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对硝基二苯乙炔系列衍生物的二阶非线性光学性质的理论研究 总被引:6,自引:1,他引:5
在ZINDO方法基础上,按完全态求和(SOS)公式编制了计算分子二阶非线性光学系数βijk和βμ的程序,研究了对硝基二苯乙炔系列衍生物的结构和非线性光学性质,考察了分子共轭链长和给电子基团对βμ的影响.结果表明,对硝基二苯乙炔系列衍生物上连有推电子基团有利于增大二阶光学非线性,扩大共轭范围也有利于增大二阶光学非线性,但对透明性则影响不大. 相似文献
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新型双重电荷转移分子的二阶非线性光学性质的 理论研究 总被引:7,自引:0,他引:7
以INDO/SCI方法为基础,按完全态求和(SOS)公式编制了计算分子二阶非线性光学系数β~i~j~k和β~μ的程序。研究了1,2-二氨基-4,5-二硝基苯1和其异构体1,3-二氨基-4,6-二硝基苯2的电子光谱和二阶非线性光学性质。计算表明分子1具有与分子2几乎相等的二阶非线性极化率。但由于分子1的偶极矩明显大于分子2的,故分子1的μβ值比分子2的μβ值大的多。在此基础上,研究了2,3-二(β-苯乙烯基)-5,6-二氰基吡嗪和2,3-二(β-噻吩乙烯基)-5,6-二氰基吡嗪和2,3-二(β-噻吩乙烯基)-5,6二氰基吡嗪衍生物的电子光谱和二阶非线性光学性质。结果表明,这些化合物均具有两个相距很近的强吸收峰,它们对β值的呈加和模式。由于这类化合物特征吸收峰均位于413nm以下且具有大的μβ值,所以,它们是一类很有前途的二阶非线性光学候选材料。 相似文献
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两种C~6~0双炔衍生物的结构、光谱和二阶非线性光学性质的 理论研究 总被引:1,自引:0,他引:1
用INDO/2和INDO/SCI方法,计算了C~6~0C(C=CH)~2基态电子结构和电子光谱,所得结果与实验结果基本一致.在此基础上,设计了C60(C=CH)~2,并用同样方法计算了电子结构和光谱.在正确的电子光谱基础上,用ZINDO-SOS方法计算了2个分子的二阶非线性光学系数β~i~j~k和β~μ,并对其结果进行了分析和讨论.结论是,乙炔基与C~6~0(C=CH)~2有更大的非线性光学系数,是有希望的非线性光学备选材料分子。 相似文献
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本文采用引入外场微扰的CNDO/S—CI方法,计算了一系列苯衍生物的分子二阶非线性光学系数,探讨了取代基的电子性质、取代位置及取代基数目对分子二阶非线性光学系数的影响.结果表明;取代基的供电能力越强,分子的二阶非线性光学系数越大.D,A对位二取代苯和1—D,2.4—A,A三取代苯具有较高的非线性光学效应,苯衍生物中取代基数目为3时分子具有最佳的非线性光学效应.文中还对上述结论给出了初步的理论解释. 相似文献
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On the basis of ZINDO methods, according to the sum-overstates (SOS) expression, the program for the calculation of the second-order nonlinear optical susceptibilities βijk and βμ of molecules was devised, and the structures and nonlinear optical properties of unsymmetric bis (phenylethynyl) benzene series derivatives were studied. The influence of the molecular conjugated chain lengths, the donor and the acceptor on βμ was examined. 相似文献
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《Liquid crystals》2008,35(2):119-132
Despite the prevalence of organised 1,4-bis(phenylethynyl)benzene derivatives in molecular electronics, the interest in the photophysics of these systems and the common occurrence of phenylethynyl moeties in molecules that exhibit liquid crystalline phases, the phase behaviour of simple alkoxy-substituted 1,4-bis(phenylethynyl)benzene derivatives has not yet been described. Two series of 1,4-bis(phenylethynyl)benzene derivatives, i.e. 1-[(4'-alkoxy)phenylethynyl]-4-(phenylethynyl)benzenes (5a-5f) and methyl 4-[(4'-alkoxy)phenylethynyl-4'-(phenylethynyl)] benzoates (18a-18f) [alkoxy = n-C4H9 (a), n-C6H13 (b), n-C9H19 (c), n-C12H25 (d), n-C14H29 (e), n-C16H33 (f)] have been prepared and characterised. Both series have good chemical stability at temperatures up to 210°C, the derivatives featuring the methyl ester head-group (18a-18f) offering rather higher melting points and generally stabilising a more diverse range of mesophases at higher temperatures than those found for the simpler compounds (5a-5f). Smectic phases are stabilised by the longer alkoxy substituents, whereas for short and intermediate chain lengths of the simpler system (5a-5c) nematic phases dominate. Diffraction analysis was used to identify the SmBhex phase in (5d-5f) that is stable within a temperature range of approximately 120-140°C. The relationships between the organisation of molecules within these moderate temperature liquid crystalline phases and other self-organised states (e.g. Langmuir-Blodgett films) remain to be explored. 相似文献
