The π–π interactions enhanced in salicylaldimines and salicylaldazines
作者:Hsiu-Ming Kuo、Yu-Te Hsu、Yi-Wen Wang、Gene-Hsiang Lee、Chung K. Lai
DOI:10.1016/j.tet.2015.07.049
日期:2015.10
Four new series of salicylaldazines 1 and salicylaldimines 2-4 were prepared, characterized and their mesomorphic properties were studied. The structures of all compounds were identified and confirmed by spectroscopic techniques such as H-1, C-13 NMR, MS and elemental analysis. Three single crystallographic structures of compounds la (n=3, 6) and 2 (n=3) were determined by X-ray analysis in order to correlate the molecular structures with the formation of mesophases. Crystallographic data indicated that the better mesomorphic properties might be controlled by CH-pi, pi-pi or/and H-bonds in such system. Except for crystalline compounds 4, all other compounds 1-3 showed mesomorphic behavior of nematic, smectic A or/and smectic C phases, which were characterized by differential scanning calorimetry, optical polarizing microscope and X-ray diffraction experiments. All compounds 1-4 showed yellow green photoluminescence in THF occurred at 519-521 nm. (C) 2015 Elsevier Ltd. All rights reserved.