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991.
By the interaction of M(η5-C5H4R)2Cl2 (M = Zr, Hf; R = H, Me, SiMe3) and 8-hydroxyquinoline (oxH) or 5-chloro-8-hydroxyquinoline (ox′H) in dichloromethane solution at 20°C, the compounds M(η5-C5H4R)Clox2 and M(η5-C5H4R)Clox2′ were prepared respectively. A similar reaction of Ti(η5-C5H5)Cl3 with ox′H in acetonitrile solution gave Ti(η5-C5H5)Clox2′. All complexes were characterized by elemental microanalysis and by IR and 1H NMR spectroscopy. X-ray analysis of M(η5-C5H5R)Clox2′ (M = Ti, Hf) shows that these molecules may be described in terms of stereochemistry of eight-coordination approximating dodecahedral geometry more closely than octahedral geometry. With respect to octahedral coordination, the nitrogen atoms lie in a cis-configuration and the oxygen atoms in a trans-configuration. Dichloromethane molecules co-crystallize with the hafnium complex and occupy a position on the 2-fold axis. The structural results are compared with those in related compounds. 相似文献
992.
Yozo Kosaka Toshiyuki Uryu 《Journal of polymer science. Part A, Polymer chemistry》1995,33(13):2221-2232
Side-chain liquid-crystalline copolymers and polymer blends containing an electron-donating (carbazolylmethylene)aniline group and electron-accepting nitrophenyl groups with various central linking groups between aromatic groups in the mesogenic units, i.e., N?CH, CH?CH, N?N, and COO, were prepared to examine effects of the mesogenic structure on thermal behaviours. The most remarkable effects of the central linking group on the thermal properties and the miscibility were observed for the polymer blends. The 1:1 miscible polymer blends were prepared from the electron-donating polymer containing (carbazolylmethylene)aniline group (PM6Cz) and the electron-accepting polymers with similar central linking groups, i.e., N?CH, CH?CH, and N?N. For example, the 1: 1 polymer blend of PM6Cz and the electron-accepting polymer containing the nitrostilbene group induced a smectic phase from 73 to 207°C. This isotropic temperature was 46°C higher than the calculated value (161°C) based on the composition without the electron donor-acceptor interaction. On the other hand, the 1: 1 polymer blend of PM6Cz and the electron-accepting polymer containing the nitrophenylbenzoate group showed phase separation. Thus, the remarkable thermal stability and the miscibility of the polymer blends containing the electron donor and acceptor groups might be caused by planar structures between the mesogenic side groups which have similar central linking groups through the electron donor-acceptor interaction. A similar tendency was seen for copolymers and binary mixtures of both low-molecular-weight compounds containing the same mesogenic groups. © 1995 John Wiley & Sons, Inc. 相似文献
993.
SynthesisandStructureoftheHexanuclearDiazenido-oxomolybdate[(n-C_4H_9)_4N]_3[Mo_6O_(18)(N_2C_6H_4-p-NO_2)]LiHai-Lian;YouXiao-Zeng;... 相似文献
994.
SANS data have been obtained for C12H25 (OC2H4)2SO4 Na. Results have been obtained for i) a series of solutions of variable concentration of the surfactant, ii) an approximately 0.07 M surfactant concentration to which variable amounts of NaCl were added, iii) a series of solutions 0.058M in surfactant but in different D2O-H2O mixtures. The SANS data can be described in terms of a model of monodispersed hard spheres interacting via a screened Coulombic potential. The micelles seem to be able to tolerate substantial amounts of salt without changing the internal structure. 相似文献
995.
