition reaction of (((Eta sup(6)-C sub(6)Me sub(6))Ru(L sub(2))N sub(3))) (2) (where; L sub(2) = tropolone) with acetylene yielded the monomeric triazole compound ((Eta sup(6)-C sub(6)Me sub(6...

  11. Well-defined polyethylene-based graft terpolymers by combining nitroxide-mediated radical polymerization, polyhomologation and azide/alkyne “click” chemistry†

    KAUST Repository

    Alkayal, Nazeeha; Durmaz, Hakan; Tunca, Umit; Hadjichristidis, Nikolaos

    2016-01-01

    AAC) “click” chemistry. Three steps were involved in this approach: (i) synthesis of alkyne-terminated polyethylene-b-poly(ε-caprolactone) (PE-b-PCL-alkyne) block copolymers (branches) by esterification of PE-b-PCL-OH with 4-pentynoic acid; the PE

  12. Browse Title Index

    African Journals Online (AJOL)

    Items 201 - 250 of 943 ... D Hu, D Grossman, C Levin, K Blanchard, R Adanu, SJ Goldie ... Esperanza Mariano, Francisco Mbofana, Terence Hull, Adriane Martin Hilber ... John K. Ganle, Bernard Obeng, Joseph Y. Yeboah, Eva Tagoe-Darko, ...

  13. Pop / Tristan Priimägi

    Index Scriptorium Estoniae

    Priimägi, Tristan, 1976-

    2004-01-01

    Heliplaatidest: Goldie Lookin Chain "Greatest Hits", Placebo "Once More With Feeling - The Singles 1996 to 2004", The Killers "Hot Fuss", Leonard Cohen "Dear Heather", Ray Conniff "The Essenttial Ray Conniff", Neurosis "The Eye Of Every Storm"

  14. Pop / Marek Kallin

    Index Scriptorium Estoniae

    Kallin, Marek

    2005-01-01

    Heliplaatidest: Cardigans "Super Extra Gravity", Earth, Wind & Fire "Illumination", Stevie Wonder "A Time To Love", Shout Out Louds "Howl Howl Gaff Gaff", Goldie Lookin Chain "Safe As Fuck", Ms. Dynamite "Judgement Days", Echosilence "Distorted Horizon", Bob Dylan "No Direction Home"

  15. Uued plaadid / Koit Raudsepp

    Index Scriptorium Estoniae

    Raudsepp, Koit

    1999-01-01

    Uutest heliplaatidest Borax "Mikrorajon", Mike Oldfield "Guitars", The Phil Collins Big Band "A Hot Night In Paris", Tom Waits "Mule Variations", UnderWorld "Beaucop Fish", INCredible Sound Of Drum"n"Bass Mixed By Goldie

  16. [Uued heliplaadid] / Marek Kallin

    Index Scriptorium Estoniae

    Kallin, Marek

    1999-01-01

    Uutest heliplaatidest: The Cranberries "Bury The Hatchet", Naughty By Nature "Nineteen Naughty Nine: Nature"s Fury", erinevad esitajad "INCredible Sound of Drum"n"Bass: Mixed by Goldie", New Radicals "Maybe You"ve Been Brainwashed Too"

  17. Reply to the 'Comment on "Hydride, gold(i) and related derivatives of the unsaturated ditungsten anion [W2Cp2(μ-PCy2)(μ-CO)2]-"' by M. Green, Dalton Transactions, 2018, 47, DOI: 10.1039/C8DT00044A.

    Science.gov (United States)

    García-Vivó, Daniel; Ruiz, Miguel A

    2018-04-25

    The half-electron and CBC representations of the hydride-bridged complexes [M2Cp2(μ-H)(μ-PR2)(CO)2] are analyzed. It is shown that the former gives a picture in good agreement with the physicochemical properties of these species, while keeping simplicity.

  18. Arene ruthenium(II) azido complexes incorporating N intersection O chelate ligands: Synthesis, spectral studies and 1,3-dipolar-cycloaddition to a coordinated azide in ruthenium(II) compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Kaminsky, W.

    showed a slightly different spectra pattern for p- cymene ligand as compared to the rest of the complexes. For instant, the complex 1 exhibits two doublets for diastereotopic methyl protons of the isopropyl group at around δ 1.12-0.99 (Fig. 1). Likewise... formed are exclusively N(2) bound isomer which is supported by their NMR spectral data. For instant, the proton NMR spectrum of 8 displayed a, singlet at δ 3.75 assignable to the protons of a methoxy carbonyl group while for complex 9 a quartet...

  19. The crystal structures of 3-O-benzyl-1,2-O-isopropylidene-5-O-methanesulfonyl-6-O-triphenylmethyl-α-d-glucofuranose and its azide displacement product

    Directory of Open Access Journals (Sweden)

    Zane Clarke

    2018-06-01

    Full Text Available The effect of different leaving groups on the substitution versus elimination outcomes with C-5 d-glucose derivatives was investigated. The stereochemical configurations of 3-O-benzyl-1,2-O-isopropylidene-5-O-methanesulfonyl-6-O-triphenylmethyl-α-d-glucofuranose, C36H38O8S (3 [systematic name: 1-[(3aR,5R,6S,6aR-6-benzyloxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxol-5-yl-2-(trityloxyethyl methanesulfonate], a stable intermediate, and 5-azido-3-O-benzyl-5-deoxy-1,2-O-isopropylidene-6-O-triphenylmethyl-β-l-idofuranose, C35H35N3O5 (4 [systematic name: (3aR,5S,6S,6aR-5-[1-azido-2-(trityloxyethyl]-6-benzyloxy-2,2-dimethyltetrahydrofuro[2,3-d][1,3]dioxole], a substitution product, were examined and the inversion of configuration for the azido group on C-5 in 4 was confirmed. The absolute structures of the molecules in the crystals of both compounds were confirmed by resonant scattering. In the crystal of 3, neighbouring molecules are linked by C—H...O hydrogen bonds, forming chains along the b-axis direction. The chains are linked by C—H...π interactions, forming layers parallel to the ab plane. In the crystal of 4, molecules are also linked by C—H...O hydrogen bonds, forming this time helices along the a-axis direction. The helices are linked by a number of C—H...π interactions, forming a supramolecular framework.

  20. Kinetic study on S_NAr reactions of 1-(Y-Substituted-phenoxy)-2,4-dinitrobenzenes with azide ion: Effect of changing nucleophile from hydroxide to zzide ion on reaction mechanism and reactivity

    International Nuclear Information System (INIS)

    Seo, Hyeon Ok; Kim, Min Young; Han, So Yeop; Um, Ik Hwan

    2015-01-01

    Second-order rate constants (k_N_3_−) for SNAr reactions of 1-(Y-substituted-phenoxy)-2,4-dinitrobenzenes (2a–2h) with math formula in 80 mol % H_2O/20 mol % DMSO at 25.0 ± 0.1 °C have been measured spectrophotometrically. The Brønsted-type plot is linear with β"l"g = −0.38. The Hammett plots correlated with math formula and math formula constants exhibit highly scattered points. In contrast, the Yukawa–Tsuno plot results in an excellent linear correlation with ρ_Y = 1.02 and r = 0.51, indicating that a negative charge develops partially on the O atom of the leaving Y-substituted-phenoxy moiety in the transition state. Accordingly, the reactions have been concluded to proceed through a stepwise mechanism, in which expulsion of the leaving group occurs in the rate-determining step. Comparison of k_N_3_− with the k_O_H_− values reported previously for the corresponding reactions with OH"− has revealed that math formula is only 6- to 26-fold less reactive than OH"− toward substrates 2a–2h, although the former is over 11 pK_a units less basic than the latter. Solvation and polarizability effects have been suggested to be responsible for the unusual reactivity shown by math formula and OH"−. Effects of changing nucleophile from OH"− to N_3"− on reaction mechanism and reactivity are discussed in detail

  1. Synthesis of DOTA-conjugated multimeric [Tyr3]octreotide peptides via a combination of Cu(I)-catalyzed "click" cycloaddition and thio acid/sulfonyl azide "sulfo-click" amidation and their in vivo evaluation.

    NARCIS (Netherlands)

    Yim, C.B.; Dijkgraaf, I.; Merkx, R.; Versluis, C.; Eek, A.; Mulder, G.E.; Rijkers, D.T.; Boerman, O.C.; Liskamp, R.M.

    2010-01-01

    Herein, we describe the design, synthesis, and biological evaluation of a series of DOTA-conjugated monomeric, dimeric, and tetrameric [Tyr(3)]octreotide-based analogues as a tool for tumor imaging and/or radionuclide therapy. These compounds were synthesized using a Cu(I)-catalyzed 1,3-dipolar

  2. Sequential Au(I-catalyzed reaction of water with o-acetylenyl-substituted phenyldiazoacetates

    Directory of Open Access Journals (Sweden)

    Jianbo Wang

    2011-05-01

    Full Text Available The gold(I-catalyzed reaction of water with o-acetylenyl-substituted phenyldiazoacetates provides 1H-isochromene derivatives in good yields. The reaction follows a catalytic sequence of gold carbene formation/water O–H insertion/alcohol-alkyne cyclization. The gold(I complex is the only catalyst in each of these steps.

  3. Graphene templated Directional Growth of an Inorganic Nanowire

    Science.gov (United States)

    2015-03-23

    14,23–25 have only formed randomly oriented or poorly aligned inorganic nanostructures. Here, we show that inorganic nanowires of gold(I) cyanide can... complex . TEM image simulation from the crystal structure The TEM image simulations are performed using MacTempas and CrystalKit. The imaging

  4. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences. SONALI RAMGOPAL MAHULE. Articles written in Journal of Chemical Sciences. Volume 129 Issue 9 September 2017 pp 1491-1498 Regular Aricle. Axially chiral benzimidazolium based silver(I) and gold(I) bis-NHC complexes of R-BINOL scaffold: synthesis, characterization ...

  5. African Zoology - Vol 50, No 1 (2015)

    African Journals Online (AJOL)

    Deep genetic divergence between geographically isolated populations of the goldie barb (Barbus pallidus) in South Africa: potential taxonomic and conservation implications · EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Albert Chakona, Willem S. Malherbe, Gavin Gouws, ...

  6. Gold(I)-selenolate complexes: Synthesis, characterization and ...

    Indian Academy of Sciences (India)

    known that the gold(I) drugs rapidly bind to the most abundant plasma protein serum albumin (Alb-SH) after ... Aldrich. The experiments were carried out under dry and oxygen-free nitrogen using standard Schlenk tech- ... To a deoxygenated aqueous solution of the disele- nide 11 (30.0mg, 0.094mmol) was added sodium.

  7. Browse Title Index

    African Journals Online (AJOL)

    Items 101 - 150 of 172 ... Vol 32, No 3 (2003): Narrative Understanding, One's remembered past: narrative thinking, emotion, and the external perspective, Abstract. Peter Goldie. Vol 32, No 2 (2003):, Ontological Order in ... Vol 34, No 2 (2005):, Revisiting Nagel on Altruism, Abstract. Brian K Powell. Vol 35, No 1 (2006):, Rowe's ...

  8. and Silver(I) Complexes of Hydrazine-Bridged Diphosphine Ligands

    African Journals Online (AJOL)

    NICO

    Gold(I), silver(I), hydrazine, diphosphine, antitumour, anticancer, mitochondrial membrane potential. 1. Introduction. The use of inorganic compounds as cancer treatment became well established with the FDA approval of cisplatin in 1978.1. Cisplatin, carboplatin and oxaliplatin are widely used in clinical settings today.

  9. Random recurrence equations and ruin in a Markov-dependent stochastic economic environment

    DEFF Research Database (Denmark)

    Collamore, Jeffrey F.

    2009-01-01

    series models.  Our results build upon work of Goldie, who has developed tail asymptotics applicable for independent sequences of random variables subject to a random recurrence equation.  In contrast, we adopt a general approach based on the theory of Harris recurrent Markov chains and the associated...

  10. Some Aspects of Ring Theory

    CERN Document Server

    Herstein, IN

    2011-01-01

    S. Amitsur: Associative rings with identities.- I.N. Herstein: Topics in ring theory.- N. Jacobson: Representation theory of Jordan algebras.- I. Kaplansky: The theory of homological dimension.- D. Buchsbaum: Complexes in local ring theory.- P.H. Cohn: Two topics in ring theory.- A.W. Goldie: Non-commutative localisation.

  11. “Electro-Click” on Conducting Polymer Films

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Lind, Johan Ulrik; Daugaard, Anders Egede

    for their own functionalization with high spatial resolution. Interdigitated microelectrodes prepared from the azide-containing conducting polymer were selectively functionalized in sequence by two alkyne-modified fluorophores by control of the applied potentials. “Electro-click” on conducting polymer films......An azide substituted 3,4-ethylenedioxythiophene monomer is polymerised to yield a PEDOT like polymer with available azide groups (Figure 1). The azide groups enable post polymerization functionalization of the conducting polymer using a 1,3 dipolar cycloaddition reaction – also denoted “click...

  12. Synthesis, characterization and gas sensing performance

    Indian Academy of Sciences (India)

    For the first time, this study reports the gas sensing performance of aluminosilicate azide cancrinite. The effect of annealing andoperating temperature on gas sensing characteristic of azide cancrinite thick film is investigated systematically for various gases at different operating temperatures. This sensor was observed to be ...

  13. Method of preparation of uranium nitride

    Science.gov (United States)

    Kiplinger, Jaqueline Loetsch; Thomson, Robert Kenneth James

    2013-07-09

    Method for producing terminal uranium nitride complexes comprising providing a suitable starting material comprising uranium; oxidizing the starting material with a suitable oxidant to produce one or more uranium(IV)-azide complexes; and, sufficiently irradiating the uranium(IV)-azide complexes to produce the terminal uranium nitride complexes.

  14. Adhesion of Photon-Driven Molecular Motors to Surfaces via 1,3-Dipolar Cycloadditions : Effect of Interfacial Interactions on Molecular Motion

    NARCIS (Netherlands)

    Carroll, Gregory T.; London, Gabor; Fernández Landaluce, Tatiana; Rudolf, Petra; Feringa, Ben L.

    We report the attachment of altitudinal light-driven molecular motors to surfaces using 1,3-dipolar cycloaddition reactions. Molecular motors were designed containing azide or alkyne groups for attachment to alkyne- or azide-modified surfaces. Surface attachment was characterized by UV-vis, IR, XPS,

  15. Stabilization of Parallel Triplexes by Twisted Intercalating Nucleic Acids (TINAs) Incorporating 1,2,3-Triazole Units and Prepared by Microwave-Accelerated Click Chemistry

    DEFF Research Database (Denmark)

    Géci, Imrich; Filitchev, Vyacheslav Viatcheslav; Pedersen, Erik Bjerreg.

    2007-01-01

    A highly efficient method for postsynthetic modification of unprotected oligonucleotides incorporating internal insertions of (R)-1-O-(4-ethynylbenzyl)glycerol has been developed through the application of click chemistry with water-insoluble pyren-1-yl azide and water-soluble benzyl azide and ac...

  16. Analytical use of zide ion. Chemical equilibrium studies and correlates in U(VI)/N3 and Co(III)/N3 systems

    International Nuclear Information System (INIS)

    Silva, T.V. da.

    1984-01-01

    A monographic study about the azide ion and its structure, as well as, references about the uranyl ion in aqueous medium, and its possible hydrolysis products are shown. Spectral studies of the U(VI), Fe (III) and Cu(II) systems, in azide medium are analyzed. (M.J.C.) [pt

  17. Mutagenic effectiveness and efficiency in varieties of sunflower ...

    African Journals Online (AJOL)

    GREGORY

    2010-09-27

    Sep 27, 2010 ... The effect of single treatment with gamma-rays, sodium azide and combination treatments of gamma- rays and sodium azide on seed germination, seedling survival, pollen fertility and seed set in sunflower. (Helianthus annuus L.) M2 generation was studied in the varieties of USH-430 and SHSF-333.

  18. Department of Chemistry, Addis Ababa Univeristy, PO Box 1176

    African Journals Online (AJOL)

    react with iron(III) in the presence of azide to form an orange coloured ternary ... Hence, the extraction of iron(III) from aqueous sodium azide medium with PCHA has been ..... K.S. Patel, K.K. Deb, and R.K. Mishra, Bull. Chem. Soc. Jpn.,.

  19. Cellulose sulphuric acid as a biodegradable catalyst for conversion ...

    Indian Academy of Sciences (India)

    This article describes simple and efficient method for the diazotization and azidation of different aromatic amines over cellulose sulphuric acid, sodium nitrite and sodium azide under mild conditions at room temperature. Various aryl amines possessing electron-withdrawing groups or electron-donating groups have been ...

  20. Mechanisms with discrete nitrene species

    Indian Academy of Sciences (India)

    identifying a dissociation path involving singlet acyl- nitrene. However, CCSD(T) and CBS-QB3 studies62 predicted acetyl azide decomposes by methyl group migration to give methyl isocyanate and N2 with a bar- rier of 27 kcal/mol. Experimentally, photolysis of pival- oyl azide gives singlet pivaloyl nitrene,45 which adds to.

  1. Crystal structure of chlorido(2-{[2-(phenylcarbamothioylhydrazin-1-ylidene](pyridin-2-ylmethyl}pyridin-1-iumgold(I chloride sesquihydrate

    Directory of Open Access Journals (Sweden)

    Claudia C. Gatto

    2015-09-01

    Full Text Available The title complex, [AuCl(C18H16N5S]Cl·1.5H2O, may be considered as a gold(I compound with the corresponding metal site coordinated by a thiosemicarbazone ligand through the S atom. The ligand adopts an E conformation and the gold(I atom displays the expected linear geometry with a Cl atom also bonded to the metal ion [Cl—Au—S = 174.23 (5°]. One of the pyridyl rings is protonated, giving the gold complex an overall positive charge. Two solvent water molecules, one of which is located on a twofold rotation axis, and a non-coordinating chloride ion complete the structural assembly. The molecular structure is stabilized by intramolecular and intermolecular N—H...Cl, N—H...N, O—H...Cl and O—H...O hydrogen bonding.

  2. Hydrofluorination of Alkynes Catalysed by Gold Bifluorides.

    Science.gov (United States)

    Nahra, Fady; Patrick, Scott R; Bello, Davide; Brill, Marcel; Obled, Alan; Cordes, David B; Slawin, Alexandra M Z; O'Hagan, David; Nolan, Steven P

    2015-01-01

    We report the synthesis of nine new N -heterocyclic carbene gold bifluoride complexes starting from the corresponding N -heterocyclic carbene gold hydroxides. A new methodology to access N,N' -bis(2,6-diisopropylphenyl)imidazol-2-ylidene gold(I) fluoride starting from N,N' -bis(2,6-diisopropylphenyl)imidazol-2-ylidene gold(I) hydroxide and readily available potassium bifluoride is also reported. These gold bifluorides were shown to be efficient catalysts in the hydrofluorination of symmetrical and unsymmetrical alkynes, thus affording fluorinated stilbene analogues and fluorovinyl thioethers in good to excellent yields with high stereo- and regioselectivity. The method is exploited further to access a fluorinated combretastatin analogue selectively in two steps starting from commercially available reagents.

  3. Structure and bonding in gold compounds

    International Nuclear Information System (INIS)

    Parish, R.V.

    1988-01-01

    Recent developments in chemical applications of 197 Au Moessbauer spectroscopy are reviewed. For gold(I) and gold(III), systematic variations in isomer shift and quadrupole splitting are seen as the ligands are changed; the effects of change in coordination number of the gold atoms are also systematic. Data for gold(II) systems involving gold-gold bonds lie between those for corresponding gold(I) and gold(III) materials, showing a small increase in isomer shift and a larger increase in quadrupole splitting as the oxidation state decreases; these trends are explained in terms of the structures. Data for mixed-metal cluster compounds are much more sensitive to structural effects than in homonuclear clusters. Both sets of data show systematic changes with increase in the number of metal atoms to which the gold atom is bound. The connectivity also influences the recoil-free fraction. (orig.)

