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21.
合成了3种化合物 [2-ClPyH]2CoCl4(1), [2-ClPyH]2NiCl4(2)和[2-ClPyH]2CuCl4(3), 单晶X射线衍射法晶体结构测定结果表明, 这3种化合物是同形加合物, 在它们的结构中, [2-ClPyH]+离子呈平面状, 而[MCl4]2-离子为变形的四面体. 晶体结构分析发现晶体中存在N—H…Cl和C—H…Cl氢键, 以及Cl…Cl分子间相互作用和π-π堆积作用. 对自由状态下独立的配位离子进行的几何构型优化, 以及三维周期性条件下几何结构优化的量子化学计算结果表明, 标题化合物中具有方向性和选择性的氢键决定延伸性结构的方向, 而相对较弱的卤素…卤素作用在最终晶体结构的确定中扮演很重要的角色. 相似文献
22.
Uma Maheswara Rao Kunda 《Phosphorus, sulfur, and silicon and the related elements》2017,192(3):276-282
The dimeric assembly of 5,11,17,23-tetrabromo-25,26,27,28-tetrahydroxy thiacalix[4]arene (2) was constructed with several interesting noncovalent interactions such as halogen bonding, sulfur···sulfur (S···S), C=O···π, and hydrogen bonding which were also supported by DFT calculations. In addition, we studied the conformational preferences of 2 using variable temperature NMR experiments. The results revealed that the compound exists in various conformations in a solution state and in a partial cone conformation in a solid state. 相似文献
23.
U.Deva Priyakumar 《Tetrahedron》2004,60(13):3037-3043
Density functional theory (B3LYP) calculations with double and triple-ζ quality basis sets were performed on the Li+ and Na+ π-complexes of corannulene 2, sumanene 3CH2, heterosumanenes 3X, triphenylene 4 and heterotrindenes 5X. The metal ions bind to both convex and concave faces of buckybowls, with a consistent preference to bind to the convex surface by about 1-4 kcal/mol. The metal ion complexation with the π-framework of the central six-membered ring span wider range compared to benzene, indicating the control of size, curvature and electronic perturbations over the strength of cation-π interactions. Computations show that the bowl-to-bowl inversion barriers are only slightly altered upon metal complexation, indicating the continuity of bowl-to-bowl inversion despite metal complexation. We have calculated the binding energies of model systems, triphenylene (4) and heterotrindenes (5X), which indicate that the interaction energies are controlled by electronic factors. While the inversion barrier is dependent mainly on the size of the heteroatom, the extent of binding is independent of the size of the atom or the bowl depth. 相似文献
24.
This article presents a full account of intramolecular vinylic substitution reactions of bromoalkenes having an acetylthio moiety, which give sulfur-containing heterocycles such as dihydrothiophene, tetrahydrothiopyran, and 2-alkylidenethietane derivatives. The reaction pathways of the substitution reactions were investigated by theoretical and experimental studies. 相似文献
25.
Three new lacunar-type derivatives of β-unsubstituted dibenzotetraaza[14]annulene have been synthesized along with a range of their open-chain pendant group containing counterparts. The crystal structures of two representative products have been determined and the noncovalent interactions explored. A number of C-H?π and π?π interactions involving aliphatic chains and aromatic regions of the macrocycle have been evidenced. The relative ease and high yield of lacunization are suggested to be largely due to self-assembly processes, driven by favorable noncovalent interactions between reacting units. 相似文献
26.
Myung-Seok Choi 《Tetrahedron letters》2008,49(49):7050-7053
A series of new porphyrin derivatives possessing the side arms of alkyl-substituted thiophene oligomer were synthesized. The effects of solvent polarity on the formation of supramolecular assembly have been studied by UV-vis absorption, fluorescence emission, and TEM measurement. The linear-shape porphyrin derivatives bearing two thiophene pentamers at meso-position showed the significant spectral changes in both blue-shift and band broadening of Soret bands which indicate the formation of a relatively larger porphyrin H-aggregate that occurred in nonpolar solvent such as n-hexane. 相似文献
27.
Two new hybrid compounds, [Cu(1)(phen)(H2O)][Cu(2)(phen)(H2O)]([Cu(3)]0.25(H2O)][P2Mo5O23]·3.75H2O (1) and [Cu(en)2]1.5[P2Mo5O23]2·(enH2)3·2H2O (2) (phen = 1,10-phenanthroline, en = ethylenediamine), have been hydrothermally synthesized and characterized by IR, UV–Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), powder XRD analyses, TG analyses, cyclic voltammogram analyses, elemental analyses, and single crystal X-ray diffraction analyses. Single crystal X-ray diffraction analyses reveal that the two compounds have a 1-D chain structure formed by Strandberg-type POMs and TMCs with –A–B–C–B–A–B–C–B– linking mode, then further extend into a 2-D layer structure through π?π or hydrogen bond interactions. 相似文献
28.
The equilibrium constants [K=anti/syn] of a pair of atropisomers due to restricted rotation about Csp3-Csp2 bond for [2-(2-hydroxynaphthalen-1-yl)-3,3-dimethylindolin-1-yl](4-substituted phenyl)methanone were determined in some solvents. The presence of the effective π-π interaction was demonstrated by the correlation between the equilibrium constants (K) and the substituent effect of the phenyl groups (σp), suggesting that the ‘neutral-type’ interaction is operative. 相似文献
29.
Satish Balasaheb Nimse Junghoon Kim Keum-Soo Song Chan-Yong Jung Sudhakara Reddy Seelam 《Tetrahedron letters》2010,51(21):2840-551
We report the new water-soluble aminocalix[4]arene hosts 1 and 2 with deep hydrophobic cavity facilitating hydrophobic mouth and hydrophilic mouth, respectively. The 1H NMR titrations revealed that host 1 shows high selectivity for neutral guests 9 and 10, with log K of 4.2 and 4.6, respectively. The host 2 shows log K of 4.9 for binding with guest 15. Moreover, the binding ability of the host 2 for guest 14 is stronger by a factor of 1000 than that of the host 1. 相似文献
30.
Hsi-Ya Huang Yi-Jie ChengWan-Ling Liu Yi-Fen HsuSzetsen Lee 《Journal of chromatography. A》2010,1217(37):5839-5847
In this study, a series of poly(divinylbenzene-alkyl methacrylate) monolithic stationary phases, which were prepared by single step in situ polymerization of divinylbenzene and various alkyl methacrylates (butyl-, octyl-, or lauryl-methacrylate), were developed as separation columns of benzophenone compounds for capillary electrochromatography (CEC). In addition to the presence of plenty of benzene moieties, the stationary phases contained long and flexible alkyl groups on the surface. With an increase in the molecular length of alkyl methacrylate, the polymeric monolith, which had higher hydrophobicity, effectively reduced the peak tailing of benzophenones, but a weaker retention was observed. The unusual phenomenon was likely due to the π–π interaction between the aromatic compound and the polymeric material. The usage of longer alkyl methacrylate as reaction monomer limited the retention of aromatic compounds on the stationary phase surface, thus the π–π interaction between them was possibly reduced. Consequently, the retention time of aromatic compounds was markedly decreased with an increase in carbon length of alkyl methacrylate that was carried on the polymeric monolith. Compared to previous reports on polystyrene-based columns in which the peak-tailing problem was reduced by decreasing the benzene moieties on the stationary phase, this study demonstrated that the undesirable retention (peak-tailing) could also be improved by the inclusion of long alkyl methacrylate to the polystyrene-based columns. 相似文献