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131.
I. I. Chuev S. M. Aldoshin E. G. Atovmyan D. B. Frolov A. N. Utenyshev 《Russian Chemical Bulletin》1996,45(4):851-855
N-Thenylidene- andN-(o-nitrobenzylidene)hydrazides of isonicotinic acid have been studied by X-ray structural analysis and IR spectroscopy. In the crystalline state, these molecules are linked through intermolecular N—H ... Npy hydrogen bonds. Carbonyl groups are not involved in intermolecular hydrogen bonds. However, it was found that the C=O group participates in an attractive interaction with the sulfur atom of the thiophene group. The energy of this interaction is comparable with the energies of intermolecular C=O ... H—N hydrogen bonds in amides.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 896–900, April, 1996. 相似文献
132.
S. V. Fedorov A. Yu. Rulev N. N. Chipanina A. M. Shulunova V. G. Nenajdenko E. S. Balenkova D. A. Tyurin V. K. Turchaninov 《Russian Chemical Bulletin》2005,54(1):103-107
The molecular structures of β-amino-α-bromovinyl trifluoromethyl ketones was studied by UV, IR, 1H, 13C, and 15N NMR spectroscopy and using the density functional (B3LYP/6-31G(d,p) and PBE/QZ3P) and ab initio riMP2/cc-pVTZm quantum-chemical calculations. Factors affecting stabilization of the EZE-conformation of the molecules, which is atypical of analogous unsubstituted amino enones, are considered.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 102–106, January, 2005. 相似文献
133.
The X-ray crystal structures of a series of lithium quinolates – lithium 8-hydroxyquinolinate (Liq), lithium 2-methyl-8-hydroxyquinolinate (MeLiq), and 2-phenyl-8-hydroxquinolinate (PhLiq), are compared. The substitution at the 2-position of the 8-hydroxyquinoline ligand has significant impact on the aggregation of the lithium complex in the crystalline state. Liq and MeLiq molecules crystallize as hexamers, whereas PhLiq crystallizes as a tetramer. The possible influence of crystal-packing forces on the preferred cluster structure was probed using density functional theory calculations on a systematically varied set of Liq, MeLiq, and PhLiq clusters. For Liq and MeLiq, the observed structures match the most stable computed structures. In the PhLiq case, the observed tetrameric structure is computed to be less stable (+1.2 kcal/mol/monomer) than the lowest energy structure, a hexamer. In this case, solid-state effects probably outweigh small differences in cluster stability. 相似文献
134.
Synthesis and Structure of Silver(II) Tetrafluoroaurate(III) Ag[AuF4]2 Intensive green single crystals of Ag[AuF4]2 can be obtained by heating up micro crystalline Ag[AuF4]2 in autoclaves (p(F2) ~ 200 bar, T ~ 400°C, t ~ 14 d). It crystallizes monoclinic, space group P21/n ? C; (No. 14) with a = 522.3(1), b = 1101.3(3), c = 550.5(2) pm, β = 94.98(3), Z = 2 and is isotypic with Pd[AuF4]2. 相似文献
135.
Tetrafluoroaurates(III) of Lanthanoides M2F[AuF4]5 (M = Tb, Dy, Ho, Er) Tetrafluoroaurates(III) M2F[AuF4]5 with M = Tb, Dy, Ho, Er, all yellow, have been obtained. From single crystal data they crystallize triclinic, space group P1 -C1i (No. 2) with Tb: a = 1 194,34(7) pm, b = 798,46(6) pm, c = 902,02(7) pm, α = 89,033(7)°, β = 88,990(6)°, γ = 89,006(7)°; Dy: a = 1 191,66(9) pm, b = 796,33(8) pm, c = 899,65(9) pm, α = 88,956(8)°, β = 89,056(8)°, γ = 88,972(8)°; Ho: a = 1 189,06(10) pm, b = 795,46(6) pm, c = 896,81(7) pm, α = 88,912(8)°, β = 89,101(7)°, γ = 88,873(8)°; Er: a = 1 185,20(40), b = 793,98(14), c = 893,83(20), α = 88,751(23)°, β = 89,187(26)°, γ = 88,884(9)° 相似文献
136.
Ab initio molecular orbital calculations using both minimal and extended basis sets have been applied to two isoelectronic sets of molecules. One set corresponds to the 18 electron species H3NO, H3CO– and H3COH while the second set contains the 42 electron fluorinated molecules F3NO, F3CO– and F3COH. The geometries of these molecules have been optimized, using both the minimal STO-3G and the extended 4-31G basis sets. These comparative calculations reveal that the 4-31G basis produced structural parameters in much better agreement with experiment. The effect of includingd-orbitals in the basis set was also investigated. For the fluorinated oxides it has been found that the optimized 4-31G structures were only slightly altered by the addition ofd-orbitals. For H3NO, on the other hand, the inclusion ofd-orbitals considerably shortens the N-O bond distance. Both H3NO and CF3OH, which are unknown experimentally, are theoretically predicted to be capable of existence. The electronic structures of these molecules have also been examined using electronic partitioning according to the Mulliken scheme. 相似文献
137.
A new complex of europium(II) with ethylenediaminetetraacetic acid was obtained by electrochemical reduction. The compound is composed of polymeric chains, guanidinium cations and water molecules. The Eu2+ cation is eight‐coordinate (two nitrogen atoms and six carboxylate oxygen atoms), and contrary to europium(III) complexes with edta, does not contain water molecules in the first coordination sphere. Relationships between the coordination mode and IR as well as UV–Vis spectra are discussed. 相似文献
138.
139.
The transmission electron microscope (TEM) visualization of the supermolecular structure of cold-drawn, oriented nylon 6 bulk material (bristles) by stained ultra-thin sections is reported. For evaluating the electron micrographs optical diffraction (OD) has been applied in comparison with small angle X-ray scattering (SAXS). The deformation of the spherulites was followed by polarization microscopy. In addition, investigations were carried out on commercial nylon 6 fibres. As the main result a transverse structure was revealed within the drawn samples at draw ratios between =4 and 4.5, consisting of mosaic crystals which show some lateral alignment. The structure is described by a modified layer lattice model. While the long period may increase slightly during drawing, the crystallite thickness remains almost constant. Fibres with =3.4 show a similarly oriented structure though the lateral alignment of the crystals is not so pronounced. 相似文献
140.
The reactions of [RuHCl(CO)(PPh3)3] and [(C6H6)RuCl2]2 with 2-benzoylpyridine have been examined, and two novel ruthenium(II) complexes – [RuCl(CO)(PPh3)2(C5H4NCOO)] and [RuCl2(C12H9NO)2] – have been obtained. The compounds have been studied by IR and UV–Vis spectroscopy, and X-ray crystallography. The molecular orbital diagrams of the complexes have been calculated with the density functional theory (DFT) method. The spin-allowed singlet–singlet electronic transitions of the compounds have been calculated with the time-dependent DFT method, and the UV–Vis spectra of the compounds have been discussed on this basis. 相似文献