文摘
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).