Novel selenoesters fluorescent liquid crystalline exhibiting a rich phase polymorphism

A simple and efficient procedure for the synthesis of a new class of selenoesters 4a and 4b was developed. Polarized-light optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction showed that the selenoester 4a with a shorter alkyl chain displayed a wide nematic range...

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Published inJournal of materials chemistry Vol. 20; no. 4; pp. 715 - 722
Main Authors Rampon, Daniel S., Rodembusch, Fabiano S., Schneider, Juliana M. F. M., Bechtold, Ivan H., Gonçalves, Paulo F. B., Merlo, Aloir A., Schneider, Paulo H.
Format Journal Article
LanguageEnglish
Published 01.01.2010
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Summary:A simple and efficient procedure for the synthesis of a new class of selenoesters 4a and 4b was developed. Polarized-light optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction showed that the selenoester 4a with a shorter alkyl chain displayed a wide nematic range (T = 110.7 'C), while 4b with a longer alkyl chain possesses a rich phase polymorphism: Cr 1 SmI 1 SmC 1 N 1 I mesophase sequence during heating cycle and I 1 N 1 SmC 1 SmI 1 SmX 1 Cr transition on cooling. For 4b, a large temperature range (135.7 'C) from crystal to isotropic phase can be observed. In addition, UV-Vis, steady-state fluorescence emission and excitation spectra in solution were also applied in order to characterize their photophysical behaviour. Compounds 4a and 4b are fluorescent in the blue region and present a Stokes shift at around 80 nm and 39 nm in dichloromethane and dioxane, respectively.
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content type line 23
ISSN:0959-9428
1364-5501
DOI:10.1039/B917366H