  4. Classes of modules

    CERN Document Server

    Dauns, John

    2006-01-01

    Because traditional ring theory places restrictive hypotheses on all submodules of a module, its results apply only to small classes of already well understood examples. Often, modules with infinite Goldie dimension have finite-type dimension, making them amenable to use with type dimension, but not Goldie dimension. By working with natural classes and type submodules (TS), Classes of Modules develops the foundations and tools for the next generation of ring and module theory. It shows how to achieve positive results by placing restrictive hypotheses on a small subset of the complement submodules, Furthermore, it explains the existence of various direct sum decompositions merely as special cases of type direct sum decompositions. Carefully developing the foundations of the subject, the authors begin by providing background on the terminology and introducing the different module classes. The modules classes consist of torsion, torsion-free, s[M], natural, and prenatural. They expand the discussion by exploring...

  5. On the behaviour of biradicaloid [P(μ-NTer)]2 towards Lewis acids and bases.

    Science.gov (United States)

    Hinz, Alexander; Schulz, Axel; Villinger, Alexander

    2016-05-07

    The well-known diphosphadiazane-1,3-diyl [P(μ-NTer)]2 (Ter = 2,6-bis(2,4,6-trimethyl-phenyl)-phenyl) was treated with Lewis bases such as N-heterocyclic carbenes and Lewis acids e.g. gold(i) chloride complexes. In the reaction with the Lewis base, fragmentation of the P2N2 framework was observed, yielding a salt of the type [(NHC)2P](+)[(TerN)2P](-) in a clean reaction. The reaction of [P(μ-NTer)]2 with gold(i) chloride afforded 1 : 1 and 1 : 2 complexes. The dinuclear complex [(ClAu)2P(μ-NTer)2P] displays a bridging P atom between both gold centers, as has been observed for P based zwitterions.

  6. Synthesis and Anticancer Activity of Gold(I)-Chloroquine Complexes

    OpenAIRE

    Navarro, Maribel; Castro, William; González, Sorenlis; Abad, María Jesús; Taylor, Peter

    2013-01-01

    Two new gold(I) -chloroquine complexes, Au(CQ)(Cl) (1) and Au(CQ)(tgta) (2), were prepared and their most probable structure were established through a combination of different spectroscopic and analytical techniques. Their interaction with two important targets of action, DNA and thioredoxin reductase (TrxR), were investigated. These studies showed that complexes 1 and 2 displayed two types of interaction with DNA, covalent binding through the metal center, and additionally a non-covalent in...

  7. Gold(I-catalyzed domino cyclization for the synthesis of polyaromatic heterocycles

    Directory of Open Access Journals (Sweden)

    Mathieu Morin

    2013-11-01

    Full Text Available Gold(I complexes have emerged as powerful and useful catalysts for the formation of new C–C, C–O and C–N bonds. Taking advantage of the specificity of [IPrAuNCMe][SbF6] complexes to favor the 5-exo-dig cyclization over the 6-endo-dig pathway, we report a high yielding and efficient method to generate substituted polyaromatic heterocycles under remarkably mild reaction conditions.

  8. The Effects of Designated Pollutants on Plants

    Science.gov (United States)

    1978-11-01

    Persea americana Mill. Haas and Bacon Barley Hordeum vulgare L. CM 67 Bean Phaseolus vulgaris L. Pinto, U.I. III Briza Briza maxima L. Ornamental...Tagetes patula L. French dwarf double goldie Marigold Tagetes erecta L. American ,Senator Dirksen Petunia Petunia hybrida Vilm. White cascade Radish...Probit analysis of five plant species: citrus seedlings, lemon, orange,, grape, French marigold, American marigold. Probit scale is the probability that a

  9. Stability and bifurcation in a model for the dynamics of stem-like cells in leukemia under treatment

    Science.gov (United States)

    Rǎdulescu, I. R.; Cândea, D.; Halanay, A.

    2012-11-01

    A mathematical model for the dynamics of leukemic cells during treatment is introduced. Delay differential equations are used to model cells' evolution and are based on the Mackey-Glass approach, incorporating Goldie-Coldman law. Since resistance is propagated by cells that have the capacity of self-renewal, a population of stem-like cells is studied. Equilibrium points are calculated and their stability properties are investigated.

  10. Insights on the mechanism of thioredoxin reductase inhibition by gold N-heterocyclic carbene compounds using the synthetic linear selenocysteine containing C-terminal peptide hTrxR(488-499): an ESI-MS investigation.

    Science.gov (United States)

    Pratesi, Alessandro; Gabbiani, Chiara; Michelucci, Elena; Ginanneschi, Mauro; Papini, Anna Maria; Rubbiani, Riccardo; Ott, Ingo; Messori, Luigi

    2014-07-01

    Gold-based drugs typically behave as strong inhibitors of the enzyme thioredoxin reductase (hTrxR), possibly as the consequence of direct Gold(I) coordination to its active site selenocysteine. To gain a deeper insight into the molecular basis of enzyme inhibition and prove gold-selenocysteine coordination, the reactions of three parent Gold(I) NHC compounds with the synthetic C-terminal dodecapeptide of hTrxR containing Selenocysteine at position 498, were investigated by electrospray ionization mass spectrometry (ESI-MS). Formation of 1:1 Gold-peptide adducts, though in highly different amounts, was demonstrated in all cases. In these adducts the same [Au-NHC](+) moiety is always associated to the intact peptide. Afterward, tandem MS experiments, conducted on a specific Gold-peptide complex, pointed out that Gold is coordinated to the selenolate group. The relatively large strength of the Gold-selenolate coordinative bond well accounts for potent enzyme inhibition typically afforded by these Gold(I) compounds. In a selected case, the time course of enzyme inhibition was explored. Interestingly, enzyme inhibition turned out to show up very quickly and reached its maximum just few minutes after mixing. Overall, the present results offer some clear insight into the process of thioredoxin reductase inhibition by Gold-based compounds. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Value of the Debris of Reduction Sculpture: Thiol Etching of Au Nanoclusters for Preparing Water-Soluble and Aggregation-Induced Emission-Active Au(I) Complexes as Phosphorescent Copper Ion Sensor.

    Science.gov (United States)

    Shu, Tong; Su, Lei; Wang, Jianxing; Lu, Xin; Liang, Feng; Li, Chenzhong; Zhang, Xueji

    2016-06-07

    Chemical etching of gold by thiols has been known to be capable of generating nonluminescent gold(I) complexes, e.g., in size-focusing synthesis of atomically precise gold nanoclusters (GNCs). These nonluminescent gold(I) complexes have usually been considered as useless or worthless byproducts. This study shows a promising potential of thiol etching of GNCs to prepare novel water-soluble and phosphorescent gold(I) materials for sensing application. First, cysteamine-induced etching of GNCs is used to produce nonluminescent oligomeric gold(I)-thiolate complexes. Then, cadmium ion induces the aggregation of these oligomeric complexes to produce highly water-soluble ultrasmall intra-aggregates. These intra-aggregates can phosphoresce both in dilute aqueous solutions and in the solid phase. Studies on the effect of pH on their phosphorescent emission reveal the importance of the interaction between the amino groups of the ligands and cadmium ion for their phosphorescent emission property. Furthermore, Cu(2+) ion is found to quickly quench the phosphorescent emission of the intra-aggregates and simultaneously cause a Cu(2+)-concentration-dependent peak wavelength shift, enabling the establishment of a novel colorimetric sensor for sensitive and selective visual sensing of Cu(2+).

  12. Precipitation of gold by the reaction of aqueous gold(III)-chloride with cyanobacteria at 25-80 C -- Studied by x-ray absorption spectroscopy

    International Nuclear Information System (INIS)

    Lengke, M. F.; Ravel, B.; Fleet, M. E.; Wanger, G.; Gordon, R. A.; Southam, G.

    2007-01-01

    The mechanisms of gold precipitation by the interaction of cyanobacteria (Plectonema boryanum UTEX 485) and gold(III) chloride aqueous solutions (7.6 mmol/L final gold) have been studied at 25, 60, and 80 C, using both laboratory and real-time synchrotron radiation absorption spectroscopy experiments. Addition of aqueous gold(III) chloride to the cyanobacterial culture initially promoted the precipitation of amorphous gold(I) sulfide at the cell walls and finally caused the formation of octahedral (111) platelets (<1 to 6 (micro)m) of gold metal near cell surfaces and in solutions. X-ray absorption spectroscopy results confirmed that the reduction mechanism of gold(III) chloride to elemental gold by cyanobacteria involves the formation of an intermediate Au(I) species, gold(I) sulfide, with sulfur originating from cyanobacterial proteins, presumably cysteine or methionine. Although the bioreduction of gold(III) chloride to gold(I) sulfide was relatively rapid at all temperatures, the reaction rate increased with the increase in temperature. At the completion of the experiments, elemental gold was the major species present at all temperatures

  13. Gold(I) Complexes with N-Donor Ligands. 2.(1) Reactions of Ammonium Salts with [Au(acac-kappaC(2))(PR(3))] To Give [Au(NH(3))L](+), [(AuL)(2)(&mgr;(2)-NH(2))](+), [(AuL)(4)(&mgr;(4)-N)](+), or [(AuL)(3)(&mgr;(3)-O)](+). A New and Facile Synthesis of [Au(NH(3))(2)](+) Salts. Crystal Structure of [{AuP(C(6)H(4)OMe-4)(3)}(3)(&mgr;(3)-O)]CF(3)SO(3).

    Science.gov (United States)

    Vicente, José; Chicote, María-Teresa; Guerrero, Rita; Jones, Peter G.; Ramírez De Arellano, M. Carmen

    1997-09-24

    The complexes [Au(acac-kappaC(2))(PR(3))] (acac = acetylacetonate, R = Ph, C(6)H(4)OMe-4) react with (NH(4))ClO(4) to give amminegold(I), [Au(NH(3))(PR(3))]ClO(4), amidogold(I), [(AuPR(3))(2)(&mgr;(2)-NH(2))]ClO(4), or nitridogold(I), [(AuPR(3))(4)(&mgr;(4)-N)]ClO(4), complexes, depending on the reaction conditions. Similarly, [Au(acac-kappaC(2))(PPh(3))] reacts with (NH(3)R')OTf (OTf = CF(3)SO(3)) (1:1) or with [H(3)N(CH(2))(2)NH(2)]OTf (1:1) to give (amine)gold(I) complexes [Au(NH(2)R')(PPh(3))]OTf (R' = Me, C(6)H(4)NO(2)-4) or [(AuPPh(3))(2){&mgr;(2)-H(2)N(CH(2))(2)NH(2)}](OTf)(2), respectively. The ammonium salts (NH(2)R'(2))OTf (R' = Et, Ph) react with [Au(acac-kappaC(2))(PR(3))] (R = Ph, C(6)H(4)OMe-4) (1:2) to give, after hydrolysis, the oxonium salts [(AuPR(3))(3)(&mgr;(3)-O)]OTf (R = Ph, C(6)H(4)OMe-4). When NH(3) is bubbled through a solution of [AuCl(tht)] (tht = tetrahydrothiophene), the complex [Au(NH(3))(2)]Cl precipitates. Addition of [Au(NH(3))(2)]Cl to a solution of AgClO(4) or TlOTf leads to the isolation of [Au(NH(3))(2)]ClO(4) or [Au(NH(3))(2)]OTf, respectively. The crystal structure of [(AuPR(3))(3)(&mgr;(3)-O)]OTf.Me(2)CO (R = C(6)H(4)OMe-4) has been determined: triclinic, space group P&onemacr;, a = 14.884(3) Å, b = 15.828(3) Å, c = 16.061(3) Å, alpha = 83.39(3) degrees, beta = 86.28(3) degrees, gamma = 65.54(3) degrees, R1 (wR2) = 0.0370 (0.0788). The [(AuPR(3))(3)(&mgr;(3)-O)](+) cation shows an essentially trigonal pyramidal array of three gold atoms and one oxygen atom with O-Au-P bond angles of ca. 175 degrees and Au.Au contacts in the range 2.9585(7)-3.0505(14) Å. These cations are linked into centrosymmetric dimers through two short Au.Au [2.9585(7), 3.0919(9) Å] contacts. The gold atoms of the dimer form a six-membered ring with a chair conformation.

  14. Lifetimes and reactivities of some 1,2-didehydroazepines commonly used in photoaffinity labeling experiments in aqueous solutions.

    Science.gov (United States)

    Rizk, Mary S; Shi, Xiaofeng; Platz, Matthew S

    2006-01-17

    The reactive 1,2-didehydroazepine (cyclic ketenimine) intermediates produced upon photolysis of phenyl azide, 3-hydroxyphenyl azide, 3-methoxyphenyl azide, and 3-nitrophenyl azide in water and in HEPES buffer were studied by laser flash photolysis techniques with UV-vis detection of the transient intermediates. The lifetimes of the 1,2-didehydroazepines were obtained along with the absolute rate constants of their reactions with typical amino acids, nucleosides, and other simple reagents present in a biochemical milieu. The nitro substituent greatly accelerates the bimolecular reactions of the cyclic ketenimines, and the 3-methoxy group greatly decelerates the absolute reactivity of 1,2-didehydroazepines. The intermediate produced by photolysis of 3-hydroxyphenyl azide is much more reactive than the intermediate produced by photolysis of 3-methoxyphenyl azide. We propose that the hydroxyl-substituted 1,2-didehydoazepines rapidly (ketenimines undergo hydrolysis. Azepinones react more rapidly with nucleophiles than do methoxy-substituted 1,2-didehydroazepines and are the active species present upon the photolysis of 3-hydroxyphenyl azide in aqueous solution.

  15. Synthesis of click-reactive HPMA copolymers using RAFT polymerization for drug delivery applications

    DEFF Research Database (Denmark)

    Ebbesen, Morten F; Schaffert, D.H.; Crowley, Michael L

    2013-01-01

    This study describes a versatile strategy combining reversible addition fragmentation transfer (RAFT) polymerization and click chemistry to synthesize well-defined, reactive copolymers of N-(2-hydroxypropyl)methacrylamide (HPMA) for drug delivery applications. A novel azide containing monomer N-(3......-azidopropyl)methacrylamide (AzMA) was synthesized and copolymerized with HPMA using RAFT polymerization to provide p(HPMA-co-AzMA) copolymers with high control of molecular weight (∼10–54 kDa) and polydispersity (≤1.06). The utility of the side-chain azide functionality by Cu(I)-catalyzed azide...

  16. High Energy Density Materials

    National Research Council Canada - National Science Library

    Bomberger, David

    2003-01-01

    .... The reaction of nitrene equivalents such as organic azides, N-haloamines, N-acyl hydroxylamines N,O-diacyl hydroxylamines, and amides in the presence of lead tetra-acetate or phenyliodine diacetate...

  17. Investigation of concept of efficient short wavelength laser. Quarterly progress report, 1 August 1978--31 October 1978

    Energy Technology Data Exchange (ETDEWEB)

    Piper, L.G.; Krech, R.H.; Pugh, E.R.; Taylor, R.L.

    1978-12-01

    A concept for the development of an efficient short wavelength laser based on a class of endoergic molecules-azides is being studied. One of these two laser-device experiments involves generating high concentrations of azide radicals in the thermal pyrolysis of solid, ionic azides, with the subsequent excitation of the N/sub 2/(B/sup 3/pi/sub g/) state from azide-radical recombination. Laser action would then take place upon the N/sub 2/(B/sup 3/pi/sub g/ - A/sup 3/Sigma/sup +//sub u/), first-postive transition. The second laser-demonstration experiment involves creating a high density of NCl(b/sup 1/Sigma/sup +/) state by uv photolysis of ClN/sub 3/. In this case laser emission is expected on the NCl(b/sup 1/Sigma/sup +/ ..-->.. X/sup 3/Sigma/sup -/) transition at 665 nm.

  18. Investigation of concept of efficient short wavelength laser. Quarterly progress report, 1 August 1978--31 October 1978

    International Nuclear Information System (INIS)

    Piper, L.G.; Krech, R.H.; Pugh, E.R.; Taylor, R.L.

    1978-01-01

    A concept for the development of an efficient short wavelength laser based on a class of endoergic molecules-azides is being studied. One of these two laser-device experiments involves generating high concentrations of azide radicals in the thermal pyrolysis of solid, ionic azides, with the subsequent excitation of the N 2 (B 3 pi/sub g/) state from azide-radical recombination. Laser action would then take place upon the N 2 (B 3 pi/sub g/ - A 3 Sigma + /sub u/), first-postive transition. The second laser-demonstration experiment involves creating a high density of NCl(b 1 Sigma + ) state by uv photolysis of ClN 3 . In this case laser emission is expected on the NCl(b 1 Sigma + → X 3 Sigma - ) transition at 665 nm

  19. Investigation of concept of efficient short wavelength laser. Quarterly progress report, 1 November 1978-31 January 1979

    Energy Technology Data Exchange (ETDEWEB)

    Krech, R.H.; Piper, L.G.; Pugh, E.R.; Taylor, R.L.

    1979-03-01

    A concept for the development of an efficient short wavelength laser based on a class of endoergic molecules-azides is being investigated. The first of two laser-device experiments involves generating high concentrations of azide radicals in the thermal pyrolysis of solid, ionic azides, with the subsequent excitation of the N/sub 2/(B/sup 3/..pi../sub g/) state from azide-radical recombination. Laser action would then take place upon the N/sub 2/(B/sup 3/..pi../sub g/-A/sup 3/..sigma../sup +//sub u/), first-positive transition. The second laser-demonstration experiment involves creating a high density of NCl(b/sup 1/..sigma../sup +/) state by uv photolysis of ClN/sub 3/. In this case laser emission is expected on the NCl(b/sup 1/..sigma../sup +/..-->..X/sup 3/..sigma../sup -/) transition at 665 nm.

  20. Characterization of cellulase production by carbon sources in two ...

    African Journals Online (AJOL)

    user7

    2013-11-27

    Nov 27, 2013 ... 7State Key Laboratory of Urban Water Resource and Environment, Harbin ... China. Accepted 28 March, 2012. The induction of cellulase production in two .... prevent the contamination with bacteria, 0.02% sodium azide was.

  1. SHORT COMMUNICATION SYNTHESIS OF AZIDO DERIVATIVES ...

    African Journals Online (AJOL)

    Preferred Customer

    Department of Chemistry & Chemical Technology, Faculty of Science, Engineering & ... substitution reactions with various nucleophiles, including azides and ... readily available substrate for the synthesis of an array of chemical compounds.

  2. Comparison of media for enumeration of Clostridium perfringens from foods

    NARCIS (Netherlands)

    Jong, A.E.I. de; Eijhusen, G.P.; Brouwer-Post, E.J.F.; Grand, M.; Johansson, T.; Kärkkäinen, T.; Marugg, J.; Veld, P.H. in 't; Warmerdam, F.H.M.; Wörner, G.; Zicavo, A.; Rombouts, F.M.; Beumer, R.R.

    2003-01-01

    Many media have been developed to enumerate Clostridium perfringens from foods. In this study, six media [iron sulfite (IS) agar, tryptose sulfite cycloserine (TSC) agar, Shahidi Ferguson perfringens (SFP) agar, sulfite cycloserine azide (SCA), differential clostridial agar (DCA), and oleandomycin

  3. A versatile method for the preparation of conjugates of peptides with DNA/PNA/analog by employing chemo-selective click reaction in water

    Science.gov (United States)

    Gogoi, Khirud; Mane, Meenakshi V.; Kunte, Sunita S.; Kumar, Vaijayanti A.

    2007-01-01

    The specific 1,3 dipolar Hüisgen cycloaddition reaction known as ‘click-reaction’ between azide and alkyne groups is employed for the synthesis of peptide–oligonucleotide conjugates. The peptide nucleic acids (PNA)/DNA and peptides may be appended either by azide or alkyne groups. The cycloaddition reaction between the azide and alkyne appended substrates allows the synthesis of the desired conjugates in high purity and yields irrespective of the sequence and functional groups on either of the two substrates. The versatile approach could also be employed to generate the conjugates of peptides with thioacetamido nucleic acid (TANA) analog. The click reaction is catalyzed by Cu (I) in either water or in organic medium. In water, ∼3-fold excess of the peptide-alkyne/azide drives the reaction to completion in 2 h with no side products. PMID:17981837

  4. Sphenostylis stenocarpa

    African Journals Online (AJOL)

    PROF HORSFALL

    With increase in world population of humans, food security and its ..... conservation and breeding. Gen. Res. ... Towards the synthesis of graphene azide from graphene oxide. Mol. ... heavy metals in serpentine soil using biochar. J. Soi. Sedim.

