- NEW POLYMERIZABLE LIQUID CRYSTAL HAVING A CARBAZOLE CORE
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The invention relates to novel anisotropic compounds of formula (I) as well as to liquid crystalline mixtures, films and electro-optical devices comprising the compound.
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Page/Page column 12
(2021/01/23)
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- Groups 5 and 6 terminal hydrazido(2-) complexes: Nβ substituent effects on ligand-to-metal charge-transfer energies and oxidation states
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Brightly colored terminal hydrazido(2-) (dme)MCl3(NNR 2) (dme = 1,2-dimethoxyethane; M = Nb, Ta; R = alkyl, aryl) or (MeCN)WCl4(NNR2) complexes have been synthesized and characterized. Perturbing the electronic environment of the β (NR 2) nitrogen affects the energy of the lowest-energy charge-transfer (CT) transition in these complexes. For group 5 complexes, increasing the energy of the Nβ lone pair decreases the ligand-to-metal CT (LMCT) energy, except for electron-rich niobium dialkylhydrazides, which pyramidalize Nβ in order to reduce the overlap between the Nb=N α π bond and the Nβ lone pair. For W complexes, increasing the energy of Nβ eventually leads to reduction from formally [WVI≡N-NR2] with a hydrazido(2-) ligand to [WIV=N=NR2] with a neutral 1,1-diazene ligand. The photophysical properties of these complexes highlight the potential redox noninnocence of hydrazido ligands, which could lead to ligand- and/or metal-based redox chemistry in early transition metal derivatives.
- Tonks, Ian A.,Durrell, Alec C.,Gray, Harry B.,Bercaw, John E.
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supporting information; experimental part
p. 7301 - 7304
(2012/06/16)
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- PS-SNAP, a practical polymer-supported nitrosation reagent in organic synthesis
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PS-SNAP was designed and evaluated as a practical nitrosating polymer-supported reagent for the nitrosation of sec-amines. Nitrosated dialkyl amines, alkyl anilines, and bis-anilines were obtained in good yields and high purities after shaking the corresponding amines in the presence of an excess of the newly described reagent followed by simple filtration and removal of solvents.
- Roche, Didier,Lardy, Claude,Tournier, Lucie,Prunier, Marc,Valeur, Eric
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experimental part
p. 2277 - 2280
(2010/05/19)
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- Carbazolyl nitrenium ion: Electron configuration and antiaromaticity assessed by laser flash photolysis, trapping rate constants, product analysis, and computational studies
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(Graph Presented) Laser flash photolysis of 1-(carbazol-9-yl)-2,4,6- trimethylpyridinium tetrafluoroborate generates the carbazolyl nitrenium ion (τ = 333 ns, kobs = 3.0 × 106 M -1S-1) having absorption bands at 570 and 620 nm in CH3CN. The nitrenium ion is found to have reactivity comparable to structurally similar closed-shell diarylnitrenium ions, but spectroscopic evidence favors an open-shell singlet diradical assignment for the observed nitrenium ion. The carbazolyl nitrenium ion is also more reactive than diarylnitrenium ions as a likely result of antiaromatic character. Ab initio and hybrid DFT calculations were performed to address the degree of antiaromaticity in this and similar nitrenium ions through analysis of optimized geometries, nucleus independent chemical shifts, and isodesmic reactions.
- Winter, Arthur H.,Gibson, Harry H.,Falvey, Daniel E.
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p. 8186 - 8195
(2008/02/13)
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- Novel nitrosation polymer in organic synthesis
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The present invention relates to a novel nitrosation polymer of the formula in which X, Y, R1, R2 and R3 are as defined in claim 1. The invention also relates to a process for the preparation of the said polymer.
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Page/Page column 7
(2008/06/13)
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- NO donors, combination products and uses as modulators of neurotransmitter release
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The present invention relates to compounds of the general formula (I) or (II): ???wherein:R1, R2, R3, R4, R5 and R10 are, independently from one another, H or a moiety of the following general formula : -(R6)n-R7, with R6 is an alkyl chain and R7 is, a moiety selected in the group consisting of -Cn'H2n'+1, a cycloalkyl moiety, -N(Cn'H2n'+1)(Cn'H2n'+1), -NH-cycloalkyl, -O(Cn'H2n'+1), -O-cycloalkyl, =O, =S, -NO2, , -I, -Br, -Cl, -F, -CF3, -OCF3, -COOH, -SO3H, -PO3H2, -CN, A3, A4, A8 and A9 are C, N, O and S, m is 0 to 2, n is 0 to 6, and to their use for the treatment and/or prevention of diseases and conditions mediated by the imbalance of acetylcholine, and for treating and/or preventing glutamate excitotoxicity.
