fulltext.study @t Gmail

Effect of the positional isomerism on the photoreactivity of styryloxazoles

Paper ID Volume ID Publish Year Pages File Format Full-Text
26294 43944 2016 9 PDF Available
Title
Effect of the positional isomerism on the photoreactivity of styryloxazoles
Abstract

•Competitive photoreactions of n-styryloxazole (n = 2, 4 and 5) were investigated.•Positional isomerism affects photocyclization more than photoisomerization.•Effects of conformers and intramolecular Hbonds evidenced by QM calculations.•Analog compound bearing two heteroaromatic rings (oxazole and furan) was also studied.

This paper describes the results obtained in the study of the photobehaviour of heteroanalogs of stilbene bearing an oxazole ring. The competitive relaxation processes (fluorescence, isomerization and cyclization) of the excited states of n-styryloxazoles (n = 2 and 4) were investigated and compared with the behaviour previously reported for n = 5. After preparation of the unknown compound with n = 4 and of its positional isomer with n = 2 (the latter with a new method of synthesis), their photobehaviour was firstly investigated in preparative conditions by NMR analysis to measure the chemical yields of their photoproducts. The study was then continued in mild irradiation conditions to measure the quantum yields of the competitive photoreactions in the primary irradiation steps.The effects of the position of the styryl group at the oxazole ring, the relative abundance of the various conformers and the possible formation of intramolecular Hbonds on the deactivation pathways are described. Quantum-mechanical Hyperchem calculations proved to be very useful to describe the conformational equilibria and the role of conformers on photoreactivity while more refined DFT calculations on the Z isomers allowed to explain the structure dependent competition between their isomerization/cyclization processes. The effect of the replacement of the phenyl ring with a second heteroaromatic group of electron donor character was investigated for the 5-(2-(furan-2-yl) ethenyl) oxazole.

First Page Preview
Effect of the positional isomerism on the photoreactivity of styryloxazoles
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 316, 1 February 2016, Pages 95–103
Authors
, , , , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us