  5. Seasonality of fibrolytic enzyme activity in herbivore microbial ...

    African Journals Online (AJOL)

    2012-08-21

    Aug 21, 2012 ... liberating end-products such as volatile fatty acids. Cellulase enzyme ... All the other common chemicals such as glacial acetic acid, sodium azide .... specific activity was observed among animal species and between seasons ...

  6. The Chemistry of Cyclic All-Nitrogen Molecules

    National Research Council Canada - National Science Library

    Wodtke, Alec M

    2006-01-01

    ..., $474,927, February 15, 2004 - December 31, 2006. During this period, we have extended our preliminary investigations of azide photochemistry, with the aim of demonstrating unambiguously the photochemical production of cyclic-N, and of revealing...

  7. Spatially Selective Functionalization of Conducting Polymers by "Electroclick" Chemistry

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Daugaard, Anders Egede; Hvilsted, Søren

    2009-01-01

    Conducting polymer microelectrodes can electrochemically generate the catalyst required for their own functionalization by "click chemistry" with high spatial resolution. Interdigitated microelectrodes prepared from an azide-containing conducting polymer are selectively functionalized in sequence...

  8. Magnetic Nanoparticle-Based Imaging of RNA Transcripts in Breast Cancer Cells

    Science.gov (United States)

    2009-06-01

    incubating thiolated ONs with gold coated NPs; (4) using Cu- catalyzed terminal alkyne-azide cycloaddition (CuAAC) to couple alkyne labeled ONs to azide...lysosomes and exhibited similar fluorescent patterns as that shown in Figure 7. We have recently ordered several additional peptides and polymers ...magnetic resonance (MR) imaging involves tracking the migration and biodistribution of superparamagnetic iron oxide (SPIO)-labeled cells in vivo

  9. Synthesis And Characterization Of Telechelic Polytetrahydrofuran

    OpenAIRE

    Temelkaya, Ecem

    2013-01-01

    The target of this study was to obtain polymers having different functional end groups with the combination of living cationic ring-opening polymerization and click chemistry methods including Cu(I)-catalyzed azide-alkyne cyclo-addition (CuAAC) reactions. In this sense, polytetrahydrofurans (PTHF) having various functionalities such as azide (-N3), hydroxyl (-OH), bromo (-Br) and anthracene were obtained using functionalization from initiator, functionalization from terminating agent and chai...

  10. "Clickable" LNA/DNA probes for fluorescence sensing of nucleic acids and autoimmune antibodies

    DEFF Research Database (Denmark)

    Jørgensen, Anna S; Gupta, Pankaj; Wengel, Jesper

    2013-01-01

    Herein we describe fluorescent oligonucleotides prepared by click chemistry between novel alkyne-modified locked nucleic acid (LNA) strands and a series of fluorescent azides for homogeneous (all-in-solution) detection of nucleic acids and autoimmune antibodies.......Herein we describe fluorescent oligonucleotides prepared by click chemistry between novel alkyne-modified locked nucleic acid (LNA) strands and a series of fluorescent azides for homogeneous (all-in-solution) detection of nucleic acids and autoimmune antibodies....

  11. Advances in knowledge of mutagenesis at the molecular level in plants

    International Nuclear Information System (INIS)

    Nilan, R.A.; Owais, W.M.; Rosichan, J.L.; Kleinhofs, A.

    1979-01-01

    The mechanism of action of the densely and sparsely ionizing types of radiation in plant cells has been investigated. The indirect actions of physical mutagens in plant cells through the modifying influences of oxygen, water content, and temperature are well known. In terms of the nature of the mutations induced by physical mutagens in plants, a vast array of mutational events can be induced by neutrons, X-ray, gamma-ray, etc. It was determined that Na azides have been highly efficient mutagen in barley, peas, soybean, maize, Chlamydomonas, rice, yeast, Chinese hamster cells and certain strains of S. typhimurium and E. coli. Na azides were used as respiration inhibitor to investigate how chromosomes break and mutations are induced and/or repaired in the cells of irradiated barley seeds. Azides alone in the presence of O 2 induced about 6% mutation of chlorophyll-deficient seedlings which could be increased to 20% when the seeds had been treated in azide solutions at the pH values below the pKa of azides. When the seeds were presoaked for 15 hours at 1 deg C and 12 - 16 hrs at 20 deg C in aerated solution prior to azide treatment, 75% mutation was obtained. This mutation frequency is compared to 17% and 40 - 45% induced in barley by X-ray and ethyl methanesulfonate, respectively. It was shown that both L-cysteine and L-cysteine inhibited azide mutagenesis, and the inhibition seemed to be specific to azides. The waxy locus of barley controlling the starch composition is used to measure forward and reverse mutations and mutant recombination frequency on the grain per million pollen basis, and provides high genetic resolution and a detailed map of the genes. (Yamashita, S.)

  12. An investigation into the interactions of gold nanoparticles and anti-arthritic drugs with macrophages, and their reactivity towards thioredoxin reductase

    Energy Technology Data Exchange (ETDEWEB)

    James, Lloyd R.A.; Xu, Zhi-Qiang; Sluyter, Ronald; Hawksworth, Emma L.; Kelso, Celine; Lai, Barry; Paterson, David J.; de Jonge, Martin D.; Dixon, Nicholas E.; Beck, Jennnifer L.; Ralph, Stephen F.; Dillon, Carolyn T.

    2014-01-01

    Gold(I) complexes are an important tool in the arsenal of established approaches for treating rheumatoid arthritis (RA), while some recent studies have suggested that gold nanoparticles (Au NPs) may also be therapeutically efficacious. These observations prompted the current biological studies involving gold(I) anti-RA agents and Au NPs, which are aimed towards improving our knowledge of how they work. The cytotoxicity of auranofin, aurothiomalate, aurothiosulfate and Au NPs towards RAW264.7 macrophages was evaluated using the MTT assay, with the former compound proving to be the most toxic. The extent of cellular uptake of the various gold agents was determined using graphite furnace atomic absorption spectrometry, while their distribution within macrophages was examined using microprobe synchrotron radiation X-ray fluorescence spectroscopy. The latter technique showed accumulation of gold in discrete regions of the cell, and co-localisation with sulfur in the case of cells treated with aurothiomalate or auranofin. Electrospray ionization mass spectrometry was used to characterize thioredoxin reductase (TrxR) in which the penultimate selenocysteine residue was replaced by cysteine. Mass spectra of solutions of TrxR and aurothiomalate, aurothiosulfate or auranofin showed complexes containing bare gold atoms bound to the protein, or protein adducts containing gold atoms retaining some of their initial ligands. These results support TrxR being an important target of gold(I) drugs used to treat RA, while the finding that Au NPs are incorporated into macrophages, but elicit little toxicity, indicates further exploration of their potential for treatment of RA is warranted.

  13. Steric and electronic parameters of a bulky yet flexible N-heterocyclic carbene: 1,3-bis(2,6-bis(1-ethylpropyl)phenyl)imidazol-2-ylidene (IPent)

    KAUST Repository

    Collado, Alba; Balogh, Já nos; Meiries, Sé bastien; Slawin, Alexandra M. Z.; Falivene, Laura; Cavallo, Luigi; Nolan, Steven P.

    2013-01-01

    The free N-heterocyclic carbene IPent (1; IPent = 1,3-bis(2,6-bis(1- ethylpropyl)phenyl)imidazol-2-ylidene) was prepared from the corresponding imidazolium chloride salt (2). The steric and electronic parameters of 1 were determined by synthesis of the gold(I) chloride complex [Au(IPent)Cl] (3) and the nickel-carbonyl complex [Ni(IPent)(CO)3] (4), respectively. 3 and 4 were fully characterized by NMR spectroscopy, elemental analysis, and X-ray diffraction studies on single crystals. © 2013 American Chemical Society.

  14. Neuropsychological effects and attitudes in patients following electroconvulsive therapy

    OpenAIRE

    Edwards, Christopher

    2008-01-01

    Miriam Feliu1,2, Christopher L Edwards1,2,3, Shiv Sudhakar4, Camela McDougald1, Renee Raynor5, Stephanie Johnson6, Goldie Byrd7, Keith Whitfield8, Charles Jonassaint8, Heather Romero1, Lekisha Edwards1, Chante’ Wellington1, LaBarron K Hill9, James Sollers, III9, Patrick E Logue11Department of Psychiatry and Behavioral Sciences; 2Duke Pain and Palliative Care Center; 3Department of Medicine, Division of Hematology; 4Drexel University Medical School; 5Brain Tumor Center, Duke Universi...

  15. Expedient Syntheses of Neutral and Cationic Au(I)–NHC Complexes

    KAUST Repository

    Veenboer, Richard M. P.

    2017-09-08

    The synthesis and isolation of gold(I) precatalysts often requires the generation of several isolable intermediates as well as numerous purification steps. New protocols for the expedient synthesis of neutral [Au(OH)(NHC)] and [Au(CH2COCH3)(NHC)] species from [AuCl(NHC)] or [AuCl(DMS)] precursors bearing a variety of N-heterocyclic carbene (NHC) ligands are presented. These methods can be employed in a telescoping manner for the synthesis of catalytically relevant [Au(NTf2)(NHC)] and [Au(NHC)(NCCH3)][BF4] complexes. These attractive methods are straightforward and practical leading to various complexes in high isolated yields and purity.

  16. A COMPARATIVE ANALYSIS OF MANAGERIAL COMPETENCIES BASED ON EVIDENCE FROM SATU MARE COUNTY, ROMANIA

    Directory of Open Access Journals (Sweden)

    Olimpia Neagu

    2014-12-01

    Full Text Available The paper explores the managerial competencies of human resources in the companies from Satu Mare County, by comparing the employers' and employees' views. The comparison is based on data collected and processed within the project HURO/0901/264/2.2.2 implemented in partnership by "Vasile Goldiș" Western University and University of Debrecen and financed by European Union through ERDF under Hungary-Romania 2007-2013 Programme, in 2012, and on data collected and processed in 2013-2014, in a new field research applied to employees from Satu Mare county.

  17. Steric and electronic parameters of a bulky yet flexible N-heterocyclic carbene: 1,3-bis(2,6-bis(1-ethylpropyl)phenyl)imidazol-2-ylidene (IPent)

    KAUST Repository

    Collado, Alba

    2013-06-10

    The free N-heterocyclic carbene IPent (1; IPent = 1,3-bis(2,6-bis(1- ethylpropyl)phenyl)imidazol-2-ylidene) was prepared from the corresponding imidazolium chloride salt (2). The steric and electronic parameters of 1 were determined by synthesis of the gold(I) chloride complex [Au(IPent)Cl] (3) and the nickel-carbonyl complex [Ni(IPent)(CO)3] (4), respectively. 3 and 4 were fully characterized by NMR spectroscopy, elemental analysis, and X-ray diffraction studies on single crystals. © 2013 American Chemical Society.

  18. CONCEPŢIA FILOSOFICĂ DESPRE STAT ŞI DREPT A LUI VASILE GOLDIŞ

    Directory of Open Access Journals (Sweden)

    Martian Iovan

    2007-05-01

    Full Text Available Being a part of a philosophic common conception, of an original way of interpretinggreat trends of the European history the judicial philosophy seen by Vasile Goldiş speaksabout values, principles and arguments which guided his entire political career. The authorof this study makes an analysis of the main elements which united a postmodern philosophy ofpower and law among which the concepts of justice, natural laws, positive laws, naturalhuman and people rights, state, power, constitutionalism and social and Christian democracyare the ones that articulates the national, European and international political projects of thegreat Romanian scholar and politic man.

  19. Whole Exome Analysis of Early Onset Alzheimer’s Disease

    Science.gov (United States)

    2017-04-01

    Alzheimer’s Disease 5a. CONTRACT NUMBER W81XWH-12-1-0013 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) Margaret A. Pericak-Vance, Ph.D...Gerald D. Schellenberg, Goldie S . Byrd, Jonathan L. Haines, Margaret A. Pericak-Vance, and the Alzheimer Disease Genetics Consortium. ABCA7 Frameshift...Alzheimer’s & Parkinson’s Diseases (AD/PD), Vienna, Austria, Mar 29-Apr 2, 2017: Cukier HN, Gross SP, Kunkle BW, Rolati S , Hamilton-Nelson KL, Whitehead PL

  20. Expedient Syntheses of Neutral and Cationic Au(I)–NHC Complexes

    KAUST Repository

    Veenboer, Richard M. P.; Gasperini, Danila; Nahra, Fady; Cordes, David B.; Slawin, Alexandra M. Z.; Cazin, Catherine S. J.; Nolan, Steven P.

    2017-01-01

    The synthesis and isolation of gold(I) precatalysts often requires the generation of several isolable intermediates as well as numerous purification steps. New protocols for the expedient synthesis of neutral [Au(OH)(NHC)] and [Au(CH2COCH3)(NHC)] species from [AuCl(NHC)] or [AuCl(DMS)] precursors bearing a variety of N-heterocyclic carbene (NHC) ligands are presented. These methods can be employed in a telescoping manner for the synthesis of catalytically relevant [Au(NTf2)(NHC)] and [Au(NHC)(NCCH3)][BF4] complexes. These attractive methods are straightforward and practical leading to various complexes in high isolated yields and purity.

  1. Linear-quadratic model predictions for tumor control probability

    International Nuclear Information System (INIS)

    Yaes, R.J.

    1987-01-01

    Sigmoid dose-response curves for tumor control are calculated from the linear-quadratic model parameters α and Β, obtained from human epidermoid carcinoma cell lines, and are much steeper than the clinical dose-response curves for head and neck cancers. One possible explanation is the presence of small radiation-resistant clones arising from mutations in an initially homogeneous tumor. Using the mutation theory of Delbruck and Luria and of Goldie and Coldman, the authors discuss the implications of such radiation-resistant clones for clinical radiation therapy

  2. An Hilbert space approach for a class of arbitrage free implied volatilities models

    OpenAIRE

    Brace, A.; Fabbri, G.; Goldys, B.

    2007-01-01

    We present an Hilbert space formulation for a set of implied volatility models introduced in \\cite{BraceGoldys01} in which the authors studied conditions for a family of European call options, varying the maturing time and the strike price $T$ an $K$, to be arbitrage free. The arbitrage free conditions give a system of stochastic PDEs for the evolution of the implied volatility surface ${\\hat\\sigma}_t(T,K)$. We will focus on the family obtained fixing a strike $K$ and varying $T$. In order to...

  3. Encoding complexity within supramolecular analogues of frustrated magnets

    Science.gov (United States)

    Cairns, Andrew B.; Cliffe, Matthew J.; Paddison, Joseph A. M.; Daisenberger, Dominik; Tucker, Matthew G.; Coudert, François-Xavier; Goodwin, Andrew L.

    2016-05-01

    The solid phases of gold(I) and/or silver(I) cyanides are supramolecular assemblies of inorganic polymer chains in which the key structural degrees of freedom—namely, the relative vertical shifts of neighbouring chains—are mathematically equivalent to the phase angles of rotating planar (‘XY’) spins. Here, we show how the supramolecular interactions between chains can be tuned to mimic different magnetic interactions. In this way, the structures of gold(I) and/or silver(I) cyanides reflect the phase behaviour of triangular XY magnets. Complex magnetic states predicted for this family of magnets—including collective spin-vortices of relevance to data storage applications—are realized in the structural chemistry of these cyanide polymers. Our results demonstrate how chemically simple inorganic materials can behave as structural analogues of otherwise inaccessible ‘toy’ spin models and also how the theoretical understanding of those models allows control over collective (‘emergent’) phenomena in supramolecular systems.

  4. Separation of thiosulfate and the polythionates in gold thiosulfate leach solutions by capillary electrophoresis.

    Science.gov (United States)

    O'Reilly, John W; Dicinoski, Greg W; Miura, Yasuyuki; Haddad, Paul R

    2003-06-01

    A technique for the separation of thiosulfate (S(2)O(3) (2-)), polythionates (S(x)O(6) (2-), x = 3 to 5) and the gold(I) thiosulfate complex (Au(S(2)O(3))(2) (3-)) using capillary electrophoresis with simultaneous UV detection at 195 and 214 nm is presented. The five species were separated in under 3 min with a total analysis time of 8 min, using an electrolyte containing 25 mM 2,2-bis(hydroxymethyl)-2,2',2"-nitrilotriethanol (bis-tris) adjusted to pH 6.0 with sulfuric acid and an applied voltage of -30 kV. While the gold(I) thiosulfate complex could be separated from the other analytes of interest under these conditions, the quantification of this complex was not possible due to inconsistent peak areas and peak splitting effects induced by the sulfur-oxygen species in the leach matrix. Detection limits calculated for 3s pressure injection at 50 mbar ranged between 0.5-2 microM. The method was linear over the ranges 40-8000, 10-2000, 10-2000, and 5-2000 microM for thiosulfate, trithionate, tetrathionate, and pentathionate, respectively. The technique was applied successfully to leach liquors containing 0.5 M ammonium thiosulfate, 2 M ammonia, 0.05 M copper sulfate and 20% w/v gold ore, diluted 1:100 prior to analysis.

  5. Comparison of TALEN scaffolds in Xenopus tropicalis

    Directory of Open Access Journals (Sweden)

    Keisuke Nakajima

    2013-11-01

    Transcription activator-like effector nucleases (TALENs are facile and potent tools used to modify a gene of interest for targeted gene knockout. TALENs consist of an N-terminal domain, a DNA-binding domain, and a C-terminal domain, which are derived from a transcription activator-like effector, and the non-specific nuclease domain of FokI. Using Xenopus tropicalis (X. tropicalis, we compared the toxicities and somatic mutation activities of four TALEN architectures in a side-by-side manner: a basic TALEN, a scaffold with the same truncated N- and C-terminal domains as GoldyTALEN, a scaffold with the truncated N- and C-terminal domains and an obligate heterodimeric nuclease domain, and a scaffold with the truncated N- and C-terminal domains and an obligate heterodimeric Sharkey nuclease domain. The strongest phenotype and targeted somatic gene mutation were induced by the injection of TALEN mRNAs containing the truncated N- and C-terminal domains and an obligate heterodimeric nuclease domain. The obligate heterodimeric TALENs exhibited reduced toxicity compared to the homodimeric TALENs, and the homodimeric GoldyTALEN-type scaffold showed both a high activity of somatic gene modification and high toxicity. The Sharkey mutation in the heterodimeric nuclease domain reduced the TALEN-mediated somatic mutagenesis.

  6. Species-specific identification of equine cyathostomes resistant to fenbendazole and susceptible to oxibendazole and moxidectin by macroarray probing.

    Science.gov (United States)

    Traversa, Donato; Iorio, Raffaella; Otranto, Domenico; Giangaspero, Annunziata; Milillo, Piermarino; Klei, Thomas R

    2009-01-01

    Cyathostome populations in horses on two farms located in central Italy with a history of fenbendazole (FBZ) resistance were investigated with the Faecal Egg Count Reduction Test to evaluate the susceptibility to oxibendazole and moxidectin. Faecal eggs were collected pre- and post-treatment on each farm and molecularly examined with a Reverse Line Blot (RLB) assay able to unequivocally detect and identify 13 cyathostome species. Resistance to FBZ was confirmed on both farms, while oxibendazole and moxidectin demonstrated 97% and 100% efficacy, respectively. Overall eight species of cyathostomes (Coronocyclus labiatus, Cylicocyclus ashworthi, Cylicocyclus nassatus, Cyathostomum catinatum, Cylicostephanus longibursatus, Cylicostephanus goldi, Cylicostephanus calicatus and Cylicocyclus insigne) were identified in pre-treatment samples. Coronocyclus labiatus and C. goldi were identified after treatment with FBZ while C. calicatus and C. labiatus were shown to be <100% susceptible to oxibendazole. These data confirm that resistance to benzimidazoles is established in cyathostome populations from horse farms in Italy and that they are susceptible to moxidectin. The oxibendazole has been successfully demonstrated for the first time as effective against Italian populations of cyathostomes resistant to other benzimidazoles. The RLB assay herein used showed to be useful to study the distribution of these parasitic populations at species level under field conditions and could represent a powerful tool in broader investigation of drug resistance in horse farms from several countries.

  7. Nano-sized metabolic precursors for heterogeneous tumor-targeting strategy using bioorthogonal click chemistry in vivo.

