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Christopher S. Frampton David D. MacNicol Derek R. Wilson 《Acta Crystallographica. Section C, Structural Chemistry》2011,67(5):o188-o191
The title compounds, C18H21NO and C18H21NS, in their enantiomerically pure forms are isostructural with the enantiomerically pure 4‐(4‐hydroxyphenyl)‐2,2,4‐trimethylchroman and 4‐(2,4‐dihydroxyphenyl)‐2,2,4‐trimethylchroman analogues and form extended linear chains via N—H...O or N—H...S hydrogen bonding along the [100] direction. The absolute configuration for both compounds was determined by anomalous dispersion methods with reference to both the Flack parameter and, for the light‐atom compound, Bayesian statistics on Bijvoet differences. 相似文献
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Nalivela Venu Peddy Vishweshwar Thaimattam Ram Devarakonda Surya Bhattacharya Apurba 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(5):o306-o308
The title compound, C8H17NO2, exists as a zwitterion, adopting a propeller conformation. Molecules self‐assemble to form a hydrogen‐bonded layer parallel to the ab crystallographic plane connected by N+—H...O− and C—H...O− hydrogen bonds. These layers are stacked along the c axis and are stabilized by van der Waals interactions. 相似文献
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Nadia M. Comerlato William T. A. Harrison R. Alan Howie John Nicolson Low Alexandre C. Silvino James L. Wardell Solange M. S. V. Wardell 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(2):m105-m108
The title compounds are salts of the general form (Q+)2[Zn(dmit)2]2?, where dmit corresponds to the ligand (C3S5)? present in both and Q+ to the counter‐cations (nBu4N)+ [or C16H36N+] and (Ph4As)+ [or C24H20As+], respectively. In the first case, Zn is in the 4e special positions of space group C2/c and hence the [Zn(dmit)2]2? dianion possesses twofold axial crystallographic symmetry. Including these, there are now 11 known examples of [Zn(dmit)2]2? or its analogues, with O replacing the exocyclic thione S, and [Zn(dmio)2]2? dianions in nine structures with various Q. Comparison of these reveals a remarkable variation in details of the conformation which the dianion may adopt in terms of Zn coordination, equivalence of the Zn—S bond lengths, displacement of Zn from the plane of the ligand and overall dianion shape. 相似文献
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Ashokkumar Subashini Kandasamy Ramamurthi Helen Stoeckli‐Evans 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(10):o408-o412
The 4‐chloro‐ [C14H11ClN2O2, (I)], 4‐bromo‐ [C14H10BrN2O2, (II)] and 4‐diethylamino‐ [C18H21N3O2, (III)] derivatives of benzylidene‐4‐hydroxybenzohydrazide, all crystallize in the same space group (P21/c), (I) and (II) also being isomorphous. In all three compounds, the conformation about the C=N bond is E. The molecules of (I) and (II) are relatively planar, with dihedral angles between the two benzene rings of 5.75 (12) and 9.81 (17)°, respectively. In (III), however, the same angle is 77.27 (9)°. In the crystal structures of (I) and (II), two‐dimensional slab‐like networks extending in the a and c directions are formed via N—H...O and O—H...O hydrogen bonds. The molecules stack head‐to‐tail viaπ–π interactions involving the aromatic rings [centroid–centroid distance = 3.7622 (14) Å in (I) and 3.8021 (19) Å in (II)]. In (III), undulating two‐dimensional networks extending in the b and c directions are formed via N—H...O and O—H...O hydrogen bonds. The molecules stack head‐to‐head viaπ–π interactions involving inversion‐related benzene rings [centroid–centroid distances = 3.6977 (12) and 3.8368 (11) Å]. 相似文献
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Alberto Insuasty Braulio Insuasty Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(1):74-76
The molecules of the title compound, C17H21N3OS, are characterized by a wide C—C—C angle at the methine C atom linking the aryl and thiazolidine rings, associated with a short repulsive intramolecular S...H contact between atoms in these two rings. A single piperidine–arene C—H...π hydrogen bond links pairs of molecules into centrosymmetric dimers. 相似文献
