40 CFR 721.1630 - 1,2-Ethanediol bis(4-methylbenzenesulfonate); 2,2-oxybis-ethane bis(4-methylbenzenesulfonate...

Science.gov (United States)

2010-07-01

...-methylbenzenesulfonate); 2,2-oxybis-ethane bis(4-methylbenzenesulfonate); ethanol, 2,2â²-[oxybis(2,1-ethanediyl oxy)]bis-, bis(4-methylbenzenesulfonate); ethanol, 2,2â²-[oxybis (2,1-ethane diyloxy)] bis-, bis(4...); 2,2-oxybis-ethane bis(4-methylbenzenesulfonate); ethanol, 2,2′-[oxybis(2,1-ethanediyl oxy)]bis-, bis...

Antiferromagnetic exchange in meta-phenylene bridged bis(tris-o-iminosemiquinonato)metal complexes

International Nuclear Information System (INIS)

Dei, A.; Gatteschi, D.; Sangregorio, C.; Sorace, L.; Vaz, M.G.F.

2004-01-01

By reaction of the ligand N,N' bis(3,5-di-tert-butyl-2-hydroxyphenyl)-1,3-phenylenediamine (1), with Fe, Co or Mn salts, three complexes were synthesized where the bis-bidentate ligand is in the bis-semiquinonato oxidation state. Although the m-phenylene linker is known to afford ferromagnetic coupling in diradicals, the antiferromagnetic interaction of intramolecular origin we observed is not unexpected, given the large torsion angles between the semiquinonato and the m-phenylene planes

Antiferromagnetic exchange in meta-phenylene bridged bis(tris-o-iminosemiquinonato)metal complexes

Energy Technology Data Exchange (ETDEWEB)

Dei, A. E-mail: andrea.dei@unifi.it; Gatteschi, D.; Sangregorio, C.; Sorace, L.; Vaz, M.G.F

2004-05-01

By reaction of the ligand N,N' bis(3,5-di-tert-butyl-2-hydroxyphenyl)-1,3-phenylenediamine (1), with Fe, Co or Mn salts, three complexes were synthesized where the bis-bidentate ligand is in the bis-semiquinonato oxidation state. Although the m-phenylene linker is known to afford ferromagnetic coupling in diradicals, the antiferromagnetic interaction of intramolecular origin we observed is not unexpected, given the large torsion angles between the semiquinonato and the m-phenylene planes.

Di-μ-iodido-bis{[(R-(+-2,2′-bis(diphenylphosphanyl-1,1′-binaphthyl-κ2P,P′]copper(I} 0.67-hydrate

Directory of Open Access Journals (Sweden)

Daniel Volz

2012-04-01

Full Text Available The structure of the title compound, [Cu2I2(C44H32P22]·0.67H2O, has been determined because of its interesting catalytic and optical features. The molecule, which has non-crystallographic C2-symmetry, consists of a core structure of two CuI ions, bridged by two iodide ions. Each CuI ion is also coordinated by one equivalent of the chiral bidentate (R-BINAP ligand [BINAP = 2,2′-bis(diphenylphosphanyl-1,1′-binaphthyl]. Thus, both cations show a distorted tetrahedral geometry being surrounded by two I atoms and two P atoms from the (R-BINAP ligands. The complex consists of isolated butterfly-shaped molecules featuring an angle of 146.11 (2° between adjacent CuI2 planes. The structure displays intramolecular C—H...I hydrogen bonding and contains disordered water. The absolute configuration of this chiral complex was determined by anomalous dispersion effects.

Bis(indenyl)zirconium(IV) complexes of monofunctional bidentate salicylidimines

International Nuclear Information System (INIS)

Sharma, A.K.; Khera, B.; Kaushik, N.K.

1983-01-01

A series of (C 9 H 7 ) 2 Zr(SB)Cl complexes where SB- is the anion of bidentate Schiff base derived from salicylaldehyde and 4-substitued anilines, viz. salicylidene-4-ansidine, salicylidene-4-phenetidine, salicylidene-4-chloroaniline, salicylidene-4-bromoaniline, salicylene-4-iodoaniline and salicylidene-4-nitroaniline, have been synthesized by the reaction of bis(indenyl)zirconium(IV) dichloride and Schiff base (SBH) in 1 : 1 molar ratio in refluxing THF in the presence of triethylamine. The new derivatives have been characterized on the basis of their elemental analyses, conductance measurements and spectral (IR, 1 H-NMR, UV-VIS) studies. (Author)

5,5′-Bis(diethylamino-2,2′-[butane-1,4-diyldioxybis(nitrilomethylidyne]diphenol

Directory of Open Access Journals (Sweden)

Wen-Kui Dong

2008-04-01

Full Text Available The title complex, C26H38N4O4, was synthesized by the reaction of 4-diethylamino-2-hydroxybenzaldehyde with 1,4-bis(aminooxybutane in ethanol. It crystallizes as discrete centrosymmetric molecules adopting an extended conformation where the two salicylaldoxime groups are separated from each other. Intramolecular O—H...N hydrogen bonding is observed between the hydroxy groups and oxime N atoms. Intermolecular π–π stacking interactions [3.979 (2 Å] between aromatic rings are apparent in the crystal structure. Each ethyl group is disordered over two positions; in one the site occupancy factors are 0.55 and 0.45, in the other 0.53 and 0.47.

Evaluation of functionalized silica's for the adsorptive recovery of homogeneous catalysts through interaction with the metal centre

NARCIS (Netherlands)

Djekic, T.; Ham, van der A.G.J.; Haan, de A.B.

2007-01-01

The goal of this paper is the evaluation of functionalized silica's for the recovery of homogeneous catalysts by adsorption via its metal centre. As model catalysts, we selected bis(triphenylphosphine)cobalt(II)dichloride (CoCl2(PPh3)2), bis(triphenylphosphine)palladium(II)dichloride (PdCl2(PPh3)2)

Evaluation of functionalized silica¿s for the adsorptive recovery of homogenous catalysts through interaction with the metal centre

NARCIS (Netherlands)

Djekic, T.; van der Ham, Aloysius G.J.; de Haan, A.B.

2007-01-01

The goal of this paper is the evaluation of functionalized silica's for the recovery of homogeneous catalysts by adsorption via its metal centre. As model catalysts, we selected bis(triphenylphosphine)cobalt(II)dichloride (CoCl2(PPh3)2), bis(triphenylphosphine)palladium(II)dichloride (PdCl2(PPh3)2)

SYNTHESIS, CHARACTERIZATION AND CRYSTAL STRUCTURE OF BIS-(2-HYDROXYBENZALDEHYDEDIAMINOGUANIZONE

Directory of Open Access Journals (Sweden)

Diana Dragancea, Vladimir B. Arion, Sergiu Shova

2008-12-01

Full Text Available The new ligand, bis(2-hydroxybenzaldehydediaminoguanizone (1 has been synthesized and characterized by elemental analysis, IR and 1H NMR spectroscopies. The crystal structure of the compound was determined by X-ray diffraction. The ligand C15H15N5O2·C2H5OH crystallizes in the monoclinic space group P21/c with unit cell parameters a = 8.9102(3, b = 10.0357(3, c = 19.7618(6 Å, β = 98.385(2°, Z = 4, V = 1748.21(9 Å3, R1 = 0.040. The amino form of the ligand adopts a planar conformation stabilized by two intramolecular hydrogen bonds of the type O–H···N, in which the H atoms of the central amino group are directed to the lone-pair regions of the azomethine nitrogen atoms.

Conformational analysis of 2,2'-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) by NMR and molecular modeling

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Marcelle de S.; Figueroa-Villar, Jose D., E-mail: jdfv2009@gmail.com [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Dept. de Quimica. Grupo de Medicina Quimica

2014-05-15

2,2'-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-ones) with para and ortho-R groups on the benzene ring were prepared and studied by nuclear magnetic resonance (NMR) and molecular modeling to determine their conformational exchanges. Experimental and calculated results indicated conformational interconversions in these compounds by rotation of benzene ring and slow movement of dimedone rings, leading to intramolecular hydrogen bond length variation. The presence of one R group at the ortho position on the benzene ring modifies conformational exchange, leading to disappearance of one intramolecular hydrogen bond and superposition of diverse NMR signals. The correlation of σ{sub p} values with chemical shifts, angles and atomic charges confirms that para-R groups electronic properties are involved in conformational exchange and chemical shift variance. These results will be used to study the interaction of these compounds with bio-molecules and their use as starting materials for design and synthesis of new bioactive agents. (author)

Surface functionalization of detonation nanodiamonds by phosphonic dichloride derivatives.

Science.gov (United States)

Presti, Charlene; Alauzun, Johan G; Laurencin, Danielle; Mutin, P Hubert

2014-08-05

A new method for the functionalization of detonation nanodiamonds (DNDs) is proposed, on the basis of surface modification with phosphonic dichloride derivatives. DNDs were first modified by phenylphosphonic dichloride, and the grafting modes and hydrolytic stability under neutral conditions were investigated using (1)H, (13)C, and (31)P solid state NMR spectroscopy, Fourier transform infrared spectroscopy, as well as elemental analysis. Then, in order to illustrate the possibilities offered by this method, DNDs functionalized by mesityl imidazolium groups were obtained by postmodification of DNDs modified by 12-bromododecylphosphonic dichloride. The oxidative thermal stability of the functionalized DNDs was investigated using thermogravimetric analysis.

Effects of supported (nBuCp)2ZrCl2 catalyst active center multiplicity on crystallization kinetics of ethylene homo- and copolymers

KAUST Repository

Atiqullah, Muhammad; Adamu, Sagir; Hossain, Mohammad Mozahar; Al-Harthi, Mamdouh A.; Anantawaraskul, Siripon; Hossaen, Anwar

2014-01-01

Two different supported zirconocene, that is, bis(n-butylcyclopentadienyl) zirconium dichloride (nBuCp)2ZrCl2, catalysts were synthesized. Each catalyst was used to prepare one ethylene homopolymer and one ethylene-1-hexene copolymer. Catalyst

Synthesis of Substituted Titanocene Dichloride Derivatives by Hydrosilylation

Czech Academy of Sciences Publication Activity Database

Strašák, Tomáš; Karban, Jindřich; Červenková Šťastná, Lucie; Maixnerová, Lucie; Březinová, Anna; Bernard, Martin; Fajgar, Radek

2014-01-01

Roč. 768, OCT 1 (2014), s. 115-120 ISSN 0022-328X Institutional support: RVO:67985858 ; RVO:61388963 Keywords : titanocene dichloride * hydrosilylation * carbohydrates Subject RIV: CC - Organic Chemistry Impact factor: 2.173, year: 2014

STYRENE/STYRENE-DERIVATIVE COPOLYMERIZATION BY PH2Zn-METALLOCENE-MAO SYSTEMS: HOMO- AND COPOLYMERIZATION OF á-METHYLSTYRENE WITH STYRENE

OpenAIRE

RABAGLIATI, FRANCO M; MUÑOZ, HÉCTOR E; MARDONES, GABRIELA V

2010-01-01

The copolymerization of styrene with á-methylstyrene has been tested using combined metallocene-MAO initiator systems with and without diphenylzinc. The metallocenes used were biscyclopentadienyltitanium dichloride, Cp2TiCl2, bis(n-butylcyclopentadienyl)titanium dichloride, (n-BuCp)2TiCl2, and the half-sandwich metallocene indenyltitanium trichloride, IndTiCl3. The results indicate that both binary metallocene-MAO, and ternary Ph2Zn-metallocene-MAO systems are capable of polymerizing á-methyl...

40 CFR 61.62 - Emission standard for ethylene dichloride plants.

Science.gov (United States)

2010-07-01

...) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission... dichloride purification. The concentration of vinyl chloride in each exhaust gas stream from any equipment used in ethylene dichloride purification is not to exceed 10 ppm (average for 3-hour period), except as...

Intramolecular electron transfer through a bridging carboxylate group coordinated to two cobalt(III)-ions

International Nuclear Information System (INIS)

Wieghardt, K.

1978-01-01

Reduction of the binuclear μ-p-nitrobenzoato -di-μ-hydroxo -bis[triammine cobalt(III)] cation with (CH 3 ) 2 COH radicals yields a radical cation with the p-nitrobenzoato radical being coordinated to two cobalt(III) ions at the carboxylic group. The unprotonated form of this species undergoes intramolecular electron transfer producing Co(II) (k = (3.3 +- 0.3). x 10 3 s -1 ). The role of the carboxylate group in the intramolecular electron transfer process is tentatively assessed in terms of an intramolecular outer-sphere reaction because of lack of overlap of the donor orbitals (π) and the acceptor orbital (sigma). The protonated form of the radical cation (pKsub(a) = 2.5) disproportionates via a bimolecular process without production of Co(II). The effect of two coordinated Co(III) ions as compared to only one on the properties of the nitrobenzoate radical anion are discussed. (orig.) 891 HK 892 GM [de

40 CFR 61.65 - Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants.

Science.gov (United States)

2010-07-01

... dichloride, vinyl chloride and polyvinyl chloride plants. 61.65 Section 61.65 Protection of Environment... AIR POLLUTANTS National Emission Standard for Vinyl Chloride § 61.65 Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants. An owner or operator of an ethylene dichloride...

Mechanism of Intramolecular Rhodium- and Palladium-Catalyzed Alkene Alkoxyfunctionalizations

KAUST Repository

Vummaleti, Sai V. C.

2015-11-13

Density functional theory calculations have been used to investigate the reaction mechanism for the [Rh]-catalyzed intramolecular alkoxyacylation ([Rh] = [RhI(dppp)+] (dppp, 1,3-bis(diphenylphosphino)propane) and [Pd]/BPh3 dual catalytic system assisted intramolecular alkoxycyanation ([Pd] = Pd-Xantphos) using acylated and cyanated 2-allylphenol derivatives as substrates, respectively. Our results substantially confirm the proposed mechanism for both [Rh]- and [Pd]/ BPh3-mediated alkoxyfunctionalizations, offering a detailed geometrical and energetical understanding of all the elementary steps. Furthermore, for the [Rh]-mediated alkoxyacylation, our observations support the hypothesis that the quinoline group of the substrate is crucial to stabilize the acyl metal complex and prevent further decarbonylation. For [Pd]/BPh3-catalyzed alkoxycyanation, our findings clarify how the Lewis acid BPh3 cocatalyst accelerates the only slow step of the reaction, corresponding to the oxidative addition of the cyanate O-CN bond to the Pd center. © 2015 American Chemical Society.

Mechanism of Intramolecular Rhodium- and Palladium-Catalyzed Alkene Alkoxyfunctionalizations

KAUST Repository

Vummaleti, Sai V. C.; Alghamdi, Miasser; Poater, Albert; Falivene, Laura; Scaranto, Jessica; Beetstra, Dirk J.; Morton, Jason G.; Cavallo, Luigi

2015-01-01

Density functional theory calculations have been used to investigate the reaction mechanism for the [Rh]-catalyzed intramolecular alkoxyacylation ([Rh] = [RhI(dppp)+] (dppp, 1,3-bis(diphenylphosphino)propane) and [Pd]/BPh3 dual catalytic system assisted intramolecular alkoxycyanation ([Pd] = Pd-Xantphos) using acylated and cyanated 2-allylphenol derivatives as substrates, respectively. Our results substantially confirm the proposed mechanism for both [Rh]- and [Pd]/ BPh3-mediated alkoxyfunctionalizations, offering a detailed geometrical and energetical understanding of all the elementary steps. Furthermore, for the [Rh]-mediated alkoxyacylation, our observations support the hypothesis that the quinoline group of the substrate is crucial to stabilize the acyl metal complex and prevent further decarbonylation. For [Pd]/BPh3-catalyzed alkoxycyanation, our findings clarify how the Lewis acid BPh3 cocatalyst accelerates the only slow step of the reaction, corresponding to the oxidative addition of the cyanate O-CN bond to the Pd center. © 2015 American Chemical Society.

GC-MS Study of Mono- and Bishaloethylphosphonates Related to Schedule 2.B.04 of the Chemical Weapons Convention: The Discovery of a New Intramolecular Halogen Transfer

Science.gov (United States)

Picazas-Márquez, Nerea; Sierra, María; Nova, Clara; Moreno, Juan Manuel; Aboitiz, Nuria; de Rivas, Gema; Sierra, Miguel A.; Martínez-Álvarez, Roberto; Gómez-Caballero, Esther

2016-09-01

A new class of compounds, mono- and bis-haloethylphosphonates (HAPs and bisHAPs, respectively), listed in Schedule 2.B.04 of the Chemical Weapons Convention (CWC), has been synthesized and studied by GC-MS with two aims. First, to improve the identification of this type of chemicals by the Organization for the Prohibition of Chemical Weapons, (OPCW). Second, to study the synergistic effect of halogen and silicon atoms in molecules undergoing mass spectrometry. Fragmentation patterns of trimethylsilyl derivatives of HAPs were found to depend on the nature of the halogen atom; this was in agreement with DFT-calculations. The data suggest that a novel intramolecular halogen transfer takes place during the fragmentation process.

Electronic Interplay between TTF and Extended-TCNQ Electrophores along a Ruthenium Bis(acetylide) Linker.

Science.gov (United States)

Vacher, Antoine; Auffray, Morgan; Barrière, Frédéric; Roisnel, Thierry; Lorcy, Dominique

2017-11-17

A bis(TTF-butadiynyl) ruthenium D-D'-D complex, with intramolecular electronic interplay between the three electron-donating electrophores, was easily converted through a cycloaddition-retroelectrocyclization with TCNQ into a D-A-D'-A-D pentad complex, which exhibits an intense intramolecular charge transfer together with an electronic interplay between the two acceptors along the conjugated organometallic bridge.

Thorium and uranium redox-active ligand complexes; reversible intramolecular electron transfer in U(dpp-BIAN)2/ U(dpp-BIAN)2(THE)

Energy Technology Data Exchange (ETDEWEB)

Schelter, Eric John [Los Alamos National Laboratory; Wu, Ruilian [Los Alamos National Laboratory; Scott, Brian L [Los Alamos National Laboratory; Thompson, Joe D [Los Alamos National Laboratory; Batista, Enrique R [Los Alamos National Laboratory; Morris, David E [Los Alamos National Laboratory; Kiplinger, Jaqueline L [Los Alamos National Laboratory

2008-01-01

Actinide complexes of the redox-active ligand dpp-BIAN{sup 2-} (dpp-BIAN = bis(2,6-diisopropylphenyl)acenaphthylene), An(dpp-BIAN){sub 2}(THF){sub n} (An = Th, n = 1; An = U, n = 0, 1) have been prepared. Solid-state magnetic and single-crystal X-ray data for U(dpp-BIAN){sub 2}(THF){sub n} show when n = 0, the complex exists in an f{sup 2}-{pi}*{sup 4} configuration; whereas an intramolecular electron transfer occurs for n = 1, resulting in an f{sup 3}-{pi}*{sup 3} ground configuration. The magnetic data also indicate that interconversion between the two forms of the complex is possible, limited only by the ability of THF vapor to penetrate the solid on cooling of the sample. Spectroscopic data indicate the complex exists solely in the f{sup 2}-{pi}*{sup 4} form in solution, evidenced by the appearance of only small changes in the electronic absorption spectra of the U(dpp-BIAN){sub 2} complex on titration with THF and by measurement of the solution magnetic moment m d{sub 8}-tetrahydrofuran using Evans method. Electrochemistry of the complexes is reported, with small differences observed in wave potentials between metals and in the presence of THF. These data represent the first example of a well-defined, reversible intramolecular electron transfer in an f-element complex and the second example of oxidation state change through dative interaction with a metal ion.

1-[3-(2-Benzyloxy-6-hydroxy-4-methylphenyl-5-[3,5-bis(trifluoromethylphenyl]-4,5-dihydro-1H-pyrazol-1-yl]propane-1-one

Directory of Open Access Journals (Sweden)

U. H. Patel

2013-06-01

Full Text Available In the title compound, C28H24F6N2O3, the mean plane of the central pyrazoline ring forms dihedral angles of 2.08 (9 and 69.02 (16° with the 2-benzyloxy-6-hydroxy-4-methylphenyl and 3,5-bis(trifluoromethylphenyl rings, respectively. The dihedral angle between the mean planes of the pyrazoline and 3,5-bis(trifluoromethylphenyl rings is 68.97 (9°. An intramolecular O—H...N hydrogen bond is observed, which forms an S(6 graph-set motif. In the crystal, pairs of weak C—H...F halogen interactions link the molecules into inversion dimers while molecular chains along [100] are formed by C—H...O contacts.

Hyaluronidase: its effects on HI-6 dichloride and dimethanesulphonate pharmacokinetic profile in pigs.

Science.gov (United States)

Karasova, Jana Zdarova; Pavlik, Michal; Chladek, Jaroslav; Jun, Daniel; Kuca, Kamil

2013-07-04

Pigs were administered intramuscularly molar equivalents of HI-6 salts (HI-6 dichloride 10.71 mg/kg and HI-6 DMS 13.59 mg/kg) either with or without hyaluronidase (60 U/kg). Hyaluronidase is supposed to increase tissue permeability and diminishes discomfort caused by the intramuscular injection. Doses of HI-6 salts corresponded with standard HI-6 dichloride dose in one autoinjector (500 mg) and were recalculated for 1 kg of body weight. According to the results, both HI-6 salts applied in combination with hyaluronidase had increased tissue absorption and improved pharmacokinetic profile. The Cmax was significantly higher in case of HI-6 DMS plus hyaluronidase (29.6 ± 2.98 μg/ml) administration increase compared to HI-6 DMS (23.8 ± 3.04 μg/ml) and HI-6 dichloride (19.0 ± 0.93 μg/ml); both without hyaluronidase. Bioavailability calculated as AUCtotal (HI-6 DMS with hyaluronidase, 4,119 ± 647 min μg/ml) was also significantly higher compared to HI-6 DMS (2,259 ± 329 min μg/ml) and HI-6 dichloride (1,969 ± 254 min μg/ml); both without hyaluronidase. The results suggest that administration of HI-6 salt with higher solubility is the first step in the improvement of application strategy, but use some substances with spreading effect (hyaluronidase) may also leads to better absorption and better bioavailability. Improved bioavailability could to go hand in hand with increased effectiveness of therapy without the need of multiple autoinjector applications. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

The controlled formation and cleavage of an intramolecular d8-d8 Pt-Pt interaction in a dinuclear cycloplatinated molecular "pivot-hinge".

Science.gov (United States)

Koo, Chi-Kin; Wong, Ka-Leung; Lau, Kai-Cheung; Wong, Wai-Yeung; Lam, Michael Hon-Wah

2009-08-03

The bis(diphenylphosphino)methane (dppm)-bridged dinuclear cycloplatinated complex {[Pt(L)](2)(mu-dppm)}(2+) (Pt(2)dppm; HL: 2-phenyl-6-(1H-pyrazol-3-yl)-pyridine) demonstrates interesting reversible "pivot-hinge"-like intramolecular motions in response to the protonation/deprotonation of L. In its protonated "closed" configuration, the two platinum(II) centers are held in position by intramolecular d(8)-d(8) Pt-Pt interaction. In its deprotonated "open" configuration, such Pt-Pt interaction is cleaved. To further understand the mechanism behind this hingelike motion, an analogous dinuclear cycloplatinated complex, {[Pt(L)](2)(mu-dchpm)}(2+) (Pt(2)dchpm) with bis(dicyclohexylphosphino)methane (dchpm) as the bridging ligand, was synthesized. From its protonation/deprotonation responses, it was revealed that aromatic pi-pi interactions between the phenyl moieties of the mu-dppm and the deprotonated pyrazolyl rings of L was essential to the reversible cleavage of the intramolecular Pt-Pt interaction in Pt(2)dppm. In the case of Pt(2)dchpm, spectroscopic and spectrofluorometric titrations as well as X-ray crystallography indicated that the distance between the two platinum(II) centers shrank upon deprotonation, thus causing a redshift in its room-temperature triplet metal-metal-to-ligand charge-transfer emission from 614 to 625 nm. Ab initio calculations revealed the presence of intramolecular hydrogen bonding between the deprotonated and negatively charged 1-pyrazolyl-N moiety and the methylene CH and phenyl C-H of the mu-dppm. The "open" configuration of the deprotonated Pt(2)dppm was estimated to be 19 kcal mol(-1) more stable than its alternative "closed" configuration. On the other hand, the open configuration of the deprotonated Pt(2)dchpm was 6 kcal mol(-1) less stable than its alternative closed configuration.

cis-[1,4-Bis(diphenylphosphanylbutane-κ2P,P′]dichlorido(cyclohexane-1,2-diamine-κ2N,N′ruthenium(II dichloromethane monosolvate

Directory of Open Access Journals (Sweden)

Ismail Warad

2012-05-01

Full Text Available In the title compound, [RuCl2(C6H14N2(C28H28P2]·CH2Cl2, the RuII ion is coordinated in a slightly distorted octahedral environment, formed by two cis-oriented chloride ligands, two cis P atoms of a 1,4-bis(diphenylphosphanylbutane ligand and two cis-chelating N atoms of a bidentate cyclohexane-1,2-diamine ligand. In the crystal, pairs of molecules form inversion dimers via N—H...Cl hydrogen bonds. In addition, intramolecular N—H...Cl and weak C—H...Cl, C—H...N, N—H...π and C—H...π hydrogen bonds are observed. One of the Cl atoms of the solvent molecule is disordered over two sites with refined occupancies of 0.62 (1 and 0.38 (1.

The extraction of plutonium with triethylene glycol dichloride

International Nuclear Information System (INIS)

Aikin, A.M.; Moss, M.; Bruce, T.

1951-03-01

The extraction of plutonium by triethylene glycol dichloride (trigly) has been investigated briefly. The effect of (1) the valence state of the plutonium, (2) the concentration of nitric acid, (3) the concentration of ammonium nitrate and (4) the conditioning of the trigly was measured. The solubility of plutonium IV in trigly was found to be 70 mgms/ml. Solutions of plutonium in trigly and in concentrated nitric acid solutions have been examined spectrophotometrically. (author)

The extraction of plutonium with triethylene glycol dichloride

Energy Technology Data Exchange (ETDEWEB)

Aikin, A M; Moss, M; Bruce, T

1951-03-15

The extraction of plutonium by triethylene glycol dichloride (trigly) has been investigated briefly. The effect of (1) the valence state of the plutonium, (2) the concentration of nitric acid, (3) the concentration of ammonium nitrate and (4) the conditioning of the trigly was measured. The solubility of plutonium IV in trigly was found to be 70 mgms/ml. Solutions of plutonium in trigly and in concentrated nitric acid solutions have been examined spectrophotometrically. (author)

Biological Interaction of Molybdenocene Dichloride with Bovine Serum Albumin Using Fluorescence Spectroscopy

Science.gov (United States)

Domínguez, Moralba; Cortes-Figueroa, Jose´ E.; Meléndez, Enrique

2018-01-01

Bioinorganic topics are ubiquitous in the inorganic chemistry curriculum; however, experiments to enhance understanding of related topics are scarce. In this proposed laboratory, upper undergraduate students assess the biological interaction of molybdenocene dichloride (Cp2MoCl2) with bovine serum albumin (BSA) by fluorescence spectroscopy.…

Synthesis of [119mSn]-mesoporphyrin IX dichloride

International Nuclear Information System (INIS)

Denissen, J.F.

1990-01-01

Tin mesoporphyrin IX dichloride (Sn-MPCl 2 ) is a heme oxygenase inhibitor of current clinical interest for the treatment of neonatal hyperbilirubinemia. The synthesis of [ 119m Sn]-MPCl 2 for drug metabolism and disposition studies is reported. [ 119m Sn]-MPCl 2 was prepared in 60% radiochemical yield by metalation of the porphyrin nucleus of mesoporphyrin IX dihydrochloride with tin(II)-119m acetate. The product had a specific activity of 43.4 mCi/mmol and a radiochemical purity of 99%, as determined by radio-HPLC analysis. (author)

Intramolecular addition of benzylic radicals onto ketenimines. Synthesis of 2-alkylindoles.

Science.gov (United States)

Alajarín, Mateo; Vidal, Angel; Ortín, María-Mar

2003-12-07

The inter- and intramolecular addition of free radicals onto ketenimines is studied. All the attempts to add intermolecularly several silicon, oxygen or carbon centered radicals to N-(4-methylphenyl)-C,C-diphenyl ketenimine were unsuccessful. In contrast, the intramolecular addition of benzylic radicals, generated from xanthates, onto the central carbon of a ketenimine function with its N atom linked to the ortho position of the aromatic ring occurred under a variety of reaction conditions. These intramolecular cyclizations provide a novel radical-mediated synthesis of 2-alkylindoles.

Influência da estrutura do catalisador a base de Zirconoceno na estereorregularidade e propriedades do polipropileno formado Influence of Zirconocene structure on polypropylene stereorregularity and properties

Directory of Open Access Journals (Sweden)

Mário R. Meneghetti

1997-03-01

Full Text Available RESUMO: Catalisadores de metalocenos com diferentes simetrias, cocatalisados por metilaluminoxanas (MAO, foram avaliados em diferentes temperaturas de polimerização do propileno. Os metalocenos com ponte interanelar, ou seja, o dicloreto de rac-etileno bis(h5-1-indenil zircônio, com simetria C2, e o dicloreto de isopropilideno(h5-ciclopentadienil(h5-9-fluorenil zircônio, com simetria Cs, produziram, respectivamente, polipropileno isotático e sindiotático. O grau de taticidade desses polímeros diminui com o aumento da temperatura de polimerização. Os metalocenos sem ponte, dicloreto de bis(h5-ciclopentadienilzircônio e bis(h5-indenilzircônio, em qualquer uma das temperaturas investigadas, produziram, somente, polipropileno atático. A estereorregularidade dos polímeros foram determinadas por Ressonância Magnética Nuclear de 13C.ABSTRACT: Metallocenes with different symmetries in combination with methylaluminoxane (MAO, have been investigated at different propylene polymerization temperatures. The metallocenes rac-ethylene bis(h5-1-indenyl zirconium dichloride, with C2 symmetry and isopropylidene (h5cyclopentadienyl(h5-9-fluorenyl zirconium dichloride, with Cs symmetry, produce isotactic and syndiotactic polypropylene respectively. The degree of tacticity of these polymers decreases with the increase of polymerization temperature. Only atactic polypropylene was formed with the unbridged zirconocenes bis(h5-cyclopentadienyl zirconium dichloride and bis(h5-indenyl zirconium dichloride at any temperature investigated. The polymer microtacticity was analysed by 13C NMR.

Bis-aryl substituted dioxaborines as electron-transport materials: a comparative density functional theory investigation with oxadiazoles and siloles

International Nuclear Information System (INIS)

Risko, C.; Zojer, E.; Brocorens, P.; Marder, S.R.; Bredas, J.L.

2005-01-01

We report on a detailed quantum-chemical comparison of the electronic structures, vertical electron affinities, and intramolecular reorganization energies for bis-aryl substituted dioxaborine, oxadiazole, and silole derivatives. The results indicate that the HOMO and LUMO energies of the substituted compounds can be tuned on the order of 2-3 eV via minor changes in the substitution patterns, with the HOMO and LUMO levels for the dioxaborine derivatives consistently the most energy stabilized. Additionally, large vertical electron affinities and comparable intramolecular reorganization energies confirm that dioxaborine systems are interesting candidates for electron transport materials

Enantioselective copper catalysed intramolecular C-H insertion reactions of α-diazo-β-keto sulfones, α-diazo-β-keto phosphine oxides and 2-diazo-1,3-diketones; the influence of the carbene substituent.

Science.gov (United States)

Shiely, Amy E; Slattery, Catherine N; Ford, Alan; Eccles, Kevin S; Lawrence, Simon E; Maguire, Anita R

2017-03-22

Enantioselectivities in C-H insertion reactions, employing the copper-bis(oxazoline)-NaBARF catalyst system, leading to cyclopentanones are highest with sulfonyl substituents on the carbene carbon, and furthermore, the impact is enhanced by increased steric demand on the sulfonyl substituent (up to 91%ee). Enantioselective intramolecular C-H insertion reactions of α-diazo-β-keto phosphine oxides and 2-diazo-1,3-diketones are reported for the first time.

Conducting polymers of decanedioic acid bis-(4-pyrrol-1-yl-phenyl) ester

International Nuclear Information System (INIS)

Cirpan, A.; Guner, Y.; Toppare, L.

2004-01-01

A dipyrrolyl monomer was synthesized via the reaction between 4-pyrrol-1-yl phenol and decanedioyl dichloride. The electrochemical behavior of this monomer was studied. Polymerization of decanedioic acid bis-(4-pyrrol-1-yl-phenyl) ester (DAPE) was achieved by chemical and constant current electrolyses methods. Copolymerization of DAPE with thiophene was performed by constant potential electrolysis in acetonitrile-tetrabutylammonium tetrafluoroborate (TBAFB), dichloromethane-TBAFB, solvent-electrolyte couples. The chemical structures and properties were investigated by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry and thermal gravimetry analysis. The conductivities of the samples were measured by a four-probe technique

Conducting polymers of decanedioic acid bis-(4-pyrrol-1-yl-phenyl) ester

Energy Technology Data Exchange (ETDEWEB)

Cirpan, A.; Guner, Y.; Toppare, L

2004-05-15

A dipyrrolyl monomer was synthesized via the reaction between 4-pyrrol-1-yl phenol and decanedioyl dichloride. The electrochemical behavior of this monomer was studied. Polymerization of decanedioic acid bis-(4-pyrrol-1-yl-phenyl) ester (DAPE) was achieved by chemical and constant current electrolyses methods. Copolymerization of DAPE with thiophene was performed by constant potential electrolysis in acetonitrile-tetrabutylammonium tetrafluoroborate (TBAFB), dichloromethane-TBAFB, solvent-electrolyte couples. The chemical structures and properties were investigated by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry and thermal gravimetry analysis. The conductivities of the samples were measured by a four-probe technique.

Asymmetric Diels–Alder reaction with >C=P– functionality of the 2-phosphaindolizine-η1-P-aluminium(O-menthoxy dichloride complex: experimental and theoretical results

Directory of Open Access Journals (Sweden)

Rajendra K. Jangid

2013-02-01

Full Text Available The Diels–Alder reaction of the 2-phosphaindolizine-η1-P-aluminium(O-menthoxy dichloride complex with dimethylbutadiene was investigated experimentally and computationally. The >C=P– functionality of the complex reacts with 2,3-dimethylbutadiene with complete diastereoselectivity to afford [2 + 4] cycloadducts. Calculation of the model substrate, 3-methoxycarbonyl-1-methyl-2-phosphaindolizine-P-aluminium(O-menthoxy dichloride (7a, at the DFT (B3LYP/6-31+G* level reveals that the O-menthoxy moiety blocks the Re face of the >C=P– functionality, due to which the activation barrier of the Diels–Alder reaction of 7a with 1,3-butadiene, involving its attack from the Si face, is lower. It is found that in this case, the exo approach of the diene is slightly preferred over the endo approach.

High pressure synthesis of BiS2

DEFF Research Database (Denmark)

Søndergaard-Pedersen, Simone; Nielsen, Morten Bormann; Bremholm, Martin

crystal structures and electrical properties.1,2 Up until now, the most sulfur rich phase in the Bi-S phase diagram was Bi2S3.3 For BiS2 the Bi atoms have anisotropic charge distribution and more complex structures are expected when comparing the layered structures of transition metal dichalcogenides....... The possibilities of using high pressure synthesis to discover new phases in the Bi-S binary system were investigated as early as the 1960’s.4 The research led to discovery of a compound with BiS2 stoichiometry, but no structure solution of BiS2 was reported. A reason behind making this new phase is to study...... the physical properties since the related compound Bi2S3 is known to be a thermoelectric material.5 In this research the BiS2 compound was synthesized by a high pressure and high temperature method using a multi-anvil large volume press and the structure was solved by single crystal diffraction. The structure...

A two-dimensional CdII coordination polymer: poly[diaqua[μ3-5,6-bis(pyridin-2-ylpyrazine-2,3-dicarboxylato-κ5O2:O3:O3,N4,N5]cadmium

Directory of Open Access Journals (Sweden)

Monserrat Alfonso

2016-09-01

Full Text Available The reaction of 5,6-bis(pyridin-2-ylpyrazine-2,3-dicarboxylic acid with cadmium dichloride leads to the formation of the title two-dimensional coordination polymer, [Cd(C16H8N4O4(H2O2]n. The metal atom is sevenfold coordinated by one pyrazine and one pyridine N atom, two water O atoms, and by two carboxylate O atoms, one of which bridges two CdII atoms to form a Cd2O2 unit situated about a centre of inversion. Hence, the ligand coordinates to the cadmium atom in an N,N′,O-tridentate and an O-monodentate manner. Within the polymer network, there are a number of O—H...O hydrogen bonds present, involving the water molecules and the carboxylate O atoms. There are also C—H...N and C—H...O hydrogen bonds present. In the crystal, the polymer networks lie parallel to the bc plane. They are aligned back-to-back along the a axis with the non-coordinating pyridine rings directed into the space between the networks.

Variation of the Sterical Properties of the N-Heterocyclic Carbene Coligand in Thermally Triggerable Ruthenium-Based Olefin Metathesis Precatalysts/Initiators

KAUST Repository

Pump, Eva; Leitgeb, Anita; Kozłowska, Anna; Torvisco, Ana; Falivene, Laura; Cavallo, Luigi; Grela, Karol; Slugovc, Christian

2015-01-01

A series of ruthenium complexes based on the κ(C,N)-(2-(benzo[h]quinolin-10-yl)methylidene ruthenium dichloride fragment featuring different neutral coligands L (L = 1,3-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazol-2-ylidene (SIPr), 1,3-bis(2

Synthesis, characterization and x-ray crystal structure of a dimethyltin (IV) dichloride complex of 2-acetylpyridine benzophenone azine

International Nuclear Information System (INIS)

Mustaffa Shamsuddin; Md Abu Affan; Ramli Atan

1998-01-01

Dimethyltin dichloride react with 2-ac ethylpyridine benzophenone azine (apba) in refluxing dry hexane to give (SnMe 2 Cl 2 (apba)) where the azine ligand acts as a bidentate N-N chelating ligand. The complex has been characterized by IR spectroscopy, 1 H and 13 C NMR spectroscopic data and elemental analyses. The crystal structure of the dimethyltin(IV) derivative has also been determined. Crystals are monoclinic with space group P2(1)/n with cell dimensions: a = 10.1819(3) Armstrong, b = 18.3113(5) Armstrong, c = 12.6451(4) Armstrong

Microwave assisted synthesis of bis and tris(ω-bromoacetophenones): versatile precursors for novel bis(imidazo[1,2-a]pyridines), bis(imidazo[1,2-a]pyrimidines) and their tris-analogs

Science.gov (United States)

2013-01-01

Background α-Bromination of the side chain of aromatic ketones using NBS in the presence of p-toluenesulfonic acid (p-TsOH) in acetonitrile is very common. However, regioselective bromination of bis and tris(ω-bromoacetophenones) with NBS in the presence of p-TsOH in acetonitrile under microwave irradiation is quite novel. The bis- and tris(ω-bromoacetophenones) are used in synthesis of bis and tris(heterocycles). bis(heterocycles) have received a great deal of attention, because many biologically active natural and synthetic products have molecular symmetry. The use of the pressurized microwave irradiation is very advantageous to many syntheses and provide a large rate enhancement. Results Bis and tris(ω-bromoacetophenones) were obtained as single monobrominated derivatives in a shorter time than the conventional conditions. The results clearly demonstrate the better reactivity and selectivity of NBS/p-TsOH/CH3CN as a brominating mixture under microwave conditions. The reaction of bis and tris(ω-bromoacetophenone) with 2-aminopyridine and 2-aminopyrimidine proceeded smoothly in a mixture of anhydrous ethanol and DMF under reflux or using 300 W/105°C/ 20 min microwave irradiation conditions to afford the corresponding bis(imidazo[1,2-a]pyridine), bis(imidazo[1,2-a]pyrimidine) and tris(imidazo[1,2-a]pyridine) derivatives in moderate to excellent yields. The carbonyl analogue of the targeted bis(imidazopyridines) could be synthesized by the reaction of N,N-dimethyl-N'-(pyridin-2-yl)formimidamide with bis(ω-bromoacetophenone) in refluxing ethanol. The structures of the newly synthesized compounds were confirmed by their spectral data as well as their elemental analyses. Conclusion In conclusion, selective α-bromination of bis- and tris(acetophenones) has been accomplished efficiently utilizing NBS/p-TsOH/CH3CN under microwave irradiation. In addition, a facile synthesis of novel series of bis- and tris(imidazopyridine) and bis(imidazopyrimidine) derivatives

Negative resists for i-line lithography utilizing acid-catalyzed intramolecular dehydration reaction

Science.gov (United States)

Ueno, Takumi; Uchino, Shou-ichi; Hattori, Keiko T.; Onozuka, Toshihiko; Shirai, Seiichiro; Moriuchi, Noboru; Hashimoto, Michiaki; Koibuchi, S.

1994-05-01

Chemical amplification negative resist system composed of a novolak resin, a carbinol and an acid generator is investigated for i-line phase-shift lithography. The reaction in this resist is based on an acid-catalyzed intramolecular dehydration reaction. The dehydration products act as aqueous-base dissolution inhibitors, and carbinol compounds in unexposed areas work as dissolution promoters. The resist composed of a novolak resin, 1,4-bis((alpha) -hydroxyisopropyl) benzene (DIOL-1) and 2- naphthoylmethyltetramethylenesulfonium triflate (PAG-2) gives the best lithographic performance in terms of sensitivity and resolution. Line-and-space patterns of 0.275 micrometers are obtained using an i-line stepper (NA:0.45) in conjunction with a phase shifting mask.

Unexpected formation and crystal structure of tetrakis(1H-pyrazole-κN2palladium(II dichloride

Directory of Open Access Journals (Sweden)

Thomas Wagner

2014-12-01

Full Text Available The title salt, [Pd(C3H4N24]Cl2, was obtained unexpectedly by the reaction of palladium(II dichloride with equimolar amounts of 1-chloro-1-nitro-2,2,2-tris(pyrazolylethane in methanol solution. The Pd2+ cation is located on an inversion centre and has a square-planar coordination sphere defined by four N atoms of four neutral pyrazole ligands. The average Pd—N distance is 2.000 (2 Å. The two chloride anions are not coordinating to Pd2+. They are connected to the complex cations through N—H...Cl hydrogen bonds. In addition, C—H...Cl hydrogen bonds are observed, leading to a three-dimensional linkage of cations and anions.

Nucleophilic reactions of hydrazido(2-) complexes of molybdenum and tungsten with succinyl dichloride and phenyl isocyanate

International Nuclear Information System (INIS)

Iwanami, Kiyotaka; Mizobe, Yasushi; Takahashi, Tamotsu; Kodama, Teruyuki; Uchida, Yasuzo

1981-01-01

Nucleophilic attack of the WNNH 2 group in the hydrazido(2-) complex [WF(NNH 2 )(dpe) 2 ][BF 4 ] (dpe = Ph 2 PCH 2 CH 2 PPh 2 ) on succinyl dichloride gives a novel ethanedioylhydrazido(2-) complex, [WF(NNCOCH 2 CH 2 CO)(dpe) 2 ][BF 4 ]. X-Ray structural analysis shows that the carbon, nitrogen, and oxygen atoms of the ethanedioylhydrazido(2-) ligand lie nearly in the same plane, indicating sp 2 character of the nitrogen atom bearing the two carbonyl groups. Phenyl isocyanate also undergoes nucleophilic attack by the hydrazido(2-) complex [MBr(NNH 2 )(dpe) 2 ]Br (M = Mo or W) to yield the phenylsemicarbazido(2-) type complex, [MBr(NNHCONHPh)(dpe) 2 ]Br. Treatment of the semicarbazido(2-) complex with triethylamine gives a new diazenido complex [MBr(NNCONHPh)(dpe) 2 ]. (author)

The enthalpies of formation of neutral and charged components of saturated vapor over europium dichloride

International Nuclear Information System (INIS)

Pogrebnoj, A.M.; Kudin, L.S.

2003-01-01

Composition of saturated vapor over europium dichloride was studied by the method of high-temperature mass spectrometry in the temperature range of 1154 - 1267 K. For neutral components of the vapor, represented by monomer and dimer molecules, partial pressures were determined. Enthalpies of sublimation of europium dichloride Δ s H 0 (298 K) as monomers (338 ± 9) and dimers (407 ± 20 kJ/mol) were calculated. Equilibrium constants of ion-molecular and ion-ionic reactions were measured, their enthalpies being ascertained. Enthalpies of formation of molecules and ions Δ f H 0 (298 K) were calculated: -486 ± 11 (EuCl 2 ), -1242 ± 22 (Eu 2 Cl 4 ), 1 ± 12 (Eu 2 Cl 2 + ), -347 ± 20 (Eu 2 Cl 3 + ), -1111 ± 42 (Eu 3 Cl 5 + ), -975 ± 20 (EuCl 3 - ), -1309 ± 17(EuCl 4 - ), -1734 ± 20 (Eu 2 Cl 5 - ) kJ/mol [ru

Diarylhalotelluronium(IV) cations [(8-Me2NC10H6)2TeX]+ (X = Cl, Br, I) stabilized by intramolecularly coordinating N-donor substituents.

Science.gov (United States)

Beckmann, Jens; Bolsinger, Jens; Duthie, Andrew; Finke, Pamela

2013-09-14

The stoichiometrically controlled halogenation of the intramolecularly coordinated diaryltelluride (8-Me2NC10H6)2Te using SO2Cl2, Br2 and I2 was studied. At an equimolar ratio, the diarylhalotelluronium cations [(8-Me2NC10H6)2TeX](+) (1, X = Cl; 2, X = Br; 3, X = I) formed and were isolated as 1·Cl(-)·H2O·1/2THF, 2·Br(-), and 3·I(-), respectively. When the same reactions were carried out in the presence of KPF6, 1·PF6(-) and 22·Br(-)·PF6(-) were obtained. The chlorination of (8-Me2NC10H6)2Te with an excess of SO2Cl2 occurred with a double electrophilic substitution at the 8-dimethylaminonaphthyl residues (in the ortho- and para-positions) and afforded the diaryltellurium dichloride (5,7-Cl2-8-Me2NC10H4)2TeCl2 (4). The bromination of (8-Me2NC10H6)2Te with three equivalents of Br2 took place with a single electrophilic substitution at the 8-dimethylaminonaphthyl residues (in the para-positions) and provided the diaryltellurium dibromide (5-Br-8-Me2NC10H5)2TeBr2 (5), while an excess of Br2 produced the diarylbromotelluronium cation [(5-Br-8-Me2NC10H5)2TeBr](+) (6) that was isolated as 6·Br3(-). The reaction of (8-Me2NC10H6)2Te with two or three equivalents of iodine provided 3·I3(-) and 3·I3(-)·I2, respectively. In the presence of water, 1·Cl(-)·H2O·1/2THF, 2·Br(-), 3·I(-) and 3·I3(-) hydrolyzed to give the previously known diarylhydroxytelluronium cation [(8-Me2NC10H6)2TeOH](+) (7) that was isolated as 7·Cl(-), 7·Br(-)·H2O·THF, 7·I(-) and 7·I3(-)·H2O, respectively. The molecular structures of 1-7 were investigated in the solid-state by (125)Te MAS NMR spectroscopy and X-ray crystallography and in solution by multinuclear NMR spectroscopy ((1)H, (13)C, (125)Te), electrospray mass spectrometry and conductivity measurements. The stabilization of cations 1-3 by the intramolecular coordination was estimated by DFT calculations at the B3PW91/TZ level of theory.

The absorption, tissue distribution and excretion of di-n-octyltin dichloride in rats

NARCIS (Netherlands)

Penninks, A.H.; Hilgers, L.; Seinen, W.

In this study the absorption, tissue distribution and excretion of 14C-labeled di-n-octyltin dichloride ([14C]DOTC) in rats were investigated after oral and intravenous (i.v.) administration. Although after i.v. administration with 1.2 mg [14C]DOTC/kg body weight the tissue radioactivity was about

Synthesis of Novel E-2-Chlorovinyltellurium Compounds Based on the Stereospecific Anti-addition of Tellurium Tetrachloride to Acetylene

Directory of Open Access Journals (Sweden)

Svetlana V. Amosova

2012-05-01

Full Text Available The reaction of tellurium tetrachloride with acetylene proceeds in a stereospecific anti-addition manner to afford the novel products E-2-chlorovinyltellurium trichloride and E,E-bis(2-chlorovinyltellurium dichloride. Reaction conditions for the selective preparation of each of these products were found. The latter was obtained in 90% yield in CHCl₃ under a pressure of acetylene of 10–15 atm, whereas the former product was formed in up to 72% yield in CCl₄ under a pressure of acetylene of 1–3 atm. Synthesis of the previously unknown E,E-bis(2-chlorovinyl telluride, E,E-bis(2-chlorovinyl ditelluride, E-2-chlorovinyl 1,2,2-trichloroethyl telluride and E,E-bis(2-chlorovinyl-tellurium dibromide is described.

Structure of diphosphine complexes of Co(II) in solutions of organic compounds

International Nuclear Information System (INIS)

Saraev, V.V.; Mandyuk, I.M.; Ratovskii, G.V.; Dmitrieva, T.V.; Shmidt, F.K.