    Science.gov (United States)

    Lee, Sangmin; Jung, Seulhee; Koo, Heebeom; Na, Jin Hee; Yoon, Hong Yeol; Shim, Man Kyu; Park, Jooho; Kim, Jong-Ho; Lee, Seulki; Pomper, Martin G; Kwon, Ick Chan; Ahn, Cheol-Hee; Kim, Kwangmeyung

    2017-12-01

    Herein, we developed nano-sized metabolic precursors (Nano-MPs) for new tumor-targeting strategy to overcome the intrinsic limitations of biological ligands such as the limited number of biological receptors and the heterogeneity in tumor tissues. We conjugated the azide group-containing metabolic precursors, triacetylated N-azidoacetyl-d-mannosamine to generation 4 poly(amidoamine) dendrimer backbone. The nano-sized dendrimer of Nano-MPs could generate azide groups on the surface of tumor cells homogeneously regardless of cell types via metabolic glycoengineering. Importantly, these exogenously generated 'artificial chemical receptors' containing azide groups could be used for bioorthogonal click chemistry, regardless of phenotypes of different tumor cells. Furthermore, in tumor-bearing mice models, Nano-MPs could be mainly localized at the target tumor tissues by the enhanced permeation and retention (EPR) effect, and they successfully generated azide groups on tumor cells in vivo after an intravenous injection. Finally, we showed that these azide groups on tumor tissues could be used as 'artificial chemical receptors' that were conjugated to bioorthogonal chemical group-containing liposomes via in vivo click chemistry in heterogeneous tumor-bearing mice. Therefore, overall results demonstrated that our nano-sized metabolic precursors could be extensively applied to new alternative tumor-targeting technique for molecular imaging and drug delivery system, regardless of the phenotype of heterogeneous tumor cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Conjugating folate on superparamagnetic Fe3O4@Au nanoparticles using click chemistry

    International Nuclear Information System (INIS)

    Shen, Xiaofang; Ge, Zhaoqiang; Pang, Yuehong

    2015-01-01

    Gold-coated magnetic core@shell nanoparticles, which exhibit magneto-optical properties, not only enhance the chemical stability of core and biocompatibility of surface, but also provide a combination of multimodal imaging and therapeutics. The conjugation of these tiny nanoparticles with specific biomolecules allows researchers to target the desired location. In this paper, superparamagnetic Fe 3 O 4 @Au nanoparticles were synthesized and functionalized with the azide group on the surface by formation of self-assembled monolayers. Folate (FA) molecules, non-immunogenic target ligands for cancer cells, are conjugated with alkyne and then immobilized on the azide-terminated Fe 3 O 4 @Au nanoparticles through copper(I)-catalyzed azide-alkyne cycloaddition (click reaction). Myelogenous leukemia K562 cells were used as a folate receptor (FR) model, which can be targeted and extracted by magnetic field after interaction with the Fe 3 O 4 @Au–FA nanoparticles. - Graphical abstract: Self-assembled azide-terminated group on superparamagnetic Fe 3 O 4 @Au nanoparticles followed by click reaction with alkyne-functionalized folate, allowing the nanoparticles target folate receptor of cancer cells. - Highlights: • Azidoundecanethiol was coated on the superparamagnetic Fe 3 O 4 @Au nanoparticles by forming self-assembled monolayers. • Alkyne-terminated folate was synthesized from a reaction between the amine and the carboxylic acid. • Conjugation of Fe 3 O 4 @Au nanoparticles with folate was made by copper-catalyzed azide-alkyne cycloaddition click chemistry

  9. Solvent-resistant organic transistors and thermally stable organic photovoltaics based on cross-linkable conjugated polymers

    KAUST Repository

    Kim, Hyeongjun

    2012-01-10

    Conjugated polymers, in general, are unstable when exposed to air, solvent, or thermal treatment, and these challenges limit their practical applications. Therefore, it is of great importance to develop new materials or methodologies that can enable organic electronics with air stability, solvent resistance, and thermal stability. Herein, we have developed a simple but powerful approach to achieve solvent-resistant and thermally stable organic electronic devices with a remarkably improved air stability, by introducing an azide cross-linkable group into a conjugated polymer. To demonstrate this concept, we have synthesized polythiophene with azide groups attached to end of the alkyl chain (P3HT-azide). Photo-cross-linking of P3HT-azide copolymers dramatically improves the solvent resistance of the active layer without disrupting the molecular ordering and charge transport. This is the first demonstration of solvent-resistant organic transistors. Furthermore, the bulk-heterojunction organic photovoltaics (BHJ OPVs) containing P3HT-azide copolymers show an average efficiency higher than 3.3% after 40 h annealing at an elevated temperature of 150 °C, which represents one of the most thermally stable OPV devices reported to date. This enhanced stability is due to an in situ compatibilizer that forms at the P3HT/PCBM interface and suppresses macrophase separation. Our approach paves a way toward organic electronics with robust and stable operations. © 2011 American Chemical Society.

  10. Preliminary characterization of propellants based on p(GA/BAMO) and pAMMO binders

    Energy Technology Data Exchange (ETDEWEB)

    Barbieri, Ugo; Polacco, Giovanni [Department of Chemical Engineering, University of Pisa (Italy); Keicher, Thomas [Fraunhofer-Institut fuer Chemische Technologie (ICT), Pfinztal (Germany); Massimi, Roberto [AVIO S.p.A., Roma (Italy)

    2009-10-15

    In previous papers, the synthesis and characterization of OH-terminated glycidyl azide-r-(3,3-bis(azidomethyl)oxetane) copolymers (GA/BAMO) and poly-3-azidomethyl-3-methyl oxetane (pAMMO) by azidation of their respective polymeric substrates were described. The main objective was the preparation of amorphous azido-polymers, as substitutes of hydroxy-terminated polybutadiene (HTPB) in new formulations of energetic propellants. Here, the subsequent characterization of both the binders is presented. First of all, several isocyanates were checked in order to optimize the curing reaction, and then two small-scale formulations of a propellant, based on aluminium and ammonium perchlorate, were prepared and characterized. Finally, the mechanical properties and burning rate were compared to those of a similar propellant based on HTPB as binder. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  11. Post Modification of Acetylene Functional Poly(oxindole biphenylylene) by Photoinduced CuAAC

    KAUST Repository

    Arslan, Mustafa; Cem Bicak, Tugrul; Pulido, Bruno; Nunes, Suzana Pereira; Yagci, Yusuf

    2018-01-01

    A novel strategy to obtain side chain modified poly(oxindole biphenylylene) (POXI) by photoinduced copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction is described. In the first step, an alkyne-functionalized poly(oxindolebiphenylylene) (POXI-alkyne) is synthesized by superacid-catalyzed condensation of isatin with aromatic hydrocarbons. Subsequently, poly(ethylene glycol) methyl ether (Me-PEG), 1-pyrenemethanol (Py-OH) and 1,3-dibromopropane (DBP) are functionalized by azide groups via simple nucleophilic substitution reaction. Visible-light-induced CuAAC reaction between POXI-alkyne and the corresponding azide functionalized click components employing dibenzoyldiethylgermane (DBDEG) as photoactivator resulted in the formation of POXI-PEG, POXI-Py and insoluble network, respectively. Successful modification of POXI was confirmed by the spectral, (1H NMR, FT-IR, Fluorescence), chromatographic (GPC) and thermal (DSC) investigations.

  12. The formation of nitrogeneous compounds in the γ-radiolyses of liquid nitrogen solutions of hydrogen, methane, and ethane

    International Nuclear Information System (INIS)

    Horigome, Keiichi; Hirokami, Shun-ichi; Sato, Shin

    1978-01-01

    The γ-radiolyses of liquid nitrogen solutions of hydrogen, methane, and ethane have been reinvestigated. A complete survey of nitrogen-containing products has been attempted. The nitrogeneous compounds observed were ammonia (0.7) and hydrogen azide (0.02) in the case of hydrogen, ammonia (0.3), hydrogen cyanide (0.1), methyl azide (0.01), and a polymer in the case of methane, and ammonia (0.3), hydrogen cyanide (0.05), acetonitrile (0.04), ethyl azide (0.01), and a polymer in the case of ethane. The values in parentheses are the G-values obtained at optimum conditions. The hydrolysis of the polymer obtained with methane gave formaldehyde in amounts which correspond to the fact that the G-value of the nitrogen atoms which were converted into the polymer is about 1.0. In order to explain these results, possible reaction mechanisms are discussed. (auth.)

  13. Post Modification of Acetylene Functional Poly(oxindole biphenylylene) by Photoinduced CuAAC

    KAUST Repository

    Arslan, Mustafa

    2018-02-08

    A novel strategy to obtain side chain modified poly(oxindole biphenylylene) (POXI) by photoinduced copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction is described. In the first step, an alkyne-functionalized poly(oxindolebiphenylylene) (POXI-alkyne) is synthesized by superacid-catalyzed condensation of isatin with aromatic hydrocarbons. Subsequently, poly(ethylene glycol) methyl ether (Me-PEG), 1-pyrenemethanol (Py-OH) and 1,3-dibromopropane (DBP) are functionalized by azide groups via simple nucleophilic substitution reaction. Visible-light-induced CuAAC reaction between POXI-alkyne and the corresponding azide functionalized click components employing dibenzoyldiethylgermane (DBDEG) as photoactivator resulted in the formation of POXI-PEG, POXI-Py and insoluble network, respectively. Successful modification of POXI was confirmed by the spectral, (1H NMR, FT-IR, Fluorescence), chromatographic (GPC) and thermal (DSC) investigations.

  14. High-efficiency synthesis of dendrimer-like poly(ethylene oxide) via “arm-first” approach

    KAUST Repository

    Zhu, Saisai

    2017-04-14

    In this study, a dendrimer-like polymer based on poly(ethylene oxide) (PEO) was synthesized through a combination of anionic ring-opening polymerization (AROP) and click reaction via arm-first method. Firstly, the polymeric arm, a linear PEO with one alkynyl group and two bromo groups, was synthesized by AROP of ethylene oxide followed by functionalization with propargyl bromide and esterified with 2-bromopropionic bromide. Second, a star PEO carrying three azide groups was synthesized though AROP of ethylene oxide used 1,1,1-tris(hydrosymethyl) ethane as initiator followed esterificated with 2-bromopropionic acid and azidation. By azide–alkyne click reactions between the azide-terminated PEO star polymer and linear PEO with functionalization alkynyl group, a three generation dendrimer-like PEO, G3-PEO-24Br, was successfully synthesized. The resulting polymers were observed to have precisely controlled molecular weights and compositions with narrow molecular weight distributions.

  15. Pore surface engineering in covalent organic frameworks.

    Science.gov (United States)

    Nagai, Atsushi; Guo, Zhaoqi; Feng, Xiao; Jin, Shangbin; Chen, Xiong; Ding, Xuesong; Jiang, Donglin

    2011-11-15

    Covalent organic frameworks (COFs) are a class of important porous materials that allow atomically precise integration of building blocks to achieve pre-designable pore size and geometry; however, pore surface engineering in COFs remains challenging. Here we introduce pore surface engineering to COF chemistry, which allows the controlled functionalization of COF pore walls with organic groups. This functionalization is made possible by the use of azide-appended building blocks for the synthesis of COFs with walls to which a designable content of azide units is anchored. The azide units can then undergo a quantitative click reaction with alkynes to produce pore surfaces with desired groups and preferred densities. The diversity of click reactions performed shows that the protocol is compatible with the development of various specific surfaces in COFs. Therefore, this methodology constitutes a step in the pore surface engineering of COFs to realize pre-designed compositions, components and functions.

  16. Active biomonitoring in freshwater environments: early warning signals from biomarkers in assessing biological effects of diffuse sources of pollutants

    CSIR Research Space (South Africa)

    Wepener, V

    2005-01-01

    Full Text Available in non-fat dried milk contain- ing 0.02% sodium azide then incubated in HSP 70 primary antibody for 20 h. The membrane was washed three times in phosphate buffer saline and once in Tris buffer saline for 10 min each then incubated in non-fat azide free... biomarker response assessment of the system. A concomitant laboratory- based WET assessment of the raw water was conducted to assess the toxicity of the water at the selected sam- pling sites using standard algal, invertebrate and fish bioassays. 2. Material...

  17. Diazo Compounds as Highly Tunable Reactants in 1,3-Dipolar Cycloaddition Reactions with Cycloalkynes†

    Science.gov (United States)

    McGrath, Nicholas A.

    2012-01-01

    Diazo compounds, which can be accessed directly from azides by deimidogenation, are shown to be extremely versatile dipoles in 1,3-dipolar cycloaddition reactions with a cyclooctyne. The reactivity of a diazo compound can be much greater or much less than its azide analog, and is enhanced markedly in polar-protic solvents. These reactivities are predictable from frontier molecular orbital energies. The most reactive diazo compound exhibited the highest known second-order rate constant to date for a dipolar cycloaddition with a cycloalkyne. These data provide a new modality for effecting chemoselective reactions in a biological context. PMID:23227302

  18. Direct Light-up of cAMP Derivatives in Living Cells by Click Reactions

    Directory of Open Access Journals (Sweden)

    Yan Xu

    2013-10-01

    Full Text Available 8-Azidoadenosine 3′,5′-cyclic monophosphate (8-azido cAMP was directly detected in living cells, by applying Cu-free azide-alkyne cycloaddition to probe cAMP derivatives by fluorescence light-up. Fluorescence emission was generated by two non-fluorescent molecules, 8-azido cAMP as a model target and difluorinated cyclooctyne (DIFO reagent as a probe. The azide-alkyne cycloaddition reaction between 8-azido cAMP and DIFO induces fluorescence in 8-azido cAMP. The fluorescence emission serves as a way to probe 8-azido cAMP in cells.

  19. Catastrophic processes in dielectrics in irradiation by high-current electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Oleshko, V. [Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); Lisitsyna, L., E-mail: lisitsyn@tpu.r [Tomsk State University of Architecture and Building, 634003 Tomsk (Russian Federation); Malys, D.; Damamme, G. [Commissariat a l' energie atomique, Paris 75015 (France); Lisitsyn, V. [Tomsk Polytechnic University, 634050 Tomsk (Russian Federation)

    2010-10-01

    The results of the research in explosive decomposition of heavy metal azides initiated by electric ('streamer') charges induced by high-current electron beam have been considered. A physical model for initiation of heavy metal azides explosive decomposition by electron beam has been suggested. The model suggests formation of strong electric field in the sample and its neutralization by ultrasound anode charges. The streamer front generates 'hot spots' which start the formation of explosive decomposition sites in a condensed reactive material.

  20. Diazido{(S-1-phenyl-N,N-bis[(2-pyridylmethyl]ethanamine}copper(II

    Directory of Open Access Journals (Sweden)

    Sankara Rao Rowthu

    2011-07-01

    Full Text Available In the title compound, [Cu(N32(C20H21N3], the CuII ion is coordinated by the three N atoms of the (S-1-phenyl-N,N-bis[(2-pyridylmethyl]ethanamine ligand and two N atoms from two azide anions, resulting in a distorted square-pyramidal environment. A weak intermolecular C—H...N hydrogen-bonding interaction between one pyridine group of the ligand and an azide N atom of an adjacent complex unit gives a one-dimensional chain structure parallel to the c axis.

  1. Complex Surface Concentration Gradients by Stenciled "Electro Click Chemistry"

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Lind, Johan Ulrik; Daugaard, Anders Egede

    2010-01-01

    Complex one- or two-dimensional concentration gradients of alkynated molecules are produced on azidized conducting polymer substrates by stenciled "electro click chemistry". The latter describes the local electrochemical generation of catalytically active Cu(I) required to complete a "click...... reaction" between alkynes and azides at room temperature. A stencil on the counter electrode defines the shape and multiplicity of the gradient(s) on the conducting polymer substrate, while the specific reaction conditions control gradient steepness and the maximum concentration deposited. Biologically...

  2. Synthesis of Diblock Codendrimer by Double Click Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Wook; Han, Seung Choul; Ji, Won Ho [Dong-A Univ., Busan (Korea, Republic of); Jin, Sungho [Pusan National Univ., Busan (Korea, Republic of); Kim, Ji Hyeon [Gachon Univ., Seongnam (Korea, Republic of)

    2012-12-15

    Efficient double click methods for the synthesis of diblock codendrimers were developed. The synthetic strategy involved the sequential click reactions between an alkyne and an azide. The short core building block, 1,4-diazidobutane, was chosen to serve as the azide functionalities for dendrimer growth via click reactions with the alkyne-functionalized PAMAM dendrons as hydrophilic dendron and alkyne-functionalized Frechet-type dendrons as hydrophobic dendron. The structure of diblock codendrimers was confirmed by {sup 1}H and {sup 13}C NMR spectroscopy, IR spectroscopy, mass spectrometry, and GPC analysis.

  3. Contribution to the study of pseudohalides complexes of tervalent, lanthanides and actinides in solution

    International Nuclear Information System (INIS)

    Cuillerdier, Christine.

    1981-10-01

    Some complexes formed with halides or pseudohalides (iodide, cyanide, azide and thiocyanate) and tervalent lanthanides and actinides have been studied in solution. Methods like solvent extraction, polarography have been used to measure inner plus outer sphere complexation and spectroscopic methods have been chosen to study inner sphere complexes only. It has been found that inner sphere complexe of americium and neodymium with cyanide exist in aqueous solutions. Tervalent actinides form stronger inner sphere complexes with azide than lanthanide in solution. Thiocyanate complexes appear to be inner sphere and N-bonded [fr

  4. Synthesis of Novel C-2- or C-15-Labeled BODIPY—Estrone Conjugates

    Directory of Open Access Journals (Sweden)

    Ildikó Bacsa

    2018-04-01

    Full Text Available Novel BODIPY–estrone conjugates were synthesized via Cu(I-catalyzed azide–alkyne cycloaddition (CuAAC. Estrone-alkynes or an estrone-azide as starting compounds were synthesized via Michael addition or Sonogashira reaction as key steps. Fluorescent dyes based on BODIPY-core were provided by azide or alkyne functional groups. Fluorescent labeling of estrone was efficiently achieved at the C-2 or C-15 position. The newly-elaborated coupling procedures might have a broad applicability in the synthesis of fluorescent-labeled estrone conjugates suitable for biological assays.

  5. Methods for the selective detection of alkyne-presenting molecules and related compositions and systems

    Science.gov (United States)

    Valdez, Carlos A.; Vu, Alexander K.

    2017-10-17

    Provided herein are methods for selectively detecting an alkyne-presenting molecule in a sample and related detection reagents, compositions, methods and systems. The methods include contacting a detection reagent with the sample for a time and under a condition to allow binding of the detection reagent to the one or more alkyne-presenting molecules possibly present in the matrix to the detection reagent. The detection reagent includes an organic label moiety presenting an azide group. The binding of the azide group to the alkyne-presenting molecules results in emission of a signal from the organic label moiety.

  6. Synthesis of Diblock Codendrimer by Double Click Chemistry

    International Nuclear Information System (INIS)

    Lee, Jae Wook; Han, Seung Choul; Ji, Won Ho; Jin, Sungho; Kim, Ji Hyeon

    2012-01-01

    Efficient double click methods for the synthesis of diblock codendrimers were developed. The synthetic strategy involved the sequential click reactions between an alkyne and an azide. The short core building block, 1,4-diazidobutane, was chosen to serve as the azide functionalities for dendrimer growth via click reactions with the alkyne-functionalized PAMAM dendrons as hydrophilic dendron and alkyne-functionalized Frechet-type dendrons as hydrophobic dendron. The structure of diblock codendrimers was confirmed by 1 H and 13 C NMR spectroscopy, IR spectroscopy, mass spectrometry, and GPC analysis

  7. Triazol-substituted titanocenes by strain-driven 1,3-dipolar cycloadditions

    Directory of Open Access Journals (Sweden)

    Andreas Gansäuer

    2014-07-01

    Full Text Available An operationally simple, convenient, and mild strategy for the synthesis of triazole-substituted titanocenes via strain-driven 1,3-dipolar cycloadditions between azide-functionalized titanocenes and cyclooctyne has been developed. It features the first synthesis of titanocenes containing azide groups. These compounds constitute ‘second-generation’ functionalized titanocene building blocks for further synthetic elaboration. Our synthesis is modular and large numbers of the complexes can in principle be prepared in short periods of time. Some of the triazole-substituted titanocenes display high cyctotoxic activity against BJAB cells. Comparison of the most active complexes allows the identification of structural features essential for biological activity.

