title: Photocyclization reaction of a diarylmaleimide derivative in polar solvents.
abstract: Photochromism of a symmetric diarylmaleimide derivative, having two thiophene rings (1), and a non-symmetric derivative having a S,S-dioxide thiophene ring and a thiophene ring (2) as the aryl moieties, was studied in various solvents. The photocyclization quantum yield of gradually decreased with increasing the solvent polarity and the reaction was not observed in polar solvents, such as ethanol and acetonitrile; on the other hand, such a strong solvent dependence of the photocyclization reaction was not observed for ; the different behavior is attributed to the weaker electron donating ability of the S,S-dioxide thiophene ring.
authors.affiliation: Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Motooka 744, Nishi-ku, Fukuoka, 819-0395, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Ohsumi
authors.forename: Masaki
authors.initials: M
authors.lastname: Hazama
authors.forename: Tuyoshi
authors.initials: T
authors.lastname: Fukaminato
authors.forename: Masahiro
authors.initials: M
authors.lastname: Irie