1987-01-01

The structure of the dichloride complexes of cobalt(II) with 1,2-bis(diphenylphosphino)ethane (DPPE) and 1,1-bis(diphenylphosphino)methane (DPPM) in organic solvents has been investigated by ESR and electronic spectroscopy. It has been shown that the low-spin complex Co(DPPE) 2 Cl 2 exists in dichloroethane and ethanol solutions in the form of a trigonal bipyramid. Cobalt dichloride reacts with DPPM to form 1:1 and 1:2 complexes, between which there is an equilibrium in a dichloroethane solution. The equilibrium is displaced under the action of the free diphosphine toward the formation of the 1:2 complex. Elimination of the diphosphine from the coordination sphere of cobalt occurs in an ethanol solution

Crystal structures of bis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III complexes containing an acetonitrile or monodentate thyminate(1− ligand

Directory of Open Access Journals (Sweden)

Mika Sakate

2016-04-01

Full Text Available The crystal structures of bis[2-(pyridin-2-ylphenyl]rhodium(III complexes with the metal in an octahedral coordination containing chloride and acetonitrile ligands, namely (OC-6-42-acetonitrilechloridobis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III, [RhCl(C11H8N2(CH3CN] (1, thyminate(1− and methanol, namely (OC-6-42-methanol(5-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-ido-κN1bis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III, [Rh(C11H8N2(C5H5N2O2(CH3OH]·CH3OH·0.5H2O (2, and thyminate(1− and ethanol, namely (OC-6-42-ethanol(5-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-ido-κN1bis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III, [Rh(C11H8N2(C5H5N2O2(C2H5OH]·C2H5OH (3, are reported. The acetonitrile complex, 1, is isostructural with the IrIII analog. In complexes 2 and 3, the monodeprotonated thyminate (Hthym− ligand coordinates to the RhIII atom through the N atom, and the resulting Rh—N(Hthym bond lengths are relatively long [2.261 (2 and 2.252 (2 Å for 2 and 3, respectively] as compared to the Rh—N bonds in the related thyminate complexes. In each of the crystals of 2 and 3, the complexes are linked via a pair of intermolecular N—H...O hydrogen bonds between neighbouring Hthym− ligands, forming an inversion dimer. A strong intramolecular O—H...O hydrogen bond between the thyminate(1− and alcohol ligands in mutually cis positions to each other is also observed.

Thermal and catalytic intramolecular [4+2]-cycloaddition in 2-alkenylfurans

International Nuclear Information System (INIS)

Zubkov, Fedor I; Nikitina, Evgenia V; Varlamov, Alexey V

2005-01-01

The published data on the intramolecular Diels-Alder reaction in compounds of the 2-alkenylfuran series are generalised. The methods and conditions for the preparation of tricyclic systems are considered. The effects of the substituents in the furan and the unsaturated fragments on the cycloaddition are discussed. The application of this reaction to the synthesis of alkaloids and terpenoids is exemplified.

Thermal and catalytic intramolecular [4+2]-cycloaddition in 2-alkenylfurans

Energy Technology Data Exchange (ETDEWEB)

Zubkov, Fedor I; Nikitina, Evgenia V; Varlamov, Alexey V [Department of Physical, Mathematical and Natural Sciences, Peoples' Friendship University of Russia (Russian Federation)

2005-07-31

The published data on the intramolecular Diels-Alder reaction in compounds of the 2-alkenylfuran series are generalised. The methods and conditions for the preparation of tricyclic systems are considered. The effects of the substituents in the furan and the unsaturated fragments on the cycloaddition are discussed. The application of this reaction to the synthesis of alkaloids and terpenoids is exemplified.

Bis(μ-bis{[4-(2-pyridylpyrimidin-2-yl]sulfanyl}methanedisilver(I bis(perchlorate

Directory of Open Access Journals (Sweden)

Hai-Bin Zhu

2010-12-01

Full Text Available In the macrocyclic centrosymmetric dinuclear complex, [Ag2(C19H14N6S22](ClO42, the AgI atom, bis{[4-(2-pyridylpyrimidin-2-yl]sulfanyl}methane (2-bppt ligand and perchlorate anion each lie on a twofold rotation axis. The 2-bppt ligand chelates two four-coordinated AgI atoms through its two bipyridine-like arms. The O atoms of the perchlorate anion are disordered each over two positions of equal occupancy. Adjacent complex molecules are linked by π–π interactions between the pyridine and pyrimidine rings [centroid–centroid distance = 3.663 (8 Å].

Crystal structure of bis[2,5-bis(pyridin-2-yl-1,3,4-thiadiazole-κ2N2,N3]bis(thiocyanato-κScopper(II

Directory of Open Access Journals (Sweden)

Abdelhakim Laachir

2016-08-01

Full Text Available The mononuclear title complex, [Cu(SCN2(C12H8N4S2], was obtained by the reaction of 2,5-bis(pyridin-2-yl-1,3,4-thiadiazole and potassium thiocyanate with copper(II chloride dihydrate. The copper cation lies on an inversion centre and displays an elongated octahedral coordination geometry. The equatorial positions are occupied by the N atoms of two 2,5-bis(pyridin-2-yl-1,3,4-thiadiazole ligands, whereas the axial positions are occupied by the S atoms of two thiocyanate anions. The thiadiazole and the pyridyl rings linked to the metal are approximately coplanar, with a maximum deviation from the mean plane of 0.190 (2 Å. The cohesion of the crystal structure is ensured by weak C—H...N hydrogen bonds and π–π interactions between parallel pyridyl rings of neighbouring molecules [centroid-to-centroid distance = 3.663 (2 Å], leading to a three-dimensional network.

Synthesis of highly reactive polyisobutylene catalyzed by EtAlCl 2/Bis(2-chloroethyl) ether soluble complex in hexanes

KAUST Repository

Kumar, Rajeev Ananda; Zheng, Bin; Huang, Kuo-Wei; Emert, Jack I.; Faust, Rudolf

2014-01-01

The polymerization of isobutylene (IB) to yield highly reactive polyisobutylene (HR PIB) with high exo-olefin content using GaCl3 or FeCl3·diisopropyl ether complexes has been previously reported.1 In an effort to further improve polymerization rates and exo-olefin content, we have studied ethylaluminum dichloride (EADC) complexes with diisopropyl ether, 2-chloroethyl ethyl ether (CEEE), and bis(2-chloroethyl) ether (CEE) as catalysts in conjunction with tert-butyl chloride as initiator in hexanes at different temperatures. All three complexes were readily soluble in hexanes. Polymerization, however, was only observed with CEE. At 0 °C polymerization was complete in 5 min at [t-BuCl] = [EADC·CEE] = 10 mM and resulted in PIB with ∼70% exo-olefin content. Studies on complexation using ATR FTIR and 1H NMR spectroscopy revealed that at 1:1 stoichiometry a small amount of EADC remains uncomplexed. By employing an excess of CEE, exo-olefin contents increased up to 90%, while polymerization rates decreased only slightly. With decreasing temperature, polymerization rates decreased while molecular weights as well as exo-olefin contents increased, suggesting that isomerization has a higher activation energy than β-proton abstraction. Density functional theory (DFT) studies on the Lewis acid·ether binding energies indicated a trend consistent with the polymerization results. The polymerization mechanism proposed previously for Lewis acid·ether complexes1 adequately explains all the findings. © 2014 American Chemical Society.

Synthesis of highly reactive polyisobutylene catalyzed by EtAlCl 2/Bis(2-chloroethyl) ether soluble complex in hexanes

KAUST Repository

Kumar, Rajeev Ananda

2014-03-25

The polymerization of isobutylene (IB) to yield highly reactive polyisobutylene (HR PIB) with high exo-olefin content using GaCl3 or FeCl3·diisopropyl ether complexes has been previously reported.1 In an effort to further improve polymerization rates and exo-olefin content, we have studied ethylaluminum dichloride (EADC) complexes with diisopropyl ether, 2-chloroethyl ethyl ether (CEEE), and bis(2-chloroethyl) ether (CEE) as catalysts in conjunction with tert-butyl chloride as initiator in hexanes at different temperatures. All three complexes were readily soluble in hexanes. Polymerization, however, was only observed with CEE. At 0 °C polymerization was complete in 5 min at [t-BuCl] = [EADC·CEE] = 10 mM and resulted in PIB with ∼70% exo-olefin content. Studies on complexation using ATR FTIR and 1H NMR spectroscopy revealed that at 1:1 stoichiometry a small amount of EADC remains uncomplexed. By employing an excess of CEE, exo-olefin contents increased up to 90%, while polymerization rates decreased only slightly. With decreasing temperature, polymerization rates decreased while molecular weights as well as exo-olefin contents increased, suggesting that isomerization has a higher activation energy than β-proton abstraction. Density functional theory (DFT) studies on the Lewis acid·ether binding energies indicated a trend consistent with the polymerization results. The polymerization mechanism proposed previously for Lewis acid·ether complexes1 adequately explains all the findings. © 2014 American Chemical Society.

Synthesis and structure of unprecedented samarium complex with bulky bis-iminopyrrolyl ligand via intramolecular C=N bond activation

Energy Technology Data Exchange (ETDEWEB)

Das, Suman; Anga, Srinivas; Harinath, Adimulam; Panda, Tarun K. [Department of Chemistry, Indian Institute of Technology, Hyderabad (India); Pada Nayek, Hari [Department of Applied Chemistry, Indian Institute of Technology, (ISM) Dhanbad, Jharkhand (India)

2017-12-29

An unprecedentate samarium complex of the molecular composition [{κ"3-{(Ph_2CH)N=CH}{sub 2}C{sub 4}H{sub 2}N}{κ"3-{(Ph_2CHN=CH)(Ph_2CHNCH)C_4H_2N}Sm}{sub 2}] (2), which was isolated by the reaction of a potassium salt of 2,5-bis{N-(diphenylmethyl)-iminomethyl}pyrrolyl ligand [K(THF){sub 2}{(Ph_2CH)N=CH}{sub 2}C{sub 4}H{sub 2}N] (1) with anhydrous samarium diiodide in THF at 60 C through the in situ reduction of imine bond is presented. The homoleptic samarium complex [[κ{sup 3}-{(Ph_2CH)-N=CH}{sub 2}C{sub 4}H{sub 2}N]{sub 3}Sm] (3) can also be obtained from the reaction of compound 1 with anhydrous samarium triiodide (SmI{sub 3}) in THF at 60 C. The molecular structures of complexes 2 and 3 were established by single-crystal X-ray diffraction analysis. The molecular structure of complex 2 reveals the formation of a C-C bond in the 2,5-bis{N-(diphenylmethyl)iminomethyl}pyrrole ligand moiety (Ph{sub 2}Py{sup -}). However, complex 3 is a homoleptic samarium complex of three bis-iminopyrrolyl ligands. In complex 2, the samarium ion adopts an octahedral arrangement, whereas in complex 3, a distorted three face-centered trigonal prismatic mode of nine coordination is observed around the metal ion. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

2,6-Bis(oxazolinyl)phenylnickel(II) Bromide and 2,6-Bis(ketimine)phenylnickel(II) Bromide: Synthesis, Structural Features, and Redox Properties

NARCIS (Netherlands)

Stol, M.; Snelders, D.J.M.|info:eu-repo/dai/nl/304836257; Godbole, M.D.; Havenith, R.W.A.|info:eu-repo/dai/nl/205279546; Haddleton, D.M.; Clarkson, G.; Lutz, M.|info:eu-repo/dai/nl/304828971; Spek, A.L.|info:eu-repo/dai/nl/156517566; van Klink, G.P.M.|info:eu-repo/dai/nl/170637964; van Koten, G.|info:eu-repo/dai/nl/073839191

2007-01-01

2,6-Bis(oxazolinyl)phenylnickel bromide complexes [NiBr(R,R'-Phebox)] (2) were synthesized via two synthetic routes (A and B). In route A, selective bis-ortho lithiation of [R,R'-PheboxBr], followed by a transmetalation reaction with [NiBr2(PEt3)2], yielded not only complexes 2 with an

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Bis[2-phenyl-1-(phenyliminioisoindoline] di-μ-chlorido-bis[dichloridopalladate(II] benzene disolvate

Directory of Open Access Journals (Sweden)

Stephen R. Foley

2008-07-01

Full Text Available In the title compound, (C20H17N22[Pd2Cl6]·2C6H6, the dichloride-bridged [Pd2Cl6]2− anion lies across an inversion center with each PdII ion in a slightly distorted square-planar environment. In the crystal structure, two cations and an anion are connected via N—H...Cl hydrogen bonds between the NH groups of the iminioisoindoline cations and terminal Cl atoms of a hexachloridodipalladate(II anion. The Pd—Cl distance of the terminal chloride engaged in hydrogen bonding is slightly longer than the Pd—Cl distance of the adjacent terminal chloride which is not involved in hydrogen bonding.

Synthesis and Molecular Structures of Two [1,4-bis(3-pyridyl-2,3-diazo-1,3-butadiene]-dichloro-Zn(II Coordination Polymers

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Hsin-Ta Wang

2006-08-01

Full Text Available Two novel coordination polymers with 3D metal-organic frameworks (MOFs have been synthesized by reacting 1,4-bis(3-pyridyl-2,3-diazo-1,3-butadiene (L with zinc dichloride. Both compounds have the same repeating unit consisting of a distorted tetrahedral Zn(II center coordinated by two chlorides and two pyridyl nitrogen atoms of two bridging bismonodentate L ligands, however, different structural conformations have been found, one forming a helical chain and the other producing a square-wave chain. The intermolecular C−H···Cl hydrogen bonds in 1 and 2 play important roles in the formation of three-dimensional coordination polymers. Compound 1 crystallized in an orthorhombic space group Pna21 with a = 7.9652(3, b = 21.4716(7, c = 8.2491(3Å, V = 1410.81(9 Å 3 and Z = 4. Compound 2 crystallized in a monoclinic space group P21/n with a = 9.1752(3, b = 14.5976(4, c = 10.3666(3 Å , β = 98.231(2°, V = 1374.16(7 Å 3 and Z = 4.

2,2′-{1,1′-[Butane-1,4-diylbis(oxynitrilo]diethylidyne}di-1-naphthol

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Wen-Kui Dong

2009-06-01

Full Text Available The title compound, C28H28N2O4, was synthesized by the reaction of 2-acetyl-1-naphthol with 1,4-bis(aminooxybutane in ethanol. The molecule, which lies about an inversion centre, adopts a linear structure, in which the oxime groups and naphthalene ring systems assume an anti conformation. The intramolecular interplanar distance between parallel naphthalene rings is 1.054 (3 Å. Intramolecular O—H...N hydrogen bonds are formed between the oxime nitrogen and hydroxy groups.

Ac conductivity and dielectric properties of bulk tin phthalocyanine dichloride (SnPcCl 2)

Science.gov (United States)

El-Nahass, M. M.; Farid, A. M.; Abd El-Rahman, K. F.; Ali, H. A. M.

2008-07-01

The ac conductivity, σac( ω), has been measured for bulk tin phthalocyanine dichloride (SnPcCl 2) in the form of compressed pellet with evaporated ohmic Au electrodes in a temperature range 303-403 K. Ac conductivity, σac( ω), is found to vary as ωs in the frequency range 42 Hz-5×10 6 Hz. At low range of frequency, s<1 and it decreases with the increase in temperature indicating a dominant hopping process. At high range of frequency, s is found to be equal to ≈1.09 and is temperature independent. The dielectric constant, ε1, and dialectic loss, ε2, have been determined for bulk SnPcCl 2. Both ε1 and ε2 decrease with the increase in frequency and increase with the increase in temperature. The Cole-Cole types have been used to determine some parameters such as; the macroscopic relaxation time ( τo), the molecular relaxation time ( τ), the activation energy for relaxation ( Eo) and the distribution parameter ( α). The temperature dependence of τ is expressed by a thermally activated process with the activation energy of 0.299 eV.

Zinc(II) complexes with intramolecular amide oxygen coordination as models of metalloamidases.

Science.gov (United States)

Rivas, Juan C Mareque; Salvagni, Emiliano; Prabaharan, Ravi; de Rosales, Rafael Torres Martin; Parsons, Simon

2004-01-07

Polydentate ligands (6-R1-2-pyridylmethyl)-R2(R1= NHCOtBu, R2= bis(2-pyridylmethyl)amine L1, bis(2-(methylthio)ethyl)amine L2 and N(CH2CH2)2S L3) form mononuclear zinc(II) complexes with intramolecular amide oxygen coordination and a range of coordination environments. Thus, the reaction of Zn(ClO4)2.6H2O with L1-3 in acetonitrile affords [(L)Zn](ClO4)2(L=L1, 1; L2, 2) and [(L3)Zn(H2O)(NCCH3)](ClO4)2 3. The simultaneous amide/water binding in resembles the motif that has been proposed to be involved in the double substrate/nucleophile Lewis acidic activation and positioning mechanism of amide bond hydrolysis in metallopeptidases. X-ray diffraction, 1H and 13C NMR and IR data suggests that the strength of amide oxygen coordination follows the trend 1>2 >3. L1-3 and undergo cleavage of the tert-butylamide upon addition of Me4NOH.5H2O (1 equiv.) in methanol at 50(1)degrees C. The rate of amide cleavage follows the order 1> 2> 3, L1-3. The extent by which the amide cleavage reaction is accelerated in 1-3 relative to the free ligands, L1-3, is correlated with the strength of amide oxygen binding and Lewis acidity of the zinc(II) centre in deduced from the X-ray, NMR and IR studies.

Synthesis and Photophysical and Electrochemical Properties of Functionalized Mono-, Bis-, and Trisanthracenyl Bridged Ru(II Bis(2,2′:6′,2″-terpyridine Charge Transfer Complexes

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Adewale O. Adeloye

2014-01-01

Full Text Available With the aim of developing new molecular devices having long-range electron transfer in artificial systems and as photosensitizers, a series of homoleptic ruthenium(II bisterpyridine complexes bearing one to three anthracenyl units sandwiched between terpyridine and 2-methyl-2-butenoic acid group are synthesized and characterized. The complexes formulated as bis-4′-(9-monoanthracenyl-10-(2-methyl-2-butenoic acid terpyridyl ruthenium(II bis(hexafluorophosphate (RBT1, bis-4′-(9-dianthracenyl-10-(2-methyl-2-butenoic acid terpyridyl ruthenium(II bis(hexafluorophosphate (RBT2, and bis-4′-(9-trianthracenyl-10-(2-methyl-2-butenoic acid terpyridyl ruthenium(II bis(hexafluorophosphate (RBT3 were characterized by elemental analysis, FT-IR, UV-Vis, photoluminescence, 1H and 13C NMR spectroscopy, and electrochemical techniques by elemental analysis, FT-IR, UV-Vis, photoluminescence, 1H and 13C NMR spectroscopy, and electrochemical techniques. The cyclic voltammograms (CVs of (RBT1, (RBT2, and (RBT3 display reversible one-electron oxidation processes at E1/2 = 1.13 V, 0.71 V, and 0.99 V, respectively (versus Ag/AgCl. Based on a general linear correlation between increase in the length of π-conjugation bond and the molar extinction coefficients, the Ru(II bisterpyridyl complexes show characteristic broad and intense metal-to-ligand charge transfer (MLCT band absorption transitions between 480–600 nm, ε=9.45×103 M−1 cm−1, and appreciable photoluminescence spanning the visible region.

Crystallization analysis fractionation of poly(ethylene-co-styrene) produced by metallocene catalysts

KAUST Repository

Kamal, Muhammad Shahzad; Bahuleyan, Bijal Kottukkal; Sohail, Omer Bin; Emwas, Abdul-Hamid M.; Bercaw, John E.; Al-Harthi, Mamdouh Ahmed

2013-01-01

Ethylene homo polymer and ethylene-styrene copolymers were synthesized using Cp2ZrCl2 (1)/methyl aluminoxane (MAO) and rac-silylene-bis (indenyl) zirconium dichloride (2)/MAO catalyst systems by varying styrene concentration and reaction conditions

Antimalarial peroxides: the first intramolecular 1,2,4,5-tetraoxane

Directory of Open Access Journals (Sweden)

BOGDAN A. SOLAJA

2002-07-01

Full Text Available An intramolecular steroidal 1,2,4,5-tetraoxane has been synthesised in six steps starting from methyl 3-oxo-7a,12a-diacetoxy-5b-cholan-24-oate. The synthesised 1,2,4,5-tetraoxane has moderate in vitro antimalarial activity against P. falciparum strains (IC50 (D6 = 0.35 mg/mL; IC50 (W2 = 0.29 mg/mL.

2-[2-Benzoyl-3,3-bis(methylsulfanylprop-2-enylidene]malononitrile

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Joseph Nirmala

2009-08-01

Full Text Available The title compound, C15H12N2OS2, is an example of a push–pull butadiene in which the electron-releasing methylsulfanyl groups and electron-withdrawing nitrile groups on either end of the butadiene chain enhance the conjugation in the system. Short intramolecular C—H...S interactions are observed. In the crystal structure, an O...C short contact of 2.917 (3 Å is observed.

Synthesis and characterization of calcium hydroxy and fluoroapatite functionalized with methyl phosphonic dichloride

Energy Technology Data Exchange (ETDEWEB)

Agougui, Hassen; Aissa, Abdallah [Laboratoire de Physico-Chimie des Materiaux, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia); Debbabi, Mongi, E-mail: m.debbabi@yahoo.fr [Laboratoire de Physico-Chimie des Materiaux, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia)

2012-11-15

Highlights: Black-Right-Pointing-Pointer Surface reactivity of apatites toward methyl phosphonic dichloride is tested. Black-Right-Pointing-Pointer Chemical analysis shows that hydroxyapatite is more reactive. Black-Right-Pointing-Pointer NMR spectra show the formation of Ca-O-P{sub org} and P{sub inorg}-O-P{sub org} bonds. Black-Right-Pointing-Pointer AFM indicated that the texture surface was changed by grafting. - Abstract: The nature of apatite-organic molecule interaction was the subject of many investigations. Grafting the organic molecule onto the inorganic support may precede through either formation of covalent bonds or ionic interaction between superficial hydroxyl on the apatite surface and organic functions. The hybrid materials obtained by functionalization of apatite surfaces with phosphonate moieties are of interest for their potential applications such in catalysis, chromatography and biomedical domain. In this scope, calcium hydroxyl and fluoroapatite (CaHAp and CaFAp) were prepared in the presence of the methyl phosphonic dichloride (MPO), by contact method in organic solvent at 25 Degree-Sign C for 2 days. The products are rigorously characterized by chemical analysis, infrared (IR), MAS-NMR spectroscopies, powder X-ray diffraction (XRD), atomic force microscopy (AFM) and specific surface area (SSA). The X-ray powder analysis showed that the crystallinity was sensibly affected by the presence of organic moieties. The IR spectroscopy showed new vibration modes appearing related to phosphonate groups essentially at 2930, 1315, 945, 764 and 514 cm{sup -1}. The {sup 31}P MAS NMR spectrum for hydroxy and fluoroapatite exhibits a single signal at 2.8 ppm. After reaction with (MPO) the spectra show the presence of new signals, assigned to the formation of organic-inorganic bond between the superficial hydroxyl groups of the apatite ({identical_to}CaOH) and ({identical_to}POH) and methyl phosphonic dichloride. The SSA decreases with increasing

From bis(imidazole-2-thion-4-yl)phosphane to a flexible P-bridged bis(NHC) ligand and its silver complex.

Science.gov (United States)

Majhi, Paresh Kumar; Schnakenburg, Gregor; Streubel, Rainer

2014-11-28

Synthesis of the first P(V)-bridged bis(NHC) ligand 7 was achieved via deprotonation of P(V)-functionalized bis(imidazolium) salt 6, which was obtained via oxidative desulfurization of bis(imidazole-2-thion-4-yl)phosphane 2. Bis(imidazolium) salt 6 was also employed to synthesize the corresponding silver complex 8. All new products were firmly established by spectroscopic and spectrometric methods as well as elemental analysis and, in addition, X-ray crystal structure analysis in the case of 3.

Diaquabis[2,6-bis(4H-1,2,4-triazol-4-ylpyridine-κN2]bis(selenocyanato-κNcobalt(II

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Yuan-Yuan Liu

2012-08-01

Full Text Available In the title compound, [Co(NCSe2(C9H7N72(H2O2], the Co2+ cation is coordinated by two selenocyanate anions, two 2,6-bis(4H-1,2,4-triazol-4-ylpyridine ligands and two water molecules within a slightly distorted N4O2 octahedron. The asymmetric unit consists of one Co2+ cation, which is located on a center of inversion, as well as one selenocyanate anion, one 2,6-bis(4H-1,2,4-triazol-4-ylpyridine ligand and one water molecule in general positions. Intermolecular O—H...N hydrogen bonds join the complex molecules into layers parallel to the bc plane. The layers are linked by C—H...N and C—H...Se hydrogen bonds into a three-dimensional supramolecular architecture.

An intramolecular [2 + 2] cycloaddition of ketenimines via palladium-catalyzed rearrangements of N-allyl-ynamides.

Science.gov (United States)

DeKorver, Kyle A; Hsung, Richard P; Song, Wang-Ze; Wang, Xiao-Na; Walton, Mary C

2012-06-15

A cascade of Pd-catalyzed N-to-C allyl transfer-intramolecular ketenimine-[2 + 2] cycloadditions of N-allyl ynamides is described. This tandem sequence is highly stereoselective and the [2 + 2] cycloaddition could be rendered in a crossed or fused manner depending on alkene substitutions, leading to bridged and fused bicycloimines.

40 CFR 721.982 - Calcium, bis(2,4-pentanedionato-O,O′).

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Calcium, bis(2,4-pentanedionato-O,Oâ²... Substances § 721.982 Calcium, bis(2,4-pentanedionato-O,O′). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance calcium, bis(2,4-pentanedionato-O,O′) (PMN P-93-214, CAS...

UV-vis, IR and 1H NMR spectroscopic studies of some mono- and bis-azo-compounds based on 2,7-dihydroxynaphthalene and aniline derivatives

Science.gov (United States)

Issa, Raafat M.; Fayed, Tarek A.; Awad, Mohammed K.; El-Kony, Sanaa M.

2005-12-01

The absorption spectra of mono- and bis-azo-derivatives obtained by coupling the diazonium salts of aromatic amines and 2,7-dihydroxynaphthalene have been studied in six organic solvents. The different absorption bands have been assigned and the effect of solvents on the charge transfer band is also discussed. The diagnostic IR spectral bands and 1H NMR signals are assigned and discussed in relation to molecular structure. Also, semi-empirical molecular orbital calculations using the atom superposition and electron delocalization molecular orbital (ASED-MO) theory have been performed to investigate the molecular and electronic structures of these compounds. According to these calculations, an intramolecular hydrogen bonding is essential for stabilization of such molecules.

Intramolecular Hydrogen Bonding in (2-Hydroxybenzoyl)benzoylmethane Enol

DEFF Research Database (Denmark)

Hansen, Bjarke Knud Vilster; Winther, Morten; Spanget-Larsen, Jens

2014-01-01

, and the dienol form of 1,3-dibenzoylacetone. But in these examples the two H-bonds are equivalent, while in the case of OHDBM they are chemically different, involving one enolic and one phenolic hydroxy group. OHDBM is thus an interesting model compound with two competing H-bonds to the same carbonyl group......In the stable enol tautomer of the title compound (OHDBM), one carbonyl group is flanked by two β-hydroxy groups, giving rise to bifold intramolecular H-bonding. A similar situation is found in other β,β'-dihydroxy carbonyl compounds like chrysazin, anthralin, 2,2'-dihydroxybenzophenone...

1. Mono([8]annulene)Uranium(4) half-sandwich complexes, 2. Novel syntheses of symmetrically substituted cyclooctatetetraenes

International Nuclear Information System (INIS)

Boussie, T.R.

1991-10-01

A reproducible, high-yield synthesis of mono([8]annulene)uranium(4)dichloride (1) is reported, along with the X-ray crystal structural of the bis(pyridine) adduct. Metathesis reactions of the half-sandwich complex 1 with a variety of simple alkyl and alkoxy reagents failed to generate any isolable mono-ring complexes. Reactions of 1 with polydentate, delocalized anions did produce stable derivatives, including mono([8]annulene)uranium(4)bis(acetylacetonate) (4). An X-ray crystal structure of 4 is reported

1. Mono([8]annulene)Uranium(4) half-sandwich complexes, 2. Novel syntheses of symmetrically substituted cyclooctatetetraenes

Energy Technology Data Exchange (ETDEWEB)

Boussie, Thomas Richard [Univ. of California, Berkeley, CA (United States)

1991-10-01

A reproducible, high-yield synthesis of mono([8]annulene)uranium(4)dichloride (1) is reported, along with the X-ray crystal structural of the bis(pyridine) adduct. Metathesis reactions of the half-sandwich complex 1 with a variety of simple alkyl and alkoxy reagents failed to generate any isolable mono-ring complexes. Reactions of 1 with polydentate, delocalized anions did produce stable derivatives, including mono([8]annulene)uranium(4)bis(acetylacetonate) (4). An X-ray crystal structure of 4 is reported.

1. Mono((8)annulene)Uranium(4) half-sandwich complexes, 2. Novel syntheses of symmetrically substituted cyclooctatetetraenes

Energy Technology Data Exchange (ETDEWEB)

Boussie, T.R.

1991-10-01

A reproducible, high-yield synthesis of mono((8)annulene)uranium(4)dichloride (1) is reported, along with the X-ray crystal structural of the bis(pyridine) adduct. Metathesis reactions of the half-sandwich complex 1 with a variety of simple alkyl and alkoxy reagents failed to generate any isolable mono-ring complexes. Reactions of 1 with polydentate, delocalized anions did produce stable derivatives, including mono((8)annulene)uranium(4)bis(acetylacetonate) (4). An X-ray crystal structure of 4 is reported.

Coumarin or benzoxazinone bearing benzimidazolium and bis(benzimidazolium salts; involvement in transfer hydrogenation of acetophenone derivatives and hCA inhibition

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Mert Olgun Karataş

2015-10-01

Full Text Available Four new salts of benzimidazolium and bis(benzimidazolium which include coumarin or benzoxazinone moieties were synthesized and the structures of the newly synthesized compounds were elucidated on the basis of spectral analyses such as 1H-NMR, 13C-NMR, HSQC, IR, LC-MS and elemental analysis. Benzimidazolium salts were used intensively as N-heterocyclic carbene (NHC precursors in the various catalytic reactions such as transfer hydrogenation (TH, C-H bond activation, Heck, Suzuki reaction etc. With the prospect of potential NHC precursor properties of the synthesized compounds, they were employed in the (TH reaction of p-substitute acetophenones (acetophenone, p-methyl acetophenone, p-chloro acetophenone and good yields were observed. Coumarin compounds are known as inhibitor of carbonic anhydrase and inhibition effects of the synthesized compounds on human carbonic anhydrases (hCA were investigated as in vitro. The in vitro results demonstrated that all compounds inhibited hCA I and hCA II activity. Among the synthesized compounds 1,4-bis(1-((6,8-dimethyl-2H-chromen-2-one-4-ylmethylbenzimidazolium-3-ylbutane dichloride was found to be the most active IC50= 5.55 mM and 6.06 mM for hCA I and hCA II, respectively.

2,2'-(Carbono-thio-yldisulfanedi-yl)bis-(2-methyl-propanoic acid).

Science.gov (United States)

Moreno-Fuquen, Rodolfo; Grande, Carlos; Advincula, Rigoberto C; Tenorio, Juan C; Ellena, Javier

2013-05-01

The mol-ecular structure of the title compound, C9H14O4S3, exhibits intra-molecular C-H⋯S hydrogen bonds. In the crystal, pairs of O-H⋯O hydrogen bonds lead to the formation of centrosymmetric dimers, which are in turn connected by weak C-H⋯O inter-actions. The combination of these inter-actions generates edge-fused R 2 (2)(8) and R 2 (2)(20) rings running along [211].

Crystal structure of ({(1R,2R-N,N′-bis[(quinolin-2-ylmethyl]cyclohexane-1,2-diamine}chloridoiron(III-μ-oxido-[trichloridoferrate(III] chloroform monosolvate

Directory of Open Access Journals (Sweden)

Hannah Swift

2017-07-01

Full Text Available The first FeIII atom in the solvated title compound, [Fe2Cl4O(C26H28N4]·CHCl3, adopts a distorted six-coordinate octahedral geometry. It is coordinated by one chloride ligand, four N atoms from the (1R,2R-N,N′-bis[(quinolin-2-ylmethyl]cyclohexane-1,2-diamine ligand, and a bridging oxido ligand attached to the second FeIII atom, which is also bonded to three chloride ions. A very weak intramolecular N—H...Cl hydrogen bond occurs. In the crystal, the coordination complexes stack in columns, and a grouping of six such columns create channels, which are populated by disordered chloroform solvent molecules. Although the Fe—Cl bond lengths for the two metal atoms are comparable to the mean Fe—Cl bond lengths as derived from the Cambridge Structural Database, the Fe—O bond lengths are notably shorter. The solvent chloroform molecule exhibits `flip' disorder of the C—H moiety in a 0.544 (3:0.456 (3 ratio. The only directional interaction noted is a weak C—H...Cl hydrogen bond.

Crystal structure of bis[μ-bis(diphenylphosphanylmethane-κ2P:P′]digold(I dichloride acetone monosolvate monohydrate

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Chien Ing Yeo

2015-08-01

Full Text Available In the title complex salt, [Au2{(C6H52PCH2P(C6H52}]Cl2·(CH32C=O·H2O, the dication forms an eight-membered {—PCPAu}2 ring with a transannular aurophilic interaction [Au...Au = 2.9743 (2 Å]. The ring approximates a flattened boat conformation, with the two methylene C atoms lying ca 0.58–0.59 Å above the least-squares plane defined by the Au2P4 atoms (r.m.s. deviation = 0.0849 Å. One Cl− anion functions as a weak bridge between the AuI atoms [Au...Cl = 2.9492 (13 and 2.9776 (12 Å]. The second Cl− anion forms two (waterO—H...Cl hydrogen bonds about a centre of inversion, forming a centrosymmetric eight-membered {...HOH...Cl}2 supramolecular square. Globally, the dications and loosely associated Cl− anions assemble into layers lying parallel to the ac plane, being connected by C—H...Cl,π(phenyl interactions. The supramolecular squares and solvent acetone molecules are sandwiched in the inter-layer region, being connected to the layers on either side by C—H...Cl,O(acetone interactions.

Effects of supported metallocene catalyst active center multiplicity on antioxidant-stabilized ethylene homo- and copolymers

KAUST Repository

Atiqullah, Muhammad; Cibulková , Zuzana; Černá , Andrea; Šimon, Peter; Hussain, Ikram; Al-Harthi, Mamdouh A.; Anantawaraskul, Siripon

2014-01-01

© 2014 Akadémiai Kiadó, Budapest, Hungary. A silica-supported bis(n-butylcyclopentadienyl) zirconium dichloride [( n BuCp)2ZrCl2] catalyst was synthesized. This was used to prepare an ethylene homopolymer and an ethylene-1-hexene copolymer

Structural and electrochemical studies of TiO2 complexes with (4,4'-((1E,1'E)-(2,5-bis(octyloxy)-1,4-phenylene)bis(ethene-2,1-diyl))bis-(E)-N-(2,5-bis(octyloxy)benzylidene)) imine derivative bases towards organic devices.

Science.gov (United States)

Rozycka, Anna; Iwan, Agnieszka; Bogdanowicz, Krzysztof Artur; Filapek, Michal; Górska, Natalia; Hreniak, Agnieszka; Marzec, Monika

2018-06-12

Three (4,4'-((1E,1'E)-(2,5-bis(octyloxy)-1,4-phenylene)bis(ethene-2,1-diyl))bis-(E)-N-(2,5-bis(octyloxy)benzylidene)) imine derivatives were synthesized via a condensation reaction with p-toluenesulfonic acid as a catalyst. The effects of the end groups and vinylene (-HC[double bond, length as m-dash]CH-) moieties on the structural, thermal, optical, electrochemical and photovoltaic properties of imines were investigated to check the influence of TiO2 on the imine properties. The thermal behavior of imines and their complexes with TiO2 was widely investigated using FT-IR, XRD, DSC and POM methods in order to determine the order type in the imine structure. All imines present the highest occupied molecular orbital (HOMO) levels of about -5.39 eV (SAI1 and SAI2) and -5.27 eV (SAI3) and the lowest unoccupied molecular orbital (LUMO) levels at about -3.17 eV. The difference of the end groups in the imines in each case did not affect redox properties. Generally, both oxidation and reduction are easier after TiO2 addition and it also changes the HOMO-LUMO levels of imines. Moreover, changes in the characteristic bands for imines in the region 1500-1700 cm-1 observed as a drastic decrease of intensity or even disappearance of bands in the imine : TiO2 mixture suggest the formation of a complex (C[double bond, length as m-dash]N)-TiO2. Organic devices with the configuration of ITO/TiO2/SAIx (or SAIx : TiO2)/Au were fabricated and investigated in the presence and absence of visible light irradiation with an intensity of 93 mW cm-2. In all imines and complexes with TiO2, the generation of the photocurrent indicates their use as photodiodes and the best result was observed for SAI3 : TiO2 complexes.

(R-N-{2-tert-Butyl-2-[(R-tert-butylsulfonamido]ethylidene}-tert-butanesulfonamide

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Cong-Bin Fan

2008-10-01

Full Text Available The title compound, C14H30N2O2S2, is the product of the monoaddition reaction of tert-butyl magnesium chloride with bis-[(R-N-tert-butanesulfinyl]ethanediimine. There are two almost identical molecules in the asymmetric unit, the molecular conformation of which is stabilized by an intramolecular N—H...N hydrogen bond.

Tris[2,2,6,6-tetramethyl-8-(trimethylsilylbenzo[1,2-d;4,5-d′]bis(1,3-dithiol-4-yl]methanol diethyl ether monosolvate

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Nico Fleck

2018-04-01

Full Text Available The title compound, a triarylmethanol, C46H64OS12Si3 1, was synthesized via lithiation of tris-2,2,6,6-tetramethylbenzo[1,2-d;4,5-d′]bis[1,3]dithiol-4-yl-methanol, 2, and electrophilic quenching with trimethylsilyl chloride. The current crystal structure reveals information about the reactivity of this compound and compares well with the structure reported for the unsubstituted parent compound 2 [Driesschaert et al. (2012. Eur. J. Org. Chem. 33, 6517–6525]. The title compound 1 forms molecular propellers and crystallizes in P\\overline{1}, featuring an unusually long Si—Car bond of 1.910 (3 Å. Moreover, the geometry at the central quaternary carbon is rather trigonal-pyramidal than tetrahedral due to vast intramolecular stress. One trimethylsilyl group is disordered over two positions in a 0.504 (4:0.496 (4 ratio and one S atom is disordered over two positions in a 0.509 (7:0.491 (7 ratio. The contribution of disordered diethyl ether solvent molecule(s was removed using the PLATON SQUEEZE (Spek, 2015 solvent masking procedure. These solvent molecules are not considered in the given chemical formula and other crystal data.

Thermal behavior of poly(2-hydroxyethyl methacrylate-bis-[trimethoxysilylpropyl]amine) networks

International Nuclear Information System (INIS)

Bustos Figueroa, L A; Salgado Delgado, R; García Hernandez, E; Vargas Galarza, Z; Rubio Rosas, E; Salgado Rodriguez, R

2013-01-01

Poly(HEMA-BisSi) networks were prepared by using acid-catalyzed sol-gel of bis-[trimethoxysilylpropyl]amine (BisSi) and free radical polymerization of 2-hydroxyethyl methacrylate (HEMA). The thermal properties of the poly(HEMA-BisSi) networks were investigated with differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The thermal behavior of these networks was also compared with homopolymers (The networks formed in both PHEMA and PBisSi gels were identified). The glass transition temperature (T g ) of PHEMA homopolymer was found as 103.74 °C. The thermal degradation of the poly(HEMA-BisSi) networks with different silica contents (e.g. 10, 15 and 25 wt%) were evaluated with use of DTG. It was observed that the thermal degradation temperature of poly(HEMA-BisSi) networks changed much with the BisSi content.

Metallocene-catalyzed ethylene−α-olefin isomeric copolymerization: A perspective from hydrodynamic boundary layer mass transfer and design of MAO anion

KAUST Repository

Adamu, Sagir; Atiqullah, Muhammad; Malaibari, Zuhair O.; Al-Harthi, Mamdouh A.; Emwas, Abdul-Hamid M.; Ul-Hamid, Anwar

2015-01-01

-catalyzed ethylene polymerization. This approach was illustrated by conducting homo- and isomeric copolymerization of ethylene with 1-hexene and 4-methyl-1-pentene in the presence of bis(n-butylcyclopentadienyl) zirconium dichloride (nBuCp)2ZrCl2, using (i) MAO anion

A Novel Bis(phosphido)pyridine [PNP] 2− Pincer Ligand and Its Potassium and Bis(dimethylamido)zirconium(IV) Complexes

KAUST Repository

Winston, Matthew S.

2010-12-13

A novel PNP bis(secondary phosphine)pyridine pincer ligand, 2,6-bis(2-(phenylphosphino)phenyl)pyridine, has been prepared in high yield, and the properties of the doubly deprotonated form as a ligand in K 4(PNP)2(THF)6 and (PNP)Zr(NMe2) 2 have been investigated. The neutral PNP ligand has been isolated as a mixture of noninterconverting diastereomers, due to the presence of two chirogenic phosphorus atoms of the secondary phopshines, but coordination of the dianionic form to potassium and zirconium allows for isolation of a single diastereomer in near-quantitative yield. The structure of a bis(dimethylamido) zirconium(IV) derivative of the bis(phosphido)pyridine ligand and DFT calculations suggest that the phosphides do not π-bond to early transition metals, likely due to geometric strain and possibly orbital size mismatch between phosphorus and zirconium. As a result, the soft phosphides are prone to formation of insoluble oligomers with substantial bridging of the phosphido lone pairs to other zirconium centers. © 2010 American Chemical Society.

A Novel Bis(phosphido)pyridine [PNP] 2− Pincer Ligand and Its Potassium and Bis(dimethylamido)zirconium(IV) Complexes

KAUST Repository

Winston, Matthew S.; Bercaw, John E.

2010-01-01

A novel PNP bis(secondary phosphine)pyridine pincer ligand, 2,6-bis(2-(phenylphosphino)phenyl)pyridine, has been prepared in high yield, and the properties of the doubly deprotonated form as a ligand in K 4(PNP)2(THF)6 and (PNP)Zr(NMe2) 2 have been investigated. The neutral PNP ligand has been isolated as a mixture of noninterconverting diastereomers, due to the presence of two chirogenic phosphorus atoms of the secondary phopshines, but coordination of the dianionic form to potassium and zirconium allows for isolation of a single diastereomer in near-quantitative yield. The structure of a bis(dimethylamido) zirconium(IV) derivative of the bis(phosphido)pyridine ligand and DFT calculations suggest that the phosphides do not π-bond to early transition metals, likely due to geometric strain and possibly orbital size mismatch between phosphorus and zirconium. As a result, the soft phosphides are prone to formation of insoluble oligomers with substantial bridging of the phosphido lone pairs to other zirconium centers. © 2010 American Chemical Society.

Long-Range Intramolecular Electronic Communication in a Trinuclear Ruthenium Tropolonate Complex.

Science.gov (United States)

Yoshida, Jun; Kuwahara, Kyohei; Suzuki, Kota; Yuge, Hidetaka

2017-02-20

Dinuclear and trinuclear ruthenium complexes, [Ru(trop) 2 (C 2 trop)Ru(dppe)Cp] [2b; trop = tropolonato, C 2 trop = ethynyltropolonato, dppe = 1,2-bis(diphenylphosphino)ethane] and [Ru(trop){(C 2 trop)Ru(dppe)Cp} 2 ] (3), were synthesized, and their electronic and electrochemical properties were investigated in comparison with our previously reported complex [Ru(acac) 2 (C 2 trop)Ru(dppe)Cp] (2a). The electron-donating Ru II (dppe)Cp unit and electron-accepting Ru III O 6 unit are connected by C 2 trop in these complexes. 2a incorporates acetylacetonate as an ancillary ligand, while 2b and 3 incorporate tropolonate as an ancillary ligand. Every complex, 2a, 2b, and 3, exhibits similar UV-vis-near-IR (NIR) absorption spectra, demonstrating the lack of explicit intramolecular electronic communication between the units at least in the neutral state. The weak NIR absorption in 2a further diminished upon electrochemical oxidation, indicating almost no electronic communication between the units. In contrast, 2b and 3 exhibit broad NIR absorptions upon oxidation. Additionally, 3 exhibits four stepwise redox couples in the electrochemical study, which are formally attributed to [Ru II (trop) 3 ] - /[Ru III (trop) 3 ], two [Ru II (dppe)Cp]/[Ru III (dppe)Cp] + , and [Ru III (trop) 3 ]/[Ru IV (trop) 3 ] + couples. Clear separation of the redox couples attributed to the two terminal [Ru(dppe)Cp] units demonstrates the thermodynamic stability of the intermediate oxidation states with respect to disproportionation. Further electrochemical studies using an electrolyte including perfluorinated weakly coordinating anions and density functional theory/time-dependent density functional theory calculations confirmed the effect of ancillary ligands, acetylacetonate and tropolonate. In the case of 2a, electronic delocalization over the whole complex, especially over the [Ru(acac) 2 (trop)] unit, appears to be small. In contrast, the electronic communication between [Ru(dppe)Cp] and [Ru

trans-Bis(5,5-diphenylhydantoinato-κN3bis(propane-1,2-diamine-κ2N,N′nickel(II

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Xiaojiao Li

2008-12-01

Full Text Available The asymmetric unit of the title complex, [Ni(pht2(pn2] (pht is 5,5-diphenylhydantoinate and pn is propane-1,2-diamine or [Ni(C15H11N2O22(C3H10N22], contains one-half [Ni(pht2(pn2] molecule. The NiII atom is situated on a crystallographic center of inversion and shows a distorted octahedral coordination geometry. A three-dimensional network structure is assembled by inter- and intramolecular N—H...O=C interactions.

New stereoselective intramolecular

Science.gov (United States)

Alajarin; Vidal; Tovar; Ramirez De Arellano MC; Cossio; Arrieta; Lecea

2000-11-03

Efficient 1,4-asymmetric induction has been achieved in the highly stereocontrolled intramolecular [2 + 2] cycloadditions between ketenimines and imines, leading to 1,2-dihydroazeto[2, 1-b]quinazolines. The chiral methine carbon adjacent to the iminic nitrogen controls the exclusive formation of the cycloadducts with relative trans configuration at C2 and C8. The stepwise mechanistic model, based on theoretical calculations, fully supports the stereochemical outcome of these cycloadditions.

Transition metal coordination chemistry ofN,N-bis(2-{pyrid-2-ylethyl})hydroxylamine.

Science.gov (United States)

Belock, Christopher W; Cetin, Anil; Barone, Natalie V; Ziegler, Christopher J

2008-08-18

Although directly relevant to metal mediated biological nitrification as well as the coordination chemistry of peroxide, the metal complexes of hydroxylamines and their functionalized variants remain largely unexplored. The chelating hydroxylamine ligand N,N-bis(2-{pyrid-2-ylethyl})hydroxylamine can be readily generated via a solvent free reaction in high purity; however, the ligand is prone to decomposition which can hamper metal reaction. N,N-bis(2-{pyrid-2-ylethyl})hydroxylamine forms stable complexes with chromium(III), manganese(II), nickel(II), and cadmium(II) ions, coordinating in a side-on mode in the case of chromium and via the nitrogen in the case of the latter three metal ions. The hydroxylamine ligand can also be reduced to form N,N-bis(2-{pyrid-2-ylethyl})amine upon exposure to a stoichiometric amount of the metal salts cobalt(II) nitrate, vanadium(III) chloride, and iron(II) chloride. In the reaction with cobalt nitrate, the reduced ligand then chelates to the metal to form [N,N-bis(2-{pyrid-2-ylethyl})amine]dinitrocobalt(II). Upon reaction with vanadium(III) chloride and iron(III) chloride, the reduced ligand is isolated as the protonated free base, resulting from a metal-mediated decomposition reaction.

Formación y estructura secundaria del 2,3 -bis-(3,4 -dimetoxibenzoíl propionitrilo

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Francisco Sánchez Viesca

2004-01-01

Full Text Available El 3,4-dimetoxibenzoílacetonitrilo y el 2,4,5-trimetoxibenzoílacetonitrilo, requeridos en la síntesis de derivados isoxazólicos, se obtuvieron a partir de las α-halocetonas, la α-bromoacetoveratrona y el cloruro de 2,4,5-trimetoxifenacilo. En el primer caso se aisló un subproducto inesperado cuya estructura se dedujo de su espectroscopía (IR, RMN de 1H y EM y de su análisis elemental cuantitativo. Se identificó como 2,3-bis-(3,4-dimetoxibenzoílpropionitrilo. Del estudio cuidadoso de su espectro de resonancia magnética protónica se dedujo la existencia de 2 puentes de hidrógeno débiles, intramoleculares, del tipo C−H---O=C, debido a los desplazamientos químicos a mayor frecuencia que presentan los hidrógenos involucrados en dichas interacciones, así como, variaciones significativas en las constantes de acoplamiento de estos hidrógenos. Se observaron corrimientos, ∆δ, de 0.5 y de 1 ppm, como se discute en el texto. Esto se confirmó con modelos moleculares y mediante un estudio teórico empleando la teoría de funcionales de la densidad.

Naphthalene Bis(4,8-diamino-1,5-dicarboxyl)amide Building Block for Semiconducting Polymers.

Science.gov (United States)

Eckstein, Brian J; Melkonyan, Ferdinand S; Manley, Eric F; Fabiano, Simone; Mouat, Aidan R; Chen, Lin X; Facchetti, Antonio; Marks, Tobin J

2017-10-18

We report a new naphthalene bis(4,8-diamino-1,5-dicarboxyl)amide (NBA) building block for polymeric semiconductors. Computational modeling suggests that regio-connectivity at the 2,6- or 3,7-NBA positions strongly modulates polymer backbone torsion and, therefore, intramolecular π-conjugation and aggregation. Optical, electrochemical, and X-ray diffraction characterization of 3,7- and 2,6-dithienyl-substituted NBA molecules and corresponding isomeric NBA-bithiophene copolymers P1 and P2, respectively, reveals the key role of regio-connectivity. Charge transport measurements demonstrate that while the twisted 3,7-NDA-based P1 is a poor semiconductor, the planar 2,6-functionalized NBA polymers (P2-P4) exhibit ambipolarity, with μ e and μ h of up to 0.39 and 0.32 cm 2 /(V·s), respectively.

