1,3,6,8-Tetrasilylpyrenes and related germyl and stannyl derivatives were synthesized, and their absorption and fluorescence spectroscopic and structural properties were elucidated. The results show that the UV-vis absorption maxima of these substances in CH₂Cl₂ solutions shift to longer wavelengths as the size of the alkyl groups and numbers of phenyl groups on silicon increase. Fluorescence quantum yields of tetrasilylpyrenes in cyclohexane are larger than that of pyrene, and a pentamethyldisilyl derivative has an emission efficiency of 0.79. Except in the case of the SiMe₂H derivative, excimer emission was not observed in concentrated solutions of these substances. The SiMe₂H and SiMe₃ derivatives were shown to form CT complexes with tetracyanoethylene in CH₂Cl₂ solutions. The calculated energy barriers for rotation of the silyl groups about the Si–C bond increase as the steric bulk of the silyl group increases. ²⁹Si NMR chemical shifts were found to depend on the sizes of the alkyl groups and numbers of phenyl groups. Data arising from theoretical calculations suggest that the silyl groups act as electron-donating groups, and the donating ability of the groups decreases in the order SiR₃ > GeR₃ > SnR₃.

中文翻译：

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甲硅烷基中取代基对1,3,6,8-四甲硅烷基py的吸收，荧光和结构性质的影响

合成了1,3,6,8-四甲硅烷基吡啶及其相关的癸基和苯乙​​烯基衍生物，并阐明了它们的吸收，荧光光谱和结构性质。结果表明，随着硅上烷基的大小和苯基数目的增加，这些物质在CH ₂ Cl ₂溶液中的最大UV-vis吸收位移移至更长的波长。环己烷中四甲硅烷基py的荧光量子产率比pyr大，五甲基二甲硅烷基衍生物的发射效率为0.79。除了SiMe ₂ H衍生物以外，在这些物质的浓溶液中均未观察到准分子发射。SiMe ₂ H和SiMe ₃该衍生物在CH ₂ Cl ₂溶液中与四氰基乙烯形成CT络合物。随着甲硅烷基的空间体积的增加，计算得出的甲硅烷基绕Si–C键旋转的能垒也随之增加。发现²⁹ Si NMR化学位移取决于烷基的大小和苯基的数目。从理论计算中得到的数据表明，甲硅烷基基团充当给电子基团，并且基团的供电能力以SiR ₃ > GeR ₃ > SnR ₃的顺序降低。