Graham A. Bowmaker Prof. Dr. Michael I. Bruce Brian W. Skelton Neil Somers Allan H. White 《无机化学与普通化学杂志》2007,633(7):1024-1030
The complexes [Cu2Br4]2?, [Cu2I4]2?, [Cu2I2Br2]2?, [Cu2I3Cl]2?, [Ag2Cl4]2? have been characterized as their isomorphous bis(triphenylphosphoranylidene)ammonium ([Ph3PNPPh3]+ = PNP+) salts by single crystal structural determinations. All anions show the centrosymmetric doubly halogen‐bridged forms [XM(μ‐X)2MX]2? with three‐coordinate metal atoms that have been observed in [M2X4]2? complexes with other large organic cations. In [Cu2I2Br2]2? the iodide ligands occupy the bridging positions and the bromide the terminal positions, while in [Cu2I3Cl]2?, obtained in an attempt to prepare [Cu2I2Cl2]2?, two of the iodide ligands occupy the bridging positions with the third iodide and the chloride ligand occupying two statistically disordered terminal positions. In [Ag2Cl4]2? the distortion from ideal trigonal coordination of the metal atom is greater than in the copper complexes, but less than in other previously reported [Ag2Cl4]2? complexes with organic cations. The ν(MX) bands have been assigned in the far‐IR spectra, and confirm previous observations regarding the unexpectedly simple IR spectra of [Cu2X4]2? complexes. 相似文献
996.
本文通过XRD、SEM、EDS研究了Ti0.4Zr0.1V1.1Mn0.5Cr0.1Nix(x=0,0.2,0.4,0.6,0.8)合金的相结构和电化学性能。该合金系由BCC结构的V基固溶体主相和六方结构的C14 Laves第二相组成,Ni能够促进第二相的生成,Ni含量的增加导致了各相中的化学组成和晶格参数的变化,并通过电化学方法研究了Ni含量对0.4Zr0.1V1.1Mn0.5Cr0.1合金电极的最大放电容量、自放电性能、高倍率放电性能、循环稳定性能等的影响。 相似文献
997.
998.
The structure, stability, and paths of formation of 11 (HF)m(DMF)n heterocomplexes (m = 1–4, n = 1, 2) were studied in terms of the B3LYP/6-31++G(d, p) density functional calculation. The results of this calculation suggest that: a) addition of hydrogen fluoride molecules to the (HF)mDMF cyclic fragment is the basic tendency in complex formation in the HF-DMF system; b) data about the structure and properties of stable molecular forms that prevail in N,N-dimethylformamide solutions of hydrogen fluoride can be obtained by quantum chemical calculations for (HF)mDMF complexes (m = 5–10). 相似文献
999.
不同软段结构聚氨酯-酰亚胺嵌段共聚物的合成及热性能研究 总被引:4,自引:2,他引:4
用二步法合成了不同软段 (PPO ,PEG ,PEPA)聚氨酯 酰亚胺 (PUI)嵌段共聚物 ,FTIR光谱表征了所有合成PUI分子主链均含有酰亚胺链段 ,并研究了PUI嵌段共聚物的热性能受软段类型及长度的影响 .DSC研究表明聚酯型PUI的软硬段之间的相容性比聚醚型PUI好 ,随相同软段分子量的增加 ,PUI体系的软硬段兼容性变差 ,并显示了相分离的特征 ;热失重 (TGA)研究得出不同软段的PUI样品的热稳定性大小顺序为 :PEPA PUI >PEG PUI>PPO PUI ;动态力学 (DMTA)研究给出了所合成的PUI样品在 5 0~ 2 0 0℃范围内均出现了较长的模量平台显示出有较好的耐热性 ,且随硬段含量的升高其储能模量不断增强 相似文献
1000.
氧气氛中紫外光辐照官能化HDPE的结构与性能研究 总被引:2,自引:0,他引:2
采用FT-IR,XPS,WAXD,DXC,凝胶和表面自由能力分析,研究了氧化氛中紫外辐照官能化高密度聚乙烯(HDPE)的化学结构、晶体结构和表面自由能的变化。与空气相比,在氧气氛中紫外辐照HDPE能提高C-O,C(=O)O和C=O等含氧基团的引入速度,同时又能降低HDPE中的凝胶含量,在空气和氧气氛中紫外辐照后,HDPE的晶型没有发生变化,仍为正交晶系;HDPE的晶胞参数a,b,c以及(110),(200),(020),(011),(111)等晶面间距基本保持不变;HDPE的熔融温度下降,但熔融热焓升高,结晶度增大,表面自由能增大,且在氧气氛中辐照HDPE的变化幅度较大。 相似文献