[μ-1,2-Bis(diphenylphosphinoethane-κ2P:P′]bis{[1,2-bis(diphenylphosphinoethane-κ2P,P′]cyanidocopper(I} methanol disolvate

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Rong Wang

2010-08-01

Full Text Available The title centrosymmetric complex, [Cu2(CN2(C26H24P23]·2CH3OH, consists of two five-membered [Cu(dppeCN] rings [dppe is 1,2-bis(diphenylphosphinoethane] bridged by one μ2-dppe ligand, and two methanol solvent molecules. The angles around the central metal atom indicate that each CuI atom is located in the center of a distorted tetrahedron. The coordination sphere of each CuI atom is formed by three P atoms from two dppe ligands, and one C atom from the cyanide ligand. The crystal structure is stabilized by O—H...N hydrogen bonds, which are formed by the O—H donor group from methanol and the N-atom acceptor from a cyanide ligand.

Radiation exposure of relatives of patients treated with Ra-223 dichloride

International Nuclear Information System (INIS)

Wanke, C.; Szermerski, B.; Solle, A.; Geworski, L.; Kranert, W.T.; Andreeff, M.; TU Dresden

2015-01-01

Since November 2013, a radiopharmaceutical containing Ra-223 dichloride as active substance is approved in the European Union for patients with castration resistant prostate cancer with symptomatic bone metastases and no known visceral metastases. Ra-223 (T 1/2 = 11.43 d) decays via a chain of 4 alpha and 2 beta decays. This therapy is presently the only application of an alpha emitter in clinical routine therapy. To show that the exposure of relatives and caregivers of patients treated with Ra-223 dichloride in an outpatient setting does not exceed a value of 1 mSv, the multicenter study ''RAPSODY'' was conducted. As Ra-223 and most of its progeny emit alpha particles, the internal exposure had to be evaluated in particular. Within this study, measurements of the radiation emitted from the patient were performed using standard dose-rate meters. Wipe-tests were taken in the patients' homes to identify significant contaminations and evaluated by liquid scintillation counting. Samples of saliva and sweat were taken and measured using gamma spectrometry. Ra-223 disintegrates to the noble gas Rn-219 and was measured in the exhaled breath from the patients using conventional Radon Monitors. Furthermore, a computational fluid dynamics simulation (CFD) was performed to assess the radioactivity in the air, which could be inhaled by persons close to the patient. Conclusions: The potential exposure of relatives and caregivers by external irradiation and incorporation of radioactivity exhaled or excreted by the patient with saliva or sweat is well below 1 mSv. No objections are seen regarding outpatient treatment. This paper summarizes contents of a poster presented at the Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging.

(μ-Acetato-κ2O:O′[μ-2,6-bis({bis[(pyridin-2-yl-κNmethyl]amino-κN}methyl-4-methylphenolato-κ2O:O](methanol-κOdizinc bis(perchlorate

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Biswanath Das

2014-04-01

Full Text Available The binuclear title complex, [Zn2(C33H33N6O(CH3COO2(CH3OH](ClO42, was synthesized by the reaction between 2,6-bis({[bis(pyridin-2-ylmethyl]amino}methyl-4-methylphenol (H-BPMP, Zn(OAc2 and NaClO4. The two ZnII ions are bridged by the phenolate O atom of the octadentate ligand and the acetate group. An additional methanol ligand is terminally coordinated to one of the ZnII ions, rendering the whole structure unsymmetric. Other symmetric dizinc complexes of BPMP have been reported. However, to the best of our knowledge, the present structure, in which the two ZnII ions are distinguishable by the number of coordinating ligands and the coordination geometries (octahedral and square-pyramidal, is unique. The dizinc complex is a dication, and two perchlorate anions balance the charge. The –OH group of the coordinating methanol solvent molecule forms a hydrogen bond with a perchlorate counter-anion. One of the anions is disordered over two sets of sites with an occupancy ratio of 0.734 (2:0.266 (2.

Intramolecular Association within the SAFT Framework

DEFF Research Database (Denmark)

Avlund, Ane Søgaard; Kontogeorgis, Georgios; Chapman, Walter G.

2011-01-01

A general theory for modelling intramolecular association within the SAFT framework is proposed. Sear and Jackson [Phys. Rev. E. 50 (1), 386 (1994)] and Ghonasgi and Chapman [J. Chem. Phys. 102 (6), 2585 (1995)] have previously extended SAFT to include intramolecular association for chains with two...... the contribution to the Helmholtz free energy from association (inter- as well as intramolecularly) at equilibrium. Sear and Jackson rederived the contribution to the Helmholtz free energy from association from the theory by Wertheim [J. Stat. Phys. 42 (3–4), 459 (1986)] with inclusion of intramolecular...

1,2-Bis(4-ethynylphenyldisulfane

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Hong-Jun Zhu

2010-03-01

Full Text Available In the title compound, C16H10S2, the S atoms are almost coplanar with the benzene rings to which they are bonded [deviations of 0.092 (1 and 0.022 (1 Å from their respective ring planes]. The benzene rings enclose a dihedral angle of 79.17 (3°. An intramolecular C—H...S hydrogen bond results in the formation of a five-membered ring. In the crystal structure, molecules are stacked parallel to the a axis direction. π–π interactions between benzene rings are present, with a face-to-face stacking distance of 3.622 (10 Å.

STRUCTURAL STUDY OF BIS(2,6-BIS(PYRAZOL-3-YLPYRIDINENICKEL(II BY CALORIMETRY AND EXAFS SPECTROMETRY

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Kristian H Sugiyarto

2010-06-01

Full Text Available The main aim of this work is to reveal the complex formation of 2,6-bis(pyrazol-3-ylpyridine, bpp, with nickel(II perchlorate in DMF by calorimetric stepwise complex formation and then followed by EXAFS spectrometry. It was found that the complex formation follows two stepwise pathways namely the formation of mono pyrazolyl-pyridine, [Ni(DMF3 bpp]2+, and bis pyrazolyl-pyridine, [Ni(bpp2]2+;  the formation constants being  log β1 = 6.57, and log β2 = 5.02, and the total value of log β  = 11.58. The final formation of six-coordinated compound was confirmed by EXAFS analysis with the mean Ni-Nbpp bond length of 2.0646(0.0014 Å.   Keywords: nickel(II, bpp, EXAFS

Crystal structures of three co-crystals of 1,2-bis-(pyridin-4-yl)ethane with 4-alk-oxy-benzoic acids: 4-eth-oxy-benzoic acid-1,2-bis-(pyridin-4-yl)ethane (2/1), 4-n-propoxybenzoic acid-1,2-bis(pyridin-4-yl)ethane (2/1) and 4-n-but-oxy-benzoic acid-1,2-bis-(pyridin-4-yl)ethane (2/1).

Science.gov (United States)

Tabuchi, Yohei; Gotoh, Kazuma; Ishida, Hiroyuki

2015-11-01

The crystal structures of three hydrogen-bonded co-crystals of 4-alk-oxy-benzoic acid-1,2-bis-(pyridin-4-yl)ethane (2/1), namely, 2C9H10O3·C12H12N2, (I), 2C10H12O3·C12H12N2, (II), and 2C11H14O3·C12H12N2, (III), have been determined at 93, 290 and 93 K, respectively. In (I), the asymmetric unit consists of one 4-eth-oxy-benzoic acid mol-ecule and one half-mol-ecule of 1,2-bis-(pyridin-4-yl)ethane, which lies on an inversion centre. In (II) and (III), the asymmetric units each comprise two crystallographically independent 4-alk-oxy-benzoic acid mol-ecules and one 1,2-bis-(pyridin-4-yl)ethane mol-ecule. In each crystal, the two components are linked by O-H⋯N hydrogen bonds, forming a linear hydrogen-bonded 2:1unit of the acid and the base. Similar to the structure of 2:1 unit of (I), the units of (II) and (III) adopt nearly pseudo-inversion symmetry. The 2:1 units of (I), (II) and (III) are linked via C-H⋯O hydrogen bonds, forming tape structures.

Reduction-Induced Cyclization and Redox Reactions of Fully Methylated Titanocene Dichlorides Bearing Pendant Alkenyldimethylsilyl Groups, [TiCl2{.eta.5-C5Me4(SiMe2R)}2] (R=Vinyl, and Allyl)

Czech Academy of Sciences Publication Activity Database

Lukešová, Lenka; Štěpnička, P.; Fejfarová, K.; Gyepes, R.; Císařová, I.; Horáček, Michal; Kubišta, Jiří; Mach, Karel

2002-01-01

Roč. 21, - (2002), s. 2639-2653 ISSN 0276-7333 R&D Projects: GA AV ČR IAA4040004; GA ČR GA203/02/0436 Institutional research plan: CEZ:AV0Z4040901 Keywords : titanocene * reduction-induced * dichlorides Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.215, year: 2002

40 CFR 152.175 - Pesticides classified for restricted use.

Science.gov (United States)

2010-07-01

...% and less All uses (domestic and nondomestic) Unclassified Paraquat (dichloride) and paraquat bis... subsoil ......do Do. ......do All subsoil uses Unclassified Sulfotepp Sprays and smoke generators All uses Restricted Inhalation hazard to humans. Zinc Phosphide All formulations 2% and less All domestic uses and non...

Topotactic synthesis of a new BiS2-based superconductor Bi2(O,F)S2

OpenAIRE

Okada, Tomoyuki; Ogino, Hiraku; Shimoyama, Jun-ichi; Kishio, Kohji

2015-01-01

A new BiS2-based superconductor Bi2(O,F)S2 was discovered. This is a layered compound consisting of alternate stacking structure of rock-salt-type BiS2 superconducting layer and fluorite-type Bi(O,F) blocking layer. Bi2(O,F)S2 was obtained as the main phase by topotactic fluorination of undoped Bi2OS2 using XeF2, which is the first topotactic synthesis of an electron-doped superconductor via reductive fluorination. With increasing F-content, a- and c-axis length increased and decreased, respe...

Intramolecular hydrogen bonding in malonaldehyde and its radical analogues.

Science.gov (United States)

Lin, Chen; Kumar, Manoj; Finney, Brian A; Francisco, Joseph S

2017-09-28

High level Brueckner doubles with triples correction method-based ab initio calculations have been used to investigate the nature of intramolecular hydrogen bonding and intramolecular hydrogen atom transfer in cis-malonaldehyde (MA) and its radical analogues. The radicals considered here are the ones that correspond to the homolytic cleavage of C-H bonds in cis-MA. The results suggest that cis-MA and its radical analogues, cis-MA RS , and cis-MA RA , both exist in planar geometry. The calculated intramolecular O-H⋯O=C bond in cis-MA is shorter than that in the radical analogues. The intramolecular hydrogen bond in cis-MA is stronger than in its radicals by at least 3.0 kcal/mol. The stability of a cis-malonaldehyde radical correlates with the extent of electron spin delocalization; cis-MA RA , in which the radical spin is more delocalized, is the most stable MA radical, whereas cis-MA RS , in which the radical spin is strongly localized, is the least stable radical. The natural bond orbital analysis indicates that the intramolecular hydrogen bonding (O⋯H⋯O) in cis-malonaldehyde radicals is stabilized by the interaction between the lone pair orbitals of donor oxygen and the σ * orbital of acceptor O-H bond (n → σ * OH ). The calculated barriers indicate that the intramolecular proton transfer in cis-MA involves 2.2 kcal/mol lower barrier than that in cis-MA RS .

Mercuric dichloride induces DNA damage in human salivary gland tissue cells and lymphocytes

Energy Technology Data Exchange (ETDEWEB)

Schmid, Katharina; Kroemer, Susanne [University of Regensburg, Regensburg (Germany); Sassen, Andrea [University of Regensburg, Department of Pathology, Regensburg (Germany); Staudenmaier, Rainer [Technical University of Munich, Department of Otorhinolaryngology, Head and Neck Surgery, Munich (Germany); Reichl, Franz-Xaver [University of Munich, Institute of Pharmacology and Toxicology, Munich (Germany); Harreus, Ulrich [University of Munich, Department of Otorhinolaryngology, Head and Neck Surgery, Munich (Germany); Hagen, Rudolf; Kleinsasser, Norbert [University of Wuerzburg, Department of Otorhinolaryngology, Head and Neck Surgery, Wuerzburg (Germany)

2007-11-15

Amalgam is still one of the most frequently used dental filling materials. However, the possible adverse effects especially that of the mercuric component have led to continued controversy. Considering that mercury may be released from amalgam fillings into the oral cavity and also reach the circulating blood after absorption and resorption, it eventually may contribute to tumorigenesis in a variety of target cells. The present investigation focuses on genotoxic effects below a cytotoxic dose level of mercuric dichloride (HgCl{sub 2}) in human samples of salivary glands and lymphocytes to elucidate a possible role in tumor initiation. DNA migration due to single strand breaks, alkali labile sites and incomplete excision repair was quantified with the aid of the single cell microgel electrophoresis (Comet) assay. The concepts of Olive Tail Moment, percentage of DNA in the Tail and Tail Length were used as measures of DNA damage. To control for cytotoxic effects, the trypan blue exclusion test was applied. Human samples of the parotid salivary gland and lymphocytes of ten donors were exposed to HgCl{sub 2} concentrations from 1 to 50 {mu}M. N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and dimethyl sulfoxide (DMSO) served as controls. Increasing dose-dependent DNA migration could be demonstrated after exposure to HgCl{sub 2} in cells of the salivary glands and lymphocytes. In both cell types a significant increase in DNA migration could be shown starting from HgCl{sub 2} concentrations of 5 {mu}M in comparison to the negative control. The viability of the cell systems was not affected except at the highest concentration (50 {mu}M) tested. These data indicate genotoxic effects of mercuric dichloride in human salivary glands and lymphocytes at concentrations not leading to cytotoxic effects or cell death. Consequently, a contributory role in oral salivary gland tumor initiation warrants further investigation. (orig.)

Modeling the structure and vibrational spectra for oxouranium dichloride monomer and dimer

Science.gov (United States)

Umreiko, D. S.; Shundalau, M. B.; Trubina, O. V.

2010-11-01

Structural models are designed and spectral characteristics are computed for the monomer and dimer of the oxouranium dichloride (UOCl2) molecule based on ab initio calculations. The calculations were carried out in the LANL2DZ effective core potential approximation for the uranium atom and all-electron basis sets using DFT methods for oxygen and chlorine atoms (B3LYP/cc-pVDZ). A close-to-planar Y-shaped equilibrium configuration with Cs symmetry is obtained for the UOCl2 monomer. The formation of the dimer is accompanied by both significant changes in the structure of the monomeric fragments and the actual loss of their identities. The obtained spectral characteristics are analyzed and compared with experimental data. The adequacy of the proposed models and qualitative agreement between calculation and experiment are demonstrated.

Bis(μ-pyridazine-3-carboxylato-κ2O:O′bis[aquadioxido(pyridazine-3-carboxylato-κ2N2,Ouranium(VI] dihydrate

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Janusz Leciejewicz

2009-01-01

Full Text Available The structure of the binuclear title complex, [U2(C5H3N2O24O4(H2O2]·2H2O, is composed of centrosymmetric dimers in which each UO22+ ion is coordinated by two ligand molecules. One donates its N,O-bonding group and the other donates both carboxylate O atoms. Each of the latter bridges adjacent uranyl ions. The coordination environment of the metal center is a distorted pentagonal bipyramid. The dimers are interconnected by O—H...O hydrogen bonds between coordinated and uncoordinated water molecules and carboxylate O atoms. An intramolecular O—H...N interaction is also present.

The Influence of Substituents on the Tautomerism of Symmetrically Substituted 2,2'-Bis-benzimidazoles

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Dall'Oglio Evandro

2002-01-01

Full Text Available The tautomerism of five symmetrically substituted 2,2'-bis-benzimidazoles [5(6,5'(6'-tetramethyl- (1; 5(6,5'(6'-dimethyl-(2; 5(6,5'(6'-dichloro- (3; 5(6,5'(6'-dimethoxy- (4 and 4(7,4'(7'-dimethyl-2,2'-bis-benzimidazole (5], was studied by means of ¹H NMR spectroscopy at variable temperatures, and the influence of the substituents on the energy barriers for tautomeric interconversion was interpreted with the aid of theoretical calculations.

Di-tert-butyl N-[2,6-bis(methoxymethoxyphenyl]iminodiacetate

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Ben Capuano

2009-04-01

Full Text Available The title molecule, C20H31NO8, has pseudo-C2 symmetry about the C—N bond, with the bis(tert-butoxycarbonylamino group twisted from the benzene ring plane by ca 60° and the bulky tert-butoxycarbonyl (Boc groups are orientated away from the substituted aniline group. As part of an antibacterial drug discovery programme furnishing analogues of platensimycin, we unexpectedly synthesized the bis-Boc-protected aniline.

Bis[4′-(4-cyanophenyl-2,2′:6′,2′′-terpyridine]cobalt(II dichloride

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Kun Qian

2009-11-01

Full Text Available The title complex, [Co(C22H14N42]Cl2, has been synthesized by a solvothermal reaction of the 4′-(4-cyanophenyl-2,2′:6′,2′′-terpyridine ligand with CoCl2·6H2O. The cobalt(II ion is six-coordinated by two tridentate ligands in a distorted octahedral geometry. The benzene rings form dihedral angles of 30.02 (7 and 30.26 (7° with the mean planes of the terpyridine ring systems. The chloride anions are statistically disordered over two positions with refined site occupancies of 0.601 (2 and 0.399 (2.

Topotactic synthesis of a new BiS2-based superconductor Bi2(O,F)S2

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Okada, Tomoyuki; Ogino, Hiraku; Shimoyama, Jun-ichi; Kishio, Kohji

2015-02-01

A new BiS2-based superconductor, Bi2(O,F)S2, was discovered. It is a layered compound consisting of alternately stacked structure of rock-salt-type BiS2 superconducting layers and fluorite-type Bi(O,F) blocking layers. Bi2(O,F)S2 was obtained as the main phase by topotactic fluorination of undoped Bi2OS2 using XeF2. This is the first topotactic synthesis of an electron-doped superconductor via reductive fluorination. With increasing F-content, a- and c-axis lengths increased and decreased, respectively, and Tc increased to 5.1 K.

4,4’-Bis(4-octylphenoxy)-2,2’-bipyridine

OpenAIRE

Zhen-Ting Du; Jun-Ru Wang; Ru Liu; Yan Xu

2009-01-01

4,4’-Bis(4-octylphenoxy)-2,2’-bipyridine which can be used in complexes of ruthenium was synthesized. This ligand bears a long chain for the purpose of increasing the solubility of the final complex. The synthesis was achieved through a nucleophilic aromatic substitution reaction of 4,4’-bromo-2,2’-bipyridine and 4-octylphenol.

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.

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.

Selective Complexation of Cyanide and Fluoride Ions with Ammonium Boranes: A Theoretical Study on Sensing Mechanism Involving Intramolecular Charge Transfer and Configurational Changes.

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Bhat, Haamid R; Jha, Prakash C

2017-05-18

The anion binding selectivity and the recognition mechanism of two isomeric boranes, namely, 4-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline ([p-(Mes 2 B)C 6 H 4 (NMe 3 )] + , 1, where "Mes" represents mesitylene and "Me" represents methyl) and 2-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline ([o-(Mes 2 B)C 6 H 4 (NMe 3 )] + , 2) has been investigated using density functional theory (DFT) and time dependent-density functional theory (TD-DFT) methods. Natural population analysis indicates that the central boron atoms in 1 and 2 are the most active centers for nucleophilic addition of anions. The negative magnitude of free energy changes (ΔG) reveals that out of CN - , F - , Cl - , Br - , NO 3 - , and HSO 4 - only the binding of CN - and F - with 1 and 2 is thermodynamically feasible and spontaneous. In addition, the calculated binding energies reveal that the CN - is showing lesser binding affinity than F - both with 1 and 2, while other ions, viz. NO 3 - , HSO 4 - , Br - , and Cl - , either do not bind at all or show very insignificant binding energy. The first excited states (S 1 ) of 1 and 2 are shown to be the local excited states with π → σ* transition by frontier molecular orbital analysis, whereas fourth excited states (S 4 ) of 4-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline cyanide ([p-(Mes 2 B)C 6 H 4 (NMe 3 )] CN, 1CN, the cyano form of 1) and 4-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline fluoride ([p-(Mes 2 B)C 6 H 4 (NMe 3 )] F, 1F, the fluoro form of 1) and fifth excited state (S 5 ) of 2-[bis(2,4,6-trimethylphenyl)boranyl]-N,N,N-trimethylaniline fluoride ([o-(Mes 2 B)C 6 H 4 (NMe 3 )] F, 2F, the fluoro form of 2) are charge separation states that are found to be responsible for the intramolecular charge transfer (ICT) process. The synergistic effect of ICT and partial configuration changes induce fluorescence quenching in 1CN, 1F, and 2F after a significant internal conversion (IC) from S 4 and

Assessment of the Mutagenic Potential of Carbon Disulfide, Carbon Tetrachloride, Dichloromethane, Ethylene Dichloride, and Methyl Bromide: A Comparative Analysis in Relation to Ethylene Dibromide

Science.gov (United States)

The document provides an evaluation of the mutagenic potential of five alternative fumigants to ethylene dibromide(EDB). These include carbon disulfide(CS2), carbon tetrachloride(CCl4), dichloromethane(DCM), ethylene dichloride(EDC), and methyl bromide (MB). Of the five proposed ...

Biochemical characterization of propylglyoxal bis(guanylhydrazone). Facile synthesis of monoalkylglyoxal bis(guanylhydrazones).

Science.gov (United States)

Elo, H; Laine, R; Alhonen-Hongisto, L; Jänne, J; Mutikainen, I; Lumme, P

1985-01-01

Propylglyoxal bis(guanylhydrazone) sulfate, a novel analog of the well-known antileukemic drug methylglyoxal bis(guanylhydrazone), has been prepared from 2,2-dibromopentanal, and the compound has been characterized biochemically. Although it is a powerful inhibitor of S-adenosylmethionine decarboxylase, its Ki value (0.2 microM) is considerably higher than that of ethylglyoxal bis(guanylhydrazone) (0.06 microM). The compound is only poorly taken up by tumor cells, and its accumulation is not stimulated by a prior exposure of the tumor cells to difluoromethylornithine, a compound that causes polyamine depletion. Thus, the uptake characteristics of the compound are similar to those of ethylglyoxal bis(guanylhydrazone), but in striking contrast to those of methylglyoxal and glyoxal bis(guanylhydrazones). Since the configuration of the double bonds in glyoxal, methylglyoxal and propylglyoxal bis(guanylhydrazones) has been shown to be identical, the different uptake characteristics are probably only due to differences in side chain size and/or hydrophobicity.

Highly efficient induction of chirality in intramolecular

Science.gov (United States)

Cossio; Arrieta; Lecea; Alajarin; Vidal; Tovar

2000-06-16

Highly stereocontrolled, intramolecular [2 + 2] cycloadditions between ketenimines and imines leading to 1,2-dihydroazeto[2, 1-b]quinazolines have been achieved. The source of stereocontrol is a chiral carbon atom adjacent either to the iminic carbon or nitrogen atom. In the first case, the stereocontrol stems from the preference for the axial conformer in the first transition structure. In the second case, the origin of the stereocontrol lies on the two-electron stabilizing interaction between the C-C bond being formed and the sigma orbital corresponding to the polar C-X bond, X being an electronegative atom. These models can be extended to other related systems for predicting the stereochemical outcome in this intramolecular reaction.

Synthesis and Characterisation of Eight Isomeric Bis(2-pyridyloxynaphthalenes

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Peter J. Steel

2006-09-01

Full Text Available Eight isomeric bis(2-pyridyloxynaphthalenes have been prepared from reactions of 2-bromopyridine with the appropriate dihydroxynaphthalene and the products fully characterised by 1- and 2-D NMR spectroscopy.

Photochemical Dynamics of Intramolecular Singlet Fission

Science.gov (United States)

Lin, Zhou; Iwasaki, Hikari; Van Voorhis, Troy

2017-06-01

Singlet fission (SF) converts a singlet exciton (S_1) into a pair of triplet ones (T_1) via a ``multi-exciton'' (ME) intermediate: S_1 \\longleftrightarrow ^1ME \\longleftrightarrow ^1(T_1T_1) \\longrightarrow 2T_1. In exothermic cases, e.g., crystalline pentacene or its derivatives, the quantum yield of SF can reach 200%. With SF doubling the electric current generated by an incident high-energy photon, the solar conversion efficiency in pentacene-based organic photovoltaics (OPVs) can exceed the Shockley-Queisser limit of 33.7%. The ME state is popularly considered to be a dimeric state with significant charge transfer (CT) character that is strongly coupled to both S_1 and ^1(T_1T_1), while this local model lacks strong support from full quantum dynamics studies. Intramolecular SF (ISF) occurring to covalently-bound dimers in the solution phase is an excellent model for a straightforward dynamics simulation of local excitons. In the present study, we investigate the ISF mechanisms for three covalently-bound dimers of pentacene derivatives, including ortho-, meta-, and para-bis(6,13-bis(triisopropylsilylethynyl)pentacene)benzene, in non-protic solvents. Specifically, we propagate the real-time, non-adiabatic quantum mechanical/molecular mechanical (QM/MM) dynamics on the potential energy surfaces associated with the states of S_1, ^1(T_1T_1) and CT. We explore how the energies of these ISF-relevant states and the non-adiabatic couplings between each other fluctuate with time and the instantaneous molecular configuration (e.g., intermonomer distance and orientation). We also quantitatively compare Condon and non-Condon ISF dynamics with solution-phase spectroscopic data. Our results allow us to understand the roles of CT energy levels in the ISF mechanism and propose a design strategy to maximize ISF efficiency. M. B. Smith and J. Michl, Chem. Rev. 110, 6891 (2010). W. Shockley and H. J. Queisser, J. Appl. Phys. 32, 510 (1961). T. C. Berkelbach, M. S. Hybertsen

μ-Carbonato-bis­(bis­{2-[(diethyl­amino)­meth­yl]phen­yl}bis­muth(III))

Science.gov (United States)

Soran, Albert P.; Nema, Mihai G.; Breunig, Hans J.; Silvestru, Cristian

2011-01-01

The mol­ecular structure of the title compound, [Bi2(C11H16N)4(CO3)], consists of a symmetrically bridging carbonato group which binds two [2-Et2NCH2C6H4]2Bi units that are crystallographically related via a twofold rotation axis bis­ecting the carbonate group. The two Bi atoms and two of the C atoms directly bonded to bis­muth are quasi-planar [deviations of 0.323 (1) and 0.330 (9)Å for the Bi and C atoms, respectively] with the carbonate group. The remaining two ligands are in a trans arrangement relative to the quasi-planar (CBi)2CO3 system. The metal atom is strongly coordinated by the N atom of one pendant arm [Bi—N = 2.739 (6) Å], almost trans to the O atom, while the N atom of the other pendant arm exhibits a weaker intra­molecular inter­action [Bi⋯N = 3.659 (7) Å] almost trans to a C atom. If both these intra­molecular N→Bi inter­actions per metal atom are considered, the overall coordination geometry at bis­muth becomes distorted square-pyramidal [(C,N)2BiO cores] and the compound can be described as a hypervalent 12-Bi-5 species. Additional quite short intra­molecular Bi⋯O inter­actions are also present [3.796 (8)–4.020 (9) Å]. Inter­molecular associations through weak η6⋯Bi inter­actions [Bi⋯centroid of benzene ring = 3.659 (1) Å] lead to a ribbon-like supra­molecular association. PMID:21522836

4,4’-Bis(4-octylphenoxy-2,2’-bipyridine

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Zhen-Ting Du

2009-12-01

Full Text Available 4,4’-Bis(4-octylphenoxy-2,2’-bipyridine which can be used in complexes of ruthenium was synthesized. This ligand bears a long chain for the purpose of increasing the solubility of the final complex. The synthesis was achieved through a nucleophilic aromatic substitution reaction of 4,4’-bromo-2,2’-bipyridine and 4-octylphenol.

Inter- and intramolecular deuterium isotope effects on the cytochrome P-450-catalyzed oxidative dehalogenation of 1,1,2,2-tetrachloroethane

International Nuclear Information System (INIS)

Hales, D.B.; Ho, B.; Thompson, J.A.

1987-01-01

The oxidation of 1,1,2,2-tetrachloroethane to dichloroacetic acid was investigated with rat liver microsomes and purified cytochrome P-450. Deuterium substitution had no effect on Km values, but both the inter- and intramolecular isotope effects (kH/kD) on Vmax were in the range 5.7-6.1. The equivalence of the inter- and intramolecular values indicates that 6.0 may be a good estimate of the intrinsic isotope effect. The intermolecular kH/kD value for the conversion of 1,1,2,2-trichloroethane and its 1- 2 H analog to chloroacetic acid was 5.5. These data, and the finding that 1 atom of 18 O was incorporated into the product when TCEA was oxidized in an 18 O 2 atmosphere, support an oxidative dechlorination mechanism that involves hydrogen atom abstraction by the P-450 intermediate oxo complex

Bis[μ-(E-N′-(4-oxido-4-phenylbut-3-en-2-ylidenebenzohydrazidato]bis[pyridinecopper(II

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Mehdi Hatefi

2010-07-01

Full Text Available In the crystal structure of the title centrosymmetric dimer, [Cu2(C17H14N2O22(C5H5N2], the CuII atom has an almost perfect square-pyramidal geometry. The CuII ion is coordinated by the NO2 donor atoms of the hydrazide Schiff base ligand, the N atom of the pyridine group and an O atom of the symmetry-related unit. The dihedral angles between the pyridine ring and the two phenyl rings of the ligand are 21.4 (3 and 24.0 (2°. The molecular structure is stabilized by intramolecular C—H...O interactions.

Interactions between 2,4-bis-pteridine-1,5-benzodiazepine and group 12 dihalides: synthesis, spectral and XRD structural studies and theoretical calculations.

Science.gov (United States)

Illán-Cabeza, Nuria A; Jiménez-Pulido, Sonia B; Hueso-Ureña, Francisco; Peña-Ruiz, Tomás; Quirós-Olozábal, Miguel; Moreno-Carretero, Miguel N

2016-11-28

2,4-Bis(1,3,7-trimethyl-pteridine-2,4(1H,3H)-dione-6-yl)-2,3-dihydro-2-methyl-1H-1,5-benzodiazepine (DLMBZD) has been prepared and its molecular and crystal structures have been determined from spectral and XRD data. The benzodiazepine ligand was reacted with zinc(ii), cadmium(ii) and mercury(ii) chloride, bromide and iodide to give complexes with general formula [M(DLMBZD)X 2 ]. The complexes have been synthesized and characterized by IR, NMR and elemental analysis. The structure of seven complexes has been obtained by single crystal X-ray diffraction. In all the cases, the metal is (2 + 2 + 1)-five-coordinated by two halide ligands, two nitrogen atoms from pyrazine and diazepine rings and a carbonyl oxygen from a pteridine ring. The coordinated-metal environment is a square-based pyramid, with increasing trigonality from Hg(ii) to Zn(ii) complexes. To coordinate the metals, the ligand folds itself, establishing four intramolecular σ-π interactions with the pyrimidine and pyrazine rings. A topological analysis of the electron density using the Quantum Theory of Atoms in Molecules and the complexes stability has been performed.

Controlling the oxidation of bis-tridentate cobalt(ii) complexes having bis(2-pyridylalkyl)amines: ligand vs. metal oxidation.

Science.gov (United States)

Anjana, S; Donring, S; Sanjib, P; Varghese, B; Murthy, Narasimha N

2017-08-22

Two bis-tridentate chelated cobalt(ii) complexes, which differ in the ligand structure by a methylene group, activate molecular oxygen (O 2 ), and give different oxidation products. The O 2 reaction of [Co II (pepma) 2 ] 2+ (1) with unsymmetrical 2-(2-pyridyl)-N-(2-pyridylmethyl)ethanamine (pepma) results in ligand oxidation, to the corresponding Co(ii) imine complex [Co II (pepmi) 2 ] 2+ (2). Contrastingly, the Co(ii) complex [Co II (bpma) 2 ] 2+ (3) of similar symmetrical bis(2-pyridylmethyl)amine (bpma), undergoes metal oxidation, yielding a cobalt(iii) complex, [Co III (bpma) 2 ] 2+ (4). The reversibility of the amine to imine conversion and the stability of the Co(ii) imine complex (2) are investigated. Furthermore, the solution dynamics of Co(ii) complexes are highlighted with the help of paramagnetic 1 H-NMR spectroscopy.

Conversion of Aryl Iodides into Aryliodine(III Dichlorides by an Oxidative Halogenation Strategy Using 30% Aqueous Hydrogen Peroxide in Fluorinated Alcohol

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Ajda Podgoršek

2010-04-01

Full Text Available Oxidative chlorination with HCl/H2O2 in 1,1,1-trifluoroethanol was used to transform aryl iodides into aryliodine(III dihalides. In this instance 1,1,1-trifluoroethanol is not only the reaction medium, but is also an activator of hydrogen peroxide for the oxidation of hydrochloric acid to molecular chlorine. Aryliodine(III dichlorides were formed in 72–91% isolated yields in the reaction of aryl iodides with 30% aqueous hydrogen peroxide and hydrochloric acid at ambient temperature. A study of the effect that substituents on the aromatic ring have on the formation and stability of aryliodine(III dichlorides shows that the transformation is easier to achieve in the presence of the electron-donating groups (i.e. methoxy, but in this case the products rapidly decompose under the reported reaction conditions to form chlorinated arenes. The results suggest that oxidation of hydrogen chloride with hydrogen peroxide is the initial reaction step, while direct oxidation of aryl iodide with hydrogen peroxide is less likely to occur.

Contrasting intermolecular and intramolecular exciplex formation of a 1,4-dicyano-2-methylnaphthalene-N,N-dimethyl-p-toluidine dyad.

Science.gov (United States)

Imoto, Mitsutaka; Ikeda, Hiroshi; Fujii, Takayuki; Taniguchi, Hisaji; Tamaki, Akihiro; Takeda, Motonori; Mizuno, Kazuhiko

2010-05-07

An intramolecular exciplex is formed upon excitation of the cyclohexane solution of the 1,4-dicyano-2-methylnaphthalene-N,N-dimethyl-p-toluidine dyad, but little if any intramolecular CT complex exists in the ground state of this substance in solution. In contrast, in the crystalline state, the dyad forms an intermolecular mixed-stack CT complex in the ground state and an intermolecular exciplex when it is photoexcited.

Bis(imidazolin-2-iminato) rare earth metal complexes: synthesis, structural characterization, and catalytic application.

Science.gov (United States)

Trambitas, Alexandra G; Melcher, Daniel; Hartenstein, Larissa; Roesky, Peter W; Daniliuc, Constantin; Jones, Peter G; Tamm, Matthias

2012-06-18

Reaction of anhydrous rare earth metal halides MCl(3) with 2 equiv of 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-imine (Im(Dipp)NH) and 2 equiv of trimethylsilylmethyl lithium (Me(3)SiCH(2)Li) in THF furnished the complexes [(Im(Dipp)N)(2)MCl(THF)(n)] (M = Sc, Y, Lu). The molecular structures of all three compounds were established by single-crystal X-ray diffraction analyses. The coordination spheres around the pentacoordinate metal atoms are best described as trigonal bipyramids. Reaction of YbI(2) with 2 equiv of LiCH(2)SiMe(3) and 2 equiv of the imino ligand Im(Dipp)NH in tetrahydrofuran did not result in a divalent complex, but instead the Yb(III) complex [(Im(Dipp)N)(2)YbI(THF)(2)] was obtained and structurally characterized. Treatment of [(Im(Dipp)N)(2)MCl(THF)(n)] with 1 equiv of LiCH(2)SiMe(3) resulted in the formation of [(Im(Dipp)N)(2)M(CH(2)SiMe(3))(THF)(n)]. The coordination arrangement of these compounds in the solid state at the metal atoms is similar to that found for the starting materials, although the introduction of the neosilyl ligand induces a significantly greater distortion from the ideal trigonal-bipyramidal geometry. [(Im(Dipp)N)(2)Y(CH(2)SiMe(3))(THF)(2)] was used as precatalyst in the intramolecular hydroamination/cyclization reaction of various terminal aminoalkenes and of one aminoalkyne. The complex showed high catalytic activity and selectivity. A comparison with the previously reported dialkyl yttrium complex [(Im(Dipp)N)Y(CH(2)SiMe(3))(2)(THF)(3)] showed no clear tendency in terms of activity.

Synthesis and characterization of 6,6'-bis(2-hydroxyphenyl)-2,2'-bipyridine ligand and its interaction with ct-DNA

Science.gov (United States)

Selamat, Norhidayah; Heng, Lee Yook; Hassan, Nurul Izzaty; Karim, Nurul Huda Abd

2015-09-01

The tetradentate ligand with four donor atoms OONN was synthesized. Bis(phenoxy)bipyridine ligand was prepared by Suzuki coupling reaction between 6,6'-dibromo-2,2'-bipyridyl and 2-hydroxyphenylboronic acid with presence of palladium (II) acetate. Bis(phenoxy)bipyridine ligand was also synthesized by demethylating of 6,6'-bis(2-methoxyphenyl)-2,2'-bipyridyl ligand through solvent free reaction using pyridine hydrocloride. The formation of both phenoxy and methoxy ligands was confirmed by 1H, 2D cosy and 13C NMR spectroscopy, ESI-MS spectrometry, FTIR spectroscopy. The purity of the ligand was confirmed by melting point. Binding studies of small molecules with DNA are useful to understand the reaction mechanism and to provide guidance for the application and design of new and more efficient drugs targeted to DNA. In this study, the binding interaction between the synthesized ligand with calf thymus-DNA (ct-DNA) has been investigated by UV/Vis DNA titration study. From the UV/Vis DNA study, it shows that bis(phenoxy)bipyridine ligand bind with ct-DNA via outside binding with binding contant Kb = 1.19 × 103 ± 0.08 M-1.

Potassium hydroxide/dimethyl sulfoxide promoted intramolecular cyclization for the synthesis of benzimidazol-2-ones.

Science.gov (United States)

Beyer, Astrid; Reucher, Christine M M; Bolm, Carsten

2011-06-03

A new protocol for intramolecular N-arylations of ureas to form benzimidazol-2-ones has been developed. The cyclization reaction occurs in the presence of KOH and DMSO at close to ambient temperature. Under these conditions the yields are high and a wide range of functional groups are tolerated.

μ(4)-Orthothio-carbonato-tetra-kis-[tri-carbonyl-iron(I)](2 Fe-Fe).

Science.gov (United States)

Shi, Yao-Cheng; Cheng, Huan-Ren; Yuan, Li-Min; Li, Qian-Kun

2011-11-01

The fused bis-butterfly-shaped title compound, [Fe(4)(CS(4))(CO)(12)], possesses an orthothio-carbonate (CS(4) (4-)) ligand that acts as a bridge between two Fe(2)(CO)(6) units. A short intra-molecular S⋯S contact [2.6984 (8) and 2.6977 (8) Å] occurs in each S(2)Fe(2)(CO)(6) fragment.

Iodine-Mediated Intramolecular Dehydrogenative Coupling: Synthesis of N-Alkylindolo[3,2-c]- and -[2,3-c]quinoline Iodides.

Science.gov (United States)

Volvoikar, Prajesh S; Tilve, Santosh G

2016-03-04

An I2/TBHP-mediated intramolecular dehydrogenative coupling reaction is developed for the synthesis of a library of medicinally important 5,11-dialkylindolo[3,2-c]quinoline salts and 5,7-dimethylindolo[2,3-c]quinoline salts. The annulation reaction is followed by aromatization to yield tetracycles in good yield. This protocol is also demonstrated for the synthesis of the naturally occurring isocryptolepine in salt form.

Bis[2,6-bis(trimethylsilylaminopyridine-κN1]{[6-bis(trimethylsilylaminopyridin-2-yl-κN1](trimethylsilylazanido-κN}lithium

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Justin A. Rave

2016-03-01

Full Text Available The title complex, [Li(C11H22N3Si2(C11H23N3Si22], contains a single lithium cation coordinated to three ligands. This is the first reported example of the ligand 2,6-bis(trimethylsilylaminopyridine supporting a monometallic complex. One ligand is mono-anionic and forms a four-membered chelate ring with the lithium cation via the pyridine and silylamido N atoms. The other two ligands are neutral and bind via the pyridine nitrogen. The lithium cation is coordinated in a tetrahedral environment. No intra- or intermolecular hydrogen bonding is observed in the crystal structure, likely indicating that weak electrostatic interactions are the dominant feature of the crystal packing.

Comprehensive and Facile Synthesis of Some Functionalized Bis-Heterocyclic Compounds Containing a Thieno[2,3-b]thiophene Motif

Science.gov (United States)

Mabkhot, Yahia N.; Barakat, Assem; Al-Majid, Abdullah M.; Alshahrani, Saeed A.

2012-01-01

A comprehensive and facile method for the synthesis of new functionalized bis-heterocyclic compounds containing a thieno[2,3-b]thiophene motif is described. The hitherto unknown bis-pyrazolothieno[2,3-b]thiophene derivatives 2a–c, bis-pyridazin othieno[2,3-b]thiophene derivatives 4, bis-pyridinothieno[2,3-b]thiophene derivatives 6a,b, and to an analogous bis-pyridinothieno[2,3-b]thiophene nitrile derivatives 7 are obtained. Additionally, the novel bis-pyradazinonothieno[2,3-b]thiophene derivatives 9, and nicotinic acid derivatives 10, 11 are obtained via bis-dienamide 8. The structures of all newly synthesized compounds have been elucidated by 1H, 13C NMR, GCMS, and IR spectrometry. These compounds represent a new class of sulfur and Nitrogen containing heterocycles that should also be of interest as new materials. PMID:22408452

Titanocene Dichloride Complexes Bonded to Carbosilane Dendrimers Via a Spacer of Variable Length – Molecular Dynamics Calculations and Catalysis of Allylic Coupling Reactions

Czech Academy of Sciences Publication Activity Database

Strašák, Tomáš; Jaroschik, F.; Malý, M.; Čermák, Jan; Sýkora, Jan; Fajgar, Radek; Karban, Jindřich; Harakat, D.

2014-01-01

Roč. 409, SI (2014), s. 137-146 ISSN 0020-1693 R&D Projects: GA MŠk(CZ) LC06070 Grant - others:UJEP(CZ) GA13-06989S Institutional support: RVO:67985858 Keywords : metallodendrimers * titanocene dichloride * allylic homocoupling * molecular dynamics Subject RIV: CC - Organic Chemistry Impact factor: 2.046, year: 2014

21 CFR 73.3106 - 1,4-Bis[4-(2-methacryloxyethyl) phenylamino]anthraquinone copolymers.

Science.gov (United States)

2010-04-01

...]anthraquinone copolymers. 73.3106 Section 73.3106 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... § 73.3106 1,4-Bis[4-(2-methacryloxyethyl) phenylamino]anthraquinone copolymers. (a) Identity. The color additive is 1,4-bis[4-(2-methacryloxyethyl) phenylamino]anthraquinone (CAS Reg. No. 121888-69-5...

BIS-2 spectrometer for search and investigation of narrow resonances

International Nuclear Information System (INIS)

Aleev, A.N.; Aref'ev, V.A.; Balandin, V.P.

1989-01-01

The configuration and main characteristics of the BIS-2 spectrometer are described. The spectrometer was intended to search for and to investigate charmed particles and narrow resonances produced in neutron-nucleus interactions. It was placed on a neutron beam of the Serpukhov accelerator. The Monte-Carlo simulated and experimentally measured characteristics of individual elements and the spectrometer as a whole are described. A brief review of the principal results based on the analysis of more than 10 7 neutron-nucleus interactions registered by means of the BIS-2 spectrometer is given. 34 refs.; 8 figs.; 5 tabs

TDDFT study on excited state intramolecular proton transfer mechanism in 2-amino-3-(2‧-benzazolyl)-quinolines

Science.gov (United States)

Jia, Xueli; Li, Chaozheng; Li, Donglin; Liu, Yufang

2018-03-01

The intramolecular proton transfer reaction of the 2-amino-3-(2‧-benzoxazolyl)-quinoline (ABO) and 2-amino-3-(2‧-benzothiazolyl)-quinoline (ABT) molecules in both S0 and S1 states at B3LYP/6-311 ++G(d,p) level in ethanol solvent have been studied to reveal the deactivation mechanism of the tautomers of the two molecules from the S1 state to the S0 state. The results show that the tautomers of ABO and ABT molecules may return to the S0 state by emitting fluorescence. In addition, the bond lengths, angles and infrared spectra are analyzed to confirm the hydrogen bonds strengthened upon photoexcitation, which can facilitate the proton transfer process. The frontier molecular orbitals (MOs) and natural bond orbital (NBO) are also calculated to indicate the intramolecular charge transfer which can be used to explore the tendency of ESIPT reaction. The potential energy surfaces of the ABO and ABT molecules in the S0 and S1 states have been constructed. According to the energy potential barrier of 9.12 kcal/mol for ABO molecule and 5.96 kcal/mol for ABT molecule, it can be indicated that the proton transfer may occur in the S1 state.

Iron(iii) bis(pyrazol-1-yl)acetate based decanuclear metallacycles: synthesis, structure, magnetic properties and DFT calculations.

Science.gov (United States)

Gajewska, Małgorzata J; Bieńko, Alina; Herchel, Radovan; Haukka, Matti; Jerzykiewicz, Maria; Ożarowski, Andrzej; Drabent, Krzysztof; Hung, Chen-Hsiung

2016-09-27

The synthesis, structural aspects, magnetic interpretation and theoretical rationalizations for a new member of the ferric wheel family, a decanuclear iron(iii) complex with the formula [Fe 10 (bdtbpza) 10 (μ 2 -OCH 3 ) 20 ] (1), featuring the N,N,O tridentate bis(3,5-di-tert-butylpyrazol-1-yl)acetate ligand, are reported. The influence of the steric effect on both the core geometry and coordination mode is observed. Temperature dependent (2.0-300 K range) magnetic susceptibility studies carried out on complexes 1 established unequivocally antiferromagnetic (AF) interactions between high-spin iron(iii) centers (S = 5/2), leading to a ground state S = 0. The mechanism of AF intramolecular coupling was proved using a broken-symmetry approach within the density functional method at the B3LYP/def2-TZVP(-f)/def2-SVP level of theory.

Surface modification of calcium fluoro and hydroxyapatite by 1-octylphosphonic dichloride

Science.gov (United States)

Aissa, Abdallah; Agougui, Hassen; Debbabi, Mongi

2011-08-01

The reactivity of the surface of calcium hydroxyapatite (CaHAp) and fluorapatite (CaFAp) was tested and compared by grafting the 1-octylphosphonic dichloride (C 8H 17OPCl 2) using a molar ratio x = 2 or 4, x = n(organic)/ n(apatite). Successful synthesis was confirmed by different characterisation techniques such as X-ray powder diffraction patterns, IR spectroscopy, MAS-NMR ( 1H and 31P) and chemical analysis. The difference between their specific surface area (SSA: 57.46 for HAp and 12.09 m 2/g for FAp), the percentage of carbon measured after treatment with (C 8H 17OPCl 2) and the intensities of IR bands attributed to the grafted moiety suggests that the surface of hydroxyapatite is more reactive than that of fluorapatite. The 31P CP-MAS-NMR spectra of treated fluorapatite show a significant change in isotropic signal due to the protonation and deprotonation of superficial phosphate group. This can be explained by the difference in the nature of inorganic material.

Surface modification of calcium fluoro and hydroxyapatite by 1-octylphosphonic dichloride

Energy Technology Data Exchange (ETDEWEB)

Aissa, Abdallah; Agougui, Hassen [Laboratoire de Physico-Chimie des Materiaux, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia); Debbabi, Mongi, E-mail: m.debbabi@yahoo.fr [Laboratoire de Physico-Chimie des Materiaux, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia)

2011-08-15

The reactivity of the surface of calcium hydroxyapatite (CaHAp) and fluorapatite (CaFAp) was tested and compared by grafting the 1-octylphosphonic dichloride (C{sub 8}H{sub 17}OPCl{sub 2}) using a molar ratio x = 2 or 4, x = n(organic)/n(apatite). Successful synthesis was confirmed by different characterisation techniques such as X-ray powder diffraction patterns, IR spectroscopy, MAS-NMR ({sup 1}H and {sup 31}P) and chemical analysis. The difference between their specific surface area (SSA: 57.46 for HAp and 12.09 m{sup 2}/g for FAp), the percentage of carbon measured after treatment with (C{sub 8}H{sub 17}OPCl{sub 2}) and the intensities of IR bands attributed to the grafted moiety suggests that the surface of hydroxyapatite is more reactive than that of fluorapatite. The {sup 31}P CP-MAS-NMR spectra of treated fluorapatite show a significant change in isotropic signal due to the protonation and deprotonation of superficial phosphate group. This can be explained by the difference in the nature of inorganic material.

Surface modification of calcium fluoro and hydroxyapatite by 1-octylphosphonic dichloride

International Nuclear Information System (INIS)

Aissa, Abdallah; Agougui, Hassen; Debbabi, Mongi

2011-01-01

The reactivity of the surface of calcium hydroxyapatite (CaHAp) and fluorapatite (CaFAp) was tested and compared by grafting the 1-octylphosphonic dichloride (C 8 H 17 OPCl 2 ) using a molar ratio x = 2 or 4, x = n(organic)/n(apatite). Successful synthesis was confirmed by different characterisation techniques such as X-ray powder diffraction patterns, IR spectroscopy, MAS-NMR ( 1 H and 31 P) and chemical analysis. The difference between their specific surface area (SSA: 57.46 for HAp and 12.09 m 2 /g for FAp), the percentage of carbon measured after treatment with (C 8 H 17 OPCl 2 ) and the intensities of IR bands attributed to the grafted moiety suggests that the surface of hydroxyapatite is more reactive than that of fluorapatite. The 31 P CP-MAS-NMR spectra of treated fluorapatite show a significant change in isotropic signal due to the protonation and deprotonation of superficial phosphate group. This can be explained by the difference in the nature of inorganic material.