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Page/Page column 17
(2008/06/13)
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- Carbazolyl nitrenium cations: Generation and reactions
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Carbazolyl nitrenium cations were generated during the thermolysis and photolysis of 1-carbazol-9-yl-2,4,6-triphenylpyridinium (Py+-Cz) tetrafluoroborate in 2,2,2-trifluoroethanol- and TFA - mesitylene mixtures. The thermolysis of Py+-Cz in TFA-mesitylene mixture gave 9-mesitylcarbazole in good yield along with carbazole, non-symmetrical mesitylene dimer, 2,4,6-triphenylpyridine, and a small amount of 9-(3,5-dimethylbenzyl)carbazole, whereas the thermolysis in trifluoroethanol - mesitylene mixture gave 9-mesitylcarbazole as the main product along with carbazole and 2,4,6-triphenylpyridine. The product distributions lead to two major conclusions. First, photolysis and thermolysis of Py+-Cz salt produce nitrenium ions that can be in singlet or triplet state dependant on the reaction conditions. Second, the carbazolyl nitrenium ion exhibits singlet state in the ground state.
- Bogdal, Dariusz
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p. 2679 - 2688
(2007/10/03)
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- CMR Spectral Studies of Substituted Carbazoles
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CMR spectra of five substituted carbazoles have been recorded and analysed.In the case of dibromocarbazole (Ie) and 1-nitrocarbazole (Ic) higher substituent shifts are observed as compared to those in benzenoid compounds.
- Sharma, K. S.,Sarita
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p. 402 - 403
(2007/10/02)
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- Crystal and molecular structure of 9-(2,4,6-trinitroanilino)-carbazole, C18H11N5O6
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The crystal structure of 9-(2,4,6-trinitroanilino)-carbazole, C18H11N5O6, has been determined by X-ray diffraction.Crystals are monoclinic, space group P21/c, a = 14.686(11), b = 24.601(12), c = 10.047(5) Angstroem, β = 107.76(5) deg at 292 K, with Z = 8.The two nitrogen atoms in the central fragment have a staggered conformation with an N-N distance of 1.381(4) Angstroem, which is considerably shorter than N-N distances in related N-picrylhydrazine molecules.The picryl moiety has a geometry similar to that of related N-picrylhydrazine molecules.The title compound contains an N-H...O intramolecular bond to one of the ortho nitro gro ups on the picryl ring.The carbazole plane of one molecule and the picryl plane of a neighboring molecule overlap to form an infinite linear chain of the form ...DhA:DhA... where D represents the carbazole donor, h the linear chain linkage within the molecule, and A represents the picryl acceptor of one molecule.The two interplanar distances between D of one molecule and A of an adjacent molecule are 3.28(13) and 3.34(13) Angstroem, indicating a strong ?-molecular interaction.
- Wang, Hong,Barton, Richard J.,Robertson, Beverly E.,Weil, John A.,Brown, Keith C.
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p. 1322 - 1326
(2007/10/02)
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- A TRIFLUOROMETHANESULFONIC ACID-CATALYZED REACTION OF ARYLHYDRAZINES WITH BENZENE
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Arylhydrazines reacted with benzene in the presence of trifluoromethanesulfonic acid (TFSA) to give aminobiphenyls.This is a general method for the synthesis of aminobiphenyls.
- Ohta, Toshiharu,Miyake, Shinji,Shudo, Koichi
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p. 5811 - 5814
(2007/10/02)
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- N-NITROSAMINES via THE PHASE-TRANSFER MEDIATED NITROSATION OF SECONDARY AMINES WITH SODIUM NITRITE AND N-HALOAMIDES
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Secondary amines are cleanly and readily converted to the corresponding N-nitrosamines in high yields under phase-transfer conditions by means of sodium nitrite and N-haloamides; the active nitrosating agent is presumed to be dinitrogen tetroxide.
- Nakajima, Masayuki,Warner, John C.,Anselme, J.-P.
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p. 2619 - 2622
(2007/10/02)
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- Photocleavage of Diarylnitrosamines in Neutral Media
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N-Nitrosodiphenylamine, N-nitroso(2-nitrophenyl)phenylamine, N-nitroso(3-methylphenyl)phenylamine, and N-nitrosocarbazole were irradiated in degassed neutral solution to give the corresponding diarylamine as the initial photoproduct.The effects of changing solvents, concentrations, and substituents and of adding catalysts were examined.Quantum yield studies, sensitization work, and ESR studies were used to study the mechanism of this photolysis.
- Crumrine, David S.,Brodbeck, Charles M.,Dombrowski, Paul H.,Haberkamp, Thomas J.,Kekstas, Rita J.,et al.
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p. 4246 - 4249
(2007/10/02)
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