  8. Nitrous oxide-forming codenitrification catalyzed by cytochrome P450nor.

    Science.gov (United States)

    Su, Fei; Takaya, Naoki; Shoun, Hirofumi

    2004-02-01

    Intact cells of the denitrifying fungus Fusarium oxysporum were previously shown to catalyze codenitrification to form a hybrid nitrous oxide (N2O) species from nitrite and other nitrogen compounds such as azide and ammonia. Here we show that cytochrome P450nor can catalyze the codenitrification reaction to form N2O from nitric oxide (NO) but not nitrite, and azide or ammonia. The results show that the direct substrate of the codenitrification by intact cells should not be nitrite but NO, which is formed from nitrite by the reaction of a dissimilatory nitrite reductase.

  9. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    ) ring opening of all these epoxides by azide ion with selectivity and the reversal of selectivity in epoxide 7 and 8 is notable. These reactions follow, in both enzymatic and non-enzymatic environment, S2 mechanism. Calculations while ...

  10. A dibenzoazacyclooctyne as a reactive chain stopper for [2]rotaxanes

    NARCIS (Netherlands)

    Hou, Z.-Y.; Yeniad, B.; van Guyse, J.; Woisel, P.; Mullen, K.M.; Rutjes, F.P J.T.; van Hest, J.C.M.; Hoogenboom, R.

    2017-01-01

    A strained dibenzoazacyclooctyne (DIBAC) derivative was introduced for the preparation of a rotaxane by strain-promoted azide-alkyne cycloaddition (SPAAC), also referred to as a copper-free click reaction. The DIBAC can efficiently act as a bulky reactive chain stopper to transform a pseudorotaxane

  11. Milk-clotting activity of berries extracts from nine Solanum plants

    African Journals Online (AJOL)

    USER

    2010-06-21

    Jun 21, 2010 ... milk than reconstituted skim milk powder (Martin et al., 2008). Preparation of coagulation ... This raw skim milk was stored at 4°C with sodium azide. (0.2 g/l) added as ..... Lait, Produit laitier et Nutrition humaine. Rome. p. 176.

  12. The effects of chemical and physical mutagens on morphological ...

    African Journals Online (AJOL)

    The lowest germination percentage belonged to ethyl methane sulfanate (0.7%). Mean comparison of radical length trait showed that the highest radical length belonged to gamma ray control, 200 Gy and sodium azide (SA) 0.5 mM and treatments of gamma ray 700 Gy, 1200 Gy and ethylmethane sulphonate (EMS) 0.7% ...

  13. Effectiveness and efficiency of chemical mutagens in cowpea (Vigna ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-11-19

    Nov 19, 2008 ... A study was undertaken in a cowpea (Vigna unguiculata (L.) Walp.) variety CO 6 to assess the efficiency and effectiveness of chemical mutagens; ethyl methane sulphonate (EMS), diethyl sulphate (DES) and sodium azide (SA). EMS treatments were found highly effective than the other chemicals.

  14. Reactivity of halide and pseudohalide ligands

    International Nuclear Information System (INIS)

    Kukushkin, Yu.N.

    1987-01-01

    Reactivity of halide and pseudohalide (cyanide, azide, thiocyanate, cyanate) ligands tending to form bridge bonds in transition metal (Re, Mo, W) complexes is considered. Complexes where transition metal salts are ligands of other, complex-forming ion, are described. Transformation of innerspheric pseudohalide ligands is an important way of directed synthesis of these metal coordination compounds

  15. Toxic effects exerted on methanogenic, nitrifying and denitrifying bacteria by chemicals used in a milk analysis laboratory

    NARCIS (Netherlands)

    Lopez-Fiuza, J.; Buys, B.; Mosquera-Corral, A.; Omil, F.; Mendez, R.

    2002-01-01

    The toxic effects caused by the chemicals contained in wastewaters generated by laboratories involved in raw milk analyses were assessed using batch assays. These assays were carried out separately with methanogenic, ammonium-oxidizing, nitrite-oxidizing and denitrifying bacteria. Since sodium azide

  16. Orientation of llama antibodies strongly increases sensitivity of biosensors.

    Science.gov (United States)

    Trilling, Anke K; Hesselink, Thamara; van Houwelingen, Adèle; Cordewener, Jan H G; Jongsma, Maarten A; Schoffelen, Sanne; van Hest, Jan C M; Zuilhof, Han; Beekwilder, Jules

    2014-10-15

    Sensitivity of biosensors depends on the orientation of bio-receptors on the sensor surface. The objective of this study was to organize bio-receptors on surfaces in a way that their analyte binding site is exposed to the analyte solution. VHH proteins recognizing foot-and-mouth disease virus (FMDV) were used for making biosensors, and azides were introduced in the VHH to function as bioorthogonal reactive groups. The importance of the orientation of bio-receptors was addressed by comparing sensors with randomly oriented VHH (with multiple exposed azide groups) to sensors with uniformly oriented VHH (with only a single azide group). A surface plasmon resonance (SPR) chip exposing cyclooctyne was reacted to azide functionalized VHH domains, using click chemistry. Comparison between randomly and uniformly oriented bio-receptors showed up to 800-fold increase in biosensor sensitivity. This technique may increase the containment of infectious diseases such as FMDV as its strongly enhanced sensitivity may facilitate early diagnostics. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Voltammetric analysis of 5-(4-Azidophenyl)-2 '-deoxycytidine nucleoside and azidophenyl-labelled single- and double-stranded DNAs

    Czech Academy of Sciences Publication Activity Database

    Daňhel, Aleš; Trošanová, Zuzana; Balintová, Jana; Havran, Luděk; Hocek, Michal; Barek, J.; Fojta, Miroslav

    2016-01-01

    Roč. 215, OCT2016 (2016), s. 72-83 ISSN 0013-4686 R&D Projects: GA ČR GBP206/12/G151 Institutional support: RVO:68081707 ; RVO:61388963 Keywords : Aromatic Azide * Enzymatic Incorporation * Mercury Electrode Subject RIV: BO - Biophysics; CC - Organic Chemistry (UOCHB-X) Impact factor: 4.798, year: 2016

  18. Efficient Synthesis of 1-Sulfonyl-1,2,3-triazoles

    Science.gov (United States)

    Raushel, Jessica; Fokin, Valery V.

    2010-01-01

    An efficient room temperature method for the synthesis of 1-sulfonyl-1,2,3-triazoles from in situ generated copper(I) acetylides and sulfonyl azides is described. Copper(I) thiophene-2-carboxylate (CuTC) catalyst produces the title compounds under both non-basic anhydrous and aqueous conditions in good yields. PMID:20931987

  19. Technology Challenges in Solid Energetic Materials for Micro Propulsion Applications

    Science.gov (United States)

    2009-11-01

    pressure and low temperature. NAB is used with/without lead rhodanide/ potassium chlorate /nitrocellulose (RK) to aid in the ignition. The impulse thrust...NAB boron/ potassium nitrate PETN Pentaerythritol tetranitrate RK lead rhodanide/ potassium chlorate /nitrocellulose Zr zirconium ZPP zirconium... potassium nitrate (NAB) propellant was selected over HTPB/AP and glycidyle azide polymer (GAP), because of its ignition capability at atmospheric

  20. Synthesis, molecular docking and biological evaluation as HDAC inhibitors of cyclopeptide mimetics by a tandem three-component reaction and intramolecular [3+2] cycloaddition.

    Science.gov (United States)

    Pirali, Tracey; Faccio, Valeria; Mossetti, Riccardo; Grolla, Ambra A; Di Micco, Simone; Bifulco, Giuseppe; Genazzani, Armando A; Tron, Gian Cesare

    2010-02-01

    Novel macrocyclic peptide mimetics have been synthesized by exploiting a three-component reaction and an azide-alkyne [3 + 2] cycloaddition. The prepared compounds were screened as HDAC inhibitors allowing us to identify a new compound with promising biological activity. In order to rationalize the biological results, computational studies have also been performed.

  1. Functional Group Analysis.

    Science.gov (United States)

    Smith, Walter T., Jr.; Patterson, John M.

    1984-01-01

    Literature on analytical methods related to the functional groups of 17 chemical compounds is reviewed. These compounds include acids, acid azides, alcohols, aldehydes, ketones, amino acids, aromatic hydrocarbons, carbodiimides, carbohydrates, ethers, nitro compounds, nitrosamines, organometallic compounds, peroxides, phenols, silicon compounds,…

  2. Azobenzene Photoswitches for Staudinger-Bertozzi Ligation

    NARCIS (Netherlands)

    Szymanski, Wiktor; Wu, Bian; Poloni, Claudia; Janssen, Dick B.; Feringa, Ben L.

    2013-01-01

    A novel family of azobenzenes containing residues needed for aqueous Staudinger–Bertozzi ligation to azides was designed. The resulting photochromes show stable and reversible switching behavior in water, with a photostationary state (PSS) of up to 95:5 cis/trans. Applications in model systems

  3. Development and hazard assessment of nanoparticles

    NARCIS (Netherlands)

    Bhattacharjee, S.

    2012-01-01

    A series of highly monodisperse silicon nanoparticles (Si NP) with either
    positively (amine), neutral (azide) or negatively (carboxylic acid) charged
    covalently attached organic monolayers were synthesized and investigated for
    their cytotoxicity. Infrared data confirmed the

  4. Attractive Interactions between Heteroallenes and the Cucurbituril Portal.

    Science.gov (United States)

    Reany, Ofer; Li, Amanda; Yefet, Maayan; Gilson, Michael K; Keinan, Ehud

    2017-06-21

    In this paper, we report on the noteworthy attractive interaction between organic azides and the portal carbonyls of cucurbiturils. Five homologous bis-α,ω-azidoethylammonium alkanes were prepared, where the number of methylene groups between the ammonium groups ranges from 4 to 8. Their interactions with cucurbit[6]uril were studied by NMR spectroscopy, IR spectroscopy, X-ray crystallography, and computational methods. Remarkably, while the distance between the portal plane and most atoms at the guest end groups increases progressively with the molecular size, the β-nitrogen atoms maintain a constant distance from the portal plane in all homologues, pointing at a strong attractive interaction between the azide group and the portal. Both crystallography and NMR support a specific electrostatic interaction between the carbonyl and the azide β-nitrogen, which stabilizes the canonical resonance form with positive charge on the β-nitrogen and negative charge on the γ-nitrogen. Quantum computational analyses strongly support electrostatics, in the form of orthogonal dipole-dipole interaction, as the main driver for this attraction. The alternative mechanism of n → π* orbital delocalization does not seem to play a significant role in this interaction. The computational studies also indicate that the interaction is not limited to azides, but generalizes to other isoelectronic heteroallene functions, such as isocyanate and isothiocyanate. This essentially unexploited attractive interaction could be more broadly utilized as a tool not only in relation to cucurbituril chemistry, but also for the design of novel supramolecular architectures.

  5. Label-Free Detection of Glycan-Protein Interactions for Array Development by Surface-Enhanced Raman Spectroscopy (SERS)

    NARCIS (Netherlands)

    Li, Xiuru; Martin, Sharon J H; Chinoy, Zoeisha S; Liu, Lin; Rittgers, Brandon; Dluhy, Richard A; Boons, Geert-Jan

    2016-01-01

    A glyco-array platform has been developed, in which glycans are attached to plasmonic nanoparticles through strain-promoted azide-alkyne cycloaddition. Glycan-protein binding events can then be detected in a label-free manner employing surface-enhanced Raman spectroscopy (SERS). As proof of concept,

  6. An assessment of the physico-chemical parameters of Kontagora ...

    African Journals Online (AJOL)

    Dissolved oxygen by modified Winkler-azide method, water hardness by Lind method and Phosphate – phosphorus by Denges method, total alkalinity by titration method, total dissolved solid by O'wen method, while Nitrate-Nitrogen was determined using Phenoldisulphonic acid method. Water depth was determined using ...

  7. Synthetic LNA/DNA nano-scaffolds for highly efficient diagnostics of nucleic acids and autoimmune antibodies

    DEFF Research Database (Denmark)

    Astakhova, Irina Kira

    2014-01-01

    ) strands and a series of fluorescent azides. The multiply labeled fluorescent LNA/DNA probes prepared herein generally display high binding affinity to complementary DNA/RNA, high quantum yields and, hence, high fluorescence brightness values. With the novel fluorescent probes, specific sensing...

  8. Mutants induced in winter rye (Secale cereale L.): Short straw-mutant No. 2714 and late-senescence mutant

    Energy Technology Data Exchange (ETDEWEB)

    Muszynski, S; Darlewska, M [Department of Plant Breeding and Seed Science, Warsaw Agricultural University, Warsaw (Poland)

    1990-01-01

    Full text: Mutants were induced by treating dormant seeds with ionizing radiation (fast neutrons) or chemicals (N-nitroso-N-ethyl urea or sodium azide). Among several mutants obtained, of special value is the short-straw mutant No. 2714 and a late senescent mutant. (author)

  9. Safety in the Chemical Laboratory: Tested Disposal Methods for Chemical Wastes from Academic Laboratories.

    Science.gov (United States)

    Armour, M. A.; And Others

    1985-01-01

    Describes procedures for disposing of dichromate cleaning solution, picric acid, organic azides, oxalic acid, chemical spills, and hydroperoxides in ethers and alkenes. These methods have been tested under laboratory conditions and are specific for individual chemicals rather than for groups of chemicals. (JN)

  10. The influence of radiation on some quality characteristics of lentil (lens culinaris medic)

    International Nuclear Information System (INIS)

    Mohammed, M.K.

    1982-01-01

    The present investigation was designed designed to carry a comparative study on the effect of three mutagenic agents, gamma - rays doses, sodium azide concentration and their combined treatments on chlorophyll mutation frequency and spectrum in M 1 and on the magnitude of recovered variability in certain economic characters in M 2 generation of the two lentil genotypes (Giza-9 and NEL-277)

  11. Characterization and stability of D-amino acid oxidase and catalase ...

    African Journals Online (AJOL)

    ajl yemi

    2011-12-19

    Dec 19, 2011 ... cells was inhibited when treated with sodium azide (0.8 M, 30 min), while no visible effect on the activity and stability of DAAO ... enzyme's persistence against inactivation and facilitate ... components of culture media of this strain were described in a previous ... incubated at different temperature (4 or 30°C).

  12. INFRARED AND ULTRAVIOLET SPECTRA OF METHANE DILUTED IN SOLID NITROGEN AND IRRADIATED WITH ELECTRONS DURING DEPOSITION AT VARIOUS TEMPERATURES

    International Nuclear Information System (INIS)

    Chin, Chih-Hao; Chen, Sian-Cong; Liu, Meng-Chen; Huang, Tzu-Ping; Wu, Yu-Jong

    2016-01-01

    We recorded the infrared and ultraviolet absorption spectra of CH 4 :N 2 matrix samples that underwent electron bombardment during deposition in the temperature range of 10–44 K. In contrast to a previous experiment on the IR spectroscopy of electron-bombarded icy samples, methyl and azide radicals became the main products upon electron bombardment during deposition; furthermore, reduced production of nitrile species was observed for deposition at 10 and 20 K. On the other hand, for deposition above 33 K, the observed bands of the radical species (such as methyl and azide) decreased, and bands of large nitriles appeared. This observation may suggest that radical species easily diffuse and recombine to form more complex molecules in solid nitrogen at higher temperatures. Further measurements of similar samples at 10–33 K in the UV region revealed the intense band of azide radicals at 272.5 nm and weak, broad, overlapping features of methyl and azide radicals in the 225–197 nm region. For deposition at 44 K, only a broad feature centered at 219.4 nm was observed, and the possible carriers of nitrile species were proposed based on the corresponding IR spectrum and theoretical predictions of excitation energy. This band is similar to the observed absorption feature of Pluto’s surface recorded by the Hubble telescope in terms of both band position and bandwidth. Our findings therefore further support the suggestion that complex nitrile species may exist on the surface of Pluto.

  13. Reactivity of nitriles

    International Nuclear Information System (INIS)

    Kukushkin, Yu.N.

    1987-01-01

    Reactivity of coordination nitriles in transition metal (Ru, Mo, W, Zr, Hf) complexes, namely: transformation of nitriles of the first coordination sphere into N-acyl-substituted amides, amidines, nitrile interaction; with water, alkalines, alcoholes, hydrogen, azide and cyanide ions is considered. Introduction of acetonitrile molecule to uranium (4)-carbon double bond is discussed

  14. Exploring strain-promoted 1,3-dipolar cycloadditions of end functionalized polymers

    NARCIS (Netherlands)

    Ledin, Petr A; Kolishetti, Nagesh; Hudlikar, Manish S; Boons, Geert-Jan

    2014-01-01

    Strain-promoted 1,3-dipolar cycloaddition of cyclooctynes with 1,3-dipoles such as azides, nitrones, and nitrile oxides, are of interest for the functionalization of polymers. In this study, we have explored the use of a 4-dibenzocyclooctynol (DIBO)-containing chain transfer agent in reversible

  15. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    [3+2] cycloaddition reaction of various types of nitriles and sodium azide (NaN3) were studied in the presence of nano-sized Cu-MCM-41 as an efficient recoverable heterogeneous catalyst. Nano-sized Cu-MCM-41 mesoporous molecular sieves with various Si/Cu molar ratios were synthesized by direct insertion of metal ...

  16. Determination of carcinogenic polycyclic aromatic hydrocarbons in ...

    African Journals Online (AJOL)

    Determination of carcinogenic polycyclic aromatic hydrocarbons in air samples in Irbid, north Jordan. A Al-Gawadreh Sat, M.B. Gasim, A.R. Hassan, A Azid. Abstract. Air samples were collected at an urban site and a rural (BERQESH) site during February (2017) until March (2017) to determine concentrations of polycyclic ...

  17. Resonance – Journal of Science Education | Indian Academy of ...

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 6. Determination of Lifetimes of Carbocations in Aqueous Solution by Azide Clock: A Simple Physical-Organic Chemistry Experiment. V Jagannadham. Classroom Volume 12 Issue 6 June 2007 pp 76-82 ...

  18. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Uncatalyzed thermal gas phase aziridination of alkenes by organic azides. ..... fluorescence spectroscopic investigation of TMU/water binary mixtures ... and its application in solid phase extraction of heavy metals from environmental samples ...... Synthesis, crystal structure and characterization of new biologically active ...

  19. Enhanced reactivity of dinuclear Copper(I) acetylides in dipolar cycloadditions

    DEFF Research Database (Denmark)

    Ahlquist, Mårten Sten Gösta; Fokin, V.V.

    2007-01-01

    Dinuclear alkynyl copper(I) complexes exhibit superior reactivity toward organic azides compared to their monomeric analogues. DFT studies indicate that the second copper center facilitates the formation of the cupracycle in the rate-determining step and stabilizes the metallacycle intermediate i...

  20. Purification and identification of O-GlcNAc-modified peptides using phosphate-based alkyne CLICK chemistry in combination with titanium dioxide chromatography and mass spectrometry

    DEFF Research Database (Denmark)

    Parker, Benjamin L; Gupta, Pankaj; Cordwell, Stuart

    2011-01-01

    A selective method for the enrichment of O-GlcNAcylated peptides using a novel CLICK chemistry reagent is described. Peptides modified by O-GlcNAc were enzymatically labeled with N-azidoacetylgalactosamine. The azide was then reacted with a phospho-alkyne using CLICK chemistry and O-GlcNAcGalNAzPO4...

  1. Miktoarm core-crosslinked star copolymers with biologically active moieties on peripheries

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Hvilsted, Søren

    2010-01-01

    ) of epsilon-caprolactone (epsilon-CL) initiated by functional alcohols provides alkyne or azide end-capped linear PCL chains. Further derivatization of the hydroxyl chain ends of these hetero-telechelic macromolecules by methacrylic acid (MA), and subsequent Cu(I) mediated "click" coupling of terminal alkyne...