Bis[O,O′-bis(4-tert-butylphenyl dithiophosphato-κ2S,S′]bis(pyridine-κNlead(II

Directory of Open Access Journals (Sweden)

Xiulan Zhang

2013-09-01

Full Text Available In the title compound, [Pb(C20H26O2PS22(C5H5N2], the PbII ion is coordinated by two S,S′-bidentate anions and two pyridine molecules. The PbN2S4 coordination geometry approximates to a pentagonal bipyramid with one equatorial site vacant. The N atoms occupy the axial sites. One of the pyridine molecules is disordered over two sets of sites in a 0.907 (7:0.093 (7 ratio and one of the tert-butyl groups is disordered over two sets of sites in a 0.534 (6:0.466 (6 ratio. An intramolecular C—H...O interaction occurs in one of the ligands. In the crystal, pairs of short Pb...S contacts [3.4018 (11 Å] generate a centrosymmetric dimeric assembly with the distant S atom lying in the region of the vacant coordination site of the metal atom. No directional packing interactions occur.

μ-Oxalato-bis[(2,2′-bipyridylcopper(II] bis(perchlorate dimethylformamide disolvate monohydrate

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Alexander N. Boyko

2010-09-01

Full Text Available The title compound, [Cu2(C2O4(C10H8N24](ClO42·2C3H7NO·H2O, contains doubly charged centrosymmetric dinuclear oxalato-bridged copper(II complex cations, perchlorate anions, and DMF and water solvate molecules. In the complex cation, the oxalate ligand is coordinated in a bis-bidentate bridging mode to the Cu atoms. Each Cu atom has a distorted tetragonal-bipyramidal environment, being coordinated by two N atoms of the two chelating bipy ligands and two O atoms of the doubly deprotonated oxalate anion. Pairs of perchlorate anions and water molecules are linked into rectangles by O—H...O bonds in which the perchlorate O atoms act as acceptors and the water molecules as donors. Methyl groups of the DMF solvent molecule are disordered over two sites with occupancies of 0.453 (7:0.547 (7, and the water molecule is half-occupied.

Spectroscopic study of 2-, 4- and 5-substituents on p Ka values of imidazole heterocycles prone to intramolecular proton-electrons transfer

Science.gov (United States)

Eseola, Abiodun O.; Obi-Egbedi, Nelson O.

2010-02-01

New 2-(1H-imidazol-2-yl)phenols ( L1Et- L8tBuPt) bearing a phenolic proton in the vicinity of the imidazole base were prepared and characterized. Experimental studies of the dependence of their protonation/deprotonation equilibrium on substituent identities and intramolecular hydrogen bonding tendencies were carried out using electronic absorption spectroscopy at varying pH values. In order to make comparison, 2-(anthracen-10-yl)-4,5-diphenyl-1H-imidazole ( L9Anthr) bearing no phenolic proton and 4,5-diphenyl-2-(4,5-diphenyl-1H-imidazol-2-yl)-1H-imidazole ( L10BisIm) bearing two symmetrical imidazole base fragments were also prepared and experimentally investigated. DFT calculations were carried out to study frontier orbitals of the investigated molecules. While electron-releasing substituents produced increase in protonation-deprotonation p Kas for the hydroxyl group, values for the imidazole base were mainly affected by polarization of the imidazole ring aromaticity across the 2-imidazole carbon and the 4,5-imidazole carbons axis of the imidazole ring. It was concluded that electron-releasing substituents on the phenol ring and/or electron-withdrawing substituents on 4,5-imidazole carbons negatively affects donor strengths/coordination chemistries of 2-(1H-imidazol-2-yl)phenols, and vice versa. Change of substituents on the phenol ring significantly altered the donor strength of the imidazole base. The understanding of p Ka variation on account of electronic effects of substituents in this work should aid the understanding of biochemical properties and substituent environments of imidazole-containing biomacromolecules.

Poly[{μ2-1,2-bis[4-(3-pyridylpyrimidin-2-ylsulfanyl]ethane}di-μ2-cyanido-dicopper(I

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Lin Cheng

2008-07-01

Full Text Available The asymmetric unit of the title complex, [Cu2(CN2(C20H16N6S2]n, contains one CuI cation, one cyanide ligand and half of a centrosymmetric 1,2-bis[4-(3-pyridylpyrimidin-2-ylsulfanyl]ethane (bppe ligand. The CuI atom displays a trigonal coordination geometry, being surrounded by one C atom from one cyanide anion and two N atoms from one cyanide and one bppe ligand. In the complex, each cyanide anion links two CuI atoms in a bis-monodentate mode into a zigzag [–Cu—CN–]n chain. Two parallel chains are linked by bppe ligands into a ladder chain.

Photochemical and electrochemical studies on lanthanide complexes of 6-(hydroxymethylpyridine- 2-carboxaldehyde[2- methyl-pyrimidine-4,6-diyl] bis-hydrazone

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María Alejandra Fernandez

2014-01-01

Full Text Available Herein we report the synthesis of the 6-(hydroxymethylpyridine-2- carboxaldehyde[2-methyl-pyrimidine- 4,6-diyl]bis-hydrazone by a condensation reaction between 6-(hydroxymethyl picolinaldehyde with 4,6-(bis-hydrazino-2- methylpyrimidine. This bis-hydrazone can be visualized as a two-arm system which exhibits photochemical induced [E,E]/[E,Z]/[Z,Z’] isomerizations and double coordination to metal centers. Configurational changes, upon UV light irradiation, were followed over time by 1 H NMR, establishing that isomerization, in both arms, is a consecutive reaction that follows first-order kinetics (k1 = 4.06 x 10-4 s-1 and k2 = 2.80 x 10-4 s-1. Furthermore, the synthesis of bis-hydrazone metal complexes with La (III and Sm (III ions was achieved; subsequently, the absorption and emission properties of these complexes were studied, determining the fluorescence quantum yields, La= 0.2024 and Sm= 0.1413. Electrochemical studies of the complexes were conducted by square wave voltammetry, demonstrating that the bis-hydrazone and its complexes are electroactive species between +1.5 and -2.5 V.

Intramolecular carbenoid ylide forming reactions of 2-diazo-3-keto-4-phthalimidocarboxylic esters derived from methionine and cysteine

Directory of Open Access Journals (Sweden)

Marc Enßle

2012-03-01

Full Text Available Methionine, S-benzylcysteine and S-allylcysteine were converted into 2-diazo-3-oxo-4-phthalimidocarboxylic esters 8a–c in three steps. Upon rhodium-catalysed dediazoniation, two intramolecular carbenoid reactions competed, namely the formation of a cyclic sulfonium ylide and that of a six-ring carbonyl ylide. The S-methyl and S-benzyl ylides 12a and b could be isolated, while S-allyl ylide 12c underwent a [2,3]-sigmatropic rearrangement. The short-lived carbonyl ylides derived from methionine and S-benzylcysteine formed head-to-tail dimers by a [3 + 3]-cycloaddition and could be trapped with external dipolarophiles, while the S-allyl derivative 14c yielded the pentacyclic compound 17 by an intramolecular [3 + 2]-cycloaddition reaction.

Conductivity and thermopower studies of bis-tetramethyltetraselenafulvalenium hexafluorophosphide, bis-tetramethyltetrathiafulvalenium hexafluorophosphide, and their solid solutions, (TMTSF1-xTMTTFx)2PF6

DEFF Research Database (Denmark)

Mortensen, Kell; Engler, E. M.

1984-01-01

The conductivity σ and the thermoelectric power S have been studied experimentally on the organic conductors bis-tetramethyltetraselenafulvalenium hexafluorophosphide [(TMTSF)2PF6] and bis-tetramethyltetrathiafulvalenium hexafluorophosphide [(TMTTF)2PF6] and their solid solutions: (TMTSF1-xTMTTFx)2......PF6. Dramatic effects are seen in σ already when dilute concentrations of TMTTF molecules are introduced in the TMTSF chains, and for x=0.1, σ shows generally activated behavior. The thermopower, on the contrary, remains basically unaffected for x at least as large as 0.25. These unusual findings...

Isolation and Characterization of Bis (2 – Methoxyethyl) Phthalate ...

African Journals Online (AJOL)

Isolation and Characterization of Bis (2 – Methoxyethyl) Phthalate and Hexashydro-1 3 – Dimethyl – 4 – Phenyl – 1h – Azepine 4 – Carboxylic Acid from the Root of Cissampelos Owariensis (P. Beauv)

Crystal structures of functional building blocks derived from bis(benzo[b]thiophen-2-yl)methane.

Science.gov (United States)

Katzsch, Felix; Gruber, Tobias; Weber, Edwin

2016-09-01

The syntheses of three bis(benzo[b]thiophen-2-yl)methane derivatives, namely bis(benzo[b]thiophen-2-yl)methanone, C17H10OS2, (I), 1,1-bis(benzo[b]thiophen-2-yl)-3-(trimethylsilyl)prop-2-yn-1-ol, C22H20OS2Si, (II), and 1,1-bis(benzo[b]thiophen-2-yl)prop-2-yn-1-ol, C19H12OS2, (III), are described and their crystal structures discussed comparatively. The conformation of ketone (I) and the respective analogues are rather similar for most of the compounds compared. This is true for the interplanar angles, the Caryl-Cbridge-Caryl angles and the dihedral angles. The best resemblance is found for a bioisotere of (I), viz. 2,2'-dinaphthyl ketone, (VII). By way of interest, the crystal packings also reveal similarities between (I) and (VII). In (I), the edge-to-face interactions seen between two napthyl residues in (VII) are substituted by S...π contacts between the benzo[b]thiophen-2-yl units in (I). In the structures of the bis(benzo[b]thiophen-2-yl)methanols, i.e. (II) and (III), the interplanar angles are also quite similar compared with analogues and related active pharmaceutical ingredients (APIs) containing the dithiophen-2-ylmethane scaffold, though the dihedral angles show a larger variability and produce unsymmetrical molecules.

Synthesis and characterization of 6,6’-bis(2-hydroxyphenyl)-2,2’-bipyridine ligand and its interaction with ct-DNA

International Nuclear Information System (INIS)

Selamat, Norhidayah; Heng, Lee Yook; Hassan, Nurul Izzaty; Karim, Nurul Huda Abd

2015-01-01

The tetradentate ligand with four donor atoms OONN was synthesized. Bis(phenoxy)bipyridine ligand was prepared by Suzuki coupling reaction between 6,6’-dibromo-2,2’-bipyridyl and 2-hydroxyphenylboronic acid with presence of palladium (II) acetate. Bis(phenoxy)bipyridine ligand was also synthesized by demethylating of 6,6’-bis(2-methoxyphenyl)-2,2’-bipyridyl ligand through solvent free reaction using pyridine hydrocloride. The formation of both phenoxy and methoxy ligands was confirmed by 1 H, 2D cosy and 13 C NMR spectroscopy, ESI-MS spectrometry, FTIR spectroscopy. The purity of the ligand was confirmed by melting point. Binding studies of small molecules with DNA are useful to understand the reaction mechanism and to provide guidance for the application and design of new and more efficient drugs targeted to DNA. In this study, the binding interaction between the synthesized ligand with calf thymus-DNA (ct-DNA) has been investigated by UV/Vis DNA titration study. From the UV/Vis DNA study, it shows that bis(phenoxy)bipyridine ligand bind with ct-DNA via outside binding with binding contant K b = 1.19 × 10 3 ± 0.08 M −1

Excited state Intramolecular Proton Transfer in Anthralin

DEFF Research Database (Denmark)

Møller, Søren; Andersen, Kristine B.; Spanget-Larsen, Jens

1998-01-01

Quantum chemical calculations performed on anthralin (1,8-dihydroxy-9(10H)-anthracenone) predict the possibility of an excited-state intramolecular proton transfer process. Fluorescence excitation and emission spectra of the compound dissolved in n-hexane at ambient temperature results in an unus......Quantum chemical calculations performed on anthralin (1,8-dihydroxy-9(10H)-anthracenone) predict the possibility of an excited-state intramolecular proton transfer process. Fluorescence excitation and emission spectra of the compound dissolved in n-hexane at ambient temperature results......, associated with an excited-state intramolecular proton transfer process....

Dosimetry of bone metastases in targeted radionuclide therapy with alpha-emitting {sup 223}Ra-dichloride

Energy Technology Data Exchange (ETDEWEB)

Pacilio, Massimiliano [Azienda Ospealiera San Camillo Forlianini, Rome (Italy). Dept. of Medical Physics; Ventroni, Guido; Mango, Lucio [Azienda Ospealiera San Camillo Forlianini, Rome (Italy). Dept. of Nuclear Medicin; De Vincentis, Giuseppe; Di Castro, Elisabetta; Frantellizzi, Viviana; Follacchio, Giulia Anna; Garkavaya, Tatiana [Rome Univ. (Italy). Dept. of Radiological, Oncological and Anatomo Pathological Sciences; Cassano, Bartolomeo; Lorenzon, Leda [Rome Univ. (Italy). Postgraduate School of Medical Physics; Pellegrini, Rosanna; Pani, Roberto [Rome Univ. (Italy). Dept. of Molecular Medicine; Ialongo, Pasquale [Azienda Ospealiera San Camillo Forlianini, Rome (Italy). Dept. of Radiology

2016-01-15

Ra-dichloride is an alpha-emitting radiopharmaceutical used in the treatment of bone metastases from castration-resistant prostate cancer. Image-based dosimetric studies remain challenging because the emitted photons are few. The aim of this study was to implement a methodology for in-vivo quantitative planar imaging, and to assess the absorbed dose to lesions using the MIRD approach. The study included nine Caucasian patients with 24 lesions (6 humeral head lesions, 4 iliac wing lesions, 2 scapular lesions, 5 trochanter lesions, 3 vertebral lesions, 3 glenoid lesions, 1 coxofemoral lesion). The treatment consisted of six injections (one every 4 weeks) of 50 kBq per kg body weight. Gamma-camera calibrations for {sup 223}Ra included measurements of sensitivity and transmission curves. Patients were statically imaged for 30 min, using an MEGP collimator, double-peak acquisition, and filtering to improve the image quality. Lesions were delineated on {sup 99m}Tc-MDP whole-body images, and the ROIs superimposed on the {sup 223}Ra images after image coregistration. The activity was quantified with background, attenuation, and scatter correction. Absorbed doses were assessed deriving the S values from the S factors for soft-tissue spheres of OLINDA/EXM, evaluating the lesion volumes by delineation on the CT images. In 12 lesions with a wash-in phase the biokinetics were assumed to be biexponential, and to be monoexponential in the remainder. The optimal timing for serial acquisitions was between 1 and 5 h, between 18 and 24 h, between 48 and 60 h, and between 7 and 15 days. The error in cumulated activity neglecting the wash-in phase was between 2 % and 12 %. The mean effective half-life (T{sub 1/2eff}) of {sup 223}Ra was 8.2 days (range 5.5-11.4 days). The absorbed dose (D) after the first injection was 0.7 Gy (range 0.2-1.9 Gy). Considering the relative biological effectiveness (RBE) of alpha particles (RBE = 5), D{sub RBE} = 899 mGy/MBq (range 340-2,450 mGy/MBq). The

One-pot synthesis of spiropyrroloquinoline-isoindolinone and their aza-analogs via the Ugi-4CR/metal-free intramolecular bis-annulation process.

Science.gov (United States)

Ghandi, Mehdi; Zarezadeh, Nahid; Abbasi, Alireza

2015-08-14

This presentation discloses a one-pot synthesis of a series of spiropyrroloquinoline isoindolinone and spiropyrroloquinoline aza-isoindolinone scaffolds. The reaction proceeds by the combination of a Ugi four-component reaction (4CR) and two intramolecular cyclizations under metal-free conditions. The proof of the structures relies on analytical investigation and X-ray crystallography.

Diazo Esters as Dienophiles in Intramolecular (4 + 2) Cycloadditions: Computational Explorations of Mechanism.

Science.gov (United States)

Duan, Abing; Yu, Peiyuan; Liu, Fang; Qiu, Huang; Gu, Feng Long; Doyle, Michael P; Houk, K N

2017-02-22

The first experimental examples of Diels-Alder (DA) reactions of diazo compounds as heterodienophiles with dienes have been studied with density functional theory (DFT) using the M06-2X functional. For comparison, the reactivities of diazo esters as dienophiles or 1,3-dipoles with 1,3-dienes in intermolecular model systems have been analyzed by the distortion/interaction model. The 1,3-dipolar cycloaddition is strongly favored for the intermolecular system. The intramolecular example is unique because the tether strongly favors the (4 + 2) cycloaddition.

An Efficient Synthesis of Substituted Furans by Cupric Halide-Mediated Intramolecular Halocyclization of 2-(1-Alkynyl)-2-alken-1-ones

International Nuclear Information System (INIS)

Fu, Weijun; Guo, Wenbo; Zhu, Mei; Xu, Chen; Xu, Fengjuan

2013-01-01

An efficient synthesis of 3-halofurans by the intramolecular cyclization of 2-(1-alkynyl)-2-alken-1-ones with cupric halide has been developed. A broad range of 3-chloro- and 3-bromofuran derivatives could be obtained in the present method in moderate to good yields. The 3-halofuran derivatives are potential synthetic intermediates for amplification of molecular complexity

4-Aminobenzoic acid–1,2-bis(4-pyridylethane (2/1

Directory of Open Access Journals (Sweden)

Fwu Ming Shen

2010-07-01

Full Text Available In the title compound, C12H12N2·2C7H7NO2, the 4-aminobenzoic acid molecules are linked by O—H...N hydrogen bonds to 1,2-bis(4-pyridylethane, forming linear hydrogen bonded chains parallel to [2overline{1}1]. The structure exhibits a hydrogen-bonding network involving COOH...N(pyridyl and amine and carboxylic N—H... O interactions. In addition, π–π stacking interactions [centroid–centroid distance = 3.8622 (14 Å] are also present.

Intramolecular and Transannular Diels-Alder Reactions

DEFF Research Database (Denmark)

Tanner, David Ackland; Ascic, Erhad

2014-01-01

Few reactions can compete with the Diels-Alder (DA) [4+2] cycloaddition for the rapid and efficient generation of molecular complexity. The DA reaction is atom-economic and stereospecific, as well as diastereo- and regioselective. The intramolecular version (IMDA) of the DA cycloaddition and its...... and dienophile, methods for acceleration of IMDA reactions (such as use of high pressure) and catalysis (using oxophilic or carbophilic metal complexes, Brønsted acids, and enzymes). The use of furans as diene components (IMDAF), intramolecular hetero-DA (IMHDA) and IMDA reactions with inverse electron demand...... are also covered. Applications of IMDA to asymmetric synthesis (from substrate control through to enantioselective catalysis, including organocatalysis) are presented, along with tandem sequences involving IMDA cycloaddition. A theme pervading the whole chapter is the use of IMDA reactions for the total...

Bis(μ-2-carboxymethyl-2-hydroxybutanedioatobis[diaquamanganese(II]–1,2-bis(pyridin-4-ylethene–water (1/1/2

Directory of Open Access Journals (Sweden)

In Hong Hwang

2012-12-01

Full Text Available The asymmetric unit of the title compound, [Mn2(C6H6O72(H2O4]·C12H10N2·2H2O, contains half of the centrosymmetric Mn complex dimer, half of a 1,2-bis(pyridin-4-ylethene molecule, which lies across an inversion center, and one water molecule. Two citrate ligands bridge two MnII ions, and each MnII atom is coordinated by four O atoms from the citrate ligands (one from hydroxy and three from carboxylate groups and two water O atoms, forming a distorted octahedral environment. In the crystal, O—H...O and O—H...N hydrogen bonds link the centrosymmetric dimers and lattice water molecules into a three-dimensional structure which is further stabilized by intermolecular π–π interactions [centroid–centroid distance = 3.959 (2 Å]. Weak C—H...O hydrogen bonding interactions are also observed.

catena-Poly[[[diaquabis(selenocyanato-κNiron(II]-μ-1,2-bis(pyridin-4-ylethane-κ2N:N′] 1,2-bis(pyridin-4-ylethane disolvate dihydrate

Directory of Open Access Journals (Sweden)

Susanne Wöhlert

2013-06-01

Full Text Available The title compound, {[Fe(NCSe2(C12H12N2(H2O2]·2C12H12N2·2H2O}n, was obtained by the reaction of iron(II sulfate heptahydrate and potassium selenocyanate with 1,2-bis(pyridin-4-ylethane (bpa in water. The FeII cation is coordinated by two N-bonded selenocyanate anions, two water molecules and two 1,2-bis(pyridin-4-ylethane (bpa ligands in a slightly distorted octahedral geometry. In addition, two non-coordinating bpa molecules and two water molecules are present. The FeII cation is located on a center of inversion while the coordinating bpa ligand is located on a twofold rotation axis. The FeII cations are linked by the bpa ligands into chains along the b-axis direction, which are further connected into layers perpedicular to the c axis by O—H...N and O—H...O hydrogen bonds to the non-coordinating bpa and the water molecules. The crystal studied was twinned by pseudo-merohedry (180° rotation along c*; contribution of the minor twin component 3.7%.

Synthesis of peptide thioacids at neutral pH using bis(2-sulfanylethyl)amido peptide precursors.

Science.gov (United States)

Pira, Silvain L; Boll, Emmanuelle; Melnyk, Oleg

2013-10-18

Reaction of bis(2-sulfanylethyl)amido (SEA) peptides with triisopropylsilylthiol in water at neutral pH yields peptide thiocarboxylates. An alkylthioester derived from β-alanine was used to trap the released bis(2-sulfanylethyl)amine and displace the equilibrium toward the peptide thiocarboxylate.

Immunomodulatory effects of intravenous bis-1 f(ab')(2) administration in renal-cell cancer-patients

NARCIS (Netherlands)

Janssen, R. A. J.; Kroesen, B. J.; Mesander, G.; Sleijfer, D. T.; The, T. Hauw; Mulder, N. H.; de Leij, L

We report the immunomodulatory effects of an intravenous treatment with F(ab')(2) fragments of the bispecific monoclonal antibody BIS-1 during subcutaneous recombinant interleukin 2 (rIL-2) therapy of renal cell cancer (RCC) patients. BIS-1 is directed against both the CD3 antigen on T cells and the

Poly[[[diisothiocyanatocobalt(II]-bis[μ-4-tert-butyl-2,6-bis(1,2,4-triazol-1-ylmethylphenol

Directory of Open Access Journals (Sweden)

2009-03-01

Full Text Available In the title compound, {[Co(NCS2(C16H20N6O2]·2C3H7NO·2H2O}n, each CoII ion located on an inversion center is six-coordinated by four equatorial N atoms from four different 4-tert-butyl-2,6-bis(1,2,4-triazol-1-ylmethylphenol (L ligands, and by two N atoms from two axial thiocyanate anions [Co—N = 2.104 (3–2.144 (3 Å]. The metal centres are connected via the bidentate L ligands into two-dimensional polymeric layers parallel to bc plane. The dimethylformamide and solvent water molecules participate in intermolecular O—H...O and O—H...S hydrogen bonds, which consolidate the crystal packing.

Hydrosilylation induced by N→Si intramolecular coordination: spontaneous transformation of organosilanes into 1-aza-silole-type molecules in the absence of a catalyst.

Science.gov (United States)

Novák, Miroslav; Dostál, Libor; Alonso, Mercedes; De Proft, Frank; Růžička, Aleš; Lyčka, Antonín; Jambor, Roman

2014-02-24

Our attempts to synthesize the N→Si intramolecularly coordinated organosilanes Ph2 L(1) SiH (1 a), PhL(1) SiH2 (2 a), Ph2 L(2) SiH (3 a), and PhL(2) SiH2 (4 a) containing a CH=N imine group (in which L(1) is the C,N-chelating ligand {2-[CH=N(C6 H3 -2,6-iPr2)]C6 H4}(-) and L(2) is {2-[CH=N(tBu)]C6 H4}(-)) yielded 1-[2,6-bis(diisopropyl)phenyl]-2,2-diphenyl-1-aza-silole (1), 1-[2,6-bis(diisopropyl)phenyl]-2-phenyl-2-hydrido-1-aza-silole (2), 1-tert-butyl-2,2-diphenyl-1-aza-silole (3), and 1-tert-butyl-2-phenyl-2-hydrido-1-aza-silole (4), respectively. Isolated organosilicon amides 1-4 are an outcome of the spontaneous hydrosilylation of the CH=N imine moiety induced by N→Si intramolecular coordination. Compounds 1-4 were characterized by NMR spectroscopy and X-ray diffraction analysis. The geometries of organosilanes 1 a-4 a and their corresponding hydrosilylated products 1-4 were optimized and fully characterized at the B3LYP/6-31++G(d,p) level of theory. The molecular structure determination of 1-3 suggested the presence of a Si-N double bond. Natural bond orbital (NBO) analysis, however, shows a very strong donor-acceptor interaction between the lone pair of the nitrogen atom and the formal empty p orbital on the silicon and therefore, the calculations show that the Si-N bond is highly polarized pointing to a predominantly zwitterionic Si(+) N(-) bond in 1-4. Since compounds 1-4 are hydrosilylated products of 1 a-4 a, the free energies (ΔG298), enthalpies (ΔH298), and entropies (ΔH298) were computed for the hydrosilylation reaction of 1 a-4 a with both B3LYP and B3LYP-D methods. On the basis of the very negative ΔG298 values, the hydrosilylation reaction is highly exergonic and compounds 1 a-4 a are spontaneously transformed into 1-4 in the absence of a catalyst. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and characterization of 6,6’-bis(2-hydroxyphenyl)-2,2’-bipyridine ligand and its interaction with ct-DNA

Energy Technology Data Exchange (ETDEWEB)

Selamat, Norhidayah; Heng, Lee Yook; Hassan, Nurul Izzaty; Karim, Nurul Huda Abd [School of Chemical Sciences and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43650 Bangi, Selangor (Malaysia)

2015-09-25

The tetradentate ligand with four donor atoms OONN was synthesized. Bis(phenoxy)bipyridine ligand was prepared by Suzuki coupling reaction between 6,6’-dibromo-2,2’-bipyridyl and 2-hydroxyphenylboronic acid with presence of palladium (II) acetate. Bis(phenoxy)bipyridine ligand was also synthesized by demethylating of 6,6’-bis(2-methoxyphenyl)-2,2’-bipyridyl ligand through solvent free reaction using pyridine hydrocloride. The formation of both phenoxy and methoxy ligands was confirmed by {sup 1}H, 2D cosy and {sup 13}C NMR spectroscopy, ESI-MS spectrometry, FTIR spectroscopy. The purity of the ligand was confirmed by melting point. Binding studies of small molecules with DNA are useful to understand the reaction mechanism and to provide guidance for the application and design of new and more efficient drugs targeted to DNA. In this study, the binding interaction between the synthesized ligand with calf thymus-DNA (ct-DNA) has been investigated by UV/Vis DNA titration study. From the UV/Vis DNA study, it shows that bis(phenoxy)bipyridine ligand bind with ct-DNA via outside binding with binding contant K{sub b} = 1.19 × 10{sup 3} ± 0.08 M{sup −1}.

Synthesis and Intramolecular [4+2] Cycloaddition Reactions of 4-Pyridazinecarbonitriles with Alkyne Side Chains

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Norbert Haider

1998-01-01

Full Text Available The preparation of a series of new 3-(alkynyl-X-substituted 4-pyridazinecarbonitriles 2-5 (X = O, NH is described. The compounds are shown to undergo thermally induced intramolecular Diels-Alder reactions with inverse electron demand, affording the fused benzonitriles 6-8. Incorporation of a 1,2-phenylene unit into the side chain, as in the case of compounds 10 and 13, results in a more favorable conformation of the dienophilic substructure and thus to a pronounced acceleration of the [4+2] cycloaddition reaction.

Synthesis, spectra and electrochemistry of dinitro-bis- {2-(phenylazo ...

Indian Academy of Sciences (India)

Unknown

2006-09-18

Sep 18, 2006 ... Synthesis, spectra and electrochemistry of dinitro-bis-. {2-(phenylazo)pyrimidine} ruthenium(II). Nitro–nitroso derivatives and reactivity of the electrophilic nitrosyl centre. PRITHWIRAJ BYABARTTA. Department of Chemistry, The University of Burdwan, Burdwan 713 104. Present address: Departmento de ...

Excimer-mediated photoionization of covalently-linked diaryl compounds: Energy thresholds for excimer formation and excimer-assisted photoionization of jet-cooled bis (9-Fluorenyl) methane

International Nuclear Information System (INIS)

Lee, Jae Kwang; Kang, Heun Kag; Cho, Han Joung; Boo, Bong Hyun; Lim, Edward C.

2001-01-01

Diarylakanes capable of adopting a face-to face arrangement of the two aromatic rings are ideal systems in which to probe the excited-state dynamics leading to excimer formation and the role of the singlet excimer in the photoionization of covalently linked bichromophoric molecules. Bis (9-eluorenyl) methane, BFM, is a good example of such diaryl compounds. Boo and co-workers have shown that BFM exhibits excrimer fluorescence in solution at ambient temperatures. An Arrhenius plot of the temperature-dependent excimer formation rate yielded activation energy of about 15 kJ·mol -1 . It has been proposed that the activation energy is related to the barrier for transforming the initial S 1 geometry to the face-to face (sandwich-pair) geometry of the intramolecular singlet excimer. This is accord with the study of an intramolecular excimer formation in jet-cooled 1, 3-diphenylpropane (DPP), and that of an intramolecular exciplex formation in 1-(9-anthryl)-3-(4-N, N-dimethylaniline) propane, which indicate that the energy threshold for such conformational changes is about 11 kJ·mol -1 .

2,6-Bis(9-ethyl-9H-carbazolylmethylenecyclohexanone

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Abdullah M. Asiri

2009-10-01

Full Text Available The title compound, 2,6-bis(ethyl-9-ethyl-9H-carbazolylmethylenecyclohexanone has been synthesized by condensation of 9-ethylcarbazole-3-aldehyde and cyclohexanone in ethanol in the presence of pyridine. The structure of this new compound was confirmed by elemental analysis, IR, 1H NMR, 13C NMR and EI-MS spectral analysis.

Crystal structure of 3-{1′-[3,5-bis(trifluoromethylphenyl]ferrocenyl}-4-bromothiophene

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Elisabeth A. Poppitz

2014-10-01

Full Text Available The molecular structure of the title compound, [Fe(C9H6BrS(C13H7F6], consists of a ferrocene backbone with a bis(trifluoromethylphenyl group at one cyclopentadienyl ring and a thiophene heterocycle at the other cyclopentadienyl ring. The latter is disordered over two sets of sites in a 0.6:0.4 ratio. In the crystal structure, intramolecular π–π interactions between the thienyl and the phenyl substituent [centroid–centroid distance 3.695 (4 Å] and additional weak T-shaped π–π interactions between the thienyl and the phenyl-substituted cyclopentadienyl ring [4.688 (6 Å] consolidate the crystal packing.

40 CFR 721.9530 - Bis(2,2,6,6-tetra-methyl-piper-idinyl) ester of cycloalkyl spir-o-ke-tal.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Bis(2,2,6,6-tetra-methyl-piper-idinyl) ester of cycloalkyl spir-o-ke-tal. 721.9530 Section 721.9530 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.9530 Bis(2,2,6,6-tetra-methyl-piper-idinyl) ester...

The Synthesis of Dicationic Extended Bis-Benzimidazoles

OpenAIRE

Kang, Zhijan; Dykstra, Christine C.; Boykin, David W.

2004-01-01

The synthesis of extended dicationic bis-benzimidazoles starting from trans-1,2-bis(4-cyanophenyl)ethene and trans-1,2-bis(4-cyanophenyl)cyclopropane is reported. The target diamidines show significant in vitro activity against B. subtilis.

Reduction of titanocene dichloride with dysprosium: access to a stable titanocene(ii) equivalent for phosphite-free Takeda carbonyl olefination.

Science.gov (United States)

Bousrez, G; Déchamps, I; Vasse, J-L; Jaroschik, F

2015-05-28

The reduction of titanocene dichloride with dysprosium yields a new titanocene(ii) equivalent without the need for further stabilising ligands. This reagent can be employed in combination with dithioacetals for the olefination of different carbonyl groups and allows for a simplified all-in-one procedure.

Effective remediation of phenol,2,4-bis(1,1-dimethylethyl) and bis(2-ethylhexyl) phthalate in farm effluent using Guar gum--A plant based biopolymer.

Science.gov (United States)

Kee, Yang Ling; Mukherjee, Sumona; Pariatamby, Agamuthu

2015-10-01

This study was carried out to evaluate the efficiency of Guar gum in removing Persistent Organic Pollutants (POPs), viz. phenol,2,4-bis(1,1-dimethylethyl) and bis(2-ethylhexyl) phthalate (DEHP), from farm effluent. The removal efficiency was compared with alum. The results indicated that 4.0 mg L(-1) of Guar gum at pH 7 could remove 99.70% and 99.99% of phenol,2,4-bis(1,1-dimethylethyl) and DEHP, respectively. Box Behnken design was used for optimization of the operating parameters for optimal POPs removal. Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) spectroscopy studies were conducted on the flocs. SEM micrographs showed numerous void spaces in the flocs produced by Guar gum as opposed to those produced by alum. This indicated why Guar gum was more effective in capturing and removal of suspended particles and POPs as compared to alum. FTIR spectra indicated a shift in the bonding of functional groups in the flocs produced by Guar gum as compared to raw Guar gum powder signifying chemical attachment of the organics present in the effluent to the coagulant resulting in their removal. Guar gum is highly recommended as a substitute to chemical coagulant in treating POPs due to its non-toxic and biodegradable characteristics. Copyright © 2015 Elsevier Ltd. All rights reserved.

Conformational switching of ethano-bridged Cu,H2-bis-porphyrin induced by aromatic amines.

Science.gov (United States)

Bettini, Simona; Maglie, Emanuela; Pagano, Rosanna; Borovkov, Victor; Inoue, Yoshihisa; Valli, Ludovico; Giancane, Gabriele

2015-01-01

Cu,H2-bis-porphyrin (Cu,H2-Por2), in which copper porphyrin and free-base porphyrin are linked together by an ethano-bridge, was dissolved in chloroform and spread at the air/liquid subphase interface of a Langmuir trough. The bis-porphyrin derivative, floating film was characterized by reflection spectroscopy and the surface pressure of the floating film was studied as a function of the mean area per molecule. When aromatic amines are dissolved in the subphase, an evident interaction between the bis-porphyrin host and the aromatic amine guest is observed. A clear-cut variation of the profile of surface pressure vs area per molecule curve is observed. Reflection spectroscopy highlights that the aromatic amines dissolved in the subphase are able to induce the syn-to-anti conformational switching in the bis-porphyrin derivative. The Langmuir-Schaefer technique has been used to transfer the floating bis-porphyrin film (when using pure water as a subphase) to a surface plasmon resonance (SPR) substrate and the resulting device was able to detect the presence of aniline at concentrations as low as 1 nM in aqueous solution. The high selectivity of the SPR sensing device has been verified by checking the spectral response of the active layer towards other analytes dissolved in the aqueous solutions.

Conformational switching of ethano-bridged Cu,H2-bis-porphyrin induced by aromatic amines

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Simona Bettini

2015-11-01

Full Text Available Cu,H2-bis-porphyrin (Cu,H2-Por2, in which copper porphyrin and free-base porphyrin are linked together by an ethano-bridge, was dissolved in chloroform and spread at the air/liquid subphase interface of a Langmuir trough. The bis-porphyrin derivative, floating film was characterized by reflection spectroscopy and the surface pressure of the floating film was studied as a function of the mean area per molecule. When aromatic amines are dissolved in the subphase, an evident interaction between the bis-porphyrin host and the aromatic amine guest is observed. A clear-cut variation of the profile of surface pressure vs area per molecule curve is observed. Reflection spectroscopy highlights that the aromatic amines dissolved in the subphase are able to induce the syn-to-anti conformational switching in the bis-porphyrin derivative. The Langmuir–Schaefer technique has been used to transfer the floating bis-porphyrin film (when using pure water as a subphase to a surface plasmon resonance (SPR substrate and the resulting device was able to detect the presence of aniline at concentrations as low as 1 nM in aqueous solution. The high selectivity of the SPR sensing device has been verified by checking the spectral response of the active layer towards other analytes dissolved in the aqueous solutions.

Process for manufacturing bis(2-methoxyethyl)-2,3,6,7-tetracyano-1,4,5,8,9,10-hexazaanthracene

Science.gov (United States)

Rasmussen, Paul George; Lawton, Richard Graham

2014-06-03

A process to manufacture substituted tetracyano-hexaazatricyclics with the substitutions occurring at the 9 and 10 hydrogens. The process begins with 2,3-dichloro-5,6-dicyanopyrazine, which is reacted to form the desired tetracyano-hexaazatricyclic. Different process embodiments enable different reaction paths to the desired tetracyano-hexaazatricyclic. Different tetracyano-hexaazatricyclic embodiments include bis(2-methoxyethyl)-2,3,6,7-tetracyano-1,4,5,8,9,10-hexazaanthracene and bis(2-methoxyethoxyethyl)-2,3,6,7-tetracyano-1,4,5,8,9,10-hexazaanthracen- e.

Excited-state intramolecular proton transfer of 2-acetylindan-1,3-dione studied by ultrafast absorption and fluorescence spectroscopy

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Pramod Kumar Verma

2016-03-01

Full Text Available We employ transient absorption from the deep-UV to the visible region and fluorescence upconversion to investigate the photoinduced excited-state intramolecular proton-transfer dynamics in a biologically relevant drug molecule, 2-acetylindan-1,3-dione. The molecule is a ß-diketone which in the electronic ground state exists as exocyclic enol with an intramolecular H-bond. Upon electronic excitation at 300 nm, the first excited state of the exocyclic enol is initially populated, followed by ultrafast proton transfer (≈160 fs to form the vibrationally hot endocyclic enol. Subsequently, solvent-induced vibrational relaxation takes place (≈10 ps followed by decay (≈390 ps to the corresponding ground state.

Dimethyl 2,2′-[Carbonylbis(azanediyl](2S,2′S-bis[3-(4-hydroxyphenylpropanoate

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Raffaella Mancuso

2018-02-01

Full Text Available The thus-far unknown ureic derivative dimethyl 2,2′-[carbonylbis(azanediyl](2S,2′S-bis[3-(4-hydroxyphenylpropanoate] has been efficiently synthesized by enantiospecific oxidative carbonylation of readily available l-tyrosine methyl ester, using a very simple catalytic system (PdI2 in conjunction with KI under relatively mild conditions (100 °C for 5 h in DME as the solvent and under 20 atm of a 4:1 mixture CO-air.

Biodegradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane (DDT) by using Serratia marcescens NCIM 2919.

Science.gov (United States)

Grewal, Jasneet; Bhattacharya, Amrik; Kumar, Sumit; Singh, Dileep K; Khare, Sunil K

2016-12-01

A solvent tolerant bacterium Serratia marcescens NCIM 2919 has been evaluated for degradation of DDT (1,1,1-trichloro-2,2-bis (4-chlorophenyl) ethane). The bacterium was able to degrade up to 42% of initial 50 mg L -1 of DDT within 10 days of incubation. The highlight of the work was the elucidation of DDT degradation pathway in S. marcescens. A total of four intermediates metabolites viz. 2,2-bis (chlorophenyl)-1,1-dichloroethane (DDD), 2,2-bis (chlorophenyl)-1,1-dichloroethylene (DDE), 2,2-bis (chlorophenyl)-1-chloroethylene (DDMU), and 4-chlorobenzoic acid (4-CBA) were identified by GC-Mass and FTIR. 4-CBA was found to be the stable product of DDT degradation. Metabolites preceding 4-CBA were not toxic to strain as reveled through luxuriant growth in presence of varying concentrations of exogenous DDD and DDE. However, 4-CBA was observed to inhibit the growth of bacterium. The DDT degrading efficiency of S. marcescens NCIM 2919 hence could be used in combination with 4-CBA utilizing strains either as binary culture or consortia for mineralization of DDT. Application of S. marcescens NCIM 2919 to DDT contaminated soil, showed 74.7% reduction of initial 12.0 mg kg -1 of DDT after 18-days of treatment.

N,N′-Bis(2-hydroxy-3-ethoxybenzylidenebutane-1,4-diamine

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Hoong-Kun Fun

2009-04-01

Full Text Available The title Schiff base compound, C22H28N2O4, lies across a crystallographic inversion centre and adopts an E configuration with respect to the C=N bond. Pairs of weak intermolecular C—H...O interactions link neighbouring molecules into dimers with an R22(28 ring motif. The crystal structure is stabilized by intermolecular C—H...π interactions. An intramolecular O—H...N hydrogen bond occurs.

Efficient white organic light-emitting devices using a thin 4,4'-bis(2,2'-diphenylvinyl)-1,1'-diphenyl layer

International Nuclear Information System (INIS)

Wang Jun; Yu Junsheng; Li Lu; Tang Xiaoqing; Jiang Yadong

2008-01-01

White organic light-emitting devices (OLEDs) were fabricated using phosphorescent material bis[2-(4-tert-butylphenyl)benzothiazolato-N,C 2' ]iridium (acetylacetonate) [(t-bt) 2 Ir(acac)] doped in 4,4'-bis(carbazol-9-yl) biphenyl (CBP) matrix as a yellow light-emitting layer and a thin layer 4,4'-bis(2,2'-diphenylvinyl)-1,1'-diphenyl (DPVBi) as the blue light-emitting layer. The light colour of the OLEDs can be adjusted by changing doped concentration and the thickness of the DPVBi thin layer. The maximum luminance and power efficiency of 5% doped device reached 15 460 cd m -2 and 8.1 lm W -1 , respectively. The 3% doped device showed the CIE coordinates of (0.344, 0.322) at 8 V and a maximum power efficiency of 5.7 lm W -1 at 4.5 V

Crystal structures of eight 3D molecular adducts derived from bis-imidazole, bis(benzimidazole), and organic acids

Science.gov (United States)

Ding, Aihua; Jin, Shouwen; Jin, Shide; Hu, KaiKai; Lin, Zhihao; Liu, Hui; Wang, Daqi

2018-01-01

Cocrystallization of the bis(imidazole)/bis(benzimidazole) with a series of organic acids gave a total of eight molecular adducts with the compositions: (3,6-bis(imidazole-1-yl)pyridazine): (trichloroacetic acid)2(1) [(H2L1)2+ · (tca-)2, L1 = 3,6-bis(imidazole-1-yl)pyridazine, tca- = trichloroacetate], (bis(N-imidazolyl)methane): (suberic acid) (2) [(L2) · (H2suba), L2 = bis(N-imidazolyl)methane, H2suba = suberic acid], bis(N-imidazolyl)methane: (3-nitrophthalic acid): 3H2O (3) [(H2L2)2+ · (3-Hnpa-)2 · 3H2O, 3-Hnpa- = 3-nitro hydrogenphthalate], (bis(N-imidazolyl)butane)0.5: (4-nitrophthalic acid): H2O (4) [(H2L3)0.5+ · (4-Hnpa-)- · H2O, L3 = bis(N-imidazolyl)butane, 4-Hnpa- = 4-nitro hydrogenphthalate], (1-(3-(1H-benzimidazol-1-yl)propyl)-1H-benzimidazole): (3,5-dinitrosalicylic acid) (5) [(HL4) · (3,5-dns-), L4 = 1-(3-(1H-benzimidazol-1-yl)propyl)-1H-benzimidazole, 3,5-dns- = 3,5-dinitrosalicylate], (1-(3-(1H-benzimidazol-1-yl)propyl)-1H-benzimidazole): (3-nitrophthalic acid) (6) [(H2L4) · (3-npa2-), L4 = 1-(3-(1H-benzimidazol-1-yl)propyl)-1H-benzimidazole, 3-npa2-=3-nitrogenphthalate], (bis(N-imidazolyl)butane): (pamoic acid) (7) [(H2L3) · (pam), pam = pamoate], and (3,6-bis(imidazole-1-yl)pyridazine): (1,5-naphthalenedisulfonic acid) [(H2L1)2+ · (npda)2- = 1,5-naphthalenedisulfonate] (8). The eight adducts have been characterized by X-ray diffraction technique, infrared spectrum, and elemental analysis, and the melting points of all adducts were also reported. And their structural and supramolecular aspects are fully analyzed. The result reveals that among the eight investigated crystals both the end ring N in the bis(imidazole) moieties are protonated when the organic acids are deprotonated except 2, and 5, and the crystal packing is interpreted in terms of the strong ionic Nsbnd H⋯O H-bond between the imidazolium and the deprotonated acidic groups. Except the Nsbnd H⋯O H-bond, the Osbnd H⋯O H-bonds were also found at the salts 3, 4

Bis(2-methoxybenzylammonium diaquabis(dihydrogen diphosphato-κ2O,O′manganate(II dihydrate

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Adel Elboulali

2013-11-01

Full Text Available The asymmetric unit of the title compound, (C8H12NO2[Mn(H2P2O72(H2O2]·2H2O, consists of half an MnII complex anion, a 2-methoxybenylammonium cation and a solvent water molecule. The MnII complex anion lies across an inversion center, and has a slightly distorted octahedral coordination environment for the MnII ion, formed by two bidentate dihydrogendiphosphate ligands and two water molecules. In the crystal, the components are linked by O—H...O and N—H...O hydrogen bonds, forming layers parallel to (100. An intramolecular N—H...O hydrogen bond is also observed.

3,14-Diethyl-2,13-diaza-6,17-diazoniatricyclo[16.4.0.07,12]docosane dichloride tetrahydrate from synchrotron radiation

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Dohyun Moon

2013-11-01

Full Text Available The asymmetric unit of title hydrated salt, C22H46N42+·2Cl−·4H2O, comprises half a centrosymmetric dication, one Cl− anion and two water molecules of crystallization. The structure determination reveals that protonation has occurred at diagonally opposite amine N atoms, and that the dication features intramolecular N—H...N hydrogen bonds. In the crystal, a three-dimensional artchitecture is formed by O—H...Cl/N and N—H...Cl/O hydrogen bonds.

Bis[2-(1,3-benzothiazol-2-ylphenyl-κ2C1,N][1,3-bis(4-bromophenylpropane-1,3-dionato-κ2O,O′]iridium(III

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Sung Kwon Kang

2013-08-01

Full Text Available The title complex, [Ir(C15H9Br2O2(C13H8NS2], lies about a crystallographic twofold rotation axis passing through the IrIII atom and the central C atom of the bis(bromophenylpropane-1,3-dionate ligand. The IrIII atom adopts a distorted octahedral geometry coordinated by two N atoms in the axial positions, and two C and two O atoms in the equatorial plane. The dihedral angle between the two thiazole ring systems in the complex is 77.45 (10°.

Dioxygen Binding by Cobalt(II Complexes of 8,8'-bis(aminomethyl-2,2'-biquinoline

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Muhammad S. Khan

2015-02-01

Full Text Available A new series of Co(II complexes of the type CoLX2 , where Lis a tetra-dentate ligand 8,8'-bis(aminomethyl-2,2'-biquinoline  and X= SCN–, BF4–, I– or NO3– ,  have been synthesized and characterized. The complexes have magnetic moments in the range typical of a low-spin d7 Co(II center. The interaction of these Co(II complexes with dioxygen was studied by E.S.R. spectroscopy. A dicobalt(III peroxo-bridged complex was formed in DMF solution, associated with the formation of an E.S.R.-silent solution compatible with the formation of low-spin d6 Co(III species. Similar behavior was also observed for the interaction of these Co(II complexes with dioxygen in the presence of ancillary ligands such as pyridine and 2-methylimidazole. The dioxygen complexes proved successful as oxygen carrier oxidation catalysts for tripehnylphosphine and 2,6-bis(t-butylphenol.

Synthesis, solid and solution studies of paraquat dichloride calixarene complexes. Molecular modelling

International Nuclear Information System (INIS)

Garcia S, I.; Ramirez, F. M.

2010-01-01

The interaction of the herbicide paraquat dichloride (P Q, substrate) with p-tert-butylcalix arenas (L, receptor) was investigated in both the solution and solid states. The isolated paraquat calixarene complexes were characterised by UV-visible, 1 H NMR, ESI-Ms, Luminescence and IR spectroscopies and elemental analysis. The stoichiometry of complexes 1 and 2 was 1:1 (1 herbicide: 1 calixarene) and both revealed a biexponential luminescence decay with lifetimes depending on the size and the conformational particularity of the calixarenes. Molecular modelling suggested that both calixarenes interact with the herbicide through cation-π interaction. P Q in included in the p-tert butylcalix a rene cavity, a situation favoured by its pinched conformation in polar solvent while it is partially included in the p-tert butylcalix a rene cavity because of its in-out cone conformation. The theoretical results, in particular using Mopac procedures, were in agreement with the experimental findings. (Author)

Synthesis, solid and solution studies of paraquat dichloride calixarene complexes. Molecular modelling

Energy Technology Data Exchange (ETDEWEB)

Garcia S, I.; Ramirez, F. M., E-mail: flor.ramirez@inin.gob.m [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

2010-07-01

The interaction of the herbicide paraquat dichloride (P Q, substrate) with p-tert-butylcalix arenas (L, receptor) was investigated in both the solution and solid states. The isolated paraquat calixarene complexes were characterised by UV-visible, {sup 1}H NMR, ESI-Ms, Luminescence and IR spectroscopies and elemental analysis. The stoichiometry of complexes 1 and 2 was 1:1 (1 herbicide: 1 calixarene) and both revealed a biexponential luminescence decay with lifetimes depending on the size and the conformational particularity of the calixarenes. Molecular modelling suggested that both calixarenes interact with the herbicide through cation-{pi} interaction. P Q in included in the p-tert butylcalix a rene cavity, a situation favoured by its pinched conformation in polar solvent while it is partially included in the p-tert butylcalix a rene cavity because of its in-out cone conformation. The theoretical results, in particular using Mopac procedures, were in agreement with the experimental findings. (Author)

Extraordinary photoluminescence behavior of an efficient electrochemiluminophore: Tb(III) chelated by 2,6-bis[N,N-bis(carboxymethyl)aminomethyl]-4-benzoylphenol

International Nuclear Information System (INIS)

Kuosmanen, Päivi; Pusa, Matti; Salminen, Kalle; Kulmala, Sakari

2016-01-01

The reactivities of lanthanide ions in their excited states are first considered in water and the energy diagrams of most important of them are sketched to illustrate the highly oxidizing and reducing species involved reacting with one-electron steps. Anomalous photoluminescence behavior of Tb(III) chelated by 2,6-bis[N,N-bis(carboxymethyl)aminomethyl]-4-benzoylphenol is studied. The present chelate is known to show relative strong chemiluminescence in the presence of hydrated electron and oxidizing radicals but it shows an extraordinarily short luminescence lifetime of radiative relaxation of its 5 D 4 state under photoexcitation.