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Stereospecific synthesis of a family of novel (E)‐2‐aryl‐1‐silylalka‐1,4‐dienes or (E)‐4‐aryl‐5‐silylpenta‐1,2,4‐trienes via a cross‐coupling of (Z)‐silyl(stannyl)ethenes with allyl halides or propargyl bromide is described. In the reaction with allyl bromide, either a Pd(dba)2? CuI combination (dba, dibenzylideneacetone) in DMF or copper(I) iodide in DMSO–THF readily catalyzes or mediates the coupling reaction of (Z)‐silyl(stannyl)ethenes at room temperature, producing novel vinylsilanes bearing an allyl group β to silicon with cis ‐disposition in good yields. Allyl chlorides as halides can be used in the CuI‐mediated reaction. CuI alone much more effectively mediates the cross‐coupling reaction with propargyl bromide in DMSO–THF at room temperature compared with a Pd(dba)2? CuI combination catalysis in DMF, providing novel stereodefined vinylsilanes bearing an allenyl group β to silicon with cis ‐disposition in good yields. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
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《Electroanalysis》2006,18(4):417-422
In dimethylformamide containing tetramethylammonium tetrafluoroborate, cyclic voltammograms for reduction of 4,4′‐(2,2,2‐trichloroethane‐1,1‐diyl)bis(chlorobenzene) (DDT) at a glassy carbon cathode exhibit five waves, whereas three waves are observed for the reduction of 4,4′‐(2,2‐dichloroethane‐1,1‐diyl)bis(chlorobenzene) (DDD). Bulk electrolyses of DDT and DDD afford 4,4′‐(ethene‐1,1‐diyl)bis(chlorobenzene) (DDNU) as principal product (67–94%), together with 4,4′‐(2‐chloroethene‐1,1‐diyl)bis(chlorobenzene) (DDMU), 1‐chloro‐4‐styrylbenzene, and traces of both 1,1‐diphenylethane and 4,4′‐(ethane‐1,1‐diyl)bis(chlorobenzene) (DDO). For electrolyses of DDT and DDD, the coulometric n values are essentially 4 and 2, respectively. When DDT is reduced in the presence of a large excess of D2O, the resulting DDNU and DDMU are almost fully deuterated, indicating that reductive cleavage of the carbon–chlorine bonds of DDT is a two‐electron process that involves carbanion intermediates. A mechanistic scheme is proposed to account for the formation of the various products. 相似文献
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Inside Cover: New Chiral Reagent for Installation of Pharmacophoric (S)‐ or (R)‐2‐(Alkoxyphosphono)‐1‐amino‐2,2‐difluoroethyl Groups (Chem. Eur. J. 21/2016)
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Chen Xie Lijun Zhang Dr. Haibo Mei Dr. Romana Pajkert Dr. Maksym Ponomarenko Dr. Yi Pan Prof. Dr. Gerd‐Volker Röschenthaler Prof. Dr. Vadim A. Soloshonok Dr. Jianlin Han 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(21):6990-6990
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Pseudohalide‐directed Assembly of Two Zinc(II) Coordination Polymers with a 3,4‐Bis(3‐pyridyl)‐5‐(4‐pyridyl)‐1,2,4‐triazole Tecton
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The zinc(II) pseudohalide complexes {[Zn(L334)(SCN)2(H2O)](H2O)2}n ( 1 ) and [Zn(L334)(dca)2]n ( 2 ) were synthesized and characterized using the ligand 3,4‐bis(3‐pyridyl)‐5‐(4‐pyridyl)‐1,2,4‐triazole (L334) and ZnCl2 in presence of thiocyanate (SCN–) and dicynamide [dca, N(CN)2–] respectively. Single‐crystal X‐ray structural analysis revealed that the central ZnII atoms in both complexes have similar octahedral arrangement. Compound 1 has a 2D sheet structure bridged by bidentate L334 and double μN,S‐thiocyanate anions, whereas complex 2 , incorporating with two monodentate dicynamide anions, displays a two‐dimensional coordination framework bridged by tetradentate L334 ligand. Structural analysis demonstrated that the influence of pseudohalide anions plays an important role in determining the resultant structure. Both complexes were characterized by IR spectroscopy, microanalysis, and powder X‐ray diffraction techniques. In addition, the solid fluorescence and thermal stability properties of both complexes were investigated. 相似文献
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Reaction of (rac)‐3,3′‐bis(methoxymethyl)‐BINOL [H2(CH3OCH2)2BINO] with excess Ti(OiPr)4 and one equivalent of H2O in CH2Cl2 affords a trinuclear titanium(IV) complex [{(CH3OCH2)2BINO}Ti3(μ3‐O)(OiPr)6(μ2‐OiPr)2]. By dissolving it in dichloromethane and hexane and cooling to 0 °C, plate‐like pale yellow single crystals (monoclinic, P21/n, a = 12.605(3), b = 21.994(5), c = 19.090(4) Å, β = 92.764(8)°, V = 5286.2(19) Å3, T = 293(2) K) were obtained. Each oxygen atom at 2 or 2′ position of the (CH3OCH2)2BINO ligand bonds to only one titanium atom. There is no interaction between the third Ti atom and the two oxygen atoms of 3,3′‐bis(methoxymethyl)‐BINOLate. 相似文献