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141.
利用密度泛函的B3LYP方法, 在6-311G*基组水平对吡啶酮系偶氮类化合物进行构型优化, 并进行了自然键轨道(NBO)分析, 然后用TDDFT方法和ZINDO/S方法分别计算了它们的可见吸收光谱, 结果均与实验值十分吻合. 通过对比发现, 对于最高吸收波长的计算, ZINDO/S能以较快的速度得到较好的结果. 在用ZINDO/S计算的过程中, 回归分析发现π-π重叠加权因子(OWFπ-π)与染料分子吡啶环上两个羰基氧原子平均电荷ZO有较好的线性关系: OWFπ-π=0.11425-1.04178ZO, 这一关系不仅可从量子化学的角度进行解释, 而且可用于同类染料可见吸收光谱的预测. 分子轨道的研究表明, 这些化合物的最高可见吸收波长主要对应着共轭体系中给电子体到受电子体的电子跃迁. 相似文献
142.
143.
A practical method has been devised for the synthesis of previously unknown push-pull azochromophores with 5-nitropyridin-2-yl
acceptor moiety from 2-amino-5-nitro-1-oxypyridine.
__________
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 35–41, January, 2007. 相似文献
144.
145.
Chinnusamy Saravanan Sengodan Senthil Palaninathan Kannan 《Journal of polymer science. Part A, Polymer chemistry》2008,46(23):7843-7860
Copolymer containing new thermally reversible click chemistry‐assisted triazole‐substituted azobenzene and fulgimide units in the pendant F‐co‐A was prepared by free‐radical solution addition polymerization technique. The F and A were also prepared for comparison. The DSC analysis of F indicates that the polymer possessing the C‐form of fulgimide unit exhibited higher Tm than that of E‐form of the same polymer and revealed that the C‐form of fulgimide unit in F is highly ordered. The cis‐trans back isomerization behavior of the click chemistry‐assisted triazole‐substituted azobenzene unit in film A has thermal irreversibility, while in F‐co‐A it exhibited thermal reversibility. The UV‐exposed film of F‐co‐A heated around Tg leads to cis‐trans back isomerization of azobenzene unit and thermally stable C‐form of fulgimide which retains its conjugated structure where both the photochromic units are converted into planar conformations and exhibit high fluorescence properties. The fluorescence maxima of C‐form in F‐co‐A red shifted compared with F , because the substituted triazole ring in the azobenzene unit stabilized the C‐form of fulgimide unit. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7843–7860, 2008 相似文献
146.
M. Eghbali 《代数通讯》2017,45(3):1134-1140
Some relations between cohomological dimensions and depths of linked ideals are investigated and discussed by various examples. 相似文献
147.
A complexing process is developed to prepare Y-Ba-Cu-O superconducting fibers. The process is not identical to typical sol-gel processes; here the resulting gel network is built up by hydrogen bonding linkage among complexing species in non-aqueous solution. Cu acetate, [Cu(OAC)2], Ba methoxyethoxide [Ba(ORE)2] and Y acetate [Y(OAC)3] are used as precursors for preparing homogeneous gels while -methacrylic acid (HOAA) and diethylenetriamine (DETA) as complexing agents, and methoxyethanol (REOH) as solvent. Fibers drawn from a sol obtained through reduced pressure present no or little deformation at 80°MoC via adjusting the amount of DETA and HOAA. Cu(OAC)2, Ba(ORE)2 and Y(OAC)3 in the complexing process have been demonstrated to form gels without hydrolysis and condensation at ambient atmosphere. The relationships between the drawing behavior of sols and gel structure with different amounts of DETA and HOAA are suggested. The concentration region of drawing the gel fibers with no or little deformation heated at 80°MoC is also found. 相似文献
148.
149.
The absorption,transmission and reflection spectra of spin-coated films of Ni(azo)2 (azo nickel chelate) were measured. Because of the intermolecular aggregation,the absorption peak of Ni(azo)2 thin film has a red-shift of about 40 nm with respect to that of it in methanol solution. The fabricated optical disk showed a reflectivity of 48% and its carrier-noise ratio (CNR) was greater than 45 dB when recording with 7.5 mW laser power at the wavelength of 780 nm. 相似文献
150.
N. I. Baram Kh. L. Ziyaev A. I. Ismailov D. Ziyamov Yu. S. Mangutova 《Chemistry of Natural Compounds》2000,36(2):185-188
New azo derivatives of gossypol are described. Their physicochemical properties are reported. The presence of hydroxyazo- and quinonhydrazo-tautomers is proposed.A. S. Sadykov Institute of Bioorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (99871) 162 70 71. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 145–148, March–April, 2000. 相似文献