Extraordinary photoluminescence behavior of an efficient electrochemiluminophore: Tb(III) chelated by 2,6-bis[N,N-bis(carboxymethyl)aminomethyl]-4-benzoylphenol

Energy Technology Data Exchange (ETDEWEB)

Kuosmanen, Päivi, E-mail: paivi.kuosmanen@aalto.fi; Pusa, Matti; Salminen, Kalle; Kulmala, Sakari

2016-05-15

The reactivities of lanthanide ions in their excited states are first considered in water and the energy diagrams of most important of them are sketched to illustrate the highly oxidizing and reducing species involved reacting with one-electron steps. Anomalous photoluminescence behavior of Tb(III) chelated by 2,6-bis[N,N-bis(carboxymethyl)aminomethyl]-4-benzoylphenol is studied. The present chelate is known to show relative strong chemiluminescence in the presence of hydrated electron and oxidizing radicals but it shows an extraordinarily short luminescence lifetime of radiative relaxation of its {sup 5}D{sub 4} state under photoexcitation.

12,12′-[2,2′-Oxybis(ethane-2,1-diylbis(oxy]bis[(Rp-4-bromo[2.2]paracyclophane

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Bing Hong

2011-04-01

Full Text Available The title compound, C36H36Br2O3, was synthesized from (Rp-4-bromo-12-hydroxy[2.2]paracyclophane and oxydiethane-2,1-diyl bis(4-methylbenzenesulfonate. The crystal packing exhibits a short O...Br interaction [Br...O = 3.185 (3 Å] and a weak intermolecular C—H...O contact.

Bis(2-hydroxy-N′-isopropylidenebenzohydrazidato-κ2N′,Obis(pyridine-κNcobalt(II

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Xiaojuan Zhao

2009-04-01

Full Text Available In the title complex, [Co(C10H11N2O22(C5H5N2], the CoII atom lies on a centre of symmetry and adopts a distorted cis-CoO2N4 octahedral geometry. The two acetone salicyloylhydrazone ligands are deprotonated and act as N,O-bidentate monoanionic ligands, forming the equatorial plane, while the axial positions are occupied by two N atoms of two pyridine molecules. The complex presents O—H...N and C—H...N intramolecular hydrogen bonds. Intermolecular C—H...N and C—H...O interactions are also present in the crystal.

Bis(2,6-dihydroxybenzoato-κ2O1,O1′(nitrato-κ2O,O′bis(1,10-phenanthroline-κ2N,N′cerium(III

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Hongxiao Jin

2011-01-01

Full Text Available The mononuclear title complex, [Ce(C7H5O32(NO3(C12H8N22], is isostructural to other related lanthanide structures. The Ce atom is in a pseudo-bicapped square-antiprismatic geometry formed by four N atoms from two chelating 1,10-phenanthroline (phen ligands and by six O atoms, four from two 2,6-dihydroxybenzoate (DHB ligands and the other two from a nitrate anion. π–π stacking interactions between phen and DHB ligands [centroid–centroid distances = 3.513 (3 and 3.762 (2 Å] and phen and phen ligands [face-to-face separation = 3.423 (7 Å] of adjacent complexes stabilize the crystal structure. Intramolecular O—H...O hydrogen bonds are observed in the DHB ligands.

Simultaneous determination of octylphenol, nonylphenol, Bis(2-ethylehxyl) phathalate in biological samples

Energy Technology Data Exchange (ETDEWEB)

Kim, J.H. [Jeonju University, Chonju (Korea)

2001-04-01

A comprehensive analytical method of endocrine disruptors[i.e., nonylphenol (NP), octylphenol (OP), bis (2-ethylhexyl) phthalate (BEHP) in meat or pork samples was developed. The method employed closed culture tube extraction with dichloromethane and solvent exchange to iso-hexane and SPE 92g) aminopropyl column, followed by determination on gas chromatography linked to mass spectrometry (GC/MS) operated in the single ion monitoring (SIM) mode. For the multipoint recovery of nonylphenol, octylphenol and bis (2-ethylhexyl) phthalate OP, NP were shown good recoveries in 0.125 {approx} 1.25 {mu}g/g range of concentration, and BEHP more good recoveries on 0.0125 {approx} 12.5 {mu}g/g wide range of concentration. The present method was applied to beef or pork samples of mart and butcher in Cheonju city and near cheonju. The range of concentrations was respectively, 0.06 {approx} 0.24 {mu}g/g in bis (2-ethylhexyl)phthalate (BEHP), but octylphenol (OP) was not dec ted in any samples. This method provides a powerful analytical tool to investigate a wide range of endocrine disruptors in biological samples of limited quantity. (author). 24 refs., 5 tabs., 3 figs.

Vanadium NMR Chemical Shifts of (Imido)vanadium(V) Dichloride Complexes with Imidazolin-2-iminato and Imidazolidin-2-iminato Ligands: Cooperation with Quantum-Chemical Calculations and Multiple Linear Regression Analyses.

Science.gov (United States)

Yi, Jun; Yang, Wenhong; Sun, Wen-Hua; Nomura, Kotohiro; Hada, Masahiko

2017-11-30

The NMR chemical shifts of vanadium ( 51 V) in (imido)vanadium(V) dichloride complexes with imidazolin-2-iminato and imidazolidin-2-iminato ligands were calculated by the density functional theory (DFT) method with GIAO. The calculated 51 V NMR chemical shifts were analyzed by the multiple linear regression (MLR) analysis (MLRA) method with a series of calculated molecular properties. Some of calculated NMR chemical shifts were incorrect using the optimized molecular geometries of the X-ray structures. After the global minimum geometries of all of the molecules were determined, the trend of the observed chemical shifts was well reproduced by the present DFT method. The MLRA method was performed to investigate the correlation between the 51 V NMR chemical shift and the natural charge, band energy gap, and Wiberg bond index of the V═N bond. The 51 V NMR chemical shifts obtained with the present MLR model were well reproduced with a correlation coefficient of 0.97.

Structure and Intramolecular Proton Transfer of Alanine Radical Cations

International Nuclear Information System (INIS)

Lee, Gab Yong

2012-01-01

The structures of the four lowest alanine conformers, along with their radical cations and the effect of ionization on the intramolecular proton transfer process, are studied using the density functional theory and MP2 method. The energy order of the radical cations of alanine differs from that of the corresponding neutral conformers due to changes in the basicity of the NH 2 group upon ionization. Ionization favors the intramolecular proton transfer process, leading to a proton-transferred radical-cation structure, [NH 3 + -CHCH 3 -COO·], which contrasts with the fact that a proton-transferred zwitterionic conformer is not stable for a neutral alanine in the gas phase. The energy barrier during the proton transfer process is calculated to be about 6 kcal/mol

Non-covalent interactions between {N,N′-bis[(2-pyridinyl)methylene]-1, 2-benzenediamine]-bis(nitrato)}Cu(II) with pyridoxine hydrochloride in methanol at T = (298.15, 308.15 and 318.15) K

International Nuclear Information System (INIS)

Brahman, Dhiraj; Sinha, Biswajit

2014-01-01

Highlights: • Methanolic solution of pyridoxine hydrochloride used as solvent. • {N,N′-bis[(2-pyridinyl)methylene]-1, 2-benzenediamine]-bis(nitrato)}Cu(II) used as solute. • Partial molar volumes and viscosity B-coefficients of the solute were determined. • Weak 1:1 association between the complex and pyridoxine hydrochloride found. • Non-covalent interactions and Cu(II) complex acts as a net structure maker in the ternary solutions. - Abstract: Non-covalent interactions between of {N,N′-bis[(2-pyridinyl)methylene]-1, 2-benzenediamine]-bis(nitrato)}Cu(II) with pyridoxine hydrochloride in methanol were investigated by a combination of physico-chemical and spectrophotometric methods at T = (298.15, 308.15 and 318.15) K under ambient pressure. From measured density and viscosity data the apparent molar volume (ϕ V ), the slope (S V ∗ ), standard partial molar volume (ϕ V 0 ), standard transfer volume (Δ t ϕ V 0 ), isobaric apparent molar expansibility (ϕ E ), standard isobaric partial molar expansibility (ϕ E 0 ), the viscosity B-coefficient, its temperature derivative (∂B/∂T), solvation number (S n ) were calculated and discussed on the basis of specific or non-specific (solute + cosolute) and (solute + solvent) interactions. Thermodynamics of viscous flow were discussed on the basis of the transition state theory. Spectrophotometric results indicated 1:1 (solute + cosolute) interaction between the complex and pyridoxine hydrochloride

Intramolecular BSSE and dispersion affect the structure of a dipeptide conformer

Science.gov (United States)

Hameed, Rabia; Khan, Afsar; van Mourik, Tanja

2018-05-01

B3LYP and MP2 calculations with the commonly-used 6-31+G(d) basis set predict qualitatively different structures for the Tyr-Gly conformer book1, which is the most stable conformer identified in a previous study. The structures differ mainly in the ψtyr Ramachandran angle (138° in the B3LYP structure and 120° in the MP2 structure). The causes for the discrepant structures are attributed to missing dispersion in the B3LYP calculations and large intramolecular BSSE in the MP2 calculations. The correct ψtyr value is estimated to be 130°. The MP2/6-31+G(d) profile identified an additional conformer, not present on the B3LYP surface, with a ψtyr value of 96° and a more folded structure. This minimum is, however, likely an artefact of large intramolecular BSSE values. We recommend the use of basis sets of at least quadruple-zeta quality in density functional theory (DFT), DFTaugmented with an empirical dispersion term (DFT-D) and second-order Møller-Plesset perturbation theory (MP2 ) calculations in cases where intramolecular BSSE is expected to be large.

Copper-Assisted Oxidative Trifluoromethylthiolation of 2,3-Allenoic Acids with AgSCF3.

Science.gov (United States)

Pan, Shen; Huang, Yangen; Xu, Xiu-Hua; Qing, Feng-Ling

2017-09-01

The oxidative trifluoromethylthiolation of 2,3-allenoic acids with AgSCF 3 in the presence of (NH 4 ) 2 S 2 O 8 and catalytic copper salt was investigated. A series of 4-aryl-2,3-allenoic acids underwent radical trifluoromethylthiolation/intramolecular cyclization to afford β-trifluoromethylthiolated butenolides, which were conveniently transformed into trifluoromethylthiolated furan derivatives. In contrast, 2-monosubstituted 2,3-allenoic acids were converted into the corresponding 3,4-bis(trifluoromethylthio)but-2-enoic-acids under similar reaction conditions.

Synthesis of 2,5-Disubstituted Octahydroquinolin-4-ones via anIntramolecular Hetero Diels-Alder Reaction

Directory of Open Access Journals (Sweden)

J. Antonio Palenzuela

2007-02-01

Full Text Available A route for the preparation of 2,5-disubstituted octahydroquinolin-4-ones, synthetic precursors of the decahydroquinoline-type toxins, is presented. The key steps are an asymmetric epoxidation and an intramolecular hetero Diels-Alder reaction between an activated diene and an imine. The presence of an allylic stereogenic center induces some selectivity and thus only two cycloadducts are obtained in 70:30 ratio and good yield.

2-[(2-{Bis[2-(2-hydroxy-5-nitrobenzylideneaminoethyl]amino}ethyliminomethyl]-4-nitrophenol acetonitrile monosolvate

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Kwang Ha

2010-12-01

Full Text Available In the title compound, C27H27N7O9·CH3CN, the three nitro groups of the polydentate tripodal Schiff base are located approximately parallel to their respective carrier benzene rings, making dihedral angles of 3.9 (4, 5.0 (4 and 6.3 (4°. Intramolecular O—H...N hydrogen bonds between the hydroxy O atoms and the imine N atoms, with O...N distances in the range 2.607 (3–2.665 (3 Å, form nearly planar six-membered rings. In the crystal, weak intermolecular C—H...O and C—H...N hydrogen bonds occur and several intra- and intermolecular π–π interactions are present between adjacent benzene rings, with a shortest centroid–centroid distance of 3.507 (2 Å.

Versatile supramolecular reactivity of zinc-tetra(4-pyridylporphyrin in crystalline solids: Polymeric grids with zinc dichloride and hydrogen-bonded networks with mellitic acid

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Sophia Lipstman

2009-12-01

Full Text Available Crystal engineering studies confirm that the zinc-tetra(4-pyridylporphyrin building block reveals versatile supramolecular chemistry. In this work, it was found to be reactive in the assembly of both (a a 2D polymeric array by a unique combination of self-coordination and coordination through external zinc dichloride linkers and (b an extended heteromolecular hydrogen-bonded network with mellitic acid sustained by multiple connectivity between the component species.

A theoretical investigation on the regioselectivity of the intramolecular hetero Diels-Alder and 1,3-dipolar cycloaddition of 2-vinyloxybenzaldehyde derivatives

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Hamzehloueian Mahshid

2014-01-01

Full Text Available The present study reports a systematic computational analysis of the two possible pathways, fused and bridged, for an intramolecular hetero Diels-Alder (IMHDA and an intramolecular 1,3-dipolar cycloaddition (IMDCA of 2-vinyloxybenzaldehyde derivatives. The potential energy surface analysis for both reactions is in agreement with experimental observations. The activation energies associated with the two regioisomeric channels in IMHDA reaction show that the bridged product is favored, although in IMDCA, the most stable TS results the fused product. The global electronic properties of fragments within each molecule were studied to discuss the reactivity patterns and charge transfer direction in the intramolecular processes. The asynchronicity of the bond formation and aromaticity of the optimized TSs in the Diels-Alder reaction as well as cycloaddition reaction were evaluated. Finally, 1H NMR chemical shifts of the possible regioisomers have been calculated using the GIAO method which of the most stable products are in agreement with the experimental data in the both reaction.

Crystal structure of bis(cyclohexylammonium diphenyldioxalatostannate(IV

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Modou Sarr

2015-02-01

Full Text Available Reaction of oxalic acid and diphenyltin dichloride in the presence of cyclohexylamine led to the formation of the title salt, (C6H14N2[Sn(C6H52(C2O42]. The dianion is made up from an Sn(C6H52 moiety cis-coordinated by two chelating oxalate anions, leading to an overall distorted octahedral coordination geometry of the SnIV atom. The negative charges are compensated by two surrounding cyclohexylammonium cations adopting chair conformations each. In the crystal, anions and cations are linked via a network of N—H...O hydrogen bonds into a layered arrangement parallel to (101.

Facile, novel two-step syntheses of benzimidazoles, bis-benzimidazoles, and bis-benzimidazole-dihydroquinoxalines.

Science.gov (United States)

Xu, Zhigang; Shaw, Arthur Y; Dietrich, Justin; Cappelli, Alexandra P; Nichol, Gary; Hulme, Christopher

2012-02-01

Three scaffolds of benzimidazoles, bis-benzimidazoles, and bis-benzimidazole-dihydroquinoxalines were synthesized via Ugi/de-protection/cyclization methodology. Benzimidazole forming ring closure was enabled under microwave irradiation in the presence of 10% TFA/DCE. The methodology demonstrates the utility of 2-(N-Boc-amino)-phenyl-isocyanide for the generation of new molecular diversity.

Facile, novel two-step syntheses of benzimidazoles, bis-benzimidazoles, and bis-benzimidazole-dihydroquinoxalines

OpenAIRE

Xu, Zhigang; Shaw, Arthur Y.; Dietrich, Justin; Cappelli, Alexandra P.; Nichol, Gary; Hulme, Christopher

2012-01-01

Three scaffolds of benzimidazoles, bis-benzimidazoles, and bis-benzimidazole-dihydroquinoxalines were synthesized via Ugi/de-protection/cyclization methodology. Benzimidazole forming ring closure was enabled under microwave irradiation in the presence of 10% TFA/DCE. The methodology demonstrates the utility of 2-(N-Boc-amino)-phenyl-isocyanide for the generation of new molecular diversity.

The gas-phase bis-uranyl nitrate complex ((UO2)2(NO3)5)-: infrared spectrum and structure

International Nuclear Information System (INIS)

Groenewold, G.S.; van Stipdonk, Michael J.; Oomens, Jos; De Jong, Wibe A.; McIlwain, Michael E.

2011-01-01

The infrared spectrum of the bis-uranyl nitrate complex ((UO 2 ) 2 (NO 3 ) 5 ) - was measured in the gas phase using multiple photon dissociation (IRMPD). Intense absorptions corresponding to the nitrate symmetric and asymmetric vibrations, and the uranyl asymmetric vibration were observed. The nitrate v 3 vibrations indicate the presence of nitrate in a bridging configuration bound to both uranyl cations, and probably two distinct pendant nitrates in the complex. The coordination environment of the nitrate ligands and the uranyl cations were compared to those in the mono-uranyl complex. Overall, the uranyl cation is more loosely coordinated in the bis-uranyl complex ((UO 2 ) 2 (NO 3 ) 5 ) - compared to the mono-complex (UO 2 (NO 3 ) 3 ) - , as indicated by a higher O-U-O asymmetric stretching (v 3 ) frequency. However, the pendant nitrate ligands are more strongly bound in the bis-complex than they are in the mono-uranyl complex, as indicated by the v 3 frequencies of the pendant nitrate, which are split into nitrosyl and O-N-O vibrations as a result of bidentate coordination. These phenomena are consistent with lower electron density donation per uranyl by the nitrate bridging two uranyl centers compared to that of a pendant nitrate in the mono-uranyl complex. The lowest energy structure predicted by density functional theory (B3LYP functional) calculations was one in which the two uranyl molecules bridged by a single nitrate coordinated in a bis-bidentate fashion. Each uranyl molecule was coordinated by two pendant nitrate ligands. The corresponding vibrational spectrum was in excellent agreement with the IRMPD measurement, confirming the structural assignment.

The gas-phase bis-uranyl nitrate complex ((UO2)2(NO3)5)-: infrared spectrum and structure

International Nuclear Information System (INIS)

Groenewold, Gary S.; van Stipdonk, Michael J.; Oomens, Jos; de Jong, Wibe; McIlwain, Michael E.

2011-01-01

The infrared spectrum of the bis-uranyl nitrate complex ((UO 2 ) 2 (NO 3 ) 5 ) - was measured in the gas phase using multiple photon dissociation (IRMPD). Intense absorptions corresponding to the nitrate symmetric and asymmetric vibrations, and the uranyl asymmetric vibration were observed. The nitrate nu3 vibrations indicate the presence of nitrate in a bridging configuration bound to both uranyl cations, and probably two distinct pendant nitrates in the complex. The coordination environment of the nitrate ligands and the uranyl cations were compared to those in the mono-uranyl complex. Overall, the uranyl cation is more loosely coordinated in the bis-uranyl complex ((UO 2 ) 2 (NO 3 ) 5 ) - compared to the mono-complex (UO 2 (NO 3 ) 3 ) - , as indicated by a higher O-U-O asymmetric stretching (nu3) frequency. However, the pendant nitrate ligands are more strongly bound in the bis-complex than they are in the mono-uranyl complex, as indicated by the ν 3 frequencies of the pendant nitrate, which are split into nitrosyl and O-N-O vibrations as a result of bidentate coordination. These phenomena are consistent with lower electron density donation per uranyl by the nitrate bridging two uranyl centers compared to that of a pendant nitrate in the mono-uranyl complex. The structure was calculated using density functional theory (B3LYP functional), which produced a structure in which the two uranyl molecules bridged by a single nitrate coordinated in a bis-bidentate fashion. Each uranyl molecule was coordinated by two pendant nitrate ligands. The corresponding vibrational spectrum was in excellent agreement with the IRMPD measurement, confirming the structural assignment.

Tandem Cu-catalyzed ketenimine formation and intramolecular nucleophile capture: Synthesis of 1,2-dihydro-2-iminoquinolines from 1-(o-acetamidophenyl)propargyl alcohols

Science.gov (United States)

Kant, Ruchir

2014-01-01

Summary The copper-catalyzed ketenimine formation reaction of 1-(o-acetamidophenyl)propargyl alcohols with various sulfonyl azides is found to undergo a concomitant intramolecular nucleophile attack to generate 1,2-dihydro-2-iminoquinolines after aromatization (via elimination of acetyl and hydroxy groups) and tautomerization. The reaction produces 4-substituted and 3,4-unsubstituted title compounds in moderate to good yields under mild reaction conditions. PMID:24991276

Bis[μ-2,5-bis(pyridin-2-yl-1,3,4-thiadiazole-κ4N2,N3:N4,N5]bis[(nitrato-κOsilver(I] tetrahydrate

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Abdelhakim Laachir

2013-06-01

Full Text Available The self-assembly of an angular 2,5-bis(pyridin-2-yl-1,3,4-thiadiazole ligand (L with silver nitrate (AgNO3 produced a new dinuclear silver(I coordination complex, [Ag2(C12H8N4S2(NO32]·4H2O, which crystallizes with two Ag atoms bridged by two L ligands. The Ag atom is surrounded by four N atoms of L and by one O from the nitrate anion defining a distorted square pyramid. The atoms comprising the dication are nearly coplanar, with an r.m.s. deviation of 0.1997 Å. Molecules are linked by C—H...O and O—H...O hydrogen bonds through nitrate anions and water molecules, forming a two-dimensional porous network. The overall structure involves stacking of Ag complex layers along the b axis. The cohesion in the three-dimensional architecture is ensured by O...Ag interactions.

Ready synthesis of free N-H 2-arylindoles via the copper-catalyzed amination of 2-bromo-arylacetylenes with aqueous ammonia and sequential intramolecular cyclization.

Science.gov (United States)

Wang, Huifeng; Li, Yaming; Jiang, Linlin; Zhang, Rong; Jin, Kun; Zhao, Defeng; Duan, Chunying

2011-07-07

A wide range of free N-H 2-arylindoles were synthesised via the copper(II)-catalyzed amination of 2-bromo-arylacetylenes with aqueous ammonia and sequential intramolecular cyclization. The convenience and atom economy of aqueous ammonia, and the low cost of the copper catalytic system make this protocol readily superior in practical application.

Different coordination modes for disulfoxides towards diorganotin(IV) dichlorides. X-ray crystal structures of 1,2-cis-bis-(phenylsulfinyl)ethene (rac-,cis-cbpse) and adducts [{l_brace}Ph{sub 2}SnCl{sub 2}(meso-bpse){r_brace}{sub n}] and [{l_brace}n-Bu{sub 2}SnCl{sub 2}(pdtd){r_brace}{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Sousa, Gerimario F. de [Universidade de Brasilia (UnB), DF (Brazil). Inst. de Quimica], e-mail: gfreitas@unb.br; Ellena, Javier [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Fisica; Malta, Valeria R.S. [Universidade Federal de Alagoas (UFAL), Maceio, AL (Brazil). Dept. de Quimica e Biotecnologia; Ardisson, Jose D. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Lab. de Fisica Aplicada

2009-07-01

The reactions of meso-1,2-bis(phenylsulfinyl)ethane (meso-bpse) with Ph{sub 2}SnCl{sub 2}, 2-phenyl-1,3-dithiane trans-1-trans-3-dioxide (pdtd) with n-Bu{sub 2}SnCl{sub 2} and 1,2-cis-bis-(phenylsulfinyl) ethene (rac-,cis-cbpse) with Ph{sub 2}SnCl{sub 2}, in 1:1 molar ratio, yielded [{l_brace}Ph{sub 2}SnCl{sub 2}(meso-bpse){r_brace}{sub n}], [{l_brace}n-Bu{sub 2}SnCl{sub 2}(pdtd){r_brace}{sub 2}] and [{l_brace}Ph{sub 2}SnCl{sub 2}(rac,cis-cbpse){r_brace}x] (x = 2 or n), respectively. All adducts were studied by IR, Moessbauer and {sup 119}Sn NMR spectroscopic methods, elemental analysis and single crystal X-ray diffractometry. The X-ray crystal structure of [{l_brace}Ph{sub 2}SnCl{sub 2}(meso-bpse){r_brace}{sub n}] revealed the occurrence of infinite chains in which the tin(IV) atoms appear in a distorted octahedral geometry with Cl atoms in cis and Ph groups in trans positions. The X-ray crystal structure of [{l_brace}n-Bu{sub 2}SnCl{sub 2}(pdtd){r_brace}{sub 2}] revealed discrete centrosymmetric dimeric species in which the tin(IV) atoms possess a distorted octahedral geometry with bridging disulfoxides in cis and n-butyl moieties in trans positions. The spectroscopic data indicated that the adduct containing the rac,cis-cbpse ligand can be dimeric or polymeric. The X-ray structural analysis of the free rac-,cis-cbpse sulfoxide revealed that the crystals belong to the C2/c space group. (author)

Fluorimetric determination of yttrium by methyl-bis(8-hydraxy--- 2-quinolyl)amine

International Nuclear Information System (INIS)

Golovina, A.P.; Kachin, S.V.; Runov, V.K.; Fakeeva, O.A.

1982-01-01

Using a method of mathematical Box-Wilson experiment planning the optimum conditions of yttrium fluorimetric determination by methyl-bis (8-hydroxy-2-quinolyl) amine (pH 7.5, csub(R)=1.4x10sup(-5) M) with the determination limit=0.05 μg/ml are found. An extraction-fluorimetric method of yttrium determination by methyl-bis (8-hydroxy-2-quinolyl) amine is developed. The extraction has been realized with aliphatic alcohols at pH > 11. The method is characteristic of the lowest determination limit (0.01 μg/ml) as compared with the known ones. The possibility is shown of yttrium determination in the presence of 5000-multiple aluminium contents, stoichiometric contents of La, Lu, Fe (3), U (6), tartrates, citrates

Report ETSI M2M-14bis JTC March 2011 meeting

NARCIS (Netherlands)

Keesmaat, N.W.

2011-01-01

The ETSI Technical Committee (TC) M2M focuses on the development of a generic M2M architecture and underlying protocols suitable for a wide range of M2M environments. Whereas in the past effort has been put in the development of several use cases, the focus of this M2M 14bis meeting – held in Sophia

Benzothiazole-Based AIEgen with Tunable Excited-State Intramolecular Proton Transfer and Restricted Intramolecular Rotation Processes for Highly Sensitive Physiological pH Sensing.

Science.gov (United States)

Li, Kai; Feng, Qi; Niu, Guangle; Zhang, Weijie; Li, Yuanyuan; Kang, Miaomiao; Xu, Kui; He, Juan; Hou, Hongwei; Tang, Ben Zhong

2018-04-23

In this work, a benzothiazole-based aggregation-induced emission luminogen (AIEgen) of 2-(5-(4-carboxyphenyl)-2-hydroxyphenyl)benzothiazole (3) was designed and synthesized, which exhibited multifluorescence emissions in different dispersed or aggregated states based on tunable excited-state intramolecular proton transfer (ESIPT) and restricted intramolecular rotation (RIR) processes. 3 was successfully used as a ratiometric fluorescent chemosensor for the detection of pH, which exhibited reversible acid/base-switched yellow/cyan emission transition. More importantly, the pH jump of 3 was very precipitous from 7.0 to 8.0 with a midpoint of 7.5, which was well matched with the physiological pH. This feature makes 3 very suitable for the highly sensitive detection of pH fluctuation in biosamples and neutral water samples. 3 was also successfully used as a ratiometric fluorescence chemosensor for the detection of acidic and basic organic vapors in test papers.

An aqueous all-organic redox-flow battery employing a (2,2,6,6-tetramethylpiperidin-1-yl)oxyl-containing polymer as catholyte and dimethyl viologen dichloride as anolyte

Science.gov (United States)

Hagemann, Tino; Winsberg, Jan; Grube, Mandy; Nischang, Ivo; Janoschka, Tobias; Martin, Norbert; Hager, Martin D.; Schubert, Ulrich S.

2018-02-01

Herein we present a new redox-flow battery (RFB) that employs a (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) containing copolymer (P1) as catholyte and the viologen derivative N,N‧-dimethyl-4,4‧-bipyridinium dichloride (MV) as anolyte in an aqueous sodium chloride solution. This is the first time that a combination of an organic polymer and a low-molar-mass organic redox-active material is presented. The electrochemical behavior of the utilized charge-storage materials were investigated by cyclic voltammetry (CV) and feature reversible redox-reactions at E½ = 0.7 V (TEMPO/TEMPO+) and E½ = -0.6 V vs. AgCl/Ag (MV++/MV+•), which lead to a promising cell voltage of 1.3 V in the subsequent battery application. Studies were performed to determine the most suitable anion-exchange membrane (AEM), the ideal conducting salt concentration and the optimal flow rate. The resulting battery reveals a stable charge/discharge performance over 100 consecutive cycles with coulombic efficiencies of up to 95%, a high energy efficiency of 85% and an overall energy density of the electrolyte system of 3.8 W h L-1.

Intramolecular Diels-Alder Reactions in Organic Synthesis

OpenAIRE

Sizemore, Nicholas Blandford Luke

2014-01-01

Intramolecular Diels-Alder (IMDA) reactions are an important class of reactions in synthetic organic chemistry for the rapid construction of polycyclic frameworks. Three classes of IMDA reactions were investigated synthetically and computationally: 1) all-carbon type 1 IMDA reactions, 2) N-acylnitroso type 2 IMDA reactions, and 3) cyano-azadiene IMDA reactions. The first class was implemented in research toward the total synthesis of maoecrystal Z and isopalhinine A. The second class was stud...

Preparation of CN /Carbon Nanotube Intramolecular Junctions by ...

African Journals Online (AJOL)

NICO

intramolecular junctions composed of CNx with a bamboo-like structure and empty hollow carbon nanotubes were observed, ... and excellent thermal and mechanical properties.1,2 In recent .... tion of hexane, and the other segment with a curved compart- ... by an arrow lies at the interface of the junction between 'b' and.

Ethyl 2,6-bis(4-chlorophenyl-4-(4-methylanilino-1-(4-methylphenyl-1,2,5,6-tetrahydropyridine-3-carboxylate

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Vivek K. Gupta

2013-03-01

Full Text Available In the title molecule, C34H32Cl2N2O2, the tetrahydropyridine ring adopts a distorted boat conformation and both 4-chlorophenyl substituents are in axial positions. An intramolecular N—H...O hydrogen bond is formed by the amino group and carbonyl O atom. In the crystal, weak C—H...Cl interactions link the molecules into chains along [010].

Binuclear Copper(I Borohydride Complex Containing Bridging Bis(diphenylphosphino Methane Ligands: Polymorphic Structures of [(µ2-dppm2Cu2(η2-BH42] Dichloromethane Solvate

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Natalia V. Belkova

2017-10-01

Full Text Available Bis(diphenylphosphinomethane copper(I tetrahydroborate was synthesized by ligands exchange in bis(triphenylphosphine copper(I tetrahydroborate, and characterized by XRD, FTIR, NMR spectroscopy. According to XRD the title compound has dimeric structure, [(μ2-dppm2Cu2(η2-BH42], and crystallizes as CH2Cl2 solvate in two polymorphic forms (orthorhombic, 1, and monoclinic, 2 The details of molecular geometry and the crystal-packing pattern in polymorphs were studied. The rare Twisted Boat-Boat conformation of the core Cu2P4C2 cycle in 1 is found being more stable than Boat-Boat conformation in 2.

Vinylcyclopropylacyl and polyeneacyl radicals. Intramolecular ketene alkyl radical additions in ring synthesis.

Science.gov (United States)

De Boeck, Benoit; Herbert, Nicola M A; Harrington-Frost, Nicole M; Pattenden, Gerald

2005-01-21

Treatment of a variety of substituted vinylcyclopropyl selenyl esters, e.g. 11, with Bu(3)SnH-AIBN in refluxing benzene leads to the corresponding acyl radical intermediates, which undergo rearrangement and intramolecular cyclisations via their ketene alkyl radical equivalents producing cyclohexenones in 50-60% yield. By contrast, treatment of conjugated triene selenyl esters, e.g. 32, with Bu(3)SnH-AIBN produces substituted 2-cyclopentenones via intramolecular cyclisations of their ketene alkyl radical intermediates. Under the same radical-initiating conditions the selenyl esters derived from o-vinylbenzoic acid and o-vinylcinnamic acid undergo intramolecular cyclisations producing 1-indanone and 5,6-dihydrobenzocyclohepten-7-one respectively in 60-70% yields. A tandem radical cyclisation from the alpha,beta,gamma,delta-diene selenyl ester 31 provides an expeditious synthesis of the diquinane 35 in 69% yield.

Interaction of 2-aminopyrimidine with dichloro-[1-alkyl-2-(naphthylazo imidazole]palladium(II complexes : Kinetic and mechanistic studies

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Saha Sushanta

2007-10-01

Full Text Available Abstract Background The anticancer properties of cisplatin and palladium(II complexes stem from the ability of the cis-MCl2 fragment to bind to DNA bases. However, cisplatin also interacts with non-cancer cells, mainly through bonding molecules containing -SH groups, resulting in nephrotoxicity. This has aroused interest in the design of palladium(II complexes of improved activity and lower toxicity. The reaction of DNA bases with palladium(II complexes with chelating N,N/donors of the cis-MCl2 configuration constitutes a model system that may help explore the mechanism of cisplatin's anticancer activity. Heterocyclic compounds are found widely in nature and are essential to many biochemical processes. Amongst these naturally occurring compounds, the most thoroughly studied is that of pyrimidine. This was one of the factors that encouraged this study into the kinetics and mechanism of the interaction of 2-aminopyrimidine (2-NH2-Pym with dichloro-{1-alkyl-2-(α-naphthylazoimidazole}palladium(II [Pd(α-NaiRCl2, 1] and dichloro-{1-alkyl-2-(β-naphthylazoimidazole}palladium(II [Pd(β-NaiRCl2, 2] complexes where the alkyl R = Me (a, Et (b, or Bz (c. Results 2-NH2-Pym reacts with 1a, 1b, and 1c to yield [{1-alkyl-2-(α-naphthylazoimidazole}bis(2-aminopyrimidine]palladium(II (3a, 3b, 3c dichloride and with 2a, 2b, and 2c to yield [{1-alkyl-2-(β-naphthylazoimidazole}bis(2-aminopyrimidine]palladium(II (4a, 4b, 4c dichloride in an acetonitrile (MeCN medium. The products were characterized using spectroscopic techniques (FT-IR, UV-Vis, NMR. The ligand substitution reactions follow second order kinetics – first order dependence on the concentration of the Pd(II complex and 2-NH2-Pym. Addition of LiCl to the reaction does not influence its rate. The thermodynamic parameters (standard enthalpy of activation, Δ‡H° and standard entropy of activation, Δ‡S° were determined from variable temperature kinetic studies. The magnitude of the second order

Zirconium and Titanium Propylene Polymerization Precatalysts Supported by a Fluxional C 2 -Symmetric Bis(anilide)pyridine Ligand

KAUST Repository

Tonks, Ian A.

2012-03-12

Titanium and zirconium complexes supported by a bis(anilide)pyridine ligand (NNN = pyridine-2,6-bis(N-mesitylanilide)) have been synthesized and crystallographically characterized. C 2-symmetric bis(dimethylamide) complexes were generated from aminolysis of M(NMe 2) 4 with the neutral, diprotonated NNN ligand or by salt metathesis of the dipotassium salt of NNN with M(NMe 2) 2Cl 2. In contrast to the case for previously reported pyridine bis(phenoxide) complexes, the ligand geometry of these complexes appears to be dictated by chelate ring strain rather than metal-ligand π bonding. The crystal structures of the five-coordinate dihalide complexes (NNN)MCl 2 (M = Ti, Zr) display a C 1-symmetric geometry with a stabilizing ipso interaction between the metal and the anilido ligand. Coordination of THF to (NNN)ZrCl 2 generates a six-coordinate C 2-symmetric complex. Facile antipode interconversion of the C 2 complexes, possibly via flat C 2v intermediates, has been investigated by variable-temperature 1H NMR spectroscopy for (NNN)MX 2(THF) n (M = Ti, Zr; X = NMe 2, Cl) and (NNN)Zr(CH 2Ph) 2. These complexes were tested as propylene polymerization precatalysts, with most complexes giving low to moderate activities (10 2-10 4 g/(mol h)) for the formation of stereoirregular polypropylene. © 2012 American Chemical Society.

CdBr2 complexes of 1,2-bis-[2-(5-H/methyl/chloro/nitro)-1H-benzimidazolyl]-1,2-ethanediols

International Nuclear Information System (INIS)

Aydin Tavman

2005-01-01

The complexes of 1,2-bis-[2-(5-H/methyl/chloro/nitro)-1H-benzimidazolyl]-1,2-ethanediols with CdBr 2 were synthesized and characterized by elemental analysis, molar conductivity, IR and NMR spectra. The ligands act as a bidentate only through both oxygen atoms of hydroxyl groups in complexes with ratio M:L=1:1 [ru

Heterocycles by Transition Metals Catalyzed Intramolecular Cyclization of Acetylene Compounds

International Nuclear Information System (INIS)

Vizer, S.A.; Yerzhanov, K.B.; Dedeshko, E.C.

2003-01-01

Review shows the new strategies in the synthesis of heterocycles, having nitrogen, oxygen and sulfur atoms, via transition metals catalyzed intramolecular cyclization of acetylenic compounds on the data published at the last 30 years, Unsaturated heterocyclic compounds (pyrroles and pyrroline, furans, dihydro furans and benzofurans, indoles and iso-indoles, isoquinolines and isoquinolinones, aurones, iso coumarins and oxazolinone, lactams and lactones with various substitutes in heterocycles) are formed by transition metals, those salts [PdCl 2 , Pd(OAc) 2 , HgCl 2 , Hg(OAc) 2 , Hg(OCOCF 3 ) 2 , AuCl 3 ·2H 2 O, NaAuCl 4 ·2H 2 O, CuI, CuCl], oxides (HgO) and complexes [Pd(OAc) 2 (PPh 3 )2, Pd(PPh 3 ) 4 , PdCl 2 (MeCN) 2 , Pd(OAc ) 2 /TPPTS] catalyzed intramolecular cyclization of acetylenic amines, amides, ethers, alcohols, acids, ketones and βdiketones. More complex hetero polycyclic systems typical for natural alkaloids can to obtain similar. Proposed mechanisms of pyrroles, isoquinolines, iso indoles and indoles, benzofurans and iso coumarins, thiazolopyrimidinones formation are considered. (author)

Crystal structures of bis- and hexakis[(6,6′-dihydroxybipyridinecopper(II] nitrate coordination complexes

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Deidra L. Gerlach

2015-12-01

Full Text Available Two multinuclear complexes synthesized from Cu(NO32 and 6,6′-dihydroxybipyridine (dhbp exhibit bridging nitrate and hydroxide ligands. The dinuclear complex (6,6′-dihydroxybipyridine-2κ2N,N′[μ-6-(6-hydroxypyridin-2-ylpyridin-2-olato-1:2κ3N,N′:O2](μ-hydroxido-1:2κ2O:O′(μ-nitrato-1:2κ2O:O′(nitrato-1κOdicopper(II, [Cu2(C10H7N2O2(OH(NO32(C10H8N2O2] or [Cu(6-OH-6′-O-bpy(NO3(μ-OH(μ-NO3Cu(6,6′-dhbp], (I, with a 2:1 ratio of nitrate to hydroxide anions and one partially deprotonated dhbp ligand, forms from a water–ethanol mixture at neutral pH. The hexanuclear complex bis(μ3-bipyridine-2,2′-diolato-κ3O:N,N′:O′tetrakis(6,6′-dihydroxybipyridine-κ2N,N′tetrakis(μ-hydroxido-κ2O:O′bis(methanol-κOtetrakis(μ-nitrato-κ2O:O′hexacopper(II, [Cu6(C10H6N2O22(CH4O2(OH4(NO34(C10H8N2O24] or [Cu(6,6′-dhbp(μ-NO32(μ-OHCu(6,6′-O-bpy(μ-OHCu(6,6′dhbp(CH3OH]2, (II, with a 1:1 NO3–OH ratio and two fully protonated and fully deprotonated dhbp ligands, was obtained by methanol recrystallization of material obtained at pH 3. Complex (II lies across an inversion center. Complexes (I and (II both display intramolecular O—H...O hydrogen bonding. Intermolecular O—H...O hydrogen bonding links symmetry-related molecules forming chains along [100] for complex (I with π-stacking along [010] and [001]. Complex (II forms intermolecular O—H...O hydrogen-bonded chains along [010] with π-stacking along [100] and [001].

Bis[1,3-bis(2,4,6-trimethylphenyl-2,3-dihydro-1H-imidazol-2-ylidene]dinitrosyl(tetrahydroborato-κ2H,H′tungsten(0

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Heinz Berke

2011-01-01

Full Text Available In the title paramagnetic 19-electron neutral complex, [W(BH4(C21H24N22(NO2], the W(0 atom is coordinated by two 1,3-bis(2,4,6-trimethylphenylimidazol-2-ylidene (IMes carbene ligands, two NO groups and two H atoms of an η2-tetrahydroborate ligand. Depending on the number of coordination sites (n assigned to the BH4− ligand, the coordination geometry of the W atom may either be described as approximately trigonal–bipyramidal (n = 1 or as very distorted octahedral with the bridging H atoms filling two coordination positions (n = 2. In the latter case, the coplanar NO groups and bridging H atoms (r.m.s. deviation = 0.032 Å form one octahedral plane, with mutually trans-oriented carbene ligands. In the crystal, molecules are connected via C—H...O interactions.

Photoluminescence and electroluminescence of a novel green-yellow emitting material-5,6-Bis-[4-(naphthalene-1-yl-phenyl-amino)-phenyl] -pyrazine-2,3-dicarbonitrile

International Nuclear Information System (INIS)

Chew Siewling; Wang Pengfei; Hong Zirou; Kwong, H.L.; Tang Jianxin; Sun Shiling; Lee, C.S.; Lee, S.-T.

2007-01-01

A new compound with intramolecular charge transfer (ICT) property-5,6-Bis-[4-(naphthalene-1-yl-phenyl-amino)-phenyl] -pyrazine-2,3-dicarbonitrile(BNPPDC) was synthesized. The new compound was strongly fluorescent in non-polar and moderately polar solvents, as well as in thin solid film. The absorption and emission maxima shifted to longer wavelength with increasing solvent polarity. The fluorescence quantum yield also increased with increasing solvent polarity from non-polar to moderately polar solvents, then decreased with further increase of solvent polarity. This indicates both 'positive' and 'negative' solvatokinetic effects co-existed. Using this material as hole-transporting emitter and host emitter, we fabricated two electroluminescent (EL) devices with structures of A (ITO/BNPPDC (45 nm)/1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI) (45 nm)/Mg:Ag (200 nm) and B (ITO/N,N'-diphenyl-N,N'-bis-(3-methylphenyl) (1,1'-diphenyl)4,4'-diamine (TPD) (50 nm)/BNPPDC (20 nm)/1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI) (45 nm)/Mg:Ag (200 nm). The devices showed green-yellow EL emission with good efficiency and high brightness. For example, the device A exhibited a high brightness of 17400 cd/m 2 at a driving voltage of 11 V and a very low turn-on voltage (2.9 V), as well as a maximum luminous efficiency 3.61 cd/A. The device B showed a similar performance with a high brightness of 12650 cd/m 2 at a driving voltage of 13 V and a maximum luminous efficiency 3.62 cd/A. In addition, the EL devices using BNPPDC as a host and 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran (DCJTB) as a dopant (configuration: ITO/TPD (60 nm)/BNPPDC:DCJTB (2%) (30 nm)/TPBI (35 nm)/Mg:Ag (200 nm)) showed a good performance with a brightness of 150 cd/m 2 at 4.5 V, a maximum brightness of 12600 cd/m 2 at 11.5 V, and a maximum luminous efficiency of 3.30 cd/A

Photoluminescence and electroluminescence of a novel green-yellow emitting material-5,6-Bis-[4-(naphthalene-1-yl-phenyl-amino)-phenyl] -pyrazine-2,3-dicarbonitrile

Energy Technology Data Exchange (ETDEWEB)

Chew Siewling [Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China); Wang Pengfei [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100101 (China)]. E-mail: wangpf@mail.ipc.ac.cn; Hong Zirou [Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China); Kwong, H.L. [Department of Biology and Chemistry, City University of Hong Kong, Hong Kong (China); Tang Jianxin [Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China); Sun Shiling [Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China); Lee, C.S. [Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China)]. E-mail: apcslee@cityu.edu.hk; Lee, S.-T. [Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China)]. E-mail: apannale@cityu.edu.hk

2007-06-15

A new compound with intramolecular charge transfer (ICT) property-5,6-Bis-[4-(naphthalene-1-yl-phenyl-amino)-phenyl] -pyrazine-2,3-dicarbonitrile(BNPPDC) was synthesized. The new compound was strongly fluorescent in non-polar and moderately polar solvents, as well as in thin solid film. The absorption and emission maxima shifted to longer wavelength with increasing solvent polarity. The fluorescence quantum yield also increased with increasing solvent polarity from non-polar to moderately polar solvents, then decreased with further increase of solvent polarity. This indicates both 'positive' and 'negative' solvatokinetic effects co-existed. Using this material as hole-transporting emitter and host emitter, we fabricated two electroluminescent (EL) devices with structures of A (ITO/BNPPDC (45 nm)/1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI) (45 nm)/Mg:Ag (200 nm) and B (ITO/N,N'-diphenyl-N,N'-bis-(3-methylphenyl) (1,1'-diphenyl)4,4'-diamine (TPD) (50 nm)/BNPPDC (20 nm)/1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI) (45 nm)/Mg:Ag (200 nm). The devices showed green-yellow EL emission with good efficiency and high brightness. For example, the device A exhibited a high brightness of 17400 cd/m{sup 2} at a driving voltage of 11 V and a very low turn-on voltage (2.9 V), as well as a maximum luminous efficiency 3.61 cd/A. The device B showed a similar performance with a high brightness of 12650 cd/m{sup 2} at a driving voltage of 13 V and a maximum luminous efficiency 3.62 cd/A. In addition, the EL devices using BNPPDC as a host and 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran (DCJTB) as a dopant (configuration: ITO/TPD (60 nm)/BNPPDC:DCJTB (2%) (30 nm)/TPBI (35 nm)/Mg:Ag (200 nm)) showed a good performance with a brightness of 150 cd/m{sup 2} at 4.5 V, a maximum brightness of 12600 cd/m{sup 2} at 11.5 V, and a maximum luminous efficiency of 3.30 cd/A.

(μ-Acetato-κ2 O:O′)[μ-2,6-bis­({bis­[(pyri­din-2-yl-κN)meth­yl]amino-κN}meth­yl)-4-methyl­phenolato-κ2 O:O](metha­nol-κO)dizinc bis­(perchlorate)

Science.gov (United States)

Das, Biswanath; Haukka, Matti; Nordlander, Ebbe

2014-01-01

The binuclear title complex, [Zn2(C33H33N6O)(CH3COO2)(CH3OH)](ClO4)2, was synthesized by the reaction between 2,6-bis­({[bis­(pyridin-2-yl)meth­yl]amino}­meth­yl)-4-methyl­phenol (H-BPMP), Zn(OAc)2 and NaClO4. The two ZnII ions are bridged by the phenolate O atom of the octadentate ligand and the acetate group. An additional methanol ligand is terminally coordinated to one of the ZnII ions, rendering the whole structure unsymmetric. Other symmetric dizinc complexes of BPMP have been reported. However, to the best of our knowledge, the present structure, in which the two ZnII ions are distinguishable by the number of coordinating ligands and the coordination geometries (octahedral and square-pyramidal), is unique. The dizinc complex is a dication, and two perchlorate anions balance the charge. The –OH group of the coordinating methanol solvent mol­ecule forms a hydrogen bond with a perchlorate counter-anion. One of the anions is disordered over two sets of sites with an occupancy ratio of 0.734 (2):0.266 (2). PMID:24826088

Bis[N,N-bis(1-allyl-1H-benzimidazol-2-ylmethyl-κN3benzylamine-κN]cadmium dipicrate

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Jing-Kun Yuan

2011-06-01

Full Text Available The crystal structure of the title compound, [Cd(C29H29N52](C6H2N3O72, consists of CdII complex cations and picrate anions. In the complex cation, the CdII ion is chelated by two bis(1-allylbenzimidazol-2-ylmethylbenzylamine (babb ligands in a distorted octahedral geometry. Extensive C—H...O hydrogen bonding occurs between cations and anions in the crystal structure.

{2,6-Bis[(di-tert-butyl-phosphino)-methyl]-phenyl}chloridonickel(II).

Science.gov (United States)

Boro, Brian J; Dickie, Diane A; Goldberg, Karen I; Kemp, Richard A

2008-09-20

In the title compound, [Ni(C(24)H(43)P(2))Cl], the Ni atom adopts a distorted square-planar geometry, with the P atoms of the 2,6-bis-[(di-tert-butyl-phosphino)meth-yl]phenyl ligand trans to one another. The P-Ni-P plane is twisted out of the plane of the aromatic ring by 21.97 (6)°.

Gamma spectrometry of EFTTRA T2BIS R280.2. Gamma scan wires 6 through 10

International Nuclear Information System (INIS)

Dassel, G.; Buurveld, H.A.; Plakman, J.C.

1996-11-01

In the frame work of the EFTTRA programme on recycling of actinides and fission products, five gamma scan wires which were included in the experiment R280.2 T2bis have been examined by gamma scanning. The results of the measurements have been described in this report. (orig.)

A Highly Stereocontrolled, One-Pot Approach toward Pyrrolobenzoxazinones and Pyrroloquinazolinones through a Lewis Acid-Catalyzed [3 + 2]-Cycloannulation Process.

Science.gov (United States)

Boomhoff, Michael; Ukis, Rostyslav; Schneider, Christoph

2015-08-21

We report herein a stereocontrolled [3 + 2]-cycloheteroannulation of bis-silyl dienediolate 1 with 2-aminobenzoic acid- and 2-aminobenzamide-derived imines to furnish highly substituted pyrrolo[1,2-a]benzoxazinones 3 and pyrrolo[1,2-a]quinazolinones 4, respectively, in good overall yields. This one-pot process rapidly generates molecular complexity and comprises a Lewis acid-catalyzed, vinylogous Mannich reaction of 1 followed by an intramolecular N,O-acetal- and N,N-aminal formation, respectively, which proceeds with good to excellent stereocontrol.

