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摘要
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Two triazine-based dendrimers were successfully prepared in 60−75% yields. These newly prepared dendrimers 2a and 2b containing the −NMe(CH2)2NMe− and the −NMe(CH2)4NMe− linkers between two G3 dendrons, respectively, exhibit columnar phases during the thermal process. However, the corresponding dendrimers 1a and 1b containing the −NH(CH2)2NH− and the −NH(CH2)4NH− linkers between two G3 dendrons, respectively, do not show any LC phases on thermal treatment. Computational investigations on molecular conformations reveal that N-methylation of the dendritic central linker leads dendrimers to possess more isomeric conformations and thus successfully converts non-LC dendrimers (1a and 1b) into LC dendrimers (2a and 2b). |