TADDOLs with unprecedented helical twisting power in liquid crystals - Preliminary communication
TADDOLs with unprecedented helical twisting power in liquid crystals - Preliminary communication
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DOI：
10.1002/hlca.19970800818
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发表时间：
1997-01-01
影响因子：
1.8
通讯作者：
Seebach, D
中科院分区：
文献类型：
--
作者：
Kuball, HG;Weiss, B;Seebach, D
A large number of TADDOL (alpha,alpha,alpha,alpha'-tetraaryl-1,3-dioxolan-4,5-dimethanol) derivatives has been tested as chiral dopants for inducing conversion of nematic to cholesteric phases. With the Merck liquid-crystal materials ZL1-1695 and K15, it was demonstrated that some TADDOLs have unprecedentedly high helical twisting powers (HTP). Thus, the TADDOL with four 9-phenanthryl alpha-substituents has a HTP in the achiral mesophase 4-(4-pentylphenyl)benzonitrile of 405 mu m(-1) between 24 and 34 degrees. The temperature-dependent HTP measurements have been performed by analyzing Grandjean textures microscopically (Cane method). The structure-dependent HTP of various types of TADDOL dopants is discussed. There are similarities between size and sign of HTP on the one hand, and between degree and relative topicity of enantioselectivity in reactions, on the other hand, as caused by TADDOLs and by 1,1'-binaphthols.