From polyethylene waxes to HDPE using an α,α'-bis(arylimino)-2,3:5,6-bis(pentamethylene)pyridyl-chromium(iii) chloride pre-catalyst in ethylene polymerisation.

Science.gov (United States)

Huang, Chuanbing; Du, Shizhen; Solan, Gregory A; Sun, Yang; Sun, Wen-Hua

2017-05-30

Five examples of α,α'-bis(arylimino)-2,3:5,6-bis(pentamethylene)pyridyl-chromium(iii) chlorides (aryl = 2,6-Me 2 Ph Cr1, 2,6-Et 2 Ph Cr2, 2,6-i-Pr 2 Ph Cr3, 2,4,6-Me 3 Ph Cr4, 2,6-Et 2 -4-MePh Cr5) have been synthesized by the one-pot template reaction of α,α'-dioxo-2,3:5,6-bis(pentamethylene)pyridine, CrCl 3 ·6H 2 O and the corresponding aniline. The molecular structures of Cr1 and Cr4 reveal distorted octahedral geometries with the N,N,N-ligand adopting a mer-configuration. On activation with an aluminium alkyl co-catalyst, Cr1-Cr5 exhibited high catalytic activities in ethylene polymerization and showed outstanding thermal stability operating effectively at 80 °C with activities up to 1.49 × 10 7 g of PE (mol of Cr) -1 h -1 . Significantly, the nature of the co-catalyst employed had a dramatic effect on the molecular weight of the polymeric material obtained. For example, using diethylaluminium chloride (Et 2 AlCl) in combination with Cr4 gave high density/high molecular weight polyethylene with broad molecular weight distributions (30.9-39.3). By contrast, using modified methylaluminoxane (MMAO), strictly linear polyethylene waxes of lower molecular weight and narrow molecular weight distribution (1.6-2.0) were obtained with vinyl end-groups.

A coordination polymer of CdII with benzene-1,3-dicarboxylate and 1,4-bis[1-(2-pyridylmethylbenzimidazol-2-yl]butane

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Wei-Ping Zhang

2009-11-01

Full Text Available The title CdII coordination polymer, catena-poly[[{1,4-bis[1-(2-pyridylmethylbenzimidazol-2-yl]butane}cadmium(II]-μ-benzene-1,3-dicarboxylato], [Cd(C8H4O4(C30H28N6]n, was obtained by reaction of CdCO3, benzene-1,3-dicarboxylic acid (H2btc and 1,4-bis[1-(2-pyridylmethylbenzimidazol-2-yl]butane (L. The CdII cation is six-coordinated by an N2O4-donor set. L acts as a bidentate ligand and btc anions link CdII centers into a chain propagating parallel to [010].

Bis(tetramethylcyclopentadienyl)titanium chemistry. Molecular structures of [(C(5)HMe(4))(mu-eta(1) : eta(5)-C(5)Me(4))Ti](2) and [(C(5)HMe(4))(2)Ti]N-2(2)

NARCIS (Netherlands)

deWolf, JM; Blaauw, R; Meetsma, A; Teuben, JH; Gyepes, R; Varga, [No Value; Mach, K; Veldman, N; Spek, AL

1996-01-01

Thermolysis of bis(tetramethylcyclopentadienyl)-stabilized titanium(III) compounds (C(5)HMe(4))(2)TiR (R = Me (2), Ph (3)) yields, in marked contrast with the bis(pentamethylcyclopentadienyl) analog, the dimeric product [(C(5)HMe(4))(mu-eta(1):eta(5)-C(5)Me(4))Ti](2) (4), With a bridging metalated

Crystal structure of 2,2′′-bis(2,7-dichloro-9-hydroxy-9H-fluoren-9-yl-1,1′:4′,1′′-terphenyl triethylamine trisolvate

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Henrik Klien

2015-12-01

Full Text Available In the title solvate, C44H26Cl4O2·3C6H15N, the asymmetric part of the unit cell comprises two halves of the diol molecules, 2,2′′-bis(2,7-dichloro-9-hydroxy-9H-fluoren-9-yl-1,1′:4′,1′′-terphenyl, and three molecules of triethylamine, i. e. the diol molecules are located on crystallographic symmetry centres. Two of the solvent molecules are disordered over two positions [occupancy ratios of 0.567 (3:0.433 (3 and 0.503 (3:0.497 (3]. In the diol molecules, the outer rings of the 1,1′:4′,1′′-terphenyl elements are twisted with reference to their central arene ring and the mean planes of the fluorenyl moieties are inclined with respect to the terphenyl ring to which they are connected, the latter making dihedral angles of 82.05 (8 and 82.28 (8°. The presence of two 9-fluoren-9-ol units attached at positions 2 and 2′′ of the terphenyl moiety induces a `folded' geometry which is stabilized by intramolecular C—H...O hydrogen bonds and π–π stacking interactions, the latter formed between the fluorenyl units and the central ring of the terphenyl unit [centroid–centroid distances = 3.559 (1 and 3.562 (1 Å]. The crystal is composed of 1:2 complex units, in which the solvent molecules are associated with the diol molecules via O—H...N hydrogen bonds, while the remaining solvent molecule is linked to the host by a C—H...N hydrogen bond. The given pattern of intermolecular interactions results in formation of chain structures extending along [010].

Chemical transformation of 3-bromo-2,2-bis(bromomethyl)-propanol under basic conditions.

Science.gov (United States)

Ezra, Shai; Feinstein, Shimon; Bilkis, Itzhak; Adar, Eilon; Ganor, Jiwchar

2005-01-15

The mechanism of the spontaneous decomposition of 3-bromo-2,2-bis(bromomethyl)propanol (TBNPA) and the kinetics of the reaction of the parent compound and two subsequent products were determined in aqueous solution at temperatures from 30 to 70 degrees C and pH from 7.0 to 9.5. TBNPA is decomposed by a sequence of reactions that form 3,3-bis(bromomethyl)oxetane (BBMO), 3-bromomethyl-3-hydroxymethyloxetane (BMHMO), and 2,6-dioxaspiro[3.3]-heptane (DOH), releasing one bromide ion at each stage. The pseudo-first-order rate constant of the decomposition of TBNPA increases linearlywith the pH. The apparent activation energy of this transformation (98+/-2 KJ/mol) was calculated from the change of the effective second-order rate constant with temperature. The pseudoactivation energies of BBMO and BMHMO were estimated to be 109 and 151 KJ/mol, respectively. Good agreement was found between the rate coefficients derived from changes in the organic molecules concentrations and those determined from the changes in the Br- concentrations. TBNPA is the most abundant semivolatile organic pollutant in the aquitard studied, and together with its byproducts they posess an environmental hazard. TBNPA half-life is estimated to be about 100 years. This implies that high concentrations of TBNPA will persist in the aquifer long after the elimination of all its sources.

Synthesis of novel pyrazoline based bis (1,2,3-triazole scaffolds via click chemistry

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Kiran Kothuri

2017-01-01

Full Text Available A series of novel bis(1,2,3-triazoles derivatives 7a–m were synthesized by the 1,3-dipolar cycloaddition (click-reaction of 1-methyl-3,5-bis(2- -(prop-2-yn-1-yloxyphenyl-4,5-dihydro-1H-pyrazole (5 with various aralkyl azides 6a–m in the presence of sodium ascorbate and copper sulphate with good yields. The required precursor 5 was synthesized by reacting (E-1,3- -bis(2-hydroxyphenylprop-2-en-1-one (3 with methylhydrazine hydrate via 2,2′-(1-methyl-4,5-dihydro-1H-pyrazole-3,5-diyldiphenol 4, followed by reaction with propargyl bromide. The homogeneity of all the newly synthesized compounds was checked by TLC. The IR, NMR, mass spectral data and elemental analysis were in accord with the assigned structure. The title compounds were evaluated for their antibacterial activity against various bacterial strains, i.e., Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis; compounds 7f–7h and 7j were found to be moderately active against the bacteria, when compared with that of the standard drug. Furthermore, the same library of compounds was evaluated for their antioxidant activity using the nitric oxide radical scavenging activity. The results of the study showed that compounds 7e–7h and 7k–7m showed good radical scavenging activity.

40 CFR 721.7780 - Poly[oxy(methyl-1,2-ethane-diyl)], α,α′-(2,2-dimethyl-1,3-pro-pan-ediyl)bis[ω-(oxi-rany-me-thoxy)-.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Poly[oxy(methyl-1,2-ethane-diyl)], α,αâ²-(2,2-dimethyl-1,3-pro-pan-ediyl)bis[Ï-(oxi-rany-me-thoxy)-. 721.7780 Section 721.7780... Poly[oxy(methyl-1,2-ethane-diyl)], α,α′-(2,2-dimethyl-1,3-pro-pan-ediyl)bis[ω-(oxi-rany-me-thoxy)-. (a...

Aqueous Synthesis of 1-H-2-Substituted Benzimidazoles via Transition-Metal-Free Intramolecular Amination of Aryl Iodides

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Chunxia Chen

2012-10-01

Full Text Available A straightforward method has been developed for the synthesis of the benzimidazole ring system through a carbon-nitrogen cross-coupling reaction. In the presence of 2.0 equiv. of K2CO3 in water at 100 °C for 30 h, the intramolecular cyclization of N-(2-iodoarylbenzamidine provides benzimidazole derivatives in moderate to high yields. Remarkably, the procedure occurs exclusively in water and doesn’t require the use of any additional reagent/catalyst, rendering the methodology highly valuable from both environmental and economical points of view.

Uptake of 153Sm-DTPA-bis-biotin and 99mTc-DTPA-bis-biotin in rat as-30D-hepatoma cells

International Nuclear Information System (INIS)

Correa-Gonzalez, Luis; Arteaga de Murphy, Consuelo; Ferro-Flores, Guillermina; Pedraza-Lopez, Martha; Murphy-Stack, Eduardo; Mino-Leon, Dolores; Perez-Villasenor, Graciela; Diaz-Torres, Yaneth; Munoz-Olvera, Rodrigo

2003-01-01

Labeled biotin has been used mainly for pretargeted therapy, an approach for increasing the amount of radioactivity delivered to a cancer cell. The aim of this investigation was to prepare 153 Sm-DTPA-bis-biotin and 99m Tc-DTPA-bis-biotin in order to study their in vitro and in vivo uptake in rat AS-30D hepatoma cells found in ascites and in implanted tumor. DTPA-bis-biotin (pH 8) was 153 Sm labeled with 153 SmCl 3 and 99m Tc-DTPA-bis-biotin was prepared via SnCl 2 reduction. Radiochemical purity was >98% in both cases. AS-30D hepatoma cells were obtained from ascites of a rat with hepatoma and were propagated in the peritoneum cavity of normal rats. In vitro ascites cell 153 Sm-DTPA-bis-biotin uptake was compared with 153 SmCl 3 cell uptake. The ratio cell 153 Sm-DTPA-bis-biotin/ 153 SmCl 3 was 39.6 and when avidin was added it increased to 50. The ratio 99m Tc-DTPA-bis-biotin/TcO 4 Na was 8.7. Concentration of 153 Sm-DTPA-bis-biotin in tumor 2, 3 and 24 h after administration, was 5, 15 and 3 times higher than in normal muscle (T/nT). Biodistribution in a 0.083-24 h time period showed that 153 Sm-DTPA-bis-biotin was taken up only by ascites tumor cells and hepatoma cells. Two and 3 h ratio ascites/liver (As/Lv) was 6.4 and 6.0. For 99m Tc-DTPA-bis-biotin 2 and 3 h T/nT was 15.7 and 4.7 and 2 h As/Lv was 1.4. In conclusion, both radiopharmaceuticals show high uptake in rat AS-30D hepatoma cells in ascites and in implanted tumor. Since lung, thyroid, kidney, liver or pancreas carcinomas are ascites producing cancers 153 Sm-DTPA-bis-biotin would be an adequate therapeutic radiopharmaceutical for these patients whose life quality would be enhanced with control of ascites, and a reduction of the primary tumor and its metastases

Facile Synthesis of Novel Vanillin Derivatives Incorporating a Bis(2-hydroxyethyl)dithhioacetal Moiety as Antiviral Agents.

Science.gov (United States)

Zhang, Jian; Zhao, Lei; Zhu, Chun; Wu, Zengxue; Zhang, Guoping; Gan, Xiuhai; Liu, Dengyue; Pan, Jianke; Hu, Deyu; Song, Baoan

2017-06-14

A series of vanillin derivatives incorporating a bis(2-hydroxyethyl)dithioacetal moiety was designed and synthesized via a facile method. A plausible reaction pathway was proposed and verified by computational studies. Bioassay results demonstrated that target compounds possessed good to excellent activities against potato virus Y (PVY) and cucumber mosaic virus (CMV), of which, compound 6f incorporating a bis(2-hydroxyethyl)dithioacetal moiety, exhibited the best curative and protection activities against PVY and CMV in vivo, with 50% effective concentration values of 217.6, 205.7 μg/mL and 206.3, 186.2 μg/mL, respectively, better than those of ribavirin (848.0, 808.1 μg/mL and 858.2, 766.5 μg/mL, respectively), dufulin (462.6, 454.8 μg/mL and 471.2, 465.4 μg/mL, respectively), and ningnanmycin (440.5, 425.3 μg/mL and 426.1, 405.3 μg/mL, respectively). Current studies provide support for the application of vanillin derivatives incorporating bis(2-hydroxyethyl)dithioacetal as new antiviral agents.

Reações de inserção intramolecular de diazo compostos polifuncionais catalisadas por ródio(II: síntese de oxetan-3-ona-2-carboxilato e outros heterociclos funcionalizados Rhodium(II-catalysed intramolecular insertion reaction of multifunctional diazo compounds: synthesis of oxetan-3-one-2-carboxilate and other heterocycles

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Albert Padwa

1999-12-01

Full Text Available gamma-Hydroxy-alpha-diazo-beta-ketoesters are key intermediates in the chemistry of penicilin-based antibiotics and natural products. The method developed here for the synthesis of ethyl 2-diazo-4-hydroxy-3-oxo-butanoate 17 (in two steps from the diazo mercurial 2 compares very favorably with those reported in the literature for similar compounds. The Rh2(OAc4-mediated intramolecular OH-insertion reaction of the diazo hydroxy ester 17 was investigated, furnishing the oxetan-3-one-2-carboxilate 18 in good yield. When the diazo ester lacks a free hydroxyl group as in the case of the phenoxy diazo ester 11 an intramolecular CH-insertion takes place, affording the 2H-chromene 20 in almost quantitative yield. The behavior of other functionalized diazo esters towards Rh2(OAc4 was also investigated.

(Acetylacetonato-κ2O,O′bis[5-methoxy-2-(naphth[1,2-d][1,3]oxazol-2-ylphenyl-κ2C1,N]iridium(III

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Yuan-Yuan Zhou

2011-10-01

Full Text Available In the title compound, [Ir(C18H12NO22(C5H7O2], the Ir atom is O,O′-chelated by the acetylacetonate group and C,N-chelated by the 2-arylnaphth[1,2-d]oxazole groups. The six-coordinate metal atom displays a distorted octahedral geometry. Intramolecular C—H...O hydrogen bonds occur. In the crystal, intermolecular C—H...O hydrogen bonds link the molecules into columns parallel to the b axis.

[μ-N,N′-Bis(2-aminoethylethane-1,2-diamine-κ4N1,N1′:N2,N2′]bis{[N,N′-bis(2-aminoethylethane-1,2-diamine-κ4N,N′,N′′,N′′′]cadmium} tetrakis(perchlorate

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Hamid Goudarziafshar

2012-09-01

Full Text Available The centrosymmetric dinuclear cadmium title complex, [Cd2(C6H18N43](ClO44, was obtained by the reaction of N,N′-bis(2-aminoethylethane-1,2-diamine (trien with Cd(NO32·4H2O and sodium perchlorate in methanol. The CdII cation is coordinated by four N atoms of a non-bridging trien ligand and by two N atoms of a bridging trien ligand in a slightly distorted octahedral coordination geometry. The bridging ligand shares another two N atoms with a neighboring symmetry-equivalent CdII cation. The structure displays C—H...O and N—H...O hydrogen bonding. The perchlorate anion is disordered over two sets of sites in a 0.854 (7: 0.146 (7 ratio.

Copper-64 Dichloride as Theranostic Agent for Glioblastoma Multiforme: A Preclinical Study

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Cristina Ferrari

2015-01-01

Full Text Available Glioblastoma multiforme (GBM is the most common primary malignant brain tumor in adults with a median survival time less than one year. To date, there are only a limited number of effective agents available for GBM therapy and this does not seem to add much survival advantage over the conventional approach based on surgery and radiotherapy. Therefore, the development of novel therapeutic approaches to GBM is essential and those based on radionuclide therapy could be of significant clinical impact. Experimental evidence has clearly demonstrated that cancer cells have a particularly high fractional content of copper inside the nucleus compared to normal cells. This behavior can be conveniently exploited both for diagnosis and for delivering therapeutic payloads (theranostic of the radionuclide copper-64 into the nucleus of cancerous cells by intravenous administration of its simplest chemical form as dichloride salt [64Cu]CuCl2. To evaluate the potential theranostic role of [64Cu]CuCl2 in GBM, the present work reports results from a preclinical study carried out in a xenografted GBM tumor mouse model. Biodistribution data of this new agent were collected using a small-animal PET tomograph. Subsequently, groups of tumor implanted nude mice were treated with [64Cu]CuCl2 to simulate single- and multiple-dose therapy protocols, and results were analyzed to estimate therapeutic efficacy.

7α-alkylation and 7,7-bis-alkylation of 20-hydroxyecdysone with propargyl bromide in a lithium-ammonia solution and catalytic reductive spirocyclization of 7,7-bis(2-propyn-1-yl)-14-deoxy-Δ(8(14))-20-hydroxyecdysone.

Science.gov (United States)

Galyautdinov, Ilgiz V; Khairullina, Zarema R; Sametov, Valery P; Muslimov, Zabir S; Khalilov, Leonard M; Odinokov, Victor N

2016-03-01

7α-Alkylation and 7,7-bis-alkylation of 20-hydroxyecdysone with propargyl bromide in a lithium-ammonia solution resulted in the formation of 7α-(2-propyn-1-yl)- and 7,7-bis(2-propyn-1-yl)-14-deoxy-Δ(8(14))-20-hydroxyecdysone in 92% and 75% yield respectively. Upon catalytic hydrogenation (10% Pd-C) of 7,7-bis(2-propyn-1-yl) derivative spirocyclization occurs by geminal 2-propyn-1-yl groups. Copyright © 2016 Elsevier Inc. All rights reserved.

Chelating agents related to ethylenediamine bis(2-hydroxyphenyl)acetic acid (EDDHA): synthesis, characterization, and equilibrium studies of the free ligands and their Mg2+, Ca2+, Cu2+, and Fe3+ chelates.

Science.gov (United States)

Yunta, Felipe; García-Marco, Sonia; Lucena, Juan J; Gómez-Gallego, Mar; Alcázar, Roberto; Sierra, Miguel A

2003-08-25

Iron chelates such as ethylenediamine-N,N'-bis(2-hydroxyphenyl)acetic acid (EDDHA) and their analogues are the most efficient soil fertilizers to treat iron chlorosis in plants growing in calcareous soils. EDDHA, EDDH4MA (ethylenediamine-N,N'-bis(2-hydroxy-4-methylphenyl)acetic acid), and EDDCHA (ethylenediamine-N,N'-bis(2-hydroxy-5-carboxyphenyl)acetic acid) are allowed by the European directive, but also EDDHSA (ethylenediamine-N,N'-bis(2-hydroxy-5-sulfonylphenyl)acetic acid) and EDDH5MA (ethylenediamine-N,N'-bis(2-hydroxy-5-methylphenyl)acetic acid) are present in several commercial iron chelates. In this study, these chelating agents as well as p,p-EDDHA (ethylenediamine-N,N'-bis(4-hydroxyphenyl)acetic acid) and EDDMtxA (ethylenediamine-N,N'-bis(2-metoxyphenyl)acetic acid) have been obtained following a new synthetic pathway. Their chemical behavior has been studied to predict the effect of the substituents in the benzene ring on their efficacy as iron fertilizers for soils above pH 7. The purity of the chelating agents has been determined using a novel methodology through spectrophotometric titration at 480 nm with Fe(3+) as titrant to evaluate the inorganic impurities. The protonation constants were determined by both spectrophotometric and potentiometric methods, and Ca(2+) and Mg(2+) stability constants were determined from potentiometric titrations. To establish the Fe(3+) and Cu(2+) stability constants, a new spectrophotometric method has been developed, and the results were compared with those reported in the literature for EDDHA and EDDHMA and their meso- and rac-isomers. pM values have been also determined to provide a comparable basis to establish the relative chelating ability of these ligands. The purity obtained for the ligands is higher than 87% in all cases and is comparable with that obtained by (1)H NMR. No significant differences have been found among ligands when their protonation and stability constants were compared. As expected, no Fe(3

Superconductivity in REO0.5F0.5BiS2 with high-entropy-alloy-type blocking layers

Science.gov (United States)

Sogabe, Ryota; Goto, Yosuke; Mizuguchi, Yoshikazu

2018-05-01

We synthesized new REO0.5F0.5BiS2 (RE: rare earth) superconductors with high-entropy-alloy-type (HEA-type) REO blocking layers. The lattice constant a systematically changed in the HEA-type samples with the RE concentration and the RE ionic radius. A sharp superconducting transition was observed in the resistivity measurements for all the HEA-type samples, and the transition temperature of the HEA-type samples was higher than that of typical REO0.5F0.5BiS2. The sharp superconducting transition and the enhanced superconducting properties of the HEA-type samples may indicate the effectiveness of the HEA states of the REO blocking layers in the REO0.5F0.5BiS2 system.

Intramolecular and nonlinear dynamics

Energy Technology Data Exchange (ETDEWEB)

Davis, M.J. [Argonne National Laboratory, IL (United States)

1993-12-01

Research in this program focuses on three interconnected areas. The first involves the study of intramolecular dynamics, particularly of highly excited systems. The second area involves the use of nonlinear dynamics as a tool for the study of molecular dynamics and complex kinetics. The third area is the study of the classical/quantum correspondence for highly excited systems, particularly systems exhibiting classical chaos.

New polymer syntheses part 46 Synthesis and characterization of New Unsaturated Terpolyesters based on Dibenzylidene cyclohexanone

International Nuclear Information System (INIS)

Aly, K.I.; Ahmed, M.S.

2005-01-01

A new series from unsaturated terployesters were synthesized by interfacial polycondensation of 2,6-bis(4-hydroxybenzylidene) cyclohexanone I, 2,6-bis( 3-hydroxybenzylidene ) cyclohexanone II and 2,6 -bis(4-hydroxy-3- methoxybenzyl-Lidene) cyclohexanone III with isophthaloyl, terephthaloyl, adipoyl and sebacoyl dichloride have been produced. The yield and the value of the inherent viscosity of the ter polyester were found to be affected by the kind of organic phase,.the quantitative ratio of organic to aqueous phase, concentration of hydrogen chloride acceptor, rate of acid chloride addition, contribution of benzyltriethylammonium chloride (BTC) as a catalyst, and the temperature of the polycondensation reaction. The resulting ter polyesters were characterized by IR, elemental analysis, viscometry. DTA, DSC, thermogravimetric analysis, dielectric constant and mechanical properties. The crystallinity of copolyester was examined by X-ray analysis. In addition the electrical properties of the copolyester were investigated and the morphology of two new copolyester have been tested by SEM

Synthesis and Characterization of New Unsaturated Copolyester based on Dibenzylidene cyclohexanone

International Nuclear Information System (INIS)

Aly, K.I.; Ahmed, M.S.

2005-01-01

New unsaturated copolyester were synthesized by the interfacial polycondensation of 2,6-bis (4-hydroxybenzylidene) cyclohexanone I, 2,6- bis( 3-hydroxybenzylidene ) cyclohexanone II, or 2,6 -bis(4-hydroxy-3- methoxybenzylidene) cyclohexanone III with 4,4'-diphenic, isophthaloyl, terephthaloyl, adipoyl and sebacoyl dichloride have been produced. The yield and the value of the inherent viscosity of the copolyester were found to be affected by the kind of organic phase , the quantitative ratio of organic to aqueous phase, concentration of hydrogen chloride acceptor, rate of acid chloride, addition, contribution of benzyltriethylammonium chloride (BTC) as catalyst, and the temperature of the polycondensation reaction. The resulting copolyester were characterized by IR, elemental analysis ,viscometry, DTA,DSC, TGA, thermogravimetric analysis dielectric constant and mechanical properties. The crystallinity of copolyester was examined by Xray analysis. In addition the electrical properties of the copolyester were investigated and morphology of two new copolyester have been tested by SEM

Synthesis of Acridine-based DNA Bis-intercalating Agents

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P. Mack

2001-02-01

Full Text Available Methods for the synthesis of N1, N8-bis(9-acridinyl-N4-(4-hydroxybenzyl-spermidine and N1, N7-(hydroxybenzyl-bis-(3-aminopropylamine were investigated. Thus monocyanoethylation of 4-methoxybenzylamine followed by treatment with 4-chlorobutyronitrile gave the dinitrile N-(2-cyanoethyl-N-(3-cyanopropyl-4-methoxybenzylamine. Subsequent in situ reduction with lithium aluminium hydride gave the corresponding diamine. Biscyanoethylation of 4-methoxybenzylamine with 2 mole of acrylonitrile followed by reduction yielded the diamine N, N-bis-(3-aminopropyl-4-methoxybenzylamine. Both diamines reacted smoothly with 9-methoxyacridine to give the bis-(9-acridinyl compounds 11 and 15 but with 4,5-dimethyl-9-methoxyacridine, the bis compound 16 was produced in only low yields. Demethylation of the dinitriles by a variety of approaches all failed to give the corresponding hydroxybenzyl derivatives. These studies yielded useful methylated tyrosine derivatives which could also be iodinated. This study has been useful for elucidating chemical methods needed for the synthesis of the desired tyrosine-based bis acridine compound and for alerting us to the need to synthesise a more labile protected tyrosine intermediate which will be easily deprotected to afford the desired tyrosine-based bis acridine compound.

Synthesis, crystal structure, and spectroscopic characterization of trans-bis[(mu-1,3-bis(4-pyridyl)propane)(mu-(3-thiopheneacetate-O))(3-thiopheneacetate-O)]dicopper(II), [[Cu2(O2CCH2C4H3S)4mu-(BPP)2

Science.gov (United States)

Marinho, Maria Vanda; Yoshida, Maria Irene; Guedes, Kassilio J; Krambrock, Klaus; Bortoluzzi, Adailton J; Hörner, Manfredo; Machado, Flávia C; Teles, Wagner M

2004-02-23

From the reaction between a dinuclear paddle-wheel carboxylate, namely [Cu2mu-(O2CCH2C4H3S)4] (1), and the flexible ligand 1,3-bis(4-pyridyl)propane (BPP) a neutral 2-D coordination polymer [[Cu2(O2CCH2C4H3S)4mu-(BPP)2

cis,cis,cis-(Acetato-κ2O,O′bis[1,2-bis(diphenylphosphanylethane-κ2P,P′]ruthenium(II 0.75-trifluoromethanesulfonate 0.25-chloride

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João Figueira

2013-04-01

Full Text Available In the title RuII carboxylate compound, [Ru(C2H3O2(C26H24P22](CF3O3S0.75Cl0.25, the distorted tris-bidentate octahedral stereochemistry about the RuII atom in the complex cation comprises four P-atom donors from two 1,2-bis(diphenylphosphanylethane ligands [Ru—P = 2.2881 (13–2.3791 (13 Å] and two O-atom donors from the acetate ligand [Ru—O = 2.191 (3 and 2.202 (3 Å]. The disordered counter-anions are located on the same site in the structure in a 3:1 ratio, the expanded formula comprising four complex cations, three trifluoromethanesulfonate anions and one chloride anion, with two such formula units in the unit cell.

Role of valence changes and nanoscale atomic displacements in BiS2-based superconductors.

Science.gov (United States)

Cheng, Jie; Zhai, Huifei; Wang, Yu; Xu, Wei; Liu, Shengli; Cao, Guanghan

2016-11-22

Superconductivity within layered crystal structures has attracted sustained interest among condensed matter community, primarily due to their exotic superconducting properties. EuBiS 2 F is a newly discovered member in the BiS 2 -based superconducting family, which shows superconductivity at 0.3 K without extrinsic doping. With 50 at.% Ce substitution for Eu, superconductivity is enhanced with Tc increased up to 2.2 K. However, the mechanisms for the T c enhancement have not yet been elucidated. In this study, the Ce-doping effect on the self-electron-doped superconductor EuBiS 2 F was investigated by X-ray absorption spectroscopy (XAS). We have established a relationship between Ce-doping and the T c enhancement in terms of Eu valence changes and nanoscale atomic displacements. The new finding sheds light on the interplay among superconductivity, charge and local structure in BiS 2 -based superconductors.

1,5-Bis(2-hydroxy-3-methoxybenzylidenecarbonohydrazide methanol 0.47-solvate

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Mouhamadou Moustapha Sow

2014-04-01

Full Text Available In the title compound, C17H18N4O5·0.47CH3OH, the virtually planar (r.m.s. deviation = 0.128 Å carbonohydrazide molecule is located on a twofold axis and conformation of its C=N bonds is E. There are short intramolecular O—H...N hydrogen bonds between the hydroxy groups and hydrazide N atoms. In the crystal, bifurcated N—H...(O,O hydrogen bonds assemble the carbonohydrazide molecules into a three-dimensional network. There are C2 symmetric voids in this network, 47% of which are occupied by disordered methanol molecules.

Thermal studies of poly(esters) containing silicon or germanium in the main chain

International Nuclear Information System (INIS)

Tagle, L.H.; Terraza, C.; Valenzuela, P.; Leiva, A.; Urzua, M.

2005-01-01

The thermal properties of poly(esters) containing Si and/or Ge in the main chain derived from the acid dichlorides bis(4-chloroformyl-phenyl)-dimethyl-silane, bis(4-chloroformyl-phenyl)-dimethyl-germane, bis(4-chloroformyl-phenyl)-diphenyl-silane and bis(4-chloroformyl-phenyl)-diphenyl-silane, and the diphenols bis(4-hydroxyphenyl)-dimethyl-silane, bis(4-hydroxyphenyl)-dimethyl-germane, bis(4-hydroxyphenyl)-diphenyl-silane and bis(4-hydroxyphenyl)-diphenyl-germane were studied by differential scanning calorimetry and dynamic thermogravimetry. Poly(esters) with two Si atoms in the main chain showed higher values of T g than those with two Ge atoms, and the same was observed for poly(esters) with phenyl groups bonded to the heteroatoms, instead of those with methyl groups. Thermal decomposition temperatures were also higher for those poly(esters) with two Si atoms in the main chain and those in which the heteroatom is bonded to phenyl groups, due to the higher polarity of the Si-C bond in front of the Ge-C

Rhodium(II)-Catalyzed and Thermally Induced Intramolecular Migration of N-Sulfonyl-1,2,3-triazoles: New Approaches to 1,2-Dihydroisoquinolines and 1-Indanones.

Science.gov (United States)

Sun, Run; Jiang, Yu; Tang, Xiang-Ying; Shi, Min

2016-04-11

New rhodium(II)-catalyzed or thermally induced intramolecular alkoxy group migration of N-sulfonyl-1,2,3-triazoles has been developed, affording divergent synthesis of 1,2-dihydroisoquinoline and 1-indanone derivatives according to different conditions. N-Sulfonyl keteneimine is the key intermediate for the synthesis of dihydroisoquinoline, whereas the aza-vinyl carbene intermediate results in the formation of 1-indanone. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sterically crowded monomeric neutral bis(benzamidinato) compounds of aluminium, [PhC(NSiMe(3))(2)](2)AlX (X=Cl, H); X-ray crystal structure of [PhC(NSiMe(3))(2)]2AlH

NARCIS (Netherlands)

Duchateau, R; Meetsma, A; Teuben, JH

1996-01-01

AlCl3 reacts with [PhC(NSiMe(3))(2)]Li(OEt(2)) to afford the bis(N,N'-bis(trimethylsilyl)benzamidinato)aluminium chloro compound which, on treatment with KBEt(3)H, yields the structurally characterized monomeric hydride derivative, [PhC(NSiMe(3))(2)]2AlH, whose reactivity towards unsaturated

Crystal structure of bis(azido-κNbis[2,5-bis(pyridin-2-yl-1,3,4-thiadiazole-κ2N2,N3]nickel(II

Directory of Open Access Journals (Sweden)

Abdelhakim Laachir

2015-02-01

Full Text Available Reaction of 2,5-bis(pyridin-2-yl-1,3,4-thiadiazole and sodium azide with nickel(II triflate yielded the mononuclear title complex, [Ni(N32(C12H8N4S2]. The NiII ion is located on a centre of symmetry and is octahedrally coordinated by four N atoms of the two bidentate heterocyclic ligands in the equatorial plane. The axial positions are occupied by the N atoms of two almost linear azide ions [N—N—N = 178.8 (2°]. The thiadiazole and pyridine rings of the heterocyclic ligand are almost coplanar, with a maximum deviation from the mean plane of 0.0802 (9 Å. The cohesion of the crystal structure is ensured by π–π interactions between parallel pyridine rings of neighbouring molecules [centroid-to-centroid distance = 3.6413 (14 Å], leading to a layered arrangement of the molecules parallel to (001.

Dibromido[1,1′-dibutyl-2,2′-(pentane-1,1-diyldi-1H-benzimidazole]copper(II

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Robert T. Stibrany

2010-07-01

Full Text Available In the title compound, [CuBr2(C27H36N4], the CuII ion exhibits a distorted tetrahedral coordination geometry provided by two bromide ions and by chelation of two imine N-atom donors from a bis(benzimidazole ligand. Chelation results in a six-membered boat-shaped ring which links the benzimidazole groups. Each bis(benzimidazole fragment contains three n-butyl substituents, two of which have the expected trans conformation; the third exhibits the higher-energy cis conformation, an orientation consistent with several short intramolecular C—H...Br interactions. Essentially planar (r.m.s. deviations of 0.0101 and 0.0183 Å benzimidazole groups are oriented so as to give the bis(benzimidazole fragment a V-shaped appearance in profile with the cis and trans n-butyl groups directed to opposite sides of the planes. In the crystal, columns of molecules along the b-axis direction form layers parallel to the (202 planes. Within a given column, the molecules are linked by C—H...Br hydrogen bonds. The molecules in adjacent columns are also linked by intermolecular C—H...π interactions, forming a three-dimensional network.

Crystal structure of bis[1,3-bis(2,6-diisopropylphenylimidazol-2-ylidene]silver(I chloride tetrahydrofuran monosolvate

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Inge Sänger

2015-05-01

Full Text Available In the title salt, [Ag(C27H36N22]Cl·C4H8O, the AgI atom is coordinated by two 1,3-bis(2,6-dimethylphenylimidazol-2-ylidene ligands. The imidazole rings are inclined to one another by 46.69 (13° and the benzene rings in each ligand are almost normal to the imdazole ring to which they are attached, with dihedral angles varying from 82.39 (13 to 88.27 (12°. There are C—H...π interactions present in the cation, involving the two ligands, and the solvent molecule is linked to the cation via a C—H...O hydrogen bond. In the crystal, molecules are linked by trifurcated C—H...(Cl,Cl,Cl hydrogen bonds, forming slabs parallel to (101. One isopropyl group is disordered over two sets of sites with an occupancy ratio of 0.447 (17:0.553 (17 and the THF molecule is disordered over two positions with an occupancy ratio of 0.589 (6:0.411 (6.

Hydrogenation of CO ₂ in Water Using a Bis(diphosphine) Ni–H Complex

Energy Technology Data Exchange (ETDEWEB)

Burgess, Samantha A. [Catalysis; Kendall, Alexander J. [Department; Tyler, David R. [Department; Linehan, John C. [Catalysis; Appel, Aaron M. [Catalysis

2017-03-17

The water soluble Ni bis(diphosphine) complex [NiL2](BF4)2 (L = 1,2- bis(di(methoxypropyl)phosphino)ethane) and the corresponding hydride, [HNiL2]BF4, were synthesized and characterized. For HNiL2+, the hydricity was determined to be 23.2(3) kcal/mol in aqueous solution. Based on the hydricity of formate of 24.1 kcal/mol, the transfer of a hydride from HNiL2 + to CO2 to produce formate is favorable by 1 kcal/mol. Starting from either NiL2 2+ or HNiL2 + in water, catalytic hydrogenation of CO2 was observed with NaHCO3 (0.8 M) as the only additive. A maximum turnover frequency of 3.6(8) h–1 was observed at 80 °C and 51 atm of a 1:1 mixture of CO2 and H2.

(E-2,2′-[3-(2-Nitrophenylprop-2-ene-1,1-diyl]bis(3-hydroxycyclohex-2-en-1-one

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Joo Hwan Cha

2012-01-01

Full Text Available In the title compound, C21H21NO6, each of the cyclohexenone rings adopts a half-chair conformation. Each of the pairs of hydroxy and carbonyl O atoms are oriented to allow for the formation of intramolecular O—H...O hydrogen bonds, which are typical of xanthene derivatives.

Triethylene glycol bis(2-ethylhexanoate) - a new contact allergen identified in a spectacle frame

DEFF Research Database (Denmark)

Andersen, Klaus Ejner; Vestergaard, M. E.; Christensen, Lars Porskjær

2014-01-01

Background. Allergic reactions to spectacle frames are not unusual. A patient had a reproducible strong allergic patch test reaction to scrapings from the plastic material, and negative patch test results with available spectacle frame chemicals. Objectives. To identify the culprit allergen...... bis(2-ethylhexanoate) was the causative allergen in the spectacle frame. Ten consecutive eczema patients tested as controls were negative. Conclusion. Triethylene glycol bis(2-ethylhexanoate) is a new, hitherto unreported contact allergen....... in this patient's spectacle frame. Materials and methods. An extract from the temple arms was analysed by gas chromatography mass spectrometry (GC-MS), and a major low molecular weight compound was detected. This compound was isolated by semi-preparative high-performance liquid chromatography and identified by GC...

1,5-Bis (2-Hydroxyphenyl)Pent-1,4-Diene-3-One: A Lead ...

African Journals Online (AJOL)

NJD

occurring chalcone nucleus to design effective antibacterial agents. The present investigation established 1,5-bis(2-hydroxyphenyl)pent-1,4-diene-3-one (1c) as a lead compound with potential against a panel of pathogenic bacterial strains, ...

Di-μ-chlorido-bis({4-[bis(trimethylsilylamino]-6-chloro-2,2,8,8-tetramethyl-5,7-bis(trimethylsilyl-3,5,7-triaza-4,6-diphospha-2,8-disilanon-3-en-4-ido-κ2P,P′}palladium(II diethyl ether disolvate

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Martha Höhne

2016-06-01

Full Text Available The title compound, [Pd2(C18H54Cl2N4P2Si62Cl2]·2C4H10O, features a dinuclear chloride-bridged palladium complex bearing two equivalents of the novel monoanionic mixed valent (λ3-P—N—(λ5-P ligand. A metal catalyzed coupling of two aminoiminophosphines and a shift of one chlorine from the metal to the phosphorus results in the (λ3-P—N—(λ5-P ligand. The molecule contains a planar bimetallic Pd2Cl2 core with a crystallographic centre of inversion at the mid-point of the Pd...Pd line. The Pd atoms are in a distorted square-planar arrangement, where the P/Pd/P and Cl/Pd/Cl planes are twisted with respect to each other by a dihedral angle of 7.57 (4°. The P—Pd—P bite angle is 71.380 (18°. Intramolecular C—H...Cl interactions are observed. In the crystal, the diethyl ether solvent molecule is disordered over two sites, with an occupancy ratio of 0.788 (5:0.212 (5.

Novel One-Pot Access to 3,3-bis(3-hydroxy-5-substituted-1H-pyrazol-4-yl) indolin-2-ones

International Nuclear Information System (INIS)

Lin, Y.; Fu, Z.; Song, Q.; Shen, T.

2016-01-01

Sodium bicarbonate was applied as catalyst for the synthesis of 3,3-bis(3-hydroxy-5-substituted-1H-pyrazol-4-yl)indolin-2-ones via the reaction of isatins, hydrazine hydrate and ethyl acetoacetate or ethyl benzoylacetate. This reaction was performed in ethanol at 78 degree C, giving 3,3-bis(3-hydroxy-5-substituted-1H-pyrazol-4-yl)indolin-2-one derivatives in good to excellent yields. The structure of 5-bromo-3,3-bis(3-hydroxy-5-methyl-1H-pyrazol-4-yl) indolin-2-one was unambiguously confirmed by X-ray single crystal structure analysis and a plausible reaction mechanism is also proposed. (author)

Clicked bis-PEG-peptide conjugates for studying calmodulin-Kv7.2 channel binding.

Science.gov (United States)

Bonache, M Angeles; Alaimo, Alessandro; Malo, Covadonga; Millet, Oscar; Villarroel, Alvaro; González-Muñiz, Rosario

2014-11-28

The recombinant Kv7.2 calmodulin (CaM) binding site (Q2AB CaMBD) shows a high tendency to aggregate, thus complicating biochemical and structural studies. To facilitate these studies we have conceived bis-PEG-peptide CaMBD-mimetics linking helices A and B in single, easy to handle molecules. Short PEG chains were selected as spacers between the two peptide molecules, and a Cu(i)-catalyzed cycloaddition (CuAAC) protocol was used to assemble the final bis-PEG-peptide conjugate, by the convenient functionalization of PEG arms with azide and alkyne groups. The resulting conjugates, with a certain helical character in TFE solutions (CD), showed nanomolar affinity in a fluorescence CaM binding in vitro assay, higher than just the sum of the precursor PEG-peptide affinities, thus validating our design. The approach to these first described examples of Kv7.2 CaMBD-mimetics could pave the way to chimeric conjugates merging helices A and B from different Kv7 subunits.

CMPO-calix[4]arenes with spacer containing intramolecular hydrogen bonding: Effect of local rigidification on solvent extraction toward f-block elements

International Nuclear Information System (INIS)

Chu, Hongzhu; He, Lutao; Jiang, Qian; Fang, Yuyu; Jia, Yiming; Yuan, Xiangyang; Zou, Shuliang; Li, Xianghui; Feng, Wen; Yang, Yuanyou; Liu, Ning; Luo, Shunzhong; Yang, Yanqiu; Yang, Liang; Yuan, Lihua

2014-01-01

Highlights: • Three CMPO-calix[4]arenes with spacer containing intramolecular hydrogen bonds were designed and synthesized. • The influence of local rigidification caused by intramolecular hydrogen bonds upon extraction of f-elements was investigated. • Selective extraction is realized via tuning local chelating surroundings by aid of intramolecular hydrogen bonds. -- Abstract: To understand intramolecular hydrogen bonding in effecting liquid–liquid extraction behavior of CMPO-calixarenes, three CMPO-modified calix[4]arenes (CMPO-CA) 5a–5c with hydrogen-bonded spacer were designed and synthesized. The impact of spacer rotation that is hindered by introduction of intramolecular hydrogen bonding upon extraction of La 3+ , Eu 3+ , Yb 3+ , Th 4+ , and UO 2 2+ has been examined. The results show that 5b and 5c containing only one hydrogen bond with a less hindered rotation spacer extract La 3+ more efficiently than 5a containing two hydrogen bonds with a more hindered rotation spacer, demonstrating the importance of local rigidification of spacer in the design of extractants in influencing the coordination environment. The large difference in extractability between La 3+ and Yb 3+ (or Eu 3+ ) by 5b (or 5c), and the small difference by 5a, suggests intramolecular hydrogen bonding do exert pronounced influence upon selective extraction of light and heavy lanthanides. Log–log plot analysis indicates a 1:1, 2:1 and 1:1 stoichiometry (ligand/metal) for the extracted complex formed between 5b and La 3+ , Th 4+ , UO 2 2+ , respectively. Additionally, their corresponding acyclic analogs 7a–7c exhibit negligible extraction toward these metal ions. These results reveal the possibility of selective extraction via tuning local chelating surroundings of CMPO-CA by aid of intramolecular hydrogen bonding

E/Z-Photoisomerization of N,N'-Bis(4-dimethylaminobenzylidene1,2-diaminoethane and N,N'-Bis(4-dimethylaminobenzylidene1,3-diaminopropane in Chloroform

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Asghar Samimi

2011-01-01

Full Text Available The E/Z-Photoisomerization of Schiff bases N,N'-bis(4-dimethylamino benzylidene1,2-diaminoethane (BDAE and N,N'-bis(4-dimethylaminobenzyli-dene1,3-diaminopropane (BDAP were studied by UV-Vis absorption spectroscopy and theoretical chemistry calculations. Photochemical investigations in solution depict the time resolved spectral changes, recorded before and after irradiation. The shift indicates the transformation from E to Z configuration of the C=N bond in solution for BDAE and BDAP. Spectra profiles and kinetic constants were evaluated using multivariate curve resolution and non-linear least squares curve fitting by toolbox of MATLAB program using the corresponding absorption spectra-time data. The experimental results show that BDAP can perform the photochromism easier than BDAE, may be due to the molecular topology difference.

Low Band Gap Donor–Acceptor Type Polymers Containing 2,3-Bis(4-(decyloxyphenylpyrido[4,3-b]pyrazine as Acceptor and Different Thiophene Derivatives as Donors

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Yan Zhang

2016-10-01

Full Text Available Four donor–acceptor type conducting polymers, namely poly(2,3-bis(4-decyloxyphenyl-5,8-bis(4-thiophen-2-ylpyrido[4,3-b]pyrazine (P1, poly(2,3-bis(4-decyloxyphenyl-5,8-bis(4-butylthiophen-2-ylpyrido[4,3-b]pyrazine (P2, poly(2,3-bis(4-(decyloxyphenyl-5,8-bis(4-hexyloxythiophen-2-ylpyrido[4,3-b]pyrazine (P3 and poly(2,3-bis(4-(decyloxyphenyl-5,8-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-7-ylpyrido[4,3-b]pyrazine (P4, containing thiophene or its derivative as the donor and pyrido[4,3-b]pyrazine as the acceptor were prepared and characterized by cyclic voltammetry, scanning electron microscopy, and UV-Vis spectroscopy to detect the influence of the donor units’ strength on the electrochromic performances. The results demonstrated that all of the polymers could be reversibly reduced and oxidized by p-type doping and n-type doping, and showed near-infrared activities and different color changes in p-type doping process. Especially, P3 and P4 showed lower optical band gap than P1 and P2 due to the strong electron-donating hexyloxythiophen group of P3 and ethylenedioxythiophene group of P4. Besides, P3 and P4 displayed the saturated green color at the neutral state and the desirable transparency at the oxidized state. All the polymers displayed desirable optical contrasts, satisfactory coloration efficiency, excellent stability and short switching time, which made the polymers fascinating candidates in the electrochromic device applications.

Crystal structure of bis(azido-κNbis[2,5-bis(pyridin-2-yl-1,3,4-thiadiazole-κ2N2,N3]cobalt(II

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Abdelhakim Laachir

2015-05-01

Full Text Available In the mononuclear title complex, [Co(N32(C12H8N4S2], the cobalt(II atom is located on an inversion centre and displays an axially weakly compressed octahedral coordination geometry. The equatorial positions are occupied by the N atoms of two 2,5-bis(pyridin-2-yl-1,3,4-thiadiazole ligands, whereas the axial positions are occupied by N atoms of the azide anions. The thiadiazole and pyridine rings linked to the metal are almost coplanar, with a maximum deviation from the mean plane of 0.0273 (16 Å. The cohesion of the crystal is ensured by weak C—H...N hydrogen bonds and by π–π interactions between pyridine rings [intercentroid distance = 3.6356 (11 Å], forming a layered arrangement parallel to (001. The structure of the title compound is isotypic with that of the analogous nickel(II complex [Laachir et al. (2013. Acta Cryst. E69, m351–m352].

Photoswitchable Intramolecular H-Stacking of Perylenebisimide

NARCIS (Netherlands)

Wang, Jiaobing; Kulago, Artem; Browne, Wesley R.; Feringa, Ben L.

2010-01-01

Dynamic control over the formation of H- or J-type aggregates of chromophores is of fundamental importance for developing responsive organic optoelectronic materials. In this study, the first example of photoswitching between a nonstacked and an intramolecularly H-stacked arrangement of

Isolation of a Bis-Iodurated Tetra-THF as a Trace Product from the Oxidation of Squalene with RuO4 and Its Double Ring Expansion to a Novel bis-THF-bis-THP Compound

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Nicola Borbone

2011-06-01

Full Text Available A novel bis-iodurated polyether compound, based on an unprecedented tetra-THF backbone, has been isolated as a trace by-product of the oxidation of squalene with the catalytic system RuO2(cat./NaIO4. The double erythro configuration of the central portion of the molecule furnishes the first indirect support of the previously postulated pathway operating in the oxidative pentacyclization of the isoprenoid substrate. A bidirectional double oxidative bis-cyclization is invoked to explain the formation of this compound. The isolated substance was successfully subjected to a double rearrangement-ring expansion to give a novel bis-THF-bis-THP compound.

Reactions of nitriles with iodonium salt of bis(1,2-dicarbollyl)cobalt

International Nuclear Information System (INIS)

Knyazev, S.P.; Kirin, V.N.; Chernyshev, E.A.

1996-01-01

Interaction of nitriles with iodonium salt bis(1,2-dicarbollyl)cobalt, resulting in the 8,8'-disubstituted derivatives, is studied. Interaction of nitrile group with iodonium fragment is accompanied by B-I bond discontinuity and by formation of B-N bond with subsequent formation of amino alcohol, which regroups into amide. 3 refs

Intramolecular electron transfer in ascorbate oxidase is enhanced in the presence of oxygen

DEFF Research Database (Denmark)

Farver, O; Wherland, S; Pecht, I

1994-01-01

Intramolecular electron transfer from the type 1 copper center to the type 3 copper(II) pair is induced in the multi-copper enzyme, ascorbate oxidase, following pulse radiolytic reduction of the type 1 Cu(II) ion. In the presence of a slight excess of dioxygen over ascorbate oxidase, interaction...... between the trinuclear copper center and O2 is observed even with singly reduced ascorbate oxidase molecules. Under these conditions, the rate constant for intramolecular electron transfer from type 1 Cu(I) to type 3 Cu(II) increases 5-fold to 1100 +/- 300 s-1 (20 degrees C, pH 5.8) as compared...