  2. The Development of a Versatile Trifunctional Scaffold for Biological Applications

    Czech Academy of Sciences Publication Activity Database

    Vaněk, Václav; Pícha, Jan; Fabre, Benjamin; Buděšínský, Miloš; Lepšík, Martin; Jiráček, Jiří

    2015-01-01

    Roč. 2015, č. 17 (2015), s. 3689-3701 ISSN 1434-193X R&D Projects: GA ČR GA14-17305S Institutional support: RVO:61388963 Keywords : solid-phase synthesis * protein mimics * click chemistry * alkynes * copper * azides Subject RIV: CC - Organic Chemistry Impact factor: 3.068, year: 2015

  3. research article

    African Journals Online (AJOL)

    NICO

    sized by well-defined copper-catalyzed azide-alkyne cyclization. (CuAAC) methods.8,9 Of relevance to this paper is that in recent years, the use of CuAAC and the incorporation of triazole into drug-like molecules with potential antimalarial activity have seen increasing popularity.10–14 In this publication, we have designed ...

  4. Regioselective iodoazidation of alkynes: synthesis of α,α-diazidoketones.

    Science.gov (United States)

    Okamoto, Noriko; Sueda, Takuya; Minami, Hideki; Miwa, Yoshihisa; Yanada, Reiko

    2015-03-06

    Aryl alkyl alkynes reacted with N-iodosuccinimide (NIS) and trimethylsilyl azide (TMSN3), leading to α,α-diazidoketones via the regioselective addition of IN3 to alkynes. Huisgen cyclization of α,α-diazidoketones generated bis-triazole compounds.

  5. Polysulfone Functionalized With Phosphonated Poly(pentafluorostyrene) Grafts for Potential Fuel Cell Applications

    DEFF Research Database (Denmark)

    Dimitrov, Ivaylo; Takamuku, Shogo; Jankova Atanasova, Katja

    2012-01-01

    A multi‐step synthetic strategy to polysulfone (PSU) grafted with phosphonated poly(pentafluorostyrene) (PFS) is developed. It involves controlled radical polymerization resulting in alkyne‐end functional PFS. The next step is the modification of PSU with a number of azide side groups. The grafting...

  6. Novel silicone compatible cross-linkers for controlled functionalization of PDMS networks

    DEFF Research Database (Denmark)

    Madsen, Frederikke Bahrt; Daugaard, Anders Egede; Hvilsted, Søren

    2013-01-01

    . In order to improve the dielectric properties of PDMS a novel system is developed where push-pull dipoles are grafted to a new silicone compatible cross-linker. The grafted cross-linkers are prepared by reaction of two different push-pull dipole alkynes as well as a fluorescent alkyne with the new azide...

  7. Stereo- and regio-selective one-pot synthesis of triazole-based unnatural amino acids and β- amino triazoles

    Science.gov (United States)

    Synthesis of triazole based unnatural amino acids and β-amino triazole has been described via stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW conditions. The developed method is applicable to a broad substrate scope a...

  8. A facile and regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles using click chemistry

    Science.gov (United States)

    The reaction of α-tosyloxy ketones, sodium azide and terminal alkynes in presence of copper(I) in aqueous polyethylene glycol afforded regioselectively 1,4-disubstituted 1,2,3-triazoles in good yield at ambient temperature. The one-pot exclusive formation of 1,4-disubstituted 1,2...

  9. BODIPY-Labeled DC-SIGN-Targeting Glycodendrons Efficiently Internalize and Route to Lysosomes in Human Dendritic Cells

    NARCIS (Netherlands)

    Ribeiro-Viana, R.; Garcia Vallejo, J.J.; Collado, D.; Perez-Inestrosa, E.; Bloem, K.; van Kooijk, Y.; Rojo, J.

    2012-01-01

    Glycodendrons bearing nine copies of mannoses or fucoses have been prepared by an efficient convergent strategy based on Cu(I) catalyzed azide-alkyne cycloaddition (CuAAC). These glycodendrons present a well-defined structure and have an adequate size and shape to interact efficiently with the

  10. Multicomponent analysis of fermentation growth media using the electronic tongue (ET)

    DEFF Research Database (Denmark)

    Legin, A.; Kirsanov, D.; Rudnitskaya, A.

    2004-01-01

    of simultaneous determination of ammonium, citrate and oxalate in complex media with good precision (typical error within 8%). The system preserved high sensitivity to the targeted substances also in the presence of sodium azide, which is commonly used for suppressing microbial activity in real-world fermentation...

  11. Regulating Prostate Cancer Sensitivity to Chemotherapy through Translational Control of CCAAT Enhancer Binding Proteins

    Science.gov (United States)

    2015-08-01

    were washed and incubated in permeabilization buffer (TBS, 2% BSA, 0.5% Triton-X 100, 0.1% sodium azide). After blocking, cells were incubated with...implications for establishment of early pregnancy . Cell cycle 2006; 5: 922–925. 15 Boruk M, Savory JG, Hache RJ. AF-2-dependent potentiation of CCAAT enhancer

  12. Equilibrium Reaction Of Human Methemoglobin A | Ogunmola | Ife ...

    African Journals Online (AJOL)

    A study has been carried out on the sulfhydryl group reactivities of human methemoglobin A and its azide complex with 2,2\\'-dithiobispyridine (2-DTP) in the presence and absence of inositol hexaphosphate (IHP) in order to evaluate electrostatic effects on reactivity and the relationship between conformational states and ...

  13. Efficient and highly enantioselective formation of the all-carbon quaternary stereocentre of lyngbyatoxin A

    DEFF Research Database (Denmark)

    Vital, Paulo J.V.; Tanner, David

    2006-01-01

    Indole 25, an advanced intermediate in a projected enantioselective total synthesis of lyngbyatoxin A 1, was prepared from allylic alcohol 11 in 9 steps and >95% ee, key transformations being the enantiospecific rearrangement of vinyl epoxide 14 and the Hemetsberger-Knittel reaction of azide 24....

  14. Syntese af amino/hydroxypyrrolidines og -piperidiner fra kulhydratderivater

    DEFF Research Database (Denmark)

    Godskesen, Michael Anders

    by methyliodide. The 5-Bromo functionality was then substituted by azid, which was hydrogenated in presence of palladium on carbon. The amino-lactones rearranged to the corresponding lactams, that could be reduced to 1,2,5-trideoxy-1,5-imino-2-C-methyl-D-arabinitol, hydrotosylate and 1,2,5-trideoxy-1,5-imino-2-C...

  15. Synthesis of Dopamine and Serotonin Derivatives for Immobilization on a Solid Support

    DEFF Research Database (Denmark)

    Funder, Erik Daa; Jensen, Anne Bjørnskov; Tørring, Thomas

    2012-01-01

    rearrangement from the allylated phenol moiety of serotonin. The tethers are azide-functionalized, which enables coupling to alkyne-modified magnetic beads. The coupling to the magnetic beads is quantified by UV spectroscopy using Fmoc-monitoring of the immobilized dopamine and serotonin derivatives....

  16. Undergraduate Organic Experiment: Tetrazole Formation by Microwave Heated (3 + 2) Cycloaddition in Aqueous Solution

    Science.gov (United States)

    DeFrancesco, Heather; Dudley, Joshua; Coca, Adiel

    2018-01-01

    An undergraduate experiment for the organic laboratory is described that utilizes microwave heating to prepare 5- substituted 1H-tetrazole derivatives through a (3 + 2) cycloaddition between aryl nitriles and sodium azide. The reaction mixture is analyzed by thin layer chromatography. The products are purified through an acid-base extraction and…

  17. One-pot Microwave-Assisted Synthesis of 1H-Phenanthro[9,10- d][1,2,3]triazole

    Directory of Open Access Journals (Sweden)

    Mehrak Faraji

    2008-09-01

    Full Text Available In this study, a fast and good yield one-pot microwave-assisted synthesis (45 seconds of 1H-phenanthro[9,10-d][1,2,3]triazole by a 1,3-dipolar cycloaddition reaction of sodium azide and 9-bromophenanthrene in the presence of potassium tert-butoxide in DMSO as solvent is reported.

  18. Fulltext PDF

    Indian Academy of Sciences (India)

    Simple Trigonometric Identities and Basic Calculus Lead- ing to Interesting Series. R Govindaraj. Can you see Air? Andal Narayanan, Joseph Samuel and Supurna Sinha. Determination of Lifetimes of Carbocations in Aqueous. Solution by Azide Clock: A Simple Physical-Organic Chem- istry Experiment. V Jagannadham.

  19. Catalase inhibition in the Arcuate nucleus blocks ethanol effects on the locomotor activity of rats.

    Science.gov (United States)

    Sanchis-Segura, Carles; Correa, Mercé; Miquel, Marta; Aragon, Carlos M G

    2005-03-07

    Previous studies have demonstrated that there is a bidirectional modulation of ethanol-induced locomotion produced by drugs that regulate brain catalase activity. In the present study we have assessed the effect in rats of intraperitoneal, intraventricular or intracraneal administration of the catalase inhibitor sodium azide in the locomotor changes observed after ethanol (1 g/kg) administration. Our results show that sodium azide prevents the effects of ethanol in rats locomotion not only when sodium azide was systemically administered but also when it was intraventricularly injected, then confirming that the interaction between catalase and ethanol takes place in Central Nervous System (CNS). Even more interestingly, the same results were observed when sodium azide administration was restricted to the hypothalamic Arcuate nucleus (ARC), a brain region which has one of the highest levels of expression of catalase. Therefore, the results of the present study not only confirm a role for brain catalase in the mediation of ethanol-induced locomotor changes in rodents but also point to the ARC as a major neuroanatomical location for this interaction. These results are in agreement with our reports showing that ethanol-induced locomotor changes are clearly dependent of the ARC integrity and, especially of the POMc-synthesising neurons of this nucleus. According to these data we propose a model in which ethanol oxidation via catalase could produce acetaldehyde into the ARC and to promote a release of beta-endorphins that would activate opioid receptors to produce locomotion and other ethanol-induced neurobehavioural changes.

  20. Oxidative Hemolysis of Erythrocytes

    Science.gov (United States)

    Wlodek, Lidia; Kusior, Dorota

    2006-01-01

    This exercise for students will allow them to simultaneously observe lipid peroxidation and consequent hemolysis of rat erythrocytes and the effect of sodium azide, a catalase inhibitor, on these processes. It will also demonstrate a protective action of antioxidants, the therapeutically used N-acetylcysteine and albumins present in plasma.

  1. Click synthesis of 1,4-disubstituted-1,2,3-triazoles catalysed by CuO ...

    Indian Academy of Sciences (India)

    Click synthesis of 1,4-disubstituted-1,2,3-triazoles catalysed by. CuO–CeO2 nanocomposite in the presence of amberlite-supported azide. JALAL ALBADIa,∗, JAFAR ABBASI SHIRANb and AZAM MANSOURNEZHADc. aBehbahan Khatam Alanbia University of Technology, Behbahan 6361647189, Iran. bFaculty of Science ...

  2. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Abstract. A CuO-CeO2 nanocomposite in the presence of amberlite-supported azide has been used for the click synthesis of 1,4-disubstituted-1,2,3-triazoles in good yields. This catalyst can be reused several times without any significant decrease in the catalytic activity.

  3. Synthesis of unnatural amino acids via microwave-assisted regio-selective one-pot multi-component reactions of sulfamidates

    Science.gov (United States)

    Synthesis of triazole-based unnatural amino acids, triazole bisaminoacids and β-amino triazole has been described via stereo and regioselective one-pot multi-component reaction of sulfamidates, sodium azide, and alkynes under MW irradiation conditions. The developed method is app...

  4. Induced mutation for disease resistance in rice with special reference to blast, bacterial blight and tungro

    International Nuclear Information System (INIS)

    Mathur, S.C.

    1983-01-01

    Rice varieties Ratna, Pusa 2-21, Vijaya and Pankaj have been treated with gamma rays, EMS or sodium azide to improve their resistance against blast, bacterial leaf blight or tungro virus. For blast and tungro, mutants with improved resistance were selected. Variation in reaction to bacterial leaf blight has been used in crossbreeding to accumulate genes for resistance. (author)

  5. Metal concentration at surface water using multivariate analysis and ...

    African Journals Online (AJOL)

    Metal concentration at surface water using multivariate analysis and human health risk assessment. F Azaman, H Juahir, K Yunus, A Azid, S.I. Khalit, A.D. Mustafa, M.A. Amran, C.N.C. Hasnam, M.Z.A.Z. Abidin, M.A.M. Yusri ...

  6. Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes

    KAUST Repository

    Chinnusamy, Tamilselvi R.; Rodionov, Valentin; Kü hn, Fritz; Reiser, Oliver

    2012-01-01

    The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H 39FeN 7O) was found to be an efficient

  7. AN ENZYME LINKED IMMUNOSORBENT ASSAY (ELISA) METHOD FOR THE URINARY BIOMONITORING OF 2,4-DICHLOROPHRENOCYACETIC ACID (2,4-D)

    Science.gov (United States)

    An enzyme-linked immunosorbent assay (ELISA) method was developed to quantitatively measure 2,4-dichlorophenoyacetic acid (2,4-D) in human urine. Samples were diluted (1:5) with phosphate-buffered saline, 0.05% Tween 20, with 0.02% sodium azide, and analyzed by a 96-microwekk pl...

  8. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    In this work, a green and efficient methodology has been developed for the synthesis of 1,2,3-triazoles by 'copper nanoparticles supported on nanocellulose (CuNPs/NC)-catalyzed azide-alkyne cycloaddition reaction in glycerol, an environmentally benign solvent, with excellent yields. The present catalyst wascharacterized ...

  9. Bio-Conjugates for Nanoscale Applications

    DEFF Research Database (Denmark)

    Villadsen, Klaus

    Bio-conjugates for Nanoscale Applications is the title of this thesis, which covers three different projects in chemical bio-conjugation research, namely synthesis and applications of: Lipidated fluorescent peptides, carbohydrate oxime-azide linkers and N-aryl O-R2 oxyamine derivatives. Lipidated...

  10. Direct electrochemical imidation of aliphatic amines via anodic oxidation.

    Science.gov (United States)

    Zhang, Li; Su, Ji-Hu; Wang, Sujing; Wan, Changfeng; Zha, Zhenggen; Du, Jiangfeng; Wang, Zhiyong

    2011-05-21

    Direct electrochemical synthesis of sulfonyl amidines from aliphatic amines and sulfonyl azides was realized with good to excellent yields. Traditional tertiary amine substrates were broadened to secondary and primary amines. The reaction intermediates were observed and a reaction mechanism was proposed and discussed. © The Royal Society of Chemistry 2011

  11. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences. R H DUNCAN LYNGDOH. Articles written in Journal of Chemical Sciences. Volume 128 Issue 5 May 2016 pp 681-693 Regular Articles. Uncatalyzed thermal gas phase aziridination of alkenes by organic azides. Part I: Mechanisms with discrete nitrene species · S PREMILA ...

  12. Sequential Multicomponent Strategy for the Diastereoselective Synthesis of Densely Functionalized Spirooxindole-Fused Thiazolidines

    NARCIS (Netherlands)

    Rainoldi, Giulia; Begnini, Fabio; De Munnik, Mariska; Lo Presti, Leonardo; Vande Velde, Christophe M.L.; Orru, Romano; Lesma, Giordano; Ruijter, Eelco; Silvani, Alessandra

    2018-01-01

    We developed two Ugi-type three-component reactions of spirooxindole-fused 3-thiazolines, isocyanides, and either carboxylic acids or trimethylsilyl azide, to give highly functionalized spirooxindole-fused thiazolidines. Two diverse libraries were generated using practical and robust procedures

  13. Sulfonamide bearing oligonucleotides: Simple synthesis and efficient RNA recognition

    DEFF Research Database (Denmark)

    Kumar, P.; Chandak, N.; Nielsen, P.

    2012-01-01

    Four pyrimidine nucleosides wherein a benzensulfonamide group is linked to the C-5 position of the uracil nucleobase through a triazolyl or an alkynyl linker were prepared by Cu(I)-assisted azide-alkyne cycloadditions (CuAAC) or Sonogashira reactions, respectively, and incorporated into oligonucl...

  14. Conductive Polymer Functionalization by Click Chemistry

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hvilsted, Søren; Hansen, Thomas Steen

    2008-01-01

    Click chemistry is used to obtain new conductive polymer films based on poly(3,4-ethylenedioxythiophene) (PEDOT) from a new azide functional monomer. Postpolymerization, 1,3-dipolar cycloadditions in DMF, using a catalyst system of CUS04 and sodium ascorbate, and different alkynes are performed...

  15. Microwave assisted click chemistry on a conductive polymer film

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hansen, Thomas S.; Larsen, Niels Bent

    2011-01-01

    Microwave (MW) irradiation has been used to accelerate the functionalization of an azide functional poly(3,4-ethylenedioxythiophene) film by click chemistry. The absorption of MW energy by the conductive polymer has been exploited for localized activation of the reaction on the polymer surface...

  16. Functional Materials by Click Chemistry

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede

    Dette ph.d.-projekt har fokuseret på fremstilling af nye funktionelle materialer ud fra konceptet bag ”Click” kemi. Her er specielt den selektive 1,3-dipolare cykloaddition imellem azider og alkyner under kobber katalyse anvendt til kobling af funktionelle grupper til polymerer. I projektet er de...

  17. Ruthenium complexes of chelating amido-functionalized N ...

    Indian Academy of Sciences (India)

    tric transfer hydrogenation reactions,5 metathesis,6 olefin epoxidation reactions,7 hydroformylation reac- tions,8 electrooxidation reactions,9 facial cycloaddition of azides with terminal alkynes regioselectively10 etc. to name a few. The phenomenal success of the N-heterocyclic car- benes in homogeneous catalysis, has ...

  18. Synthesis of azido derivatives of mucobromic acid | D. Jumbam ...

    African Journals Online (AJOL)

    Mucobromic acid is a highly reactive multicentered molecule. It was converted to its corresponding but unstable diazido derivative by reaction with two equivalents of sodium azide. The resultant 3,4-diazido-5-hydroxyfuran-2(5H)-one was obtained in moderate yield (42%) but decomposed readily even at low temperatures.

  19. Versatile Route to Synthesize Heterobifunctional Poly(ethylene glycol of Variable Functionality for Subsequent Pegylation

    Directory of Open Access Journals (Sweden)

    Redouan Mahou

    2012-02-01

    Full Text Available Pegylation using heterotelechelic poly(ethylene glycol (PEG offers many possibilities to create high-performance molecules and materials. A versatile route is proposed to synthesize heterobifunctional PEG containing diverse combinations of azide, amine, thioacetate, thiol, pyridyl disulfide, as well as activated hydroxyl end groups. Asymmetric activation of one hydroxyl end group enables the heterobifunctionalization while applying selective monotosylation of linear, symmetrical PEG as a key step. The azide function is introduced by reacting monotosyl PEG with sodium azide. A thiol end group is obtained by reaction with sodium hydrosulfide. The activation of the hydroxyl end group and subsequent reaction with potassium carbonate/thioacetic acid yields a thioacetate end group. The hydrolysis of the thioester end group by ammonia in presence of 2,2′-dipyridyl disulfide provides PEG pyridyl disulfide. Amine terminated PEG is prepared either by reduction of the azide or by nucleophilic substitution of mesylate terminated PEG using ammonia. In all cases, >95% functionalization of the PEG end groups is achieved. The PEG derivatives particularly support the development of materials for biomedical applications. For example, grafting up to 13% of the Na-alg monomer units with α-amine-ω-thiol PEG maintains the gelling capacity in presence of calcium ions but simultaneous, spontaneous disulfide bond formation reinforces the initial physical hydrogel.

  20. Synthesis of Electron-Rich Sterically Hindered P-1 Phosphazene Bases by the Staudinger Reaction

    Czech Academy of Sciences Publication Activity Database

    Alexandrova, Anastasia; Mašek, Tomáš; Polyakova, Svetlana; Císařová, I.; Saame, J.; Leito, I.; Lyapkalo, Ilya

    -, č. 9 (2013), s. 1811-1823 ISSN 1434-193X Institutional research plan: CEZ:AV0Z40550506 Keywords : phosphazenes * phosphazides * Staudinger reaction * azides * basicity * structure-activity relationships Subject RIV: CC - Organic Chemistry Impact factor: 3.154, year: 2013

  1. Synthesis and characterization of a Schiff base Cobalt (III) complex ...

    African Journals Online (AJOL)

    Schiff base molecule acts as tridentate ligand to form two five-membered chelate rings with the Co(III) ion. In the crystal structure three meridionally arranged nitrogen atoms from three azide ligands complete a distorted octahedral geometry around the metal center. The distortion from an ideal octahedron is evident from the ...

