title: Diindenopyrenes: Extended 1,6- and 1,8-Pyrenoquinodimethanes with Singlet Diradical Characters.
abstract: Diindenopyrene 4b and its diastereomer, which are extended homologues of 1,6- and 1,8-pyrenoquinodimethanes fused by indene units, respectively, were synthesized by reaction of 1,4,5,8-tetrakis(mesitylethynyl)naphthalene (7) with bis(2,4,6-trimethylpyridine)iodine(I) hexafluorophosphate via cationic cyclization mechanisms at both centers of reaction. Unexpectedly, reaction of 7 with iodine, a reagent that typically gives products of cationic cyclization, gave cycloheptapentalenoindenophenalene derivative 9b and its diastereomer incorporating an azulene unit at one end of the π framework, via two different modes (radical and cationic) of cyclization at each reaction site. The physical properties of the products are presented, and the dual modes of cyclization of 7 and its model compound with only one reaction center are discussed.
authors.affiliation: Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University , 1-3 Machikaneyama, Toyonaka 560-8531, Japan.
authors.forename: Daijiro
authors.initials: D
authors.lastname: Hibi
authors.affiliation: Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University , 1-3 Machikaneyama, Toyonaka 560-8531, Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kitabayashi
authors.affiliation: Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University , 1-3 Machikaneyama, Toyonaka 560-8531, Japan.
authors.forename: Kazuya
authors.initials: K
authors.lastname: Fujita
authors.affiliation: Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University , 1-3 Machikaneyama, Toyonaka 560-8531, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Takeda
authors.affiliation: Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University , 1-3 Machikaneyama, Toyonaka 560-8531, Japan.
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Tobe