Synthesis of novel steroid-tetrahydroquinoline hybrid molecules and D-homosteroids by intramolecular cyclization reactions.

Science.gov (United States)

Magyar, Angéla; Wölfling, János; Kubas, Melanie; Cuesta Seijo, Jose Antonio; Sevvana, Madhumati; Herbst-Irmer, Regine; Forgó, Péter; Schneider, Gyula

2004-05-01

Steroidal aryliminium salts were prepared from D-seco-pregnene aldehyde 2b, and their BF3.OEt2-catalyzed reactions were studied. The nature of the substituent R1 in the anilines 3-6 essentially influenced the chemoselectivity. Using unsubstituted 3, 4-methoxy- (4) or 4-bromoaniline (5), different tetrahydroquinoline derivatives 7a-13a via intramolecular hetero Diels-Alder reaction were formed. In the case of 4-nitroaniline (6) the N-arylamino-D-homopregnane (14a) were also obtained. We assume, that an intramolecular Prins reaction led to this type of fluoro-D-homosteroid. The main products represent a new class of tetrahydroquinolino-androstenes.

Degradation of the blister agent sulfur mustard, bis(2-chloroethyl) sulfide, on concrete

International Nuclear Information System (INIS)

Brevett, Carol A.S.; Sumpter, Kenneth B.; Wagner, George W.; Rice, Jeffrey S.

2007-01-01

The products formed from the degradation of the blister agent sulfur mustard [bis(2-chloroethyl) sulfide] on concrete were identified using gas chromatography with mass spectrometry detection (GC/MSD), 1 H NMR, 2D 1 H- 13 C NMR and 13 C solid state magic angle spinning (SSMAS) NMR. In situ and extraction experiments were performed. Sulfur mustard was detected in the in situ 13 C SSMAS samples for 12 weeks, whereas less than 5% of the sulfur mustard was detected in extracts from the concrete monoliths after 8 days. Sulfonium ions and (2-chloroethylthio)ethyl ether (T) were observed on the in situ samples after a period of 12 weeks, whereas vinyl species and bis(2-chloroethyl) sulfoxide were observed in the extracts of the concrete monoliths within 24 h. The differences between the extraction and the SSMAS data indicated that the sulfur mustard existed in the concrete in a non-extractable form prior to its degradation. Extraction methods alone were not sufficient to identify the products; methods to identify the presence of non-extractable degradation products were also required

Intramolecular Diels-Alder reactions of pyrimidines, a synthetic and computational study

NARCIS (Netherlands)

Stolle, W.A.W.

1992-01-01

This thesis deals with an investigation on the ringtransformation reactions of 2and 5-(ω-alkynyl)pyrimidine derivatives, which undergo upon heating an intramolecular Diels-Alder reaction and subsequently a spontaneous retro Diels- Alder reaction. To get a better insight into the

Aggregation-enhanced emission and piezochromic luminescence of 9,10-bis(p-dibutylaminostyryl)-2,6-bis(p-t-butylstyryl)anthracene

Energy Technology Data Exchange (ETDEWEB)

Sun, Mingxiao; Zhang, Deteng; Li, Yiping; Wang, Jianfeng; Gao, Yangyang; Yang, Wenjun, E-mail: ywjph2004@qust.edu.cn

2014-04-15

A cruciform 9,10-distyrylanthracene-containing luminogen, 9,10-bis(p-dibutylaminostyryl)-2,6-bis(p-t-butylstyryl)anthracene (DDC), has been synthesized and the optical properties investigated. The results show that DDC is an aggregation-induced enhanced emission (AIEE) and piezofluorochromic (PFC) dye. The fluorescence quantum yield in THF/water=1/9 (18.1%) is about 12-fold over that in THF (1.53%). PFC experiment shows that the fluorescence colors (emission spectra) of DDC solid change reversibly between orange-red (602 nm) and red (632 nm) emissions upon pressing and annealing. Wide-angle X-ray diffraction and differential scanning calorimetric analyses reveal that the grinding has induced the phase transition of DDC solid from pristine crystalline to ground amorphous states, and annealing could cause the re-crystallization of amorphized DDC solid. This transformation between crystalline and amorphous states is responsible for the reversible PFC behavior upon external stimuli. Highlights: • A two-dimensional cross-conjugated luminogen (DDC) was synthesized. • DDC exhibits aggregation-enhanced emission and piezofluorochromic behaviors. • DDC emits bluer light in the crystalline phase than in the amorphous phase. • The PFC mechanism is ascribed to grinding-induced amorphization.

Intramolecular stacking interactions in ternary copper(II) complexes formed by a heteroaromatic amine and 9-[2-(2-phosphonoethoxy)ethyl]adenine, a relative of the antiviral nucleotide analogue 9-[2-(phosphonomethoxy)ethyl]adenine

Czech Academy of Sciences Publication Activity Database

Fernández-Botello, A.; Holý, Antonín; Moreno, V.; Sigel, H.

2004-01-01

Roč. 98, - (2004), s. 2114-2124 ISSN 0162-0134 R&D Projects: GA MŠk OC D20.002 Institutional research plan: CEZ:AV0Z4055905 Keywords : adenine nucleotide analogues * intramolecular equilibria * isomeric complexes Subject RIV: CC - Organic Chemistry Impact factor: 2.225, year: 2004

Study of complex formation of 5,5'-(2 E, 2' E)-2,2'-(ethane-1,2-diylidene)bis(hydrazine-1-yl-2-ylidene)bis(4-amino-4H-1,2,4-triazole-3-thiol) (HYT) macrocyclic ligand with Cd2+ cation in non-aqueous solution by spectroscopic and conductometric methods

Science.gov (United States)

Mallaekeh, Hassan; Shams, Alireza; Shaker, Mohammad; Bahramzadeh, Ehsan; Arefi, Donya

2014-12-01

In this paper the complexation reaction of the 5,5'-(2 E,2' E)-2,2'-(ethane-1,2-diylidene)bis(hydrazine-1-yl-2-ylidene)bis(4-amino-4H-1,2,4-triazole-3-thiol) ligand (HYT) with Cd2+ education was studied in some binary mixtures of methanol (MeOH), n-propanol (PrOH) and dimethyl-formamide (DMF) at different temperatures using the conductometry and spectrophotometry. The stability constants of the complex was determined using a GENPLOT computer program. The conductance data and absorbance-mole ratio plots show that in all solvent systems, the stoichiometry of the complex formed between (HYT) and Cd2+ cation is 1: 1. The obtained results show that the stability of (HYT)-Cd complex is sensitive to the mixed solvents composition. The values of thermodynamic parameters (Δ G ∘, Δ H ∘, and Δ S ∘) for formation of (HYT)-Cd complex were obtained from temperature dependence of the stability constant using the van't Hoff plots. The results show that in most cases, the complex are enthalpy destabilized but entropy stabilized and the complex formation is affected by pH, time, temperature and the nature of the solvent.

Electrochemical properties of novel organodisulfide poly 1,2-bis(thiophen-3-ylmethyl)disulfane as cathode material for secondary lithium batteries

International Nuclear Information System (INIS)

Weng, Guoming; Su, Yuzhi; Liu, Zhaoqing; Zhang, Jianhua; Dong, Wen; Xu, Changwei

2009-01-01

We successfully synthesized a new organodisulfide poly 1,2-bis(thiophen-3-ylmethyl)disulfane by a facile preparation method. The types of the chemical groups of poly-3-thienylthiophene were characterized by Fourier transform infrared spectroscopy (FTIR). The electrochemical properties of S-S bonds redox behavior in the organodisulfides were investigated in CH 3 CN/0.1 M [Bu 4 N] [PF 6 ] solution. The separation of the anodic and cathodic peak potentials for poly 1,2-bis(thiophen-3-ylmethyl)disulfane is 180 mV. The results indicated that poly 1,2-bis(thiophen-3-ylmethyl)disulfane has an excellent electrochemical reversibility. The average specific capacity of 230 mAh g -1 for poly-3-thienylthiophene is about 2 times higher than that of LiCoO 2 .

Approaches to lung cancer treatment using the CD3E x GP-2-directed bispecific monoclonal antibody BIS-1

NARCIS (Netherlands)

Kroesen, BJ; Nieken, J; Sleijfer, DT; Molema, G; deVries, EGE; Groen, HJM; Helfrich, W; The, TH; Mulder, NH; deLeij, L

1997-01-01

The bispecific monoclonal antibody (bsAb) BIS-1 combines a monoclonal-antibody(mAb)-defined specificity for the CD3 complex, as present on all T lymphocytes, with a mAb-defined specificity for the pancarcinoma/epithelium associated glycoprotein EGP-2. In vitro studies indicate that BIS-1 can direct

Hexaaquabis[3,5-bis(hydroxyimino-1-methyl-2,4,6-trioxocyclohexanido-κ2N3,O4]barium tetrahydrate

Directory of Open Access Journals (Sweden)

Nguyen Dinh Do

2013-11-01

Full Text Available In the title compound, [Ba(C7H5N2O52(H2O6]·4H2O, the Ba2+ cation lies on a twofold rotation axis and is ten-coordinated by two 3,5-bis(hydroxyimino-1-methyl-2,4,6-trioxocyclohexanide oxo O atoms [Ba—O = 2.8715 (17 Å], two hydroxyimino N atoms [Ba—N = 3.036 (2 Å], and six water molecules [Ba—O = 2.847 (2, 2.848 (2, and 2.880 (2 Å]. The 3,5-bis(hydroxyimino-1-methyl-2,4,6-trioxocyclohexanide monoanions act in a bidentate chelating manner, coordinating through an N atom of the non-deprotonated hydroxyimino group and an O atom of the neighboring oxo group. Two lattice water molecules are located in the cavities of the framework and are involved in hydrogen bonding to O atoms of one of the coordinating water molecules and the O atom of a keto group of the ligand. As a result, a three-dimensional network is formed.

3′,6′-Bis(diethylamino-3H-spiro[2-benzothiophene-1,9′-xanthene]-3-thione

Directory of Open Access Journals (Sweden)

Bing-Yuan Su

2008-11-01

Full Text Available The title compound, C28H30N2OS2, was obtained by thionation of 3′,6′-bis(diethylamino-3H-spiro[isobenzofuran-1,9′-xanthene]-3-one with 2,4-bis(p-methoxyphenyl-1,3-dithiadiphosphetane disulfide (Lawesson's reagent. The planes of the two benzene rings of the xanthene system are inclined at a dihedral angle of 17.4 (1°, and the plane of the dithiophthalide group and the planes through the two benzene rings of the xanthene system make dihedral angles of 80.2 (1 and 82.8 (1°, respectively.

Rapid examination of the kinetic process of intramolecular lactamization of gabapentin using DSC-FTIR

International Nuclear Information System (INIS)

Hsu, C.-H.; Lin, S.-Y.

2009-01-01

The thermal stability and thermodynamics of gabapentin (GBP) in the solid state were investigated by DSC and TG techniques, and FTIR microspectroscopy. The detailed intramolecular lactamization process of GBP to form gabapentin-lactam (GBP-L) was also determined by thermal FTIR microspectroscopy. GBP exhibited a DSC endothermic peak at 169 deg. C. The weight loss in TG curve of GBP suggested that the evaporation process of water liberated via intramolecular lactamization was simultaneously combined with the evaporation process of GBP-L having a DSC endothermic peak at 91 deg. C. A thermal FTIR microspectroscopy clearly evidenced the IR spectra at 3350 cm -1 for water liberated and at 1701 cm -1 for lactam structure formed due to the lactam formation of GBP. This study indicates that the activation energy for combined processes of intramolecular lactamization of GBP and evaporation of GBP-L was about 114.3 ± 23.3 kJ/mol, but for the evaporation of GBP-L alone was 76.2 ± 1.5 kJ/mol. A powerful simultaneous DSC-FTIR combined technique was easily used to quickly examine the detailed kinetic processes of intramolecular cyclization of GPB and evaporation of GBP-L in the solid state

The general properties of water - nitrobenzene - crown - bis-1,2-dicarbollylcobaltate extraction systems

International Nuclear Information System (INIS)

Vanura, P.

2003-01-01

The extraction and stability constants in the system water - nitrobenzene have been collected and general rules valid for water - nitrobenzene - crown - bis-1,2-dicarbollylcobaltate extraction system have been found. The main principles are size compatibility of ion diameter and crown cavity diameters, the flexibility of crown, the basicity of crown and the steric factor of both the ligand and the extracted ion. The extraction in the system water - mineral acid or salt polyoxyethylene compound - bis-1,2-dicarbollylcobaltate - nitrobenzene is more complicated than can be expected from usually used ion diameter - crown cavity diameter compatibility principle. The other important factors are the basicity and the deformability of crown, steric aspect and the angles of bonds of extracted ion. The binuclear 'sandwich' complexes with H + ion and Sr 2+ or Ba 2+ ions have been proved for dibenzo-18-crown-6 (DB18C6). On the other hand, only SrL 2 and BaL 2 (L = 15C5) complexes are formed in nitrobenzene saturated with water. The addition of polyoxyethylene compound usually increases the distribution ratio of alkali earth metal ions and the selectivity of its mutual separation. (authors)

Conductance and activation energy for electron transport in series and parallel intramolecular circuits.

Science.gov (United States)

Hsu, Liang-Yan; Wu, Ning; Rabitz, Herschel

2016-11-30

We investigate electron transport through series and parallel intramolecular circuits in the framework of the multi-level Redfield theory. Based on the assumption of weak monomer-bath couplings, the simulations depict the length and temperature dependence in six types of intramolecular circuits. In the tunneling regime, we find that the intramolecular circuit rule is only valid in the weak monomer coupling limit. In the thermally activated hopping regime, for circuits based on two different molecular units M a and M b with distinct activation energies E act,a > E act,b , the activation energies of M a and M b in series are nearly the same as E act,a while those in parallel are nearly the same as E act,b . This study gives a comprehensive description of electron transport through intramolecular circuits from tunneling to thermally activated hopping. We hope that this work can motivate additional studies to design intramolecular circuits based on different types of building blocks, and to explore the corresponding circuit laws and the length and temperature dependence of conductance.

Synthesis of strigolactones analogues by intramolecular [2+2] cycloaddition of ketene-iminium salts to olefins and their activity on Orobanche cumana seeds.

Science.gov (United States)

Lachia, Mathilde; Wolf, Hanno Christian; De Mesmaeker, Alain

2014-05-01

Strigolactones have been the latest identified phytohormones. Among the strigolactones analogues described recently, GR-24 remains the most studied derivative which is used as standard in this field. In order to improve several properties of GR-24 for potential agronomical applications, we investigated the effect of substituents on the B and C-rings on the activity for seed germination induction. We report here the synthesis of 9 GR-24 analogues via a [2+2] intramolecular cycloaddition of ketene-iminium salts and a summary of their activity for the germination of Orobanche cumana (broomrape) seeds. Copyright © 2014 Elsevier Ltd. All rights reserved.

Tetrakis[bis(pyridin-2-ylamine-κN2](nitrato-κOsilver(I

Directory of Open Access Journals (Sweden)

Yuliia Parashchenko

2014-02-01

Full Text Available In the title complex, [Ag(NO3(C10H9N34], the nitrate ligand is found to be disordered over two sets of positions, with occupancy factors of 0.473 (5 and 0.527 (5. The AgI ion is located in a square-pyramidal coordination environment formed by four N atoms from four bis(pyridin-2-ylamine ligands and one O atom from a nitrate ligand. Weak interactions between the AgI ions and the nitrate anions acting in a monodentate mode [Ag...O = 2.791 (13 and 2.816 (9 Å for the major component of the nitrate ligand, and 2.865 (8 and 2.837 (8 Å for the minor component] link the complex molecules into a chain along [001]. N—H...O hydrogen bonds are observed.

Rh(I) -Catalyzed Intramolecular Carbonylative C-H/C-I Coupling of 2-Iodobiphenyls Using Furfural as a Carbonyl Source.

Science.gov (United States)

Furusawa, Takuma; Morimoto, Tsumoru; Nishiyama, Yasuhiro; Tanimoto, Hiroki; Kakiuchi, Kiyomi

2016-08-19

Synthesis of fluoren-9-ones by a Rh-catalyzed intramolecular C-H/C-I carbonylative coupling of 2-iodobiphenyls using furfural as a carbonyl source is presented. The findings indicate that the rate-determining step is not a C-H bond cleavage but, rather, the oxidative addition of the C-I bond to a Rh(I) center. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structure of poly[diaqua[μ-1,2-bis(pyridin-4-ylethane-κ2N:N′]bis(μ3-cyclobutane-1,1-dicarboxylato-κ3O,O′:O′′:O′′′dimanganese(II

Directory of Open Access Journals (Sweden)

Do Nam Lee

2015-08-01

Full Text Available In the title compound, [Mn(C6H6O4(C12H12N2(H2O]n, the cyclobutane-1,1-dicarboxylate (cbdc ligands bridge three MnII ions, forming layers parallel to the ac plane. These layers are additionally connected by 1,2-bis(pyridin-4-ylethane ligands to form a three-dimensional polymeric framework. An inversion centre is located at the mid-point of the central C—C bond of the 1,2-bis(pyridin-4-ylethane ligand. The coordination geometry of the MnII ion is distorted octahedral and is built up by four carboxylate O atoms, one water O atom and a pyridyl N atom. The pyridine ligand and the coordinating water molecule are in a trans configuration. One carboxylate group of the cbdc ligand acts as a chelating ligand towards one MnII atom, whereas the second carboxylate group coordinates two different MnII atoms.

Off-on fluorescent sensor based on the bis(2,4,7,8,9-pentamethyldipyrrolylmethene-3-yl)methane for detection of Cd{sup 2+} and Hg{sup 2+} cations

Energy Technology Data Exchange (ETDEWEB)

Bumagina, Natalia A., E-mail: nad@isc-ras.ru [G.A. Krestov Institute of Solution Chemistry of Russian Academy of Sciences (ISC RAS), 1 Akademicheskaya St., 153045 Ivanovo (Russian Federation); Antina, Elena V., E-mail: eva@isc-ras.ru [G.A. Krestov Institute of Solution Chemistry of Russian Academy of Sciences (ISC RAS), 1 Akademicheskaya St., 153045 Ivanovo (Russian Federation); Sozonov, Dmitry I., E-mail: super_dk@mail.ru [Ivanovo State University of Chemistry and Technology (ISUCT), 7 Sheremetevskij Prosp., 153000 Ivanovo (Russian Federation)

2017-03-15

The off-on fluorescent chemosensor based on the bis(2,4,7,8,9-pentamethyldipyrrolylmethene-3-yl)methane for detection of Cd{sup 2+} and Hg{sup 2+} ions was obtained and its metal ion sensing properties were investigated. The bis(dipyrrin) exhibited remarkably fluorescence enhancement (150- and 40-fold) to Cd{sup 2+} and Hg{sup 2+} ions, respectively, with significant color change on the background of other metal ions in propanol-1/cyclohexane (1:30) binary mixture. Consequently, it can be used as a “naked eye” indicator with an obvious color change from yellow-orange to orange-green color upon the addition of Cd{sup 2+} and Hg{sup 2+}. The fluorescent response mechanism of bis(dipyrrin) to Cd{sup 2+} and Hg{sup 2+} was based on the fluorescence enhancement effect upon complexation (CHEF) due to formation of a metal–ligand (2:2) complex [M{sub 2}L{sub 2}]. The detection limit of Cd{sup 2+} and Hg{sup 2+} ions was 2 × 10{sup –9} and 1.7 × 10{sup –8} M ions, respectively.

40 CFR 721.7160 - 2-Oxepanone, polymer with 4,4′-(1-methylethylidene)bisphenol and 2,2-[(1-methylethylidene)bis(4,1...

Science.gov (United States)

2010-07-01

...-methylethylidene)bisphenol and 2,2-[(1-methylethylidene)bis(4,1-phe-ny-lene-oxy-methyl-ene)]-bi-sox-i- rane, graft... Substances § 721.7160 2-Oxepanone, polymer with 4,4′-(1-methylethylidene)bisphenol and 2,2-[(1... new uses subject to reporting. (1) The chemical substance 2-oxepanone, polymer with 4,4′(1-meth-yl-eth...

The potential of {sup 223}Ra and {sup 18}F-fluoride imaging to predict bone lesion response to treatment with {sup 223}Ra-dichloride in castration-resistant prostate cancer

Energy Technology Data Exchange (ETDEWEB)

Murray, Iain; Chittenden, Sarah J.; Denis-Bacelar, Ana M.; Flux, Glenn D. [Royal Marsden NHS Foundation Trust, Joint Department of Physics, Sutton, Surrey (United Kingdom); The Institute of Cancer Research, London (United Kingdom); Hindorf, Cecilia [Royal Marsden NHS Foundation Trust, Joint Department of Physics, Sutton, Surrey (United Kingdom); The Institute of Cancer Research, London (United Kingdom); Skaane University Hospital, Department of Radiation Physics, Lund (Sweden); Parker, Christopher C. [Royal Marsden NHS Foundation Trust, Department of Urology, Sutton (United Kingdom); Chua, Sue [Royal Marsden NHS Foundation Trust, Department of Nuclear Medicine, Sutton (United Kingdom)

2017-10-15

The aims of this study were to calculate bone lesion absorbed doses resulting from a weight-based administration of {sup 223}Ra-dichloride, to assess the relationship between those doses and corresponding {sup 18}F-fluoride uptake and to assess the potential of quantitative {sup 18}F-fluoride imaging to predict response to treatment. Five patients received two intravenous injections of {sup 223}Ra-dichloride, 6 weeks apart, at 110 kBq/kg whole-body weight. The biodistribution of {sup 223}Ra in metastatic lesions as a function of time after administration as well as associated lesion dosimetry were determined from serial {sup 223}Ra scans. PET/CT imaging using {sup 18}F-fluoride was performed prior to the first treatment (baseline), and at week 6 immediately before the second treatment and at week 12 after baseline. Absorbed doses to metastatic bone lesions ranged from 0.6 Gy to 44.1 Gy. For individual patients, there was an average factor difference of 5.3 (range 2.5-11.0) between the maximum and minimum lesion dose. A relationship between lesion-absorbed doses and serial changes in {sup 18}F-fluoride uptake was demonstrated (r{sup 2} = 0.52). A log-linear relationship was demonstrated (r{sup 2} = 0.77) between baseline measurements of {sup 18}F-fluoride uptake prior to {sup 223}Ra-dichloride therapy and changes in uptake 12 weeks after the first cycle of therapy. Correlations were also observed between both {sup 223}Ra and {sup 18}F-fluoride uptake in lesions (r = 0.75) as well as between {sup 223}Ra absorbed dose and {sup 18}F-fluoride uptake (r = 0.96). There is both inter-patient and intra-patient heterogeneity of absorbed dose estimates to metastatic lesions. A relationship between {sup 223}Ra lesion absorbed dose and subsequent lesion response was observed. Analysis of this small group of patients suggests that baseline uptake of {sup 18}F-fluoride in bone metastases is significantly correlated with corresponding uptake of {sup 223}Ra, the associated {sup 223

Synthesis, characterization, and molecular structure of tetraethylammonium pentakis(isothiocyanato)bis(2,2'-bipyridine)uranate(IV)

International Nuclear Information System (INIS)

Wiley, R.O.; Von Dreele, R.B.; Brown, T.M.

1980-01-01

The synthesis of tetraethylammonium pentakis(isothiocyanato)bis(2,2'-bipyridine)uranate(IV) has been accomplished, and it was characterized by classical physical methods. The crystal and molecular structure was determined from single-crystal x-ray data collected by the theta-2theta technique on an automated diffractometer. The compound consists of pentakis(isothiocyanato)bis (2,2'-bipyridine)uranate(IV) anions and disordered tetraethylammonium cations. Uranium is bound to nine nitrogen atoms in a highly distorted monocapped square antiprism in which one bipyridine occupies a position bridging the cap and the near square while the other bipyridine spans the opposite edge of the far square. Distortion from the ideal geometry is caused by the small ligand bite of the bipyridine ligand. An alternative description of the coordination geometry is derived from the seven-coordinate pentagonal bipyramid in which each bipyridine ligand is assumed to occupy an axial position with the five thiocyanato ligands forming the pentagonal girdle. The U-N bond distances vary from 2.35 to 2.47 A for the thiocyanato ligands and from 2.61 to 2.65 A for the bipyridine ligands. The structure was solved by standard heavy-atom techniques and refined by large-block matrix least squares to a final R value of 0.083 for 3878 independent observed reflections. The compound crystallized in the monoclinic space group P2 1 /c, Z = 4, with lattice parameters a = 14.427 (10) A, b = 18.612 (17) A, c = 15.710 (10) A, and β = 105.17 (7) 0 , rho/sub obsd/ = 1.57 g cm -3

Intramolecular dynamics within the N-Cap-SH3-SH2 regulatory unit of the c-Abl tyrosine kinase reveal targeting to the cellular membrane.

Science.gov (United States)

de Oliveira, Guilherme A P; Pereira, Elen G; Ferretti, Giulia D S; Valente, Ana Paula; Cordeiro, Yraima; Silva, Jerson L

2013-09-27

c-Abl is a key regulator of cell signaling and is under strict control via intramolecular interactions. In this study, we address changes in the intramolecular dynamics coupling within the c-Abl regulatory unit by presenting its N-terminal segment (N-Cap) with an alternative function in the cell as c-Abl becomes activated. Using small angle x-ray scattering, nuclear magnetic resonance, and confocal microscopy, we demonstrate that the N-Cap and the Src homology (SH) 3 domain acquire μs-ms motions upon N-Cap association with the SH2-L domain, revealing a stabilizing synergy between these segments. The N-Cap-myristoyl tether likely triggers the protein to anchor to the membrane because of these flip-flop dynamics, which occur in the μs-ms time range. This segment not only presents the myristate during c-Abl inhibition but may also trigger protein localization inside the cell in a functional and stability-dependent mechanism that is lost in Bcr-Abl(+) cells, which underlie chronic myeloid leukemia. This loss of intramolecular dynamics and binding to the cellular membrane is a potential therapeutic target.

In vivo distribution and elimination of hemoglobin modified by intramolecular cross-linking with 2-nor-2-formylpyridoxal 5'-phosphate

International Nuclear Information System (INIS)

Bleeker, W.K.; van der Plas, J.; Feitsma, R.I.; Agterberg, J.; Rigter, G.; de Vries-van Rossen, A.; Pauwels, E.K.; Bakker, J.C.

1989-01-01

Modified hemoglobin solutions have potential application as plasma expanders with oxygen-transporting capacity. In a previous study it was found that modification of hemoglobin by intramolecular cross-linking with 2-nor-2-formylpyridoxal 5'-phosphate (NFPLP) improves the vascular retention time by a factor of three, and it also improves the oxygen-transporting properties. In the present study we investigated in rats how, after exchange transfusion of a clinically relevant dose, the modified hemoglobin (HbNFPLP) was distributed in the body compared with how the unmodified hemoglobin was distributed. By using a new technetium 99m labeling technique, we found in a scintigraphic study that accumulation of hemoglobin in the kidneys was greatly diminished by the intramolecular cross-linking with NFPLP. These findings were confirmed by light-microscopic observations after diaminobenzidine staining. It was concluded that the impairment of kidney function caused by blockade of the tubuli is not to be expected from HbNFPLP. In the liver and spleen, where the free HbNFPLP is possibly eliminated, some accumulation of 99mTc label was observed, but the major part of the extravascular label was diffusely spread throughout the body. This led to the conclusion that important accumulation of undegraded HbNFPLP does not occur in the liver and spleen. Rapid appearance of both hemoglobin and HbNFPLP in the lymph showed that cross-linking with NFPLP does not prevent the distribution of hemoglobin over the interstitial space in the first hours after administration. However, pharmacokinetic analysis demonstrated that transcapillary transfer contributes only to a limited extent to the disappearance from the circulation. During 24-hour infusions of HbNFPLP, a steady state with a constant plasma concentration was easily reached

Bis(phenylethylamide) derivatives of Gd-DTPA as potential receptor-specific MRI contrast agents

OpenAIRE

Laurent, Sophie; Parac-Vogt, Tatjana; Kimpe, Kristof; Thirifays, Coralie; Binnemans, Koen; Muller, Robert N.; Vander Elst, Luce

2007-01-01

DTPA-bis(amide) derivatives bearing phenyl, phenol or catechol groups that mimic side chains of naturally occurring amino acids, such as phenylatanine, tyrosine or dopamine, were synthesized and characterized by elemental analysis, electrospray mass spectrometry, NMR spectroscopy and IR spectroscopy. The gadolinium(III) complexes of the ligands DTPA-bis(tyramide) [DTPA-(TA)(2)], DTPA-bis(3-hydroxytyramide) [DTPA-(HTA)(2)] and DTPA-bis(phenylalanine ethyl ester) [DTPA-(PAE)(2)], were prepared ...

DNA-Directed alkylating agents. 7. Synthesis, DNA interaction, and antitumor activity of bis(hydroxymethyl)- and bis(carbamate)-substituted pyrrolizines and imidazoles.

Science.gov (United States)

Atwell, G J; Fan, J Y; Tan, K; Denny, W A

1998-11-19

A series of bis(hydroxymethyl)-substituted imidazoles, thioimidazoles, and pyrrolizines and related bis(carbamates), linked to either 9-anilinoacridine (intercalating) or 4-(4-quinolinylamino)benzamide (minor groove binding) carriers, were synthesized and evaluated for sequence-specific DNA alkylation and cytotoxicity. The imidazole and thioimidazole analogues were prepared by initial synthesis of [(4-aminophenyl)alkyl]imidazole-, thioimidazole-, or pyrrolizine dicarboxylates, coupling of these with the desired carrier, and reduction to give the required bis(hydroxymethyl) alkylating moiety. The pyrrolizines were the most reactive alkylators, followed by the thioimidazoles, while the imidazoles were unreactive. The pyrrolizines and some of the thioimidazoles cross-linked DNA, as measured by agarose gel electrophoresis. Strand cleavage assays showed that none of the compounds reacted at purine N7 or N3 sites in the gpt region of the plasmid gpt2Eco, but the polymerase stop assay showed patterns of G-alkylation in C-rich regions. The corresponding thioimidazole bis(carbamates) were more selective than the bis(hydroxymethyl) pyrrolizines, with high-intensity bands at 5'-NCCN, 5'-NGCN and 5'-NCGN sequences in the PCR stopping assay ( indicates block sites). The data suggest that these targeted compounds, like the known thioimidazole bis(carbamate) carmethizole, alkylate exclusively at guanine residues via the 2-amino group, with little or no alkylation at N3 and N7 guanine or adenine sites. The cytotoxicities of the compounds correlated broadly with their reactivities, with the bis(hydroxymethyl)imidazoles being the least cytotoxic (IC50s >1 microM; P388 leukemia) and with the intercalator-linked analogues being more cytotoxic than the corresponding minor-groove-targeted ones. This was true also for the more reactive thioimidazole bis(carbamates) (IC50s 0.8 and 11 microM, respectively), but both were more active than the analogous "untargeted" carmethizole (IC50 20

Optical and magneto-optical properties of spin coated films of novel trinuclear bis(oxamato) and bis(oxamidato) type complexes

Energy Technology Data Exchange (ETDEWEB)

Abdulmalic, Mohammad A. [Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Chemie, Straße der Nationen 62, D-09111 Chemnitz (Germany); Fronk, Michael [Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Physik, Reichenhainer Straße 70, D-09107 Chemnitz (Germany); Bräuer, Björn [Stanford Institute of Materials and Energy Science, Stanford University, Stanford, CA 94025 (United States); Zahn, Dietrich R.T. [Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Physik, Reichenhainer Straße 70, D-09107 Chemnitz (Germany); Salvan, Georgeta, E-mail: salvan@physik.tu-chemnitz.de [Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Physik, Reichenhainer Straße 70, D-09107 Chemnitz (Germany); Eya' ane Meva, Francois [Department of Pharmaceutical Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, BP 2701 (Cameroon); and others

2016-12-01

This work reports the first example of the spectroscopic measurements of the Magneto-Optical Kerr Effect (MOKE) of films being composed of trinuclear transition metal complexes on a non-transparent substrate at room temperature. The thin films of the tailor-made trinuclear bis(oxamidato) type complex 5 ([Cu{sub 3}(opbo{sup n}Pr{sub 2})(tmcd){sub 2}(NO{sub 3}){sub 2}], opbo{sup n}Pr{sub 2} = o-phenylenebis(N’-{sup n}propyloxamido, tmcd=trans-(1 R,2 R)-N,N,N′,N′-tetramethyl-cyclohexanediamine) and of the bis(oxamato) type complexes 11 ([Cu{sub 2}Ni(opbaCF{sub 3})(pmdta){sub 2}(NO{sub 3}){sub 2}], opbaCF{sub 3} = 4-trifluoromethyl-o-phenylenebis(oxamato), pmdta = N,N,N,′N″,N″-pentamethyldiethylenetriamine) and 12 ([Cu{sub 3}(opba)(bppe){sub 2}(NO{sub 3}){sub 2}] (opba = o-phenylenebis(oxamato), bppe = S-N,N-bis(2-picolyl)−1-phenylethylamine) were fabricated by spin-coating and their thicknesses in the range between 0.5 µm and 2 µm was determined by spectroscopic ellipsometry. Based on the spectroscopic ellipsometry results it was also possible to determine the optical constants of the film and compare them with the absorption of the complexes in solution in order to confirm the complex integrity after the film deposition. The fabrication of high-quality films which exhibit Kerr rotation up to 0.2 mrad (11.5 mdeg) was only possible due to tailor-made synthesis, which allows circumventing intermolecular interactions of the trinuclear complexes during the film formation. - Highlights: • Tailor-made trinuclear bis(oxamidato) and bis(oxamato) type complexes were synthesized. • Thin films (between 0.5 µm and 2 µm) were fabricated by spin-coating. • The film optical constants indicate the complex integrity after the deposition. • Film quality enabled first spectroscopic MOKE measurements of multi-nuclear complexes. • Magneto-optical Kerr rotation up to 11.5 mdeg was observed at RT (in 1.7 T).

Bis{2-[(diisopropylphosphanylamino]pyridine-κ2N1,P}copper(I hexafluoridophosphate

Directory of Open Access Journals (Sweden)

Özgür Öztopcu

2010-07-01

Full Text Available The crystal structure of the title compound, [Cu(C11H19N2P2]PF6, is composed of discrete [Cu(PN-iPr2]+ cations [PN-iPr is 2-(diisopropylphosphanylaminopyridine] and PF6− anions. The Cu(I atom is bis-chelated by two independent PN-iPr ligands. It has a distorted tetrahedral coordination by two P atoms [Cu—P = 2.2277 (4 and 2.2257 (4 Å] and two pyridine N atoms [Cu—N = 2.0763 (11 and 2.0845 (12 Å]. Bond angles about Cu vary from 85.11 (3 (P—Cu—N to 130.37 (2° (P—Cu—P. In the crystal, N—H...F hydrogen bonds link the Cu complexes and the PF6− anions into continuous chains, which show a cross-bedded spatial arrangement. In addition, several weaker C—H...F interactions contribute to the coherence of the structure.

Convenient synthesis of [2-14C]-methylglyoxal bis(guanylhydrazone), [14C]-mitoguazone

International Nuclear Information System (INIS)

Burgos, A.; Ellames, G.J.

1995-01-01

[2- 14 C]-Methylglyoxal bis(guanylhydrazone) dihydrochloride, [ 14 C]-mitoguazone has been prepared in three steps from potassium[1- 14 C]-acetate in an overall radiochemical yield of 16%. The key steps in this procedure are the formation of the sodium salt of[acetone-2- 14 C]-methylsulfinylacetone, and Pummerer rearrangement to the [ 14 C] labelled hermithioacetal, which is trapped with two equivalents of aminoguanidine to afford the desired [ 14 C]-mitoguazone. (Author)

Tetrakis(μ3-2-{[1,1-bis(hydroxymethyl-2-oxidoethyl]iminomethyl}-6-nitrophenolatotetracopper(II

Directory of Open Access Journals (Sweden)

Eduard N. Chygorin

2014-02-01

Full Text Available The title cluster, [Cu4(C11H12N2O64], was obtained from the Cu0–FeCl2·4H2O–H4L–Et3N–DMF reaction system (in air, where H4L is 2-hydroxymethyl-2{[(2-hydroxy-3-nitrophenylmethylidene]amino}propane-1,3-diol and DMF is dimethylformamide. The asymmetric unit consists of one Cu2+ ion and one dianionic ligand; a -4 symmetry element generates the cluster, which contains a {Cu4O4} cubane-like core. The metal ion has an elongated square-based pyramidal CuNO4 coordination geometry with the N atom in a basal site. An intramolecular O—H...O hydrogen bond is observed. The solvent molecules were found to be highly disordered and their contribution to the scattering was removed with the SQUEEZE procedure in PLATON [Spek (2009. Acta Cryst. D65, 148–155], which indicated a solvent cavity of volume 3131 Å3 containing approximately 749 electrons. These solvent molecules are not considered in the given chemical formula.

Synthesis, crystal structure and properties of [Co(L2](ClO42 (L=1,3-bis(1H-benzimidazol-2-yl-2-oxapropane

Directory of Open Access Journals (Sweden)

Tavman Aydin

2015-01-01

Full Text Available The reaction of 1,3-bis(1H-benzimidazol-2-yl-2-oxapropane (L with Co(ClO42•6H2O in absolute ethanol produces di[1,3-bis(1H-benzimidazol-2-yl-2-oxapropane-k2N,N’]cobalt(IIdiperchlorate chelate complex ([Co(L2](ClO42, 1. The complex 1 was characterized by elemental analysis, magnetic moment, molar conductivity, thermogravimetric analysis, FT-IR, UV-visible, mass spectrometry, and its solid state structure was determined by single crystal X-ray diffraction. According to the thermogravimetric analysis data, there is no any water coordinated or uncoordinated in 1 as well as elemental analysis. The complex 1 has 1:2 M:L ionic characteristic according to the molar conductivity. In the complex, the distances between the cobalt and the ethereal oxygen atoms (Co1-O2: 2.805(3; Co2-O1: 2.752(2 Å show the semi-coordination bonding and the Co(II ion is six-coordinated with a N4O2 ligand set, resulting in a distorted octahedron.

Bis-guanylhydrazone diimidazo[1,2-a:1,2-c]pyrimidine as a novel and specific G-quadruplex binding motif.

Science.gov (United States)

Sparapani, Silvia; Bellini, Stefania; Gunaratnam, Mekala; Haider, Shozeb M; Andreani, Aldo; Rambaldi, Mirella; Locatelli, Alessandra; Morigi, Rita; Granaiola, Massimiliano; Varoli, Lucilla; Burnelli, Silvia; Leoni, Alberto; Neidle, Stephen

2010-08-21

A bis-guanylhydrazone derivative of diimidazo[1,2-a:1,2-c]pyrimidine has unexpectedly been found to be a potent stabiliser of several quadruplex DNAs, whereas there is no significant interaction with duplex DNA. Molecular modeling suggests that the guanylhydrazone groups play an active role in quadruplex binding.

Chiral Diamine Bis(phenolate) Ti-IV and Zr-IV Complexes - Synthesis, Structures and Reactivity

NARCIS (Netherlands)

Barroso, Sonia; Adao, Pedro; Duarte, M. Teresa; Meetsma, Auke; Pessoa, Joao Costa; Bouwkamp, Marco W.; Martins, Ana M.

Neutral and cationic titanium and zirconium diamine bis(phenolate) complexes supported by chiral ligands L-1 and L-2 are described [L-1 = (R)-6,6'-{1-(dimethylamino)propan-2-ylazanediyl}bis(methylene)-bis(2,4-di-tert-butylphenolate); L-2 =

BIODEGRADATION OF DDT [1,1,1-TRICHLORO-2,2-BIS(4- CHLOROPHENYL) ETHANE] BY THE WHITE ROT FUNGUS PHANEROCHAETE CHRYSOSPORIUM

Science.gov (United States)

Extensive biodegradation of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) by the white rot fungus Phanerochaete chrysosporium was demonstrated by disappearance and mineralization of [14C]DDT in nutrient nitrogen-deficient cultures. Mass balance studies demonstrated the form...

Solvent control of intramolecular proton transfer

DEFF Research Database (Denmark)

Manolova, Y.; Marciniak, Heinz; Tschierlei, S.

2017-01-01

of molecules in the enol and zwitterionic proton transfer (PT) form exists in the ground state. However, the zwitterion is the energetically favored one in the electronically excited state. Optical excitation of the enol form results in intramolecular proton transfer and formation of the PT form within 1.4 ps...

Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution

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Peter I. Nagy

2014-10-01

Full Text Available A hydrogen bond for a local-minimum-energy structure can be identified according to the definition of the International Union of Pure and Applied Chemistry (IUPAC recommendation 2011 or by finding a special bond critical point on the density map of the structure in the framework of the atoms-in-molecules theory. Nonetheless, a given structural conformation may be simply favored by electrostatic interactions. The present review surveys the in-solution competition of the conformations with intramolecular vs. intermolecular hydrogen bonds for different types of small organic molecules. In their most stable gas-phase structure, an intramolecular hydrogen bond is possible. In a protic solution, the intramolecular hydrogen bond may disrupt in favor of two solute-solvent intermolecular hydrogen bonds. The balance of the increased internal energy and the stabilizing effect of the solute-solvent interactions regulates the new conformer composition in the liquid phase. The review additionally considers the solvent effects on the stability of simple dimeric systems as revealed from molecular dynamics simulations or on the basis of the calculated potential of mean force curves. Finally, studies of the solvent effects on the type of the intermolecular hydrogen bond (neutral or ionic in acid-base complexes have been surveyed.

Monolithic poly(1,2-bis(p-vinylphenyl)ethane) capillary columns for simultaneous separation of low- and high-molecular-weight compounds.

Science.gov (United States)

Greiderer, Andreas; Ligon, S Clark; Huck, Christian W; Bonn, Günther K

2009-08-01

Monolithic poly(1,2-bis(p-vinylphenyl)ethane (BVPE)) capillary columns were prepared by thermally initiated free radical polymerisation of 1,2-bis(p-vinylphenyl)ethane in the presence of inert diluents (porogens) and alpha,alpha'-azoisobutyronitrile (AIBN) as initiator. Polymerisations were accomplished in 200 microm ID fused silica capillaries at 65 degrees C and for 60 min. Mercury intrusion porosimetry measurements of the polymeric RP support showed a broad bimodal pore-size-distribution of mesopores and small macropores in the range of 5-400 nm and flow-channels in the mum range. N(2)-adsorption (BET) analysis resulted in a tremendous enhancement of surface area (101 m(2)/g) of BVPE stationary phases compared to typical organic monoliths (approximately 20 m(2)/g), indicating the presence of a considerable amount of mesopores. Consequently, the adequate proportion of both meso- and (small) macropores allowed the rapid and high-resolution separation of low-molecular-weight compounds as well as biomolecules on the same monolithic support. At the same time, the high fraction of flow-channels provided enhanced column permeability. The chromatographic performance of poly(1,2-bis(p-vinylphenyl)ethane) capillary columns for the separation of biomolecules (proteins, oligonucleotides) and small molecules (alkyl benzenes, phenols, phenons) are demonstrated in this article. Additionally, pressure drop versus flow rate measurements of novel poly(1,2-bis(p-vinylphenyl)ethane) capillary columns confirmed high mechanical robustness, low swelling in organic solvents and high permeability. Due to the simplicity of monolith fabrication, comprehensive studies of the retention and separation behaviour of monolithic BVPE columns resulted in high run-to-run and batch-to-batch reproducibilities. All these attributes prove the excellent applicability of monolithic poly(1,2-bis(p-vinylphenyl)ethane) capillary columns for micro-HPLC towards a huge range of analytes of different

Synthesis, characterization and antioxidant study of N,N’-bis(2-chlorobenzamidothiocarbonyl)hydrazine

Energy Technology Data Exchange (ETDEWEB)

Firdausiah, Syadza; Hasbullah, Siti Aishah; Yamin, Bohari M. [School of Chemical Science and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

2015-09-25

N,N’-bis(2-chlorobenzamidothiocarbonyl)hydrazine was synthesized from 2-chlorobenzoylisothiocyanate and hydrazine in acetone. The compound was characterized by infrared, {sup 1}H and {sup 13}C NMR, and UV-Vis spectroscopies. X-ray crystallography study showed the molecule adopt trans configuration at both N-N and C-N bonds. The compound showed high antioxidant activity, EC{sub 50} of 374.89 µM, compared to ascorbic acid (EC{sub 50} of 561.36 µM)

Structure, vibrations and quantum chemical investigations of hydrogen bonded complex of bis(1-hydroxy-2-methylpropan-2-aminium)selenate

Science.gov (United States)

Thirunarayanan, S.; Arjunan, V.; Marchewka, M. K.; Mohan, S.

2017-04-01

The hydrogen bonded molecular complex bis(1-hydroxy-2-methylpropan-2-aminium)selenate (C8H24N2O6Se) has been prepared by the reaction of 2-amino-2-methyl propanol and selenic acid. The X-ray diffraction analysis revealed that the intermolecular proton transfer from selenic acid (SeO4H2) to 2-amino-2-methylpropanol results in the formation of bis(1-hydroxy-2-methylpropan-2-aminium)selenate (HMPAS) salt and the fragments are connected through H-bonding and ion pairing. The N-H⋯O and O-H⋯O interactions between 2-amino-2-methylpropanol and selenic acid determine the supramolecular arrangement in three-dimensional space. The salt crystallises in the space group P121/n1 of monoclinic system. The complete vibrational assignments of HMPAS have been performed by FTIR and FT-Raman spectroscopy. The experimental data are correlated with the structural properties namely the energy, thermodynamic parameters, atomic charges, hybridization concepts and vibrational frequencies determined by quantum chemical studies performed with B3LYP method using 6-311++G*, 6-31+G* and 6-31G** basis sets.

Activity-guided isolation of cytotoxic bis-bibenzyl constituents from Dumortiera hirsuta.

Science.gov (United States)

Toyota, Masao; Ikeda, Risa; Kenmoku, Hiromichi; Asakawa, Yoshinori

2013-01-01

Activity-guided fractionation of the ether extract of Dumortiera hirsute (Japanese liverwort), using cytotoxicity testing with cultured HL 60 and KB cells, resulted in the isolation of a new cytotoxic bis-bibenzyl compound, along with the two known bis-bibenzyls: isomarchantin C and isoriccardin C. The structural determination of the new bis-bibenzyl through extensive NMR spectral data indicated a derivative of marchantin A, which has been isolated from the liverwort Marchantia polymorpha. The cytotoxicity of the bis-bibenzyls was evaluated by the MTT (3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay using cultured HL 60 and KB cells.

Interaction and Binding Modes of bis-Ruthenium(II Complex to Synthetic DNAs

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Hasi Rani Barai

2016-06-01

Full Text Available [μ-(linkerL2(dipyrido[3,2-a:2′,3′-c]phenazine2(phenanthroline2Ru(II2]2+ with linker: 1,3-bis-(4-pyridyl-propane, L: PF6 (bis-Ru-bpp was synthesized and their binding properties to a various polynucleotides were investigated by spectroscopy, including normal absorption, circular dichroism(CD, linear dichroism(LD, and luminescence techniques in this study. On binding to polynucleotides, the bis-Ru-bpp complex with poly[d(A-T2], and poly[d(I-C2] exhibited a negative LDr signal whose intensity was as large as that in the DNA absorption region, followed by a complicated LDr signal in the metal-to-ligand charge transfer region. Also, the emission intensity and equilibrium constant of the bis-Ru-bpp complex with poly[d(A-T2], and poly[d(I-C2] were enhanced. It was reported that both of dppz ligand of the bis-Ru-bpp complex intercalated between DNA base-pairs when bound to native, mixed sequence DNA. Observed spectral properties resemble to those observed for poly[d(A-T2] and poly[d(I-C2], led us to be concluded that both dppz ligands intercalate between alternated AT and IC bases-pairs In contrast when bis-Ru-bpp complex was bound to poly[d(G-C2], the magnitude of the LDr in the dppz absorption region, as well as the emission intensity, was half in comparison to that of bound to poly[d(A-T2], and poly[d(I-C2]. Therefore the spectral properties of the bis-Ru-bpp-poly[d(G-C2] complex suggested deviation from bis-intercalation model in the poly[d(G-C2] case. These results can be explained by a model whereby one of the dppz ligands is intercalated while the other is exposed to solvent or may exist near to phosphate. Also it is indicative that the amine group of guanine in the minor groove provides the steric hindrance for incoming intercalation binder and it also takes an important role in a difference in binding of bis-Ru-bpp bound to poly[d(A-T2] and poly[d(I-C2].

[N,N-Bis(2-aminoethylethane-1,2-diamine](ethane-1,2-diaminenickel(II thiosulfate trihydrate

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Beatrix Seidlhofer

2012-02-01

Full Text Available The title compound, [Ni(C2H8N2(C6H18N4]S2O3·3H2O, was accidentally synthesized under solvothermal conditions applying [Ni(en3]Cl2 (en is ethane-1,2-diamine as the Ni source. The asymmetric unit consists of one discrete [Ni(tren(en]2+ complex [tren is N,N-bis(2-aminoethylethane-1,2-diamine] in which the Ni2+ cation is sixfold coordinated within a slightly distorted octahedron, one thiosulfate anion and three water molecules. In the crystal, the complex cations, anions and water molecules are linked by an intricate hydrogen-bonding network. One C atom of the tren ligand, as well as one O atom of a water molecule, are disordered over two sites and were refined using a split model (occupancy ratios = 0.85:15 and 0.60:0.40, respectively.

The effect of methylglyoxal-bis(guanylhydrazone) on mitochondrial Ca(2+) fluxes.