  2. Effect of gamma irradiation and chemical mutations on production and genetic behaviour of spathiphyllum wallisii regel in vitro

    International Nuclear Information System (INIS)

    EL-sharnouby, M.E.

    2005-01-01

    In vitro culture of Spathiphyllum wallisii using different types of nutrient media, different explants, growth regulators, different mutations treatments; gamma irradiation, colchicine and sodium azide, and SDS protein electrophoresis was investigated. The study was carried out during 2004 in tissue culture laboratory of natural products department, National Center for Radiation Research and Technology, Egypt. The obtained results showed that culturing shoot tip of Spathiphyllum wallisii on Murashige and Skoog medium (MS) was effective in enhancing establishment stage than Lavopivre or White media. Also, exposing plantlets to gamma irradiation at 0.5, 1, 2, 3 and 4 Krad induced the best results for mutation followed with sodium azide at concentrations 0.01, 0.05 and 0.1 g/l then colchicine at concentrations 0.01, 0.05 and 0.1 g/l after culturing on MS medium. Growing the explant of Spathiphyllum wallisii in MS medium supplemented with 1 mg/l BAP + 0.1 mg/l IBA gave the best development. Adding 3 mg/l BAP encouraged the highest proliferation, while 4 mg/l GA3 induced the best shoot elongation. Also, IBA at 1 mg/l caused the best rooting than naphthalene acetic acid. The most effective band was band number (6) with molecular weight 83Kda, which was present with sodium azide treatment at 0.01 while it was absent in all treatments and for this reason, this band considered a negative marker associated with sodium azide

  3. A general access to organogold(iii) complexes by oxidative addition of diazonium salts.

    Science.gov (United States)

    Huang, Long; Rominger, Frank; Rudolph, Matthias; Hashmi, A Stephen K

    2016-05-11

    At room temperature under mild photochemical conditions, namely irradiation with a simple blue light LED, gold(i) chloro complexes of both phosphane and carbene ligands in combination with aryldiazonium salts afford arylgold(iii) complexes. With chelating P,N-ligands cationic six- or five-membered chelate complexes were isolated in the form of salts with weakly coordinating counter anions that were brought in from the diazonium salt. With monodentate P ligands or N-heterocyclic carbene ligands and diazonium chlorides neutral arylgold(iii) dichloro complexes were obtained. The coordination geometry was determined by X-ray crystal structure analyses of representative compounds, a cis arrangement of the aryl and the phosphane ligand at the square planar gold(iii) center is observed.

  4. LIBRARY MANAGEMNT INFORMATION SYSTEM

    Directory of Open Access Journals (Sweden)

    Magnolia Tilca

    2013-06-01

    Full Text Available The focus of any educational institution is the content and services of the university library. The mission of the library is to obtain, organize, preserve and update the information with the greatest possible accuracy, minimum effort and time. This requires automation of the library’s operations. This paper presents a software application for managing the activity of the territorial "Vasile Goldiş" West University library. The application is developed using Visual Basic for Application programming language and using the database management system Microsoft Access 2010. The goal of this application is to optimize the inner workings of local library and to meet the requests of the institution and of the readers.

  5. Catalysis with Gold Complexes Immobilised on Carbon Nanotubes by π-π Stacking Interactions: Heterogeneous Catalysis versus the Boomerang Effect.

    Science.gov (United States)

    Vriamont, Charles; Devillers, Michel; Riant, Olivier; Hermans, Sophie

    2013-09-02

    A new pyrene-tagged gold(I) complex has been synthesised and tested as a homogeneous catalyst. First, a simple 1,6-enyne was chosen as a model substrate for cyclisation by using different solvents to optimise the reaction conditions. The non-covalent immobilisation of our pyrene-tagged gold complex onto multi-walled carbon nanotubes through π-π stacking interactions was then explored to obtain a supported homogeneous catalyst. The heterogenised catalyst and its homogeneous counterpart exhibited similar activity in a range of enyne cyclisation reactions. Bearing in mind that π-π interactions are affected by temperature and solvent polarity, the reuse and robustness of the supported homogeneous catalyst was tested to explore the scope and limitations of the recyclability of this catalyst. Under the optimised conditions, recyclability was observed by using the concept of the boomerang effect. Copyright © 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Die deuntjie draal': Op die spoor van Koos du Plessis

    Directory of Open Access Journals (Sweden)

    P. B. Boshoff

    1995-12-01

    Full Text Available 'The melody lingers on': On the trail of Koos du Plessis. The angst experienced by Du Plessis assumes the form of a problem on which he ponders in his poetry.The questions that he poses differ in form only from the bewilderment experienced by the narve. The poetic art of the singer and the faltering intimations of the despondent heart are two languages that express the same human anxiety. The truth of both languages lies therein that the one can develop into the other. This article listens from a Christian viewpoint. Themes that are dealt with are wandering, the goldy Other, past and future, anxiety, waiting, dreaming and temptation.

  7. Gold-Based Medicine: A Paradigm Shift in Anti-Cancer Therapy?

    Science.gov (United States)

    Yeo, Chien Ing; Ooi, Kah Kooi; Tiekink, Edward R T

    2018-06-11

    A new era of metal-based drugs started in the 1960s, heralded by the discovery of potent platinum-based complexes, commencing with cisplatin [(H₃N)₂PtCl₂], which are effective anti-cancer chemotherapeutic drugs. While clinical applications of gold-based drugs largely relate to the treatment of rheumatoid arthritis, attention has turned to the investigation of the efficacy of gold(I) and gold(III) compounds for anti-cancer applications. This review article provides an account of the latest research conducted during the last decade or so on the development of gold compounds and their potential activities against several cancers as well as a summary of possible mechanisms of action/biological targets. The promising activities and increasing knowledge of gold-based drug metabolism ensures that continued efforts will be made to develop gold-based anti-cancer agents.

  8. Alkyne hydroarylation with Au N-heterocyclic carbene catalysts

    Directory of Open Access Journals (Sweden)

    Cristina Tubaro

    2013-02-01

    Full Text Available Mono- and dinuclear gold complexes with N-heterocyclic carbene (NHC ligands have been employed as catalysts in the intermolecular hydroarylation of alkynes with simple unfunctionalised arenes. Both mono- and dinuclear gold(III complexes were able to catalyze the reaction; however, the best results were obtained with the mononuclear gold(I complex IPrAuCl. This complex, activated with one equivalent of silver tetrafluoroborate, exhibited under acidic conditions at room temperature much higher catalytic activity and selectivity compared to more commonly employed palladium(II catalysts. Moreover, the complex was active, albeit to a minor extent, even under neutral conditions, and exhibited lower activity but higher selectivity compared to the previously published complex AuCl(PPh3. Preliminary results on intramolecular hydroarylations using this catalytic system indicate, however, that alkyne hydration by traces of water may become a serious competing reaction.

  9. A General Ligand Design for Gold Catalysis allowing Ligand-Directed Anti Nucleophilic Attack of Alkynes

    Science.gov (United States)

    Wang, Yanzhao; Wang, Zhixun; Li, Yuxue; Wu, Gongde; Cao, Zheng; Zhang, Liming

    2014-01-01

    Most homogenous gold catalyses demand ≥0.5 mol % catalyst loading. Due to the high cost of gold, these reactions are unlikely to be applicable in medium or large scale applications. Here we disclose a novel ligand design based on the privileged biphenyl-2-phosphine framework that offers a potentially general approach to dramatically lowering catalyst loading. In this design, an amide group at the 3’ position of the ligand framework directs and promotes nucleophilic attack at the ligand gold complex-activated alkyne, which is unprecedented in homogeneous gold catalysis considering the spatial challenge of using ligand to reach antiapproaching nucleophile in a linear P-Au-alkyne centroid structure. With such a ligand, the gold(I) complex becomes highly efficient in catalyzing acid addition to alkynes, with a turnover number up to 99,000. Density functional theory calculations support the role of the amide moiety in directing the attack of carboxylic acid via hydrogen bonding. PMID:24704803

  10. Anticancer Gold N-Heterocyclic Carbene Complexes: A Comparative in vitro and ex vivo Study.

    Science.gov (United States)

    Estrada-Ortiz, Natalia; Guarra, Federica; de Graaf, Inge A M; Marchetti, Lorella; de Jager, Marina H; Groothuis, Geny M M; Gabbiani, Chiara; Casini, Angela

    2017-09-07

    A series of organometallic Au I N-heterocyclic carbene (NHC) complexes was synthesized and characterized for anticancer activity in four human cancer cell lines. The compounds' toxicity in healthy tissue was determined using precision-cut kidney slices (PCKS) as a tool to determine the potential selectivity of the gold complexes ex vivo. All evaluated compounds presented cytotoxic activity toward the cancer cells in the nano- or low micromolar range. The mixed Au I NHC complex, (tert-butylethynyl)-1,3-bis-(2,6-diisopropylphenyl)imidazol-2-ylidene gold(I), bearing an alkynyl moiety as ancillary ligand, showed high cytotoxicity in cancer cells in vitro, while being barely toxic in healthy rat kidney tissues. The obtained results open new perspectives toward the design of mixed NHC-alkynyl gold complexes for cancer therapy. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Mechanism of the Transmetalation of Organosilanes to Gold

    KAUST Repository

    Falivene, Laura

    2015-09-01

    Density functional theory (DFT) calculations were carried out to study the reaction mechanism of the first transmetalation of organosilanes to gold as a cheap fluoride-free process. The versatile gold(I) complex [Au(OH)(IPr)] permits very straightforward access to a series of aryl-, vinyl-, and alkylgold silanolates by reaction with the appropriate silane reagent. These silanolate compounds are key intermediates in a fluoride-free process that results in the net transmetalation of organosilanes to gold, rather than the classic activation of silanes as silicates using external fluoride sources. However, here we propose that the gold silanolate is not the active species (as proposed during experimental studies) but is, in fact, a resting state during the transmetalation process, as a concerted step is preferred.

  12. Mechanism of the Transmetalation of Organosilanes to Gold

    KAUST Repository

    Falivene, Laura; Nelson, David J.; Dupuy, Sté phanie; Nolan, Steven P.; Poater, Albert; Cavallo, Luigi

    2015-01-01

    Density functional theory (DFT) calculations were carried out to study the reaction mechanism of the first transmetalation of organosilanes to gold as a cheap fluoride-free process. The versatile gold(I) complex [Au(OH)(IPr)] permits very straightforward access to a series of aryl-, vinyl-, and alkylgold silanolates by reaction with the appropriate silane reagent. These silanolate compounds are key intermediates in a fluoride-free process that results in the net transmetalation of organosilanes to gold, rather than the classic activation of silanes as silicates using external fluoride sources. However, here we propose that the gold silanolate is not the active species (as proposed during experimental studies) but is, in fact, a resting state during the transmetalation process, as a concerted step is preferred.

  13. On some properties of ⊕-supplemented modules

    Directory of Open Access Journals (Sweden)

    A. Idelhadj

    2003-01-01

    Full Text Available A module M is ⊕-supplemented if every submodule of M has a supplement which is a direct summand of M. In this paper, we show that a quotient of a ⊕-supplemented module is not in general ⊕-supplemented. We prove that over a commutative ring R, every finitely generated ⊕-supplemented R-module M having dual Goldie dimension less than or equal to three is a direct sum of local modules. It is also shown that a ring R is semisimple if and only if the class of ⊕-supplemented R-modules coincides with the class of injective R-modules. The structure of ⊕-supplemented modules over a commutative principal ideal ring is completely determined.

  14. First report of scuticociliatosis caused by Uronema sp. in ornamental reef fish imported into Brazil

    Directory of Open Access Journals (Sweden)

    Pedro Henrique Magalhães Cardoso

    Full Text Available Abstract Scuticociliatosis, which is caused by an opportunistic ciliate protozoan, is responsible for significant economic losses in marine ornamental fish. This study reports the occurrence of Uronema sp., which was found to be parasitizing three species of marine reef fish imported into Brazil and maintained in quarantine: Vanderbilt’s Chromis (Chromis vanderbilti, blue-green damselfish (Chromis viridis, and sea goldie (Pseudanthias squamipinnis. During the quarantine period, some fish presented with behavioral disorders and hemorrhages and ulcerative lesions on the body surface. Histopathological analysis showed hemorrhages, inflammation comprising mononuclear and granular cells in the skeletal muscle, and necrosis of the skin and the secondary lamellae of the gills, and parasites were also observed in the renal capsule. The absence of transboundary measures available to prevent the occurrence of ornamental fish diseases is also discussed.

  15. Artificial Chemical Reporter Targeting Strategy Using Bioorthogonal Click Reaction for Improving Active-Targeting Efficiency of Tumor.

    Science.gov (United States)

    Yoon, Hong Yeol; Shin, Min Lee; Shim, Man Kyu; Lee, Sangmin; Na, Jin Hee; Koo, Heebeom; Lee, Hyukjin; Kim, Jong-Ho; Lee, Kuen Yong; Kim, Kwangmeyung; Kwon, Ick Chan

    2017-05-01

    Biological ligands such as aptamer, antibody, glucose, and peptide have been widely used to bind specific surface molecules or receptors in tumor cells or subcellular structures to improve tumor-targeting efficiency of nanoparticles. However, this active-targeting strategy has limitations for tumor targeting due to inter- and intraheterogeneity of tumors. In this study, we demonstrated an alternative active-targeting strategy using metabolic engineering and bioorthogonal click reaction to improve tumor-targeting efficiency of nanoparticles. We observed that azide-containing chemical reporters were successfully generated onto surface glycans of various tumor cells such as lung cancer (A549), brain cancer (U87), and breast cancer (BT-474, MDA-MB231, MCF-7) via metabolic engineering in vitro. In addition, we compared tumor targeting of artificial azide reporter with bicyclononyne (BCN)-conjugated glycol chitosan nanoparticles (BCN-CNPs) and integrin α v β 3 with cyclic RGD-conjugated CNPs (cRGD-CNPs) in vitro and in vivo. Fluorescence intensity of azide-reporter-targeted BCN-CNPs in tumor tissues was 1.6-fold higher and with a more uniform distribution compared to that of cRGD-CNPs. Moreover, even in the isolated heterogeneous U87 cells, BCN-CNPs could bind artificial azide reporters on tumor cells more uniformly (∼92.9%) compared to cRGD-CNPs. Therefore, the artificial azide-reporter-targeting strategy can be utilized for targeting heterogeneous tumor cells via bioorthogonal click reaction and may provide an alternative method of tumor targeting for further investigation in cancer therapy.

  16. Metabolic inhibitors as stimulating factors for citric acid production

    International Nuclear Information System (INIS)

    Adham, N.Z.; Ahmed, E.M.; Refai, H.A.E.

    2008-01-01

    The effect of some metabolic inhibitors on citric acid (CA) production by Aspergillus niger in cane molasses medium was investigated. Addition of 0.01-0.1 mM iodoacetic acid and sodium arsenate, 0.05-1.0 mM sodium malonate, 0.01 mM sodium azide, 0.01-0.05 mM sodium fluoride, 0.1-1.0 mM EDTA stimulated CA production (5-49%). Higher concentrations (10 mM) of iodoacetic acid, sodium malonate and 0.5 mM sodium azide caused a complete inhibition of fungal growth, Iodoacetic acid, sodium arsenate and sodium fluoride (0.2 mM) caused a remarkable inhibition of CA production. The implications of those preliminary functions was discussed. (author)

  17. Mutagenic strain improvement of aspergillus niger (MBL-1511) and optimization of cultural conditions for boosted lipolytic potential through submerged fermentation

    International Nuclear Information System (INIS)

    Sidra, A.; Aftikhar, T.

    2016-01-01

    In present study an isolated hyper producer of Aspergillus niger (MBL-1511) was treated for sodium azide mutagenesis. Results showed 147.27 % enhanced extracellular lipase activity after 150 minutes of sodium azide treatment. Wild and mutant hyper lipase producer strains were exploited to submerged fermentation (SmF). Brassica meal as an additive agro waste product to the basal medium was optimized. Experimental conditions optima were 10% inoculum size, 30 degree C temperature, 96 h rate of fermentation and pH 6 for maximum lipases production. Molasses and Ammonium nitrate were optimized as the best carbon and nitrogen sources (0.6% and 0.4%) w/v respectively and sunflower oil 1% (v/v) as better inducer. Finally, an effective mutant (MBL-1511SA-4(150 min)) having of 176.10% enhanced extracellular lipases production over wild (MBL-1511) strain was acquired. (author)

  18. Investigation of concept of efficient short wavelength laser. Quarterly progress report, 1 May 1978-31 July 1978

    Energy Technology Data Exchange (ETDEWEB)

    Piper, L.G.; Krech, R.H.; Pugh, E.R.; Kothandaraman, G.; Taylor, R.L.

    1978-08-01

    Emphasis on this program has shifted to the design and construction of two proof-of-concept laser device experiments based on azide chemistry. The laser concepts and the resulting experiments are briefly described in this quarterly report. Preliminary shake-down of the apparatus is now underway. In addition, measurements to provide critical kinetic and spectroscopic data in support of these laser-demonstration experiments have continued at a reduced level of effort. In particular, the solid azide pyrolysis experiment has been reactivated to obtain more quantitative data on branching ratios of certain critical processes. Finally, design and construction has begun on a system to provide 4.9 ..mu.. radiation to explore multiphoton dissociation of C1N/sub 3/ as an initiation technique.

  19. Investigation of concept of efficient short wavelength laser. Interim progress report, 1 April 1977-30 April 1978

    Energy Technology Data Exchange (ETDEWEB)

    Piper, L.G.; Krech, R.H.; Taylor, R.L.

    1978-05-01

    Under this program PSI is investigating the photolytic decomposition of a class of endoergic molecules - azides. Because these compounds contain substantial chemical energy, they offer a potentially more efficient approach for the production of electronically excited fragments. The goal of the present program was to acquire sufficient data and understanding of certain fundamental processes to permit the critical evaluation of this approach for laser development. An apparatus was built to study the wavelength-selected photolysis of gaseous, covalent azides. The photolysis source is a frequency doubled, tuneable dye laser. Detection of fragment species is accomplished by observation of primary fluorescence, or by laser-induced fluorescence (LIF) using a second tuneable dye laser. The design of the apparatus is discussed in detail.

  20. Aryl nitrene rearrangements: spectroscopic observation of a benzazirine and its ring expansion to a ketenimine by heavy-atom tunneling.

    Science.gov (United States)

    Inui, Hiroshi; Sawada, Kazuhiro; Oishi, Shigero; Ushida, Kiminori; McMahon, Robert J

    2013-07-17

    In the photodecompositions of 4-methoxyphenyl azide (1) and 4-methylthiophenyl azide (5) in argon matrixes at cryogenic temperatures, benzazirine intermediates were identified on the basis of IR spectra. As expected, the benzazirines photochemically rearranged to the corresponding ketenimines and triplet nitrenes. Interestingly, with the methylthio substituent, the rearrangement of benzazirine 8 to ketenimine 7 occurred at 1.49 × 10(-5) s(-1) even in the dark at 10 K, despite a computed activation barrier of 3.4 kcal mol(-1). Because this rate is 10(57) times higher than that calculated for passing over the barrier and because it shows no temperature dependence, the rearrangement mechanism is interpreted in terms of heavy-atom tunneling.

  1. Tricyanomethane and Its Ketenimine Tautomer: Generation from Different Precursors and Analysis in Solution, Argon Matrix, and as a Single Crystal.

