| Summary: | 碩士 === 國立中央大學 === 化學研究所 === 92 === This thesis describes the synthesis, characterization and meso- morphic properties of three series (Series I , II , III) of organic ligands and their copper(II) complexes. These compounds include; Series I dicopper (II) complexes of 3, 4, 5-trialkoxybenzoic acid-(2-hydroxy-4- alkoxybenzyidine)hydrazides; Series II dicopper (II) complexes of 4-(tetradecanoxybenzoicacid4-[(3, 4-dialkoxybenzoyl)hydrazonomethy] -3-hydroxyphenyl esters and Series III: 2, 6-bis-(3,4,5-trialkoxphenyl) benzo[1, 2-d; 5, 4-d’]bisoxazoles.
By molecular modification of the carbon chain lengths, the number of the terminal flexible side chains and/or the linkers, the mesomorphic properties observed by these compounds were characterized and also studied in detail. For the spectroscopic characterization of all compounds, 1H and 13C NMR spectra were used to identify the structure and the purity of the compounds, and elemental analysis was also used to confirm the purity. DSC thermal analysis and optical polarised microscopy were used to characterize and confirm the structure of the liquid crystalline mesophases.
The data indicated that for the Series I, dicopper (II) complexes of 3, 4, 5-trialkoxybenzoic acid-(2-hydroxy-4-alkoxybenzyidine)hydrazides, when the numbers of the terminal flexible side chains were either six or eight these copper complexes exhibited Colh phase. The Colh phases were observed for the Series II, dicopper (II) complexes of 4-(tetradeca noxybenzoic acid 4-[(3, 4-dialkoxybenzoyl)hydrazonomethy]-3-hydroxy phenyl esters with the ether group as linker, when the carbon numbers is six, however, the same Colh phases were also formed for the copper(II) complexes with ester group as linker and side chains of ten. For the series III, 2, 6-bis-(3,4,5-trialkoxphenyl)benzo[1,2-d; 5, 4-d’]bisoxazole, these compounds exhibited Colh phases when the carbon numbers of the terminal flexible side chains are 8, 10, 12 and 14
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