Science.gov (United States)

Salvi, Mauro; Toninello, Antonio

2002-01-15

Methylglyoxal-bis(guanylhydrazone) (MGBG) induces a dose-dependent inhibition of the electrophoretic Ca(2+) uptake by rat liver mitochondria (RLM) without affecting the electrical membrane potential. MGBG is also able to inhibit the electroneutral Ca(2+) release from mitochondria. These effects result in a progressive increase of Ca(2+) level in suspending medium indicating that Ca(2+) uptake is inhibited at higher extent than Ca(2+) efflux. Spermine instead, induces a lowering of external Ca(2+) concentration. This action is reversed by MGBG which again raises the external Ca(2+) concentration then in the absence of spermine, though at a lower extent. The mechanism of MGBG effects and their implications on energy metabolism are discussed.

40 CFR 180.205 - Paraquat; tolerances for residues.

Science.gov (United States)

2010-07-01

... the bis(methyl sulfate) or the dichloride salt (both calculated as the cation) in or on the following..., kidney 0.5 Hog, meat 0.05 Hog, meat byproducts, except kidney 0.05 Hop, dried cones 0.5 Horse, fat 0.05 Horse, kidney 0.5 Horse, meat 0.05 Horse, meat byproducts, except kidney 0.05 Kiwifruit 0.05 Lentil...

Bis(acetylacetonato-κ2O,O′(2-amino-1-methyl-1H-benzimidazole-κN3oxidovanadium(IV

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Zukhra Ch. Kadirova

2009-07-01

Full Text Available The title mixed-ligand oxidovanadium(IV compound, [VO(C5H7O22(C8H9N3], contains a VIV atom in a distorted octahedral coordination, which is typical for such complexes. The vanadyl group and the N-heterocyclic ligand are cis to each other. The coordination bond is located at the endocyclic N atom of the benzimidazole ligand. Intramolecular hydrogen bonds between the exo-NH2 group H atoms and acetylacetonate O atoms stabilize the crystal structure.

Intramolecular symmetry-adapted perturbation theory with a single-determinant wavefunction

Energy Technology Data Exchange (ETDEWEB)

Pastorczak, Ewa; Prlj, Antonio; Corminboeuf, Clémence, E-mail: clemence.corminboeuf@epfl.ch [Laboratory for Computational Molecular Design, Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Gonthier, Jérôme F. [Center for Computational Molecular Science and Technology, School of Chemistry and Biochemistry, School of Computational Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0400 (United States)

2015-12-14

We introduce an intramolecular energy decomposition scheme for analyzing non-covalent interactions within molecules in the spirit of symmetry-adapted perturbation theory (SAPT). The proposed intra-SAPT approach is based upon the Chemical Hamiltonian of Mayer [Int. J. Quantum Chem. 23(2), 341–363 (1983)] and the recently introduced zeroth-order wavefunction [J. F. Gonthier and C. Corminboeuf, J. Chem. Phys. 140(15), 154107 (2014)]. The scheme decomposes the interaction energy between weakly bound fragments located within the same molecule into physically meaningful components, i.e., electrostatic-exchange, induction, and dispersion. Here, we discuss the key steps of the approach and demonstrate that a single-determinant wavefunction can already deliver a detailed and insightful description of a wide range of intramolecular non-covalent phenomena such as hydrogen bonds, dihydrogen contacts, and π − π stacking interactions. Intra-SAPT is also used to shed the light on competing intra- and intermolecular interactions.

Effect of mercury dichloride on some biochemical characteristics of brain, blood, and liver in Rutilus caspicus (JAK)

Energy Technology Data Exchange (ETDEWEB)

Dokholyan, V K; Akhmedova, T P

1977-07-12

Rutilus was subjected to various concentrations of mercury dichloride (100, 10, and 5 micrograms/ml). Brain tissue was then tested to determine nitrogen and carbon metabolism. All the fish in the highest concentration died, while those in the latter groups showed marked changes in metabolism. Ammonia content increased 135% in the first day, then dropped. Data on nitrogen metabolites are presented in two tables. For young fish (1 year), the ammonia content only increased 79%. Protein content in blood was reduced by 20 to 22% within 3 days then started to increase. There was an increase in alpha and beta globulins and a drop in blood sugar and liver glycogen.

Electron-rich anthracene semiconductors containing triarylamine for solution-processed small-molecule organic solar cells.

Science.gov (United States)

Choi, Hyeju; Ko, Haye Min; Cho, Nara; Song, Kihyung; Lee, Jae Kwan; Ko, Jaejung

2012-10-01

New electron-rich anthracene derivatives containing triarylamine hole stabilizers, 2,6-bis[5,5'-bis(N,N'-diphenylaniline)-2,2'-bithiophen-5-yl]-9,10-bis-[(triisopropylsilyl)ethynyl]anthracene (TIPSAntBT-TPA) and 2,6-bis(5,5'-bis{4-[bis(9,9-dimethyl-9H-fluoren-2-yl)amino]phenyl}-2,2'-bithiophen-5-yl)-9,10-bis-[(triisopropylsilyl)ethynyl]anthracene (TIPSAntBT-bisDMFA), linked with π-conjugated bithiophene bridges, were synthesized and their photovoltaic characteristics were investigated in solution-processed small-molecule organic solar cells (SMOSCs). These new materials exhibited superior intramolecular charge transfer from triarylamine to anthracene, leading to a more electron-rich anthracene core that facilitated electron transfer into phenyl-C(61)-butyric acid methyl ester. Compared with TIPSAntBT and triarylamine, these materials show a threefold improvement in hole-transporting properties and better photovoltaic performance in solution-processed SMOSCs, with the best power conversion efficiency being 2.96 % at a high open-circuit voltage of 0.85 V. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spectral and cyclic voltammetric studies on some intramolecularly hydrogen bonded arylhydrazones: Crystal and molecular structure of 2-(2-(3-nitrophenyl)hydrazono)-5,5-dimethylcyclohexane-1,3-dione

Science.gov (United States)

Sethukumar, A.; Arul Prakasam, B.

2010-01-01

A series of arylhydrazone derivatives ( 1- 7) were prepared by the coupling of acetylacetone/dimedone with respective aromatic diazonium salts and characterized by IR, 1H and 13C NMR spectra. The IR and NMR spectral data clearly manifests the effective intramolecular hydrogen bonding in all the cases. Cyclic voltammetric studies certainly indicate that in all the cases the reduced center is C dbnd N bond of hydrazonic moiety. The single crystal X-ray structural analysis of 2-(2-(3-nitrophenyl)hydrazono)-5,5-dimethylcyclohexane-1,3-dione ( 6) is also reported. Single crystal X-ray analysis of 6 evidences the intramolecular hydrogen bonding with the N(2)⋯O(4) distance of 2.642(15) Å, which can be designated as S(6) according to Etter's graph nomenclature. The cyclohexane ring conformation in the molecule ( 6) can be described as an envelope. RAHB studies suggest that the resonance assistance for hydrogen bonding is significantly reduced for the compound ( 6) due to the non-planarity of the six atoms which are involved in resonant cycle S(6) of Etter's graph. The planarity of the resonant cycle S(6) is very much disturbed by the conformational requirement of the cyclohexane ring and hence RAHB concept is less operative in this case.

Different efflux rates may determine the cellular accumulation of various bis(guanylhydrazones).

Science.gov (United States)

Alhonen-Hongisto, L; Fagerström, R; Laine, R; Elo, H; Jänne, J

1984-01-01

Three bis(guanylhydrazones) (those of methylglyoxal, glyoxal and ethylglyoxal) were compared for their affinity for the putative polyamine carrier and for their cellular retention in L1210 mouse leukaemia cells. All the bis(guanylhydrazones) inhibited equally effectively the uptake of spermidine by the tumour cells, indicating that the compounds had roughly equal affinity for the polyamine carrier. The fact that methylglyoxal bis(guanylhydrazone) and glyoxal bis(guanylhydrazone) were much more effectively concentrated in the animal cells than was ethylglyoxal bis(guanylhydrazone) was obviously attributable to the finding that the efflux rate of ethylglyoxal bis(guanylhydrazone) greatly exceeded that of the other bis(guanylhydrazones). The rate of efflux of the drugs was slowed down if the tumour cells were treated with 2-difluoromethylornithine before exposure to the bis(guanylhydrazones). These results suggest that intracellular binding of the bis(guanylhydrazones) determines their cellular accumulation. PMID:6431972

Intramolecularly Hydrogen-Bonded Polypyrroles as Electro-Optical Sensors

National Research Council Canada - National Science Library

Nicholson, Jesse

2001-01-01

We have developed a new class of polypyrroles bearing both hydrogen-bond acceptor and hydrogen-donor groups such that the intramolecular hydrogen bonding holds the system planar enhancing conjugation...

Cytotoxicity and Pro-Apoptotic Activity of 2,2´-Bis[4,5-bis(4-hydroxybenzyl-2-(4-hydroxyphenylcyclopent-4-en-1,3-dione], a Phenolic Cyclopentenedione Isolated from the Cyanobacterium Strain Nostoc sp. str. Lukešová 27/97

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Jan Vacek

2011-05-01

Full Text Available The cytotoxicity of the polyphenol 2,2´-bis[4,5-bis(4-hydroxybenzyl-2-(4-hydroxyphenylcyclopent-4-en-1,3-dione], nostotrebin 6 (NOS-6, was tested under in vitro conditions using mouse fibroblasts (BALB/c cells. Identification of NOS-6 and its uptake into fibroblasts was examined by multi-stage mass spectrometry analysis with the following fragmentation pattern: MS (m/z [M+H]+ 799.1 → MS2 399.1 → MS3 305.1 → MS4 277.1. Using several cell viability assays, the IC50 of NOS-6 after 24 h incubation was found to be 8.48 ± 0.16/12.15 ± 1.96 µM (neutral red/MTT assay which was higher than that of doxorubicin. It was found that NOS-6 is capable of inducing both types of cell death, apoptosis and necrosis in a dose-dependent manner. The biological activities of the cyclopentenediones and preliminary data on NOS-6 cytotoxicity are discussed.

INTRAMOLECULAR ISOTOPE EFFECTS IN HYDROCARBON MASS SPECTRA

Energy Technology Data Exchange (ETDEWEB)

Stevenson, D. P.; Schachtschneider, J. H.

1963-07-15

Approximate calculations based on the quasi-equilibrium rate theory of the origin of mass spectra are shown to lead to an approximately correct magnitude for the intramolecular ( pi /sup -/) isotope effect on C--H bond dissociation probabilities of various deuterohydrocarbons. (auth)

Bis[μ-1,3-bis(diphenylphosphanylpropane-κ2P:P′]digold(I tetrachloridonickelate(II diethyl ether monosolvate

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Asako Igashira-Kamiyama

2013-06-01

Full Text Available The title compound, [Au2(C27H26P22][NiCl4]·C4H10O, consists of a digold(I complex cation, an [NiCl4]2− complex anion and a diethyl ether solvent molecule. Two 1,3-bis(diphenylphosphanylpropane (dppp ligands bridge two AuI atoms, forming a metallacycle in which each of the AuI atoms is coordinated in a slightly distorted linear environment by two P atoms. In the complex anion, the NiII atom is coordinated by four chloride ligands in a distorted tetrahedral geometry. The complex cation and the complex anion form a cation–anion pair through two Au...Cl contacts of 3.040 (1 and 3.021 (2 Å. One of the phenyl groups of the dppp ligand is disordered over two positions with equal occupancies.

A dinuclear copper complex: bis(μ-4-aminobenzoatobis[aqua(1,10-phenanthrolinecopper(II] dichloride bis(4-aminobenzoic acid dihydrate

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Miao-Ling Huang

2008-08-01

Full Text Available The title complex, [Cu2(C7H6NO22(C12H8N22(H2O2]·2C7H7NO2·2H2O, consists of a dinuclear [Cu2(C7H6NO22(C12H8N22(H2O2]2+ cation, two Cl− anions, two 4-aminobenzoic acid molecules and two disordered water molecules (site occupancy factors 0.5. The Cu(II ion adopts a distorted square-pyramidal geometry formed by two N atoms from the 1,10-phenanthroline ligand and two O atoms of the two 4-aminobenzoic acid ligands and one water O atom. The Cu...Cu separation is 3.109 (2 Å. A twofold axis passes through the mid-point of the Cu...Cu vector.

Studies on the reduction of technetate(VII) by 1,2 bis(diphenylphosphino)ethane

International Nuclear Information System (INIS)

Muenze, R.; Seifert, S.; Kloetzer, D.; Maeding, P.; Goerner, W.

1984-01-01

The reduction of technetate(VII) by using 1,2 bis(diphenylphosphino)ethane (DPPE) has been investigated as a model for the preparation of new myotropic technetium compounds. Phosphino complexes were isolated and characterized which contain technetium in the oxidation state V([TcO 2 DPPE 2 ][TcO 4 ]), IV([TcCl 2 DPPE 2 ][TcCl 6 ]), III ([TcCl 3 DPPE 2 ] 0 ), ([TcCl 2 DPPE 2 ]Cl, and II ([TcCl 2 DPPE 2 ] 0 ) dependent on the reaction conditions, in particular Tc/DPPE and Tc/HCl ratios. (author)

Does the Intramolecular Hydrogen Bond Affect the Spectroscopic Properties of Bicyclic Diazole Heterocycles?

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Paweł Misiak

2018-01-01

Full Text Available The formation of an intramolecular hydrogen bond in pyrrolo[1,2-a]pyrazin-1(2H-one bicyclic diazoles was analyzed, and the influence of N-substitution on HB formation is discussed in this study. B3LYP/aug-cc-pVDZ calculations were performed for the diazole, and the quantum theory of atoms in molecules (QTAIM approach as well as the natural bond orbital (NBO method was applied to analyze the strength of this interaction. It was found that the intramolecular hydrogen bond that closes an extra ring between the C=O proton acceptor group and the CH proton donor, that is, C=O⋯H–C, influences the spectroscopic properties of pyrrolopyrazine bicyclic diazoles, particularly the carbonyl frequencies. The influence of N-substitution on the aromaticity of heterocyclic rings is also discussed in this report.

MCBIS2 - Monte-Carlo package for preparing and analyzing experiments with the BIS-2 spectrometer

International Nuclear Information System (INIS)

Nowak, H.; Nowak, V.-D.

1978-01-01

The MCBIS2 user package is designed to simulate the diffraction dissociation reaction np→K 0 Λp and related background reactions. The MCBIS2 user package is written in JINR for the BIS-2 spectrometer consisting of multiwire proportional chambers, multichannel Cherenkov counter and scintillator hodoscopes. The MCBIS2 user package is divided into three sections: initial, working and final. Each section is a group of subprograms belonging to the corresponding GEANT stage. The generation of all primary vertex kinematics for the reaction np→K 0 Λp and tracking in space is considered in detail. Problems of the preparation of necessary information about detectors are discussed

An unexpected oxidation: NaK5Cl2(S2O62 revisited

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William T. A. Harrison

2017-02-01

Full Text Available The title compound, NaK5Cl2(S2O62 [systematic name: sodium pentapotassium dichloride bis(dithionate], arose as an unexpected product from an organic synthesis that used dithionite (S2O42− ions as a reducing agent to destroy excess permanganate ions. Compared to the previous study [Stanley (1953. Acta Cryst. 6, 187–196], the present tetragonal structure exhibits a root 2a × root 2a × c super-cell due to subtle changes in the orientations of the dithionate anions. The structure can be visualized as a three-dimensional framework of [001] columns of alternating trans-NaO4Cl2 and KO4Cl2 octahedra cross-linked by the dithionate ions with the interstices occupied by KO6Cl2 polyhedra to generate a densely packed three-dimensional framework. The asymmetric unit comprises two sodium ions (site symmetries 4 and -4, four potassium ions (site symmetries = -4, 4, 1 and 1, three chloride ions (site symmetries = 4, 4 and 2 and two half-dithionate ions (all atoms on general positions. Both dithionate ions are completed by crystallographic inversion symmetry. The crystal chosen for data collection was found to be rotationally twinned by 180° about the [100] axis in reciprocal space with a 0.6298 (13:0.3702 (13 domain ratio.

Solid-state deep blue and UV fluorescent dyes based on para-bis(2-thienyl)phenylene

Energy Technology Data Exchange (ETDEWEB)

Krajčovič, Jozef; Kovalenko, Alexander, E-mail: kovalenko.alx@gmail.com; Heinrichová, Patricie; Vala, Martin; Weiter, Martin

2015-11-15

Despite the general rule of strong acceptor substituents having a tendency to quench fluorescence due to molecular stacking, it is shown how tetra-fluorination of the central phenylene unit of para-bis(2-thienyl)phenylene can augment the quantum yields of solid state fluorescent dyes. Another significant part of the present research was the study of the influence of the position of the solubilization alkyl chains position on the fluorescent properties of the abovementioned non- and tetra-fluorinated materials. Tenfold augmentation of quantum yields, depending on the position of the alkyl chains is reported. - Highlights: • Solid state luminescence was observed in para-bis(2-thienyl)phenylene molecules. • Quantum yields was augmented by polyfluorination of the central phenylene unit. • Tenfold augmentation of luminescence was observed by changing alkyls position. • Possibilities of steric hindrance and charge transfer were studied.

Inhibitory effect of a tyrosine-fructose Maillard reaction product, 2,4-bis(p-hydroxyphenyl-2-butenal on amyloid-β generation and inflammatory reactions via inhibition of NF-κB and STAT3 activation in cultured astrocytes and microglial BV-2 cells

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Choi Im Seup

2011-10-01

Full Text Available Abstract Background Amyloidogenesis is linked to neuroinflammation. The tyrosine-fructose Maillard reaction product, 2,4-bis(p-hydroxyphenyl-2-butenal, possesses anti-inflammatory properties in cultured macrophages, and in an arthritis animal model. Because astrocytes and microglia are responsible for amyloidogenesis and inflammatory reactions in the brain, we investigated the anti-inflammatory and anti-amyloidogenic effects of 2,4-bis(p-hydroxyphenyl-2-butenal in lipopolysaccharide (LPS-stimulated astrocytes and microglial BV-2 cells. Methods Cultured astrocytes and microglial BV-2 cells were treated with LPS (1 μg/ml for 24 h, in the presence (1, 2, 5 μM or absence of 2,4-bis(p-hydroxyphenyl-2-butenal, and harvested. We performed molecular biological analyses to determine the levels of inflammatory and amyloid-related proteins and molecules, cytokines, Aβ, and secretases activity. Nuclear factor-kappa B (NF-κB DNA binding activity was determined using gel mobility shift assays. Results We found that 2,4-bis(p-hydroxyphenyl-2-butenal (1, 2, 5 μM suppresses the expression of inducible nitric oxide synthase (iNOS and cyclooxygenase-2 (COX-2 as well as the production of nitric oxide (NO, reactive oxygen species (ROS, tumor necrosis factor-α (TNF-α, and interleukin-1β (IL-1β in LPS (1 μg/ml-stimulated astrocytes and microglial BV-2 cells. Further, 2,4-bis(p-hydroxyphenyl-2-butenal inhibited the transcriptional and DNA binding activity of NF-κB--a transcription factor that regulates genes involved in neuroinflammation and amyloidogenesis via inhibition of IκB degradation as well as nuclear translocation of p50 and p65. Consistent with the inhibitory effect on inflammatory reactions, 2,4-bis(p-hydroxyphenyl-2-butenal inhibited LPS-elevated Aβ42 levels through attenuation of β- and γ-secretase activities. Moreover, studies using signal transducer and activator of transcription 3 (STAT3 siRNA and a pharmacological inhibitor showed that 2

Radiation grafting of bis[2-(methacryloyloxy)ethyl]phosphate unto kenaf fiber for adsorption of rare earth elements

International Nuclear Information System (INIS)

Nor Azillah Fatimah Othman; Selambakkannu, S.; Norliza Ishak; Nor Azwin Shukri; Zulkafli Ghazali

2016-01-01

Full text: In this work kenaf bast fibers were used as trunk polymer for grafting with bis[2-(methacryloyloxy)ethyl]phosphate monomer through radiation induced grafting technique. Kenaf fibers were treated with different concentration of sodium chlorite (NaClO_2) solution at 70 degree Celsius for 6 hours. Kenaf fibers were irradiated with electron beam and reacted with bis[2-(methacryloyloxy)ethyl]phosphate/ water emulsion. Formation of grafting was observed from the increase in degree of grafting and confirmed by FTIR and SEM results. Effects of irradiation dose, reaction time, reaction temperature and monomer concentration on the degree of grafting were studied. Performance of the grafted kenaf fibers were then tested for adsorption of rare earth elements, namely Dysprosium, Neodymium and Holmium. (author)

Synergistic extraction of Eu(III) with N-phosphorylated bis-ureas and chlorinated cobalt bis(dicarbollide) ion

Energy Technology Data Exchange (ETDEWEB)

Selucky, P.; Bubenikova, M.; Rais, J. [UJV Rez, a.s., Rez near Prague (Czech Republic); Gruener, B. [Academy of Sciences of the Czech Republic, Rez near Prague (Czech Republic). Inst. of Inorganic Chemistry; Brusko, V.V. [JSC NIIneftepromchim, Kazan (Russian Federation)

2013-03-01

Extraction of Eu(III) with a synergistic mixture of polydentate N-phosphorylated bis-ureas with the general formula (i-PrO){sub 2}P(O)NHC(O)NHXNHC(O)NHP(O)(Oi-Pr){sub 2} (X = (CH{sub 2}){sub 7}, (CH{sub 2}){sub 2}O(CH{sub 2}){sub 2} and (CH{sub 2}){sub 2}O(CH{sub 2}){sub 2}O(CH{sub 2}){sub 2}) and chlorinated cobalt bis(dicarbollide) ion (CCD-) with formula closo-[(1,2-C{sub 2}B{sub 9}H{sub 8}Cl{sub 3}){sub 2}-3-Co]{sup -} was studied using nitrobenzene as the solvent. Extraction of Eu(III) was very effective up to high concentrations of nitric acid. Eu(III) is most likely extracted into the organic phase as the [EuL{sub 2}]{sup 3+} species whereas the positive charge of extracted complex is compensated by CCD and/or nitrate anions. (orig.)

A fluoride-sensing receptor based on 2,2'-bis(indolyl)methane by dual-function of colorimetry and fluorescence.

Science.gov (United States)

Wei, Wei; Shao, Shi Jun; Guo, Yong

2015-10-05

A compound based on 2,2'-bis(indolyl)methane containing nitro group was studied as a new anion receptor. It could recognize selectively F(-) by an increasing fluorescence signal and a visible color change from colorless to blue. The introduction of nitro group induced the spectral dual-function related to the deprotonation of N-H protons. Copyright © 2015 Elsevier B.V. All rights reserved.

Competing intramolecular N-H⋯O=C hydrogen bonds and extended intermolecular network in 1-(4-chlorobenzoyl)-3-(2-methyl-4-oxopentan-2-yl) thiourea analyzed by experimental and theoretical methods

Energy Technology Data Exchange (ETDEWEB)

Saeed, Aamer, E-mail: aamersaeed@yahoo.com [Department of Chemistry, Quaid-I-Azam University, Islamabad 45320 (Pakistan); Khurshid, Asma [Department of Chemistry, Quaid-I-Azam University, Islamabad 45320 (Pakistan); Jasinski, Jerry P. [Department of Chemistry, Keene State College, 229 Main Street Keene, NH 03435-2001 (United States); Pozzi, C. Gustavo; Fantoni, Adolfo C. [Instituto de Física La Plata, Departamento de Física, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, 49 y 115, La Plata, Buenos Aires (Argentina); Erben, Mauricio F., E-mail: erben@quimica.unlp.edu.ar [CEQUINOR (UNLP, CONICET-CCT La Plata), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, C.C. 962, (1900) La Plata, Buenos Aires (Argentina)

2014-03-18

Highlights: • Two distinct N-H⋯O=C intramolecular competing hydrogen bonds are feasible in the title molecule. • Crystal structures and vibrational properties were determined. • The C=O and C=S double bonds of the acyl-thiourea group are mutually oriented in opposite directions. • A strong hyperconjugative lpO1 → σ{sup ∗}(N2-H) remote interaction was detected. • Topological analysis reveals a Cl⋯N interaction playing a relevant role in crystal packing. - Abstract: The synthesis of a novel 1-acyl-thiourea species (C{sub 14}H{sub 17}N{sub 2}O{sub 2}SCl), has been tailored in such a way that two distinct N-H⋯O=C intramolecular competing hydrogen bonds are feasible. The X-ray structure analysis as well as the vibrational (FT-IR and FT-Raman) data reveal that the S conformation is preferred, with the C=O and C=S bonds of the acyl-thiourea group pointing in opposite directions. The preference for the intramolecular N-H⋯O=C hydrogen bond within the -C(O)NHC(S)NH- core is confirmed. The Natural Bond Orbital and the Atom in Molecule approaches demonstrate that a strong hyperconjugative lpO → σ{sup ∗}(N-H) remote interaction between the acyl and the thioamide N-H groups is responsible for the stabilization of the S conformation. Intermolecular interactions have been characterized in the periodic system electron density and the topological analysis reveals the presence of an extended intermolecular network in the crystal, including a Cl⋯N interaction playing a relevant role in crystal packing.

Zn2+, Cd2+, Hg2+ thiolates - derivatives of 2, 3, 5-trifluoro-4,6-bis(trifluoromethyl)thiophenol and heptafluoro-2-thionaphthol

International Nuclear Information System (INIS)

Larionov, S.V.; Kirichenko, V.N.; Platonov, V.E.; Maksimov, A.M.; Rodionov, P.P.; Fadeeva, V.P.; Oglezneva, I.M.; Lisojvan, V.I.; AN SSSR, Novosibirsk

1992-01-01

Zn 2+ , Cd 2+ , Hg 2+ coordination compounds with 2, 3, 5 -trifluoro- 4,6 bis(trifluoromethyl)trhiophenol (MHal) and heptafluoro-2-thionophthal (HT) of ZnHal 2 (CH 3 OH), CdHal 2 , HgHal 2 and MT 2 (M=Zn, Cd, Hg) composition, are obtained. Complexes are studied using thermal and X-ray phase analysis, vapour phase osmometry and IR spectroscopy, ZnHal 2 (CH 3 OH), CdHal 2 , ZnT 2 , HgHfl 2 , HgT 2 compounds in acetone solutions are in monomeric state, while in CdT 2 commeric particles. Frequencies of mostly valent vibrations of Cd-S bond are observed at 241 (CdHal 2 ), 225 (CdT 2 )

Di-μ-chlorido-bis{[μ-1,8-bis(diisopropylphosphanyl-9,10-dihydro-9,10-ethanoanthracene-κ2P:P′]-μ-chlorido-μ-methylidene-dipalladium(II} tetrahydrofuran pentasolvate

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Thomas Schnetz

2010-04-01

Full Text Available The title compound, [Pd4(CH22Cl4(C28H40P22]·5C4H8O, possesses a tetranuclear palladium core with four bridging chlorido ligands and two bridging methylene units, as well as two bridging anthracene-based bis-phosphine ligands. This tetranuclear complex can be considered as being composed of two μ-chlorido-bridged LPd2 units. The structural motif of these LPd2 units shows two doubly bridged palladium centers between the P atoms of the bis-phosphine ligand. One of these bridges is a μ-Cl atom, the other a μ-methylene group. The coordination environment around each palladium center is essentially square planar. We ascribe the oxidation state +II to the palladium centers and do not assume Pd—Pd bonds [shortest distances 2.8110 (5 and 2.8109 (6 Å]. Co-crystallized with the palladium complex we found five non-coordinating tetrahydrofuran solvent molecules, one of which is disordered over two positions in a 0.429 (9:0.571 (8 ratio.

Unique Intramolecular Electronic Communications in Mono-ferrocenylpyrimidine Derivatives: Correlation between Redox Properties and Structural Nature

International Nuclear Information System (INIS)

Xiang, Debo; Noel, Jerome; Shao, Huibo; Dupas, Georges; Merbouh, Nabyl; Yu, Hua-Zhong

2015-01-01

Highlights: • Unique intramolecular electronic communications (electron withdrawing and π-bond delocalization effects) exist in the mono-ferrocenylpyrimidine derivatives. • The redox potential shift correlates the pyrimidine ring torsion angle with the extent of electron delocalization. • The correlation between redox properties and structural nature in mono-ferrocenylpyrimidine derivatives is evident. - Abstract: The correlation between redox properties and structural nature in a complete set of mono-ferrocenylpyrimidine derivatives (2-ferrocenylpyrimidine, 2-FcPy; 4-ferrocenylpyrimidine, 4-FcPy; 5-ferrocenylpyrimidine, 5-FcPy) was evaluated by investigating the intramolecular electronic communications. Both conventional electrochemical measurements in organic solvents and thin-film voltammetric studies of these compounds were carried out. It was discovered that their formal potentials are significantly different from each other, and shift negatively in the order of 4-FcPy > 5-FcPy > 2-FcPy. This result suggests that the intramolecular electronic communication is dictated by the delocalization effect of the π-bonding systems in 2-FcPy, and that the electron-withdrawing effect of the nitrogen atoms in the pyrimidine ring plays the key role in 4-FcPy and 5-FcPy. The single crystal X-ray structure analyis and Density Functional Theory (DFT) calculation provided additional evidence (e.g., different torsion angles between the cyclopentadienyl and pyrimidine rings) to support the observed correlation between the redox properties and structural nature

Synthesis of benzannelated sultams by intramolecular Pd-catalyzed arylation of tertiary sulfonamides

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Valentin A. Rassadin

2017-09-01

Full Text Available A new and efficient approach to five- and six-membered benzannelated sultams by intramolecular C-arylation of tertiary 1-(methoxycarbonylmethanesulfonamides under palladium catalysis is described. In case of the α-toluenesulfonamide derivative, an unexpected formation of a 2,3-diarylindole was observed under the same conditions.

Effects of supported (nBuCp)2ZrCl2 catalyst active center multiplicity on crystallization kinetics of ethylene homo- and copolymers

KAUST Repository

Atiqullah, Muhammad

2014-07-01

Two different supported zirconocene, that is, bis(n-butylcyclopentadienyl) zirconium dichloride (nBuCp)2ZrCl2, catalysts were synthesized. Each catalyst was used to prepare one ethylene homopolymer and one ethylene-1-hexene copolymer. Catalyst active center multiplicity and polymer crystallization kinetics were modeled. Five separate active center types were predicted, which matched the successive self-nucleation and annealing (SSA) peak temperatures. The predicted crystallinity well matched the differential scanning calorimetric (DSC) values for a single Avrami-Erofeev index, which ranged between 2 and 3 for the polymers experimented. The estimated apparent crystallization activation energy Ea did not vary with cooling rates, relative crystallinity α, and crystallization time or temperature. Therefore, the concept of variable/instantaneous activation energy was not found to hold. Ea linearly increased with the weight average lamellar thickness Lwav DSC-GT; and for each homopolymer, it exceeded that of the corresponding copolymer. Higher Ea, hence slower crystallization, was identified as a pre-requisite to attain higher crystallinity. Crystallization parameters were correlated to polymer backbone parameters, which are influenced by catalyst active center multiplicity. © 2013 Taiwan Institute of Chemical Engineers.

Intravenous application of HI-6 salts (dichloride and dimethansulphonate) in pigs: comparison with pharmacokinetics profile after intramuscular administration.

Science.gov (United States)

Zdarova Karasova, Jana; Zemek, Filip; Kunes, Martin; Kvetina, Jaroslav; Chladek, Jaroslav; Jun, Daniel; Bures, Jan; Tachecí, Ilja; Kuca, Kamil

2013-01-01

Oxime HI-6 is an acetylcholinesterase reactivator therapeutically efficient against nerve agents. Because of their physico-chemical properties, oximes are typically applied intramuscularly (i.m.). This route of administration has also some disadvantages, and alternative strategies ought to be examined. We evaluated the pharmacokinetic profiles of two HI-6 salts after their intravenous (i.v.) administration, and compare the results with the known pharmacokinetics after i.m. administration. Pigs were administered with HI-6 salts (i.v), either HI-6 dichloride (10.71 mg/kg) or molar equivalent HI-6 dimethansulphonate (13.59 mg/kg). Doses of the HI-6 salts corresponded with a standard HI-6 dichloride dose in one autoinjector (500 mg) and were recalculated for one kilogram of body weight. The main pharmacokinetic parameters are comparable after i.v. and i.m. HI-6 administration. The compared pharmacokinetic parameters were half-life, terminal rate constant, mean residence time of the molecule in the body, clearance, and the apparent volume in the terminal phase. The bioavailability after i.m. administration was comparable with that of i.v.; these results suggest that the oxime is well released from the muscle depot. Significant differences were found in parameters Cmax and Tmax which are important in cases of emergency when rapidity and bioavailability are paramount for the success of treatment. I.v. administration should solve the problem of rapid clearance. Infusion or bolus administration may be considered as a logical subsequent step in oxime treatment strategy. The main advantage is in maintenance of an effective therapeutic plasma concentration, a more easily achievable effective therapeutic concentration, and fewer local adverse reactions.

Solid-State Examination of Conformationally Diverse Sulfonamide Receptors Based on Bis(2-anilinoethynyl)pyridine, -Bipyridine, and -Thiophene.

Science.gov (United States)

Berryman, Orion B; Johnson, Charles A; Vonnegut, Chris L; Fajardo, Kevin A; Zakharov, Lev N; Johnson, Darren W; Haley, Michael M

2015-03-04

Utilizing an induced-fit model and taking advantage of rotatable acetylenic C(sp)-C(sp 2 ) bonds, we disclose the synthesis and solid-state structures of a series of conformationally diverse bis-sulfonamide arylethynyl receptors using either pyridine, 2,2'-bipyridine, or thiophene as the core aryl group. Whereas the bipyridine and thiophene structures do not appear to bind guests in the solid state, the pyridine receptors form 2 + 2 dimers with water molecules, two halides, or one of each, depending on the protonation state of the pyridine nitrogen atom. Isolation of a related bis-sulfonimide derivative demonstrates the importance of the sulfonamide N-H hydrogen bonds in dimer formation. The pyridine receptors form monomeric structures with larger guests such as BF 4 - or HSO 4 - , where the sulfonamide arms rotate to the side opposite the pyridine N atom.

Tidbits for the synthesis of bis(2-sulfanylethyl)amido (SEA) polystyrene resin, SEA peptides and peptide thioesters.

Science.gov (United States)

Ollivier, Nathalie; Raibaut, Laurent; Blanpain, Annick; Desmet, Rémi; Dheur, Julien; Mhidia, Reda; Boll, Emmanuelle; Drobecq, Hervé; Pira, Silvain L; Melnyk, Oleg

2014-02-01

Protein total chemical synthesis enables the atom-by-atom control of the protein structure and therefore has a great potential for studying protein function. Native chemical ligation of C-terminal peptide thioesters with N-terminal cysteinyl peptides and related methodologies are central to the field of protein total synthesis. Consequently, methods enabling the facile synthesis of peptide thioesters using Fmoc-SPPS are of great value. Herein, we provide a detailed protocol for the preparation of bis(2-sulfanylethyl)amino polystyrene resin as a starting point for the synthesis of C-terminal bis(2-sulfanylethyl)amido peptides and of peptide thioesters derived from 3-mercaptopropionic acid. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.

One-pot synthesis of 4,8-dibromobenzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole.

Science.gov (United States)

Tam, Teck Lip; Li, Hairong; Wei, Fengxia; Tan, Ke Jie; Kloc, Christian; Lam, Yeng Ming; Mhaisalkar, Subodh G; Grimsdale, Andrew C

2010-08-06

A one-step synthesis of 4,8-dibromobenzo[1,2-c;4,5-c']bis[1,2,5]thiadiazole with use of 1,2,4,5-tetraaminobenzene tetrahydrobromide and thionyl bromide in good yield is reported. This unit can then be used in the synthesis of low bandgap materials via palladium-catalyzed coupling reactions. The approach offers a quick and easy way to prepare low bandgap materials as compared to the current literature methods.

Crystal structure of a dinuclear CoII complex with bridging fluoride ligands: di-μ-fluorido-bis{tris[(6-methylpyridin-2-ylmethyl]amine}dicobalt(II bis(tetrafluoridoborate

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Masataka Inomata

2014-11-01

Full Text Available Reaction of Co(BF42·6H2O with tris[(6-methylpyridin-2-ylmethyl]amiine in methanol results in a fluoride abstraction from BF4−, yielding the unexpected title compound, [Co2F2(C21H24N42](BF42. The complex cation consists of two inversion-related [Co(C21H24N4]2+ moieties bridged by a pair of fluoride ligands. The CoII cation is six-coordinated in a distorted octahedral geometry and forms a +II high-spin state. In the crystal, the complex cation and the BF4− anion are connected by C—H...F hydrogen bonds, forming a three-dimensional network. An intramolecular C—H...F hydrogen bond is also observed.

[1,4-Bis(diphenylphosphanylbutane-κ2P,P′]dibromidopalladium(II

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Kwang Ha

2014-02-01

Full Text Available In the title complex, [PdBr2(C28H28P2], the PdII ion has a distorted cis-Br2P2 square-planar coordination geometry defined by two P atoms from the chelating 1,4-bis(diphenylphosphanylbutane ligand and two Br− anions. The four phenyl rings are inclined to the least-squares plane of the PdBr2P2 unit [maximum deviation = 0.1294 (7 Å], making dihedral angles of 66.3 (2, 87.2 (2, 68.8 (2 and 86.8 (2°. The butylene chain is in a gauche conformation, with a C—C—C—C torsion angle of 57.0 (8°. Intermolecular C—H...Br hydrogen bonds link the complex molecules into supramolecular layers in the ab plane. Weak π–π interactions, both intra- and intermolecular [shortest inter-centroid distance = 4.598 (5 Å], are also noted in the three-dimensional architecture.

Effects of acid concentration on intramolecular charge transfer ...

Indian Academy of Sciences (India)

rate. Time-dependent density functional theory calculations have been performed to understand the observed spectroscopic results. Keywords. Intramolecular charge transfer; absorption and fluorescence; time resolved fluorescence measurements; acid concentration dependence; time-dependent density functional theory.

Intramolecular energy transfer and mode-specific effects in unimolecular reactions of 1,2-difluoroethane

Science.gov (United States)

Raff, Lionel M.

1989-06-01

The unimolecular decomposition reactions of 1,2-difluoroethane upon mode-specific excitation to a total internal energy of 7.5 eV are investigated using classical trajectory methods and a previously formulated empirical potential-energy surface. The decomposition channels for 1,2-difluoroethane are, in order of importance, four-center HF elimination, C-C bond rupture, and hydrogen-atom dissociation. This order is found to be independent of the particular vibrational mode excited. Neither fluorine-atom nor F2 elimination reactions are ever observed even though these dissociation channels are energetically open. For four-center HF elimination, the average fraction of the total energy partitioned into internal HF motion varies between 0.115-0.181 depending upon the particular vibrational mode initially excited. The internal energy of the fluoroethylene product lies in the range 0.716-0.776. Comparison of the present results with those previously obtained for a random distribution of the initial 1,2-difluoroethane internal energy [J. Phys. Chem. 92, 5111 (1988)], shows that numerous mode-specific effects are present in these reactions in spite of the fact that intramolecular energy transfer rates for this system are 5.88-25.5 times faster than any of the unimolecular reaction rates. Mode-specific excitation always leads to a total decomposition rate significantly larger than that obtained for a random distribution of the internal energy. Excitation of different 1,2-difluoroethane vibrational modes is found to produce as much as a 51% change in the total decomposition rate. Mode-specific effects are also seen in the product energy partitioning. The rate coefficients for decomposition into the various channels are very sensitive to the particular mode excited. A comparison of the calculated mode-specific effects with the previously determined mode-to-mode energy transfer rate coefficients [J. Chem. Phys. 89, 5680 (1988)] shows that, to some extent, the presence of mode

Crystal structure of tris(1,10-phenanthroline-κ2N,N′iron(II bis[bis(trifluoromethylsulfonylimide] monohydrate

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Kazunori Teramoto

2015-01-01

Full Text Available The crystal structure of the title complex, [Fe(C12H8N23][(CF3SO22N]2·H2O, is constructed by one octahedral [Fe(phen3]2+ (phen = 1,10-phenanthroline cation (point group symmetry 2, two Tf2N− [bis(trifluoromethylsulfonylimide] anions, and one water molecule of crystallization (point group 2. The Fe—N bond lengths are indicative of a d6 low-spin state for the FeII ion in the complex. The dihedral angle between the phen ligands in the cation is 87.64 (6°. The Tf2N− counter-anion is non-coordinating, with the –CF3 groups arranged in a trans fashion with respect to each other, leading to an anti,anti conformation of the –CF3 groups and –SO2N– moieties relative to the S—C bonds. The water molecule of crystallization connects two O atoms of the Tf2N− anions through weak hydrogen bonds. C—H...O hydrogen-bonding interactions are also observed, consolidating the packing of the molecules into a three-dimensional network structure.

trans-Bis(methanol-κObis(quinoline-2-carboxylato-κ2N,Omanganese(II

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Lucjan B. Jerzykiewicz

2008-11-01

Full Text Available The title compound, [Mn(C10H6NO22(CH4O2], was obtained unintentionally as the product of an attempt to synthesize a polynuclear carboxylate bridged manganese(III/IV complex, using methanol to reduce the permanganate ion. The molecule is centrosymmetric; the pairs of equivalent ligands coordinate trans to each other in a distorted octahedral geometry. Intramolecular C—H...O bonds lying in the equatorial plane stabilize the molecule. In the crystal, molecules are linked by O—H...O and C—H...O hydrogen bonds, creating a three-dimensional supramolecular structure. π–π and C—H...π interactions are also observed. The dihedral angle and centroid-to-centroid distance between the pyridine ring (A and the benzene ring (Bi of a symmetrically related molecule [symmetry code: (i −1 − x, −y, −z] are 1.27 (11° and 3.974 (2 Å, respectively. For the C—H...π interactions, the relevant distances and angles are: C...Cg[Aii] = 3.643 (2 Å, H...Cg[Aii] = 2.750 (2 Å and C—H...Cg[Aii] = 155 (1° [symmetry code: (ii x, −1 + y, z].

SYNTHESIS AND HEMOLYTIC PROPERTIES OF DERIVATIVES OF 4,4'-DIHYDROXYBIPHENYL – 2,2'-[BIPHENYL-4,4'- DIYLBIS(OXY]BIS[N-(METHYLAMINOALKILACETAMIDES

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S. O. Zanoza

2016-04-01

Full Text Available The purpose of this work was synthesis of 4,4’-dihydroxybiphenyl derivatives, namely 2,2’-[biphenyl-4,4’-diylbis(oxy]bis[N-(2-aminoalkylacetamide], study of their hemolytic properties and the effect of the side chain structure on hemolytic properties. 2,2’-[Biphenyl-4,4’-diylbis(oxy]diacetic acid was synthesized by alkylation of 4,4’-dihydroxybiphenyl with methylbromoacetate, followed by alkaline hydrolysis. Chloroanhydride was obtained by treatment of this acid with thionyl chloride. 2,2’-[Biphenyl-4,4’-diylbis(oxy]  bis-[N-(2-aminoalkylacetamides] were synthesized in the biphasic media (dichloromethane/ aqueous sodium carbonate. Structures of synthesized compounds were proved by mass-spectrometryand 1Н NMR. Hemolytic properties were studied using healthy donors’ erythrocytes 0(I/Rh+. The absence of hemolytic properties for obtained compounds was shown, unlike similar 4,4’-aminoalkoxybiphenyls for which a significant hemolysis was shown. Thus, replacement of the ethylene group with amide group in the side chain of 4,4’-bissubstituted biphenyls significantly reduces hemolytic properties.

Electron paramagnetic resonance and density-functional theory studies of Cu(II)-bis(oxamato) complexes.

Science.gov (United States)

Bräuer, Björn; Weigend, Florian; Fittipaldi, Maria; Gatteschi, Dante; Reijerse, Edward J; Guerri, Annalisa; Ciattini, Samuele; Salvan, Georgeta; Rüffer, Tobias

2008-08-04

In this work we present the investigation of the influence of electronic and structural variations induced by varying the N,N'-bridge on the magnetic properties of Cu(II)- bis(oxamato) complexes. For this study the complexes [Cu(opba)] (2-) ( 1, opba = o-phenylene- bis(oxamato)), [Cu(nabo)] (2-) ( 2, nabo = 2,3-naphthalene- bis(oxamato)), [Cu(acbo)] (2-) ( 3, acbo = 2,3-anthrachinone- bis(oxamato)), [Cu(pba)] (2-) ( 4, pba = propylene- bis(oxamato)), [Cu(obbo)] (2-) ( 5, obbo = o-benzyl- bis(oxamato)), and [Cu(npbo)] (2-) ( 6, npbo = 1,8-naphthalene- bis(oxamato)), and the respective structurally isomorphic Ni(II) complexes ( 8- 13) have been prepared as ( (n)Bu 4N) (+) salts. The new complex ( (n)Bu 4N) 2[Cu(R-bnbo)].2H 2O ( 7, R-bnbo = (R)-1,1'-binaphthalene-2,2'- bis(oxamato)) was synthesized and is the first chiral complex in the series of Cu(II)-bis(oxamato) complexes. The molecular structure of 7 has been determined by single crystal X-ray analysis. The Cu(II) ions of the complexes 1- 7 are eta (4)(kappa (2) N, kappa (2) O) coordinated with a more or less distorted square planar geometry for 1- 6 and a distorted tetrahedral geometry for 7. Using pulsed Electron Nuclear Double Resonance on complex 6, detailed information about the relative orientation of the hyperfine ( A) and nuclear quadrupole tensors ( Q) of the coordinating nitrogens with respect to the g tensor were obtained. Electron Paramagnetic Resonance studies in the X, Q, and W-band at variable temperatures were carried out to extract g and A values of N ligands and Cu ion for 1- 7. The hyperfine values were interpreted in terms of spin population on the corresponding atoms. The obtained trends of the spin population for the monomeric building blocks were shown to correlate to the trends obtained in the dependence of the exchange interaction of the corresponding trinuclear complexes on their geometry.

(1R,2R,3R,4R,5S-2,3-Bis[(2S′-2-acetoxy-2-phenylacetoxy]-4-azido-1-[(2,4-dinitrophenylhydrazonomethyl]bicyclo[3.1.0]hexane

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Robert McDonald

2008-02-01

Full Text Available In the title compound, C38H29N7O12, the five-membered ring adopts an envelope conformation in which the `flap' is cis to the cyclopropane group. This conformation is similar to those of other bicyclo[3.1.0]hexane analogues for which crystal structures have been reported. The absolute configuration of the stereogenic centers on the cyclopentane ring, as determined by comparison with the known configurations of the stereogenic centers in the (2S-2-acetoxy-2-phenylacetoxy groups, is 1(R, 2(R, 3(R, 4(R and 5(S. An intramolecular N—H...O hydrogen bond is present.

Data from one test "Semi-Volatile Organic Compound Small Chamber for bis (2-Ethylhexyl) phthalate in Vinyl Flooring Test 2"

Science.gov (United States)

This data was generated from a small chamber bis(2-ethylhexyl) phthalate (DEHP) emission test. It was to participate an interaboratory study of DEHP emissions from vinyl flooring in a SVOC emission chamber organized by Virginia Polytechnic Institute and State University (VT).

Intramolecular Hydrogen Bonding and Conformational Preferences of Arzanol—An Antioxidant Acylphloroglucinol

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Liliana Mammino

2017-08-01

Full Text Available Arzanol is a naturally-occurring prenylated acylphloroglucinol isolated from Helichrysum italicum and exhibiting anti-oxidant, antibiotic and antiviral activities. The molecule contains an α-pyrone moiety attached to the phloroglucinol moiety through a methylene bridge. The presence of several hydrogen bond donor or acceptor sites makes intramolecular hydrogen bonding patterns the dominant stabilising factor. Conformers with all the possible different hydrogen bonding patterns were calculated at the HF/6-31G(d,p and DFT/B3LYP/6-31+G(d,p levels with fully relaxed geometry in vacuo and in three solvents—chloroform, acetonitrile and water (these levels being chosen to enable comparisons with previous studies on acylphloroglucinols. Calculations in solution were performed with the Polarisable Continuum Model. The results show that the lowest energy conformers have the highest number of stronger intramolecular hydrogen bonds. The influence of intramolecular hydrogen bonding patterns on the other molecular properties is also analysed.

Solid-State Examination of Conformationally Diverse Sulfonamide Receptors Based on Bis(2-anilinoethynyl)pyridine, -Bipyridine, and -Thiophene

Science.gov (United States)

Berryman, Orion B.; Johnson, Charles A.; Vonnegut, Chris L.; Fajardo, Kevin A.; Zakharov, Lev N.; Johnson, Darren W.; Haley, Michael M.

2015-01-01

Utilizing an induced-fit model and taking advantage of rotatable acetylenic C(sp)–C(sp2) bonds, we disclose the synthesis and solid-state structures of a series of conformationally diverse bis-sulfonamide arylethynyl receptors using either pyridine, 2,2′-bipyridine, or thiophene as the core aryl group. Whereas the bipyridine and thiophene structures do not appear to bind guests in the solid state, the pyridine receptors form 2 + 2 dimers with water molecules, two halides, or one of each, depending on the protonation state of the pyridine nitrogen atom. Isolation of a related bis-sulfonimide derivative demonstrates the importance of the sulfonamide N–H hydrogen bonds in dimer formation. The pyridine receptors form monomeric structures with larger guests such as BF4− or HSO4−, where the sulfonamide arms rotate to the side opposite the pyridine N atom. PMID:26405435

Briefwechsel uber die Partikel "bis" (An Exchange of Letters about the Particle "bis").

Science.gov (United States)

Ludwig, Horst; Holschuh, Albrecht

1990-01-01

A discussion, in the form of an animated letter exchange, argues that, contrary to most current grammatical descriptions, the German particle "bis" should not be viewed as a preposition governing the accusative case. Rather, it is demonstrated that "bis" most often occurs as a proclitic adverb. (16 references) (JTC)

Light induced intramolecular electron and energy transfer events in rigidly linked borondipyrromethene: Corrole Dyad