Liquid-crystalline properties of unsaturated piperazine-2,5-dione derivatives

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/28364

Title:	Liquid-crystalline properties of unsaturated piperazine-2,5-dione derivatives
Authors:	Li,WR;Kao,KC;Yo,YC;Lai,CK
Contributors:	中央大學
Keywords:	HEXAGONAL ARRANGEMENTS;COMPLEXES
Date:	1999
Issue Date:	2010-06-29 19:47:07 (UTC+8)
Publisher:	化學研究所
Abstract:	The synthesis, characterization, and mesomorphic properties of a new type of liquid-crystalline compounds, (3Z,6Z)-3,6-bis(3,4-dialkoxybenzylidene)piperazine-2,5-diones are reported. These compounds were derived from unsaturated piperazine-2,5-dione as the core group, and were prepared by condensation reactions of 1,4-diacetylpiperazine-2,5-dione and 3,4-dialkoxybenzaldehydes. The products were characterized by H-1- and C-13-NMR spectroscopy, and elemental analysis, and the phase behavior of these compounds was characterized and studied by differential scanning calorimetry (DSC) and polarization microscopy. The results indicate that these rod-like compounds exhibit smectic C (S-c) phases. However, for the derivatives with two flexible alkoxy side chains, highly ordered smectic G (S-G) phases were also formed and confirmed by X-ray powder diffraction. The liquid crystallinity of these molecules was attributed to the presence of intermolecular hydrogen bonds involving the NH groups of the heterocyclic rings. The correlation of phase behavior and molecular shape is also discussed.
Relation:	HELVETICA CHIMICA ACTA
Appears in Collections:	[Graduate Institute of Chemistry] journal & Dissertation

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