Azobenzene Derivatives Carrying a Nitroxide Radical
作者:Shin'ichi Nakatsuji、Masahiro Fujino、Satoko Hasegawa、Hiroki Akutsu、Jun-ichi Yamada、Vladimir S. Gurman、Andrey Kh.Vorobiev*
DOI:10.1021/jo062266f
日期:2007.3.1
Several trans-azobenzene derivatives carrying a nitroxide (aminoxyl) radical (2a, 6a-12a) were prepared, and their photoisomerization reactions to the corresponding cis-isomers were investigated. Although no fruitful results could be obtained for the photoisomerizations of the derivatives with para-subsituents (9a-12a), the unsubstututed derivatives at the para-position (2a, 6a, 7a, 8a) were found to show photoisomerizations by irradiation to give the corresponding cis-isomers (2b, 6b, 7b, 8b), being isolated as relatively stable solid materials, and the change of the intermolecular magnetic interactions was apparently observed by the structural change for each photochromic couple.
Radical compounds and metal complexes with azobenzene chromophore
Series of organic radical compounds with trans-azobenzene chromophore have been prepared to see the photo-induced isomerizations to the corresponding cis-azobenzenes and the possible changes of intermolecular magnetic interactions based on the isomerizations. Although the cis-isomers with p-nitro- or p-dimethylamino-substituent on one side and TEMPO-attached long alkoxy group on the other side could not be isolated as stable solids, the cis-isomers of unsubstituted derivatives at 4-position and with a TEMPO group at 4 '-position have successfully been isolated as relatively stable solid materials showing apparent changes of intermolecular magnetic interactions. A couple of Mn(hfac)(2) complexes derived from isomeric TEMPO-substituted esters were found to be reluctant to the photo-isomerization upon irradiation. 2006 Elsevier Ltd. All rights reserved.