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Nine new bisdonor/bisacceptor-functionalized tetrakis(phenylethynyl)benzene (TPEB) and six new bis(dehydrobenzoannuleno)benzene (DBA) chromophores have been synthesized. The compounds consist of electron-donating dibutylaniline groups connected through a conjugated phenyl-acetylene scaffold to benzotrifluoride, bis(trifluoromethyl)phenyl, or pentafluorophenyl acceptor groups. In comparison to previously reported analogues utilizing nitrophenyl or benzonitrile acceptor groups, the weaker acceptor groups exhibit visibly fluorescent intramolecular charge transfer (ICT) behavior, moderately narrow optical band gaps, moderately high quantum yields, and strong fluorescence solvatochromism. In this series of molecules, the strongly inductive fluoro acceptor groups result in optical properties similar to the resonance acceptor analogues, making them promising candidates for optical materials device components. The data also support recent investigations that question the utility of using UV/vis spectroscopy alone as a qualitative measure of conjugation. The bisDBAs exhibit weaker ICT behavior and self-association in solution than their corresponding nitro analogues, but show greater stability to decomposition via polymerization and smaller optical band gaps than their acyclic analogues. 相似文献
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Donocadh P. Lydon David Albesa‐Jové Gemma C. Shearman Judith A. K. Howard Todd B. Marder 《Liquid crystals》2013,40(2):119-132
Despite the prevalence of organised 1,4‐bis(phenylethynyl)benzene derivatives in molecular electronics, the interest in the photophysics of these systems and the common occurrence of phenylethynyl moeties in molecules that exhibit liquid crystalline phases, the phase behaviour of simple alkoxy‐substituted 1,4‐bis(phenylethynyl)benzene derivatives has not yet been described. Two series of 1,4‐bis(phenylethynyl)benzene derivatives, i.e. 1‐[(4′‐alkoxy)phenylethynyl]‐4‐(phenylethynyl)benzenes (5a–5f) and methyl 4‐[(4″‐alkoxy)phenylethynyl‐4′‐(phenylethynyl)] benzoates (18a–18f) [alkoxy = n‐C4H9 (a), n‐C6H13 (b), n‐C9H19 (c), n‐C12H25 (d), n‐C14H29 (e), n‐C16H33 (f)] have been prepared and characterised. Both series have good chemical stability at temperatures up to 210°C, the derivatives featuring the methyl ester head‐group (18a–18f) offering rather higher melting points and generally stabilising a more diverse range of mesophases at higher temperatures than those found for the simpler compounds (5a–5f). Smectic phases are stabilised by the longer alkoxy substituents, whereas for short and intermediate chain lengths of the simpler system (5a–5c) nematic phases dominate. Diffraction analysis was used to identify the SmBhex phase in (5d–5f) that is stable within a temperature range of approximately 120–140°C. The relationships between the organisation of molecules within these moderate temperature liquid crystalline phases and other self‐organised states (e.g. Langmuir‐Blodgett films) remain to be explored. 相似文献
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Two series of 2,5-disubstituted thiophene derivatives (series 1: 2,5-bis(p-alkoxyphenylethynyl)thiophene and series 2: 2,5-bis[p-(p-alkoxyphenylethynyl)(phenylethynyl)]thiophene) were synthesized and characterized by ^1H NMR, ^13C NMR, HRMS and elemental analysis. The relationship between the structure and the mesogenic and spectroscopic properties has been discussed. The results show that compounds 1a-1f all exhibited an enantiotropic nematic mesophase, which was confirmed by the polarized optical microscopy (POM), differential scanning calorimeter (DSC) and variable temperature powder X-ray diffraction (PXRD). In contrast, the extended conjugated analogues 2a-2b had no liquid crystal properties. As for the spectroscopic properties, incorporating more phenylethynyl units results in red-shifted absorption and emission spectra, greatly enhanced quantum efficiency. 相似文献