Synthesis and thermal behavior of new liquid crystals arylaldoxime esters

We report the synthesis of a series of liquid-crystalline materials based on arylaldoxime esters and the characterization of these materials by ¹H, 13C NMR, ATR/FT-IR spectroscopy and elemental analysis. The chemical stability and liquid-crystalline as well as photophysical properties of the compounds are described being dependent on the heating/cooling cycles. The changes in chemical stability and the liquid crystals properties of arylaldoxime esters were observed during these thermal cycles by IR analysis. All samples underwent a thermal degradation yielding the corresponding nitriles and carboxylic acid as evidenced by IR and ¹H NMR spectra. Due to the decomposition process, information about the mesomorphic behaviour is lost. The UV-Vis absorption spectra in solution display three absorption bands between 230 and 340 nm. The fluorescence spectra exhibit a broad and structureless emission band located at 430 nm. Ab initio calculations were performed to obtain information on the molecular structure and properties of the title compounds.

Bibliographic Details

Main Authors:	Tavares,Aline, Arruda,Bárbara C., Boes,Elvis S., Stefani,Valter, Stassen,Hubert K., Campo,Leandra F., Bechtold,Ivan H., Merlo,Aloir A.
Format:	Digital revista
Language:	English
Published:	Sociedade Brasileira de Química 2012
Online Access:	http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532012000500013
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