    Science.gov (United States)

    Banert, Klaus; Chityala, Madhu; Hagedorn, Manfred; Beckers, Helmut; Stüker, Tony; Riedel, Sebastian; Rüffer, Tobias; Lang, Heinrich

    2017-08-01

    Solutions of azidomethylidenemalononitrile were photolyzed at low temperatures to produce the corresponding 2H-azirine and tricyanomethane, which were analyzed by low-temperature NMR spectroscopy. The latter product was also observed after short thermolysis of the azide precursor in solution whereas irradiation of the azide isolated in an argon matrix did not lead to tricyanomethane, but to unequivocal detection of the tautomeric ketenimine by IR spectroscopy for the first time. When the long-known "aquoethereal" greenish phase generated from potassium tricyanomethanide, dilute sulfuric acid, and diethyl ether was rapidly evaporated and sublimed, a mixture of hydronium tricyanomethanide and tricyanomethane was formed instead of the previously claimed ketenimine tautomer. Under special conditions of sublimation, single crystals of tricyanomethane could be isolated, which enabled the analysis of the molecular structure by X-ray diffraction. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Tunable Surface Properties of a Conductive PEDOT/EVAL blend

    DEFF Research Database (Denmark)

    Pizzi, Elisa; Martinelli, Andrea; D'Ilario, Lucio

    Conductive polymers have been studied extensively during recent years. Especially,poly(3,4-ethylenedioxythiophene) (PEDOT) have found many application areas and arebroadly considered one of the most promising conductive polymers. In order to broadenthe application field of PEDOT we have developed...... an azide functional poly(3,4-ethylenedioxythiophene) (PEDOT-N3)1. The azide functional conductive polymer canbe postpolymerization functionalized to introduce a large range of molecules onto theconductive backbone through click chemistry2.Here we present a study of the incorporation of poly......(ethylene-co-vinyl alcohol) (EVAL)into a copolymer of EDOT and EDOT-N3 (poly(EDOT-co-EDOT-N3)). Poly(ethyleneco-vinyl alcohol) (EVAL) is known to swell in polar solvents, which was exploited inthis study to permit a good blending of the two polymers. Since both polymers haveresidual functional groups the polymer blend...

  3. Vitamin B12 Phosphate Conjugation and Its Effect on Binding to the Human B12 -Binding Proteins Intrinsic Factor and Haptocorrin

    DEFF Research Database (Denmark)

    Ó Proinsias, Keith; Ociepa, Michał; Pluta, Katarzyna

    2016-01-01

    The binding of vitamin B12 derivatives to human B12 transporter proteins is strongly influenced by the type and site of modification of the cobalamin original structure. We have prepared the first cobalamin derivative modified at the phosphate moiety. The reaction conditions were fully optimized...... and its limitations examined. The resulting derivatives, particularly those bearing terminal alkyne and azide groups, were isolated and used in copper-catalyzed alkyne-azide cycloaddition reactions (CuAAC). Their sensitivity towards light revealed their potential as photocleavable molecules. The binding...... abilities of selected derivatives were examined and compared with cyanocobalamin. The interaction of the alkylated derivatives with haptocorrin was less affected than the interaction with intrinsic factor. Furthermore, the configuration of the phosphate moiety was irrelevant to the binding process....

  4. Effect of single and combined treatment with gamma rays and some chemical mutagens in rice

    International Nuclear Information System (INIS)

    Lyong Van Hin; Mekhandzhiev, A.; Murzova, P.; Chilikov, I.

    1991-01-01

    Dry rice seeds of 3 cvs and 2 lines have been irradiated (Co 60 , 10 krad) and treated with 0.0012% sodium azide (NaN 3 ) and 0.2% ethylmethanesulfonate (EMS) in definite combinations. It is found that chlorophyll mutations are less frequent after single gamma irradiation. Sodium azide produces a higher percentage of mutations than EMS. Highest mutation frequency has been observed following combined treatment with gamma rays and chemical mutagens. The combined treatment has resulted in a considerably higher mutation effect than the theoretically expected one in the lines Nora and Mega, and in cv. Krasnodarski 424. Highest mutation spectrum has been found in cv. Krasnodarski 424 and in Nora line following combined treatment. 1 tab., 5 figs., 20 refs

  5. Photoreactive polymer brushes for high-density patterned surface derivatization using a Diels-Alder photoclick reaction.

    Science.gov (United States)

    Arumugam, Selvanathan; Orski, Sara V; Locklin, Jason; Popik, Vladimir V

    2012-01-11

    Reactive polymer brushes grown on silicon oxide surfaces were derivatized with photoreactive 3-(hydroxymethyl)naphthalene-2-ol (NQMP) moieties. Upon 300 or 350 nm irradiation, NQMP efficiently produces o-naphthoquinone methide (oNQM), which in turn undergoes very rapid Diels-Alder addition to vinyl ether groups attached to a substrate, resulting in the covalent immobilization of the latter. Any unreacted oNQM groups rapidly add water to regenerate NQMP. High-resolution surface patterning is achieved by irradiating NQMP-derivatized surfaces using photolithographic methods. The Diels-Alder photoclick reaction is orthogonal to azide-alkyne click chemistry, enabling sequential photoclick/azide-click derivatizations to generate complex surface functionalities. © 2011 American Chemical Society

  6. Au-Cu core-shell nanocube-catalyzed click reactions for efficient synthesis of diverse triazoles.

    Science.gov (United States)

    Madasu, Mahesh; Hsia, Chi-Fu; Huang, Michael H

    2017-06-01

    Au-Cu core-shell nanocubes and octahedra synthesized in aqueous solution were employed to catalyze a 1,3-dipolar cycloaddition reaction between phenylacetylene and benzyl azide in water at 50 °C for 3 h. Interestingly, the nanocubes were far more efficient in catalyzing this reaction, giving 91% yield of a regioselective 1,4-triazole product, while octahedra only recorded 46% yield. The Au-Cu nanocubes were subsequently employed to catalyze the click reaction between benzyl azide and a broad range of aromatic and aliphatic alkynes. The product yields ranged from 78 to 99%. Clearly the Au-Cu cubes exposing {100} surfaces are an excellent and green catalyst for click reactions.

  7. Microwave-assisted synthesis of new pyrazole derivatives bearing 1,2,3-triazole scaffold as potential antimicrobial agents

    Directory of Open Access Journals (Sweden)

    Ashok Dongamanti

    2017-01-01

    Full Text Available A new series of (E-3-(3-(4-substituted phenyl-1-phenyl-1H-pyrazol- 4-yl-1-(2-hydroxy-4-((1-aryl-1H-1-2,3-triazol-4-ylmethoxyphenyl- prop-2-en-1-one derivatives was synthesized. The synthesis of the title compounds involved the 1,3-dipolar Cu(I-catalyzed alkyne–azide cycloaddition (CuAAC reaction of (E-3-(3-(4-substituted phenyl-1-phenyl-1H-pyrazol-4- -yl-1-(2-hydroxy-4-(prop-2-yn-1-yloxyphenylprop-2-en-1-ones with aromatic azides. The structures were confirmed by NMR, FT-IR, mass and elemental analysis. All the synthesized compounds (6a–j were evaluated for their antimicrobial activity. Compounds 6a, 6d and 6e demonstrated promising inhibitory effects on both bacterial and fungal strains.

  8. Generation of Oxygen Free Radicals by Proflavine: Implication in Protein Degradation

    Directory of Open Access Journals (Sweden)

    Mansour K.M. Gatasheh

    2017-07-01

    Full Text Available Proflavine, an acridine dye, is a known DNA intercalating agent. In the present study, we show that proflavine alone on photoillumination can generate reactive oxygen species (ROS. These proflavine-derived ROS cause damage to proteins, and this effect is enhanced when the divalent metal ion Cu (II is included in the reaction. Bathocuproine, a specific Cu (I sequestering agent, when present in the reaction mixture containing Cu (II, was found to inhibit the protein degradation, showing that Cu (I is an essential intermediate in the reaction. The effect of several scavengers of ROS such as superoxide dismutase, sodium azide, potassium iodide, and thiourea were examined on the protein damaging reaction. Potassium iodide was found to be the most effective in inhibiting protein damage followed by sodium azide and thiourea. Our results indicate the involvement of superoxide, singlet oxygen, triplet oxygen, and hydroxyl radicals in proflavine-induced damage to proteins.

  9. Strain-promoted copper free click chemistry for 64Cu radiolabeling of integrin-αvβ6 targeted peptide

    International Nuclear Information System (INIS)

    Satpati, Drishty; Bauer, Nadine; Hausner, Sven H.; Sutcliffe, Julie L.

    2014-01-01

    Strain promoted copper free click chemistry offers a fast and efficient method for preparation of radio labeled molecular probes and pre-targeted imaging in vivo. The fast reaction kinetics, driven by the release of strain energy ranging from 10-19 kcal/mol for cyclooctynes, precludes the need for toxic copper catalyst for chemical ligation between alkynes and azides. In particular this catalyst free approach provides a favorable platform for synthesis of radiometalated probes requiring macrocycle chelates for formation of stable and kinetically inert complexes where Cu(I) can interfere with metal chelates. In present studies DOTA-ADIBO (azadibenzocyclooctyne amine), a strained chelate-alkyne system has been constructed for bioconjugation with the azide-modified PEGylated peptide, N 3 -Ala-PEG 28 -A20FMDV2 and radiolabeled with ( 64 Cu) Cu for assessment as a integrin-α v β 6 , targeting molecular probe

  10. FRET-mediated pH-responsive dual fluorescent nanoparticles prepared via click chemistry

    Science.gov (United States)

    Ouadahi, Karima; Sbargoud, Kamal; Allard, Emmanuel; Larpent, Chantal

    2012-01-01

    Herein, we report an easy preparation of azide-coated polystyrene-based nanoparticles (15 nm in diameter) and their surface functionalization via CuAAC with fluorophores in water. Resultant dual fluorescent nanoparticles coated with dansyl and pH-sensitive fluorescein moieties as the donor/acceptor FRET pair show a ratiometric response to pH upon excitation at a single wavelength.Herein, we report an easy preparation of azide-coated polystyrene-based nanoparticles (15 nm in diameter) and their surface functionalization via CuAAC with fluorophores in water. Resultant dual fluorescent nanoparticles coated with dansyl and pH-sensitive fluorescein moieties as the donor/acceptor FRET pair show a ratiometric response to pH upon excitation at a single wavelength. Electronic supplementary information (ESI) available: Experimental details and figures S1-S16 as mentioned in the text. See DOI: 10.1039/c2nr11413e

  11. Gadolinium(III-DOTA Complex Functionalized with BODIPY as a Potential Bimodal Contrast Agent for MRI and Optical Imaging

    Directory of Open Access Journals (Sweden)

    Matthias Ceulemans

    2015-11-01

    Full Text Available The synthesis and characterization of a novel gadolinium(III DOTA complex functionalized with a boron-dipyrromethene derivative (BODIPY is described. The assembly of the complex relies on azide diazotransfer chemistry in a copper tube flow reactor. The azide thus formed is coupled directly with an alkyne via click chemistry, resulting into a paramagnetic and luminescent gadolinium(III complex. Luminescent data and relaxometric properties of the complex have been evaluated, suggesting the potential applicability of the complexes as a bimodal contrast agent for magnetic resonance and optical imaging. The complex displays a bright emission at 523 nm with an absorption maximum of 507 nm and high quantum yields of up to 83% in water. The proton relaxivity of the complex measured at 310 K and at frequencies of 20 and 60 MHz had the values of 3.9 and 3.6 s−1·mM−1, respectively.

  12. Kinetically inert lanthanide complexes as reporter groups for binding of potassium by 18-crown-6

    DEFF Research Database (Denmark)

    Junker, Anne Kathrine Ravnsborg; Tropiano, Manuel; Faulkner, Stephen

    2016-01-01

    in a copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) “click” reaction with azide-functionalized crown ethers. The resulting complexes were investigated using NMR and optical methods. Titrations with potassium chloride in methanol observing the sensititzed europium- and terbium-centered emissions were......-centered emission to report on the binding of potassium in an 18-crown-6 binding pocket. The responsive systems were made by linking a crown ether to a kinetically inert lanthanide binding pocket using a molecular building block approach. Specifically, an alkyne-appended Ln.DO3A was used as a building block...... used to investigate the response of the systems. The molecular reporters based on aliphatic crown ethers were found to have strongly inhibited binding of potassium, while the benzo-18-crown-6 derived systems had essentially the same association constants as the native crown ethers. The shape...

  13. {sup 68}Ga labelling strategies for nanodimensional and polymeric systems for the positron-emission topmography; {sup 68}Ga-Markierungsstrategien fuer nanodimensionale und polymere Systeme fuer die Positronen-Emissions-Tomographie

    Energy Technology Data Exchange (ETDEWEB)

    Stockhofe, Katharina

    2016-10-15

    Positron Emission Tomography (PET) is a non-invasive imaging technique that depicts metabolic processes in the body. With PET it becomes possible to get detailed information about the pharmacokinetics of polymeric and nanodimensional drug delivery systems, in a very elegant way. Therefore, it is absolutely necessary to have a reliable and robust technique to introduce the radioactive nuclide. In the presented work the positron emitting {sup 68}Ga was attached to homopolymers, various inorganic nanoparticles and core-crosslinked polymermicelles via different strategies. One of the used techniques was stain promoted alkyne azide cycloaddition (SPAAC), for which the presence of a strained alkyne and an azide is required. The conditions for this reactions are very mild. To have suitable chelating agents for ligation via SPAAC, the chelators DOTA, NODA-GA and DATA were functionalized with either an azide or a strained cycloalkyne. The derivatized chelators were radiolabeled with {sup 68}Ga, {sup 44}Sc and {sup 177}Lu and showed excellent complexation of the respective metal ions. The azide-functionalized chelators showed very good stabilities after complexation of the metal ions, in contrast to the Dibenzylcyclooctyne (DBCO)-derivatized ones. The reason lies here in the lipophilic character of the DBCO, as well as in sterical hindrances. Polysarcosine homopolymers carrying either an azide or a DBCO as one of their terminal groups were radiolabeled via SPAAC with the chelators described above. The focus was to investigate the radiochemical yields after and before the clickreaction with the particular chelator has taken place. Those reactions are called ''direct'' and ''indirect'' radiolabeling. Due to the very mild conditions the indirect strategy is a good and elegant alternative to the direct one. NODA-GA-TEG-azide and DOTA-TEG-azide both showed very good results for the direct and the indirect radiolabeling strategy. Polymer

  14. Concise and diversity-oriented synthesis of ligand arm-functionalized azoamides.

    Science.gov (United States)

    Urankar, Damijana; Kosmrlj, Janez

    2008-01-01

    Azoamides, previously established as bioactive intracellular GSH-depleting agents, were decorated with a terminal alkyne moiety to 4 and then were transformed, by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC), into different ligand-arm functionalized azoamides 6. Azides 5 having ligand-arms amenable for binding to platinum(II) were selected for this study. Because, for the fragile azoamides 4, the typically employed reaction conditions for CuAAC failed, several alternative solvents and copper catalysts were tested. Excellent results were obtained with copper(II) sulfate pentahydrate/metallic copper and especially with heterogeneous catalysts, such as copper-in-charcoal, cupric oxide, and cuprous oxide. The heterogeneous catalysts were employed to obtain the desired products in almost quantitative yields by a simple three-step "stir-filter-evaporate" protocol with no or negligible contamination with copper impurities. This is of particular importance because compounds 6 have been designed for coordination.

  15. Synthesis of C-glycosyl-bis-1,2,3-triazole derivatives from 3,4,6-tri-O-acetyl-D-glucal.

    Science.gov (United States)

    Shamim, Anwar; Souza, Frederico B; Trossini, Gustavo H G; Gatti, Fernando M; Stefani, Hélio A

    2015-08-01

    We have developed an efficient, CuI-catalyzed, microwave-assisted method for the synthesis of bis-1,2,3-triazole derivatives starting from a 3,4,6-tri-O-acetyl-D-glucal-derived mesylate. This mesylate was obtained from 3,4,6-tri-O-acetyl-D-glucal through C-glycosidation, deprotection of acetate groups to alcohols, and selective mesylation of the primary alcohol. This mesylate moiety was then converted to an azide through a microwave-assisted method with good yield. The azide, once synthesized, was then treated with different terminal alkynes in the presence of CuI to synthesize various bis-triazoles in high yields and short reaction times.

  16. General method for labeling siRNA by click chemistry with fluorine-18 for the purpose of PET imaging.

    Science.gov (United States)

    Mercier, Frédéric; Paris, Jérôme; Kaisin, Geoffroy; Thonon, David; Flagothier, Jessica; Teller, Nathalie; Lemaire, Christian; Luxen, André

    2011-01-19

    The alkyne-azide Cu(I)-catalyzed Huisgen cycloaddition, a click-type reaction, was used to label a double-stranded oligonucleotide (siRNA) with fluorine-18. An alkyne solid support CPG for the preparation of monostranded oligonucleotides functionalized with alkyne has been developed. Two complementary azide labeling agents (1-(azidomethyl)-4-[(18)F]fluorobenzene) and 1-azido-4-(3-[(18)F]fluoropropoxy)benzene have been produced with 41% and 35% radiochemical yields (decay-corrected), respectively. After annealing with the complementary strand, the siRNA was directly labeled by click chemistry with [(18)F]fluoroazide to produce the [(18)F]-radiolabeled siRNA with excellent radiochemical yield and purity.

  17. Click-to-Chelate: Development of Technetium and Rhenium-Tricarbonyl Labeled Radiopharmaceuticals

    Directory of Open Access Journals (Sweden)

    Thomas L. Mindt

    2013-03-01

    Full Text Available The Click-to-Chelate approach is a highly efficient strategy for the radiolabeling of molecules of medicinal interest with technetium and rhenium-tricarbonyl cores. Reaction of azide-functionalized molecules with alkyne prochelators by the Cu(I-catalyzed azide-alkyne cycloaddition (CuAAC; click reaction enables the simultaneous synthesis and conjugation of tridentate chelating systems for the stable complexation of the radiometals. In many cases, the functionalization of (biomolecules with the ligand system and radiolabeling can be achieved by convenient one-pot procedures. Since its first report in 2006, Click-to-Chelate has been applied to the development of numerous novel radiotracers with promising potential for translation into the clinic. This review summarizes the use of the Click-to-Chelate approach in radiopharmaceutical sciences and provides a perspective for future applications.

  18. Integrating Protein Engineering and Bioorthogonal Click Conjugation for Extracellular Vesicle Modulation and Intracellular Delivery.

    Directory of Open Access Journals (Sweden)

    Ming Wang

    Full Text Available Exosomes are small, cell-secreted vesicles that transfer proteins and genetic information between cells. This intercellular transmission regulates many physiological and pathological processes. Therefore, exosomes have emerged as novel biomarkers for disease diagnosis and as nanocarriers for drug delivery. Here, we report an easy-to-adapt and highly versatile methodology to modulate exosome composition and conjugate exosomes for intracellular delivery. Our strategy combines the metabolic labeling of newly synthesized proteins or glycan/glycoproteins of exosome-secreting cells with active azides and bioorthogonal click conjugation to modify and functionalize the exosomes. The azide-integrated can be conjugated to a variety of small molecules and proteins and can efficiently deliver conjugates into cells. The metabolic engineering of exosomes diversifies the chemistry of exosomes and expands the functions that can be introduced into exosomes, providing novel, powerful tools to study the roles of exosomes in biology and expand the biomedical potential of exosomes.

  19. A Platform for Functional Conductive Polymers

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hoffmann, Christian; Lind, Johan Ulrik

    Conductive polymers have been studied extensively during recent years. In order to broaden the application field of conductive polymers different methods have been tested and recently an azide functional poly(3,4-ethylenedioxythiophene) (PEDOT-N3) was developed(1, 2). The azide functional...... conductive polymer can be postpolymerization functionalized to introduce a large number of functionalities through click chemistry(3). Through selection of reaction conditions it is possible control the depth of the reaction into the polymer film to the upper surface or the entire film(4). Thus a conductive...... polymer can be prepared with a subsurface layer of highly conductive polymer where only the upper surface has been grafted with functional groups to ensure selectivity of the surface layer for e.g. interaction with specific biospecies. The conductive polymer can be patterned using selective etching, which...

  20. Rapid Analysis of Protein Farnesyltransferase Substrate Specificity Using Peptide Libraries and Isoprenoid Diphosphate Analogues

    OpenAIRE

    Wang, Yen-Chih; Dozier, Jonathan K.; Beese, Lorena S.; Distefano, Mark D.

    2014-01-01

    Protein farnesytransferase (PFTase) catalyzes the farnesylation of proteins with a carboxy-terminal tetrapeptide sequence denoted as a Ca1a2X box. To explore the specificity of this enzyme, an important therapeutic target, solid-phase peptide synthesis in concert with a peptide inversion strategy was used to prepare two libraries, each containing 380 peptides. The libraries were screened using an alkyne-containing isoprenoid analogue followed by click chemistry with biotin azide and subsequen...