title: Preparation, structure, and unique redox properties of mono-, bis-, and Tris(diarylmethylene)-1,3,5-trithianes and related compounds
abstract: A series of 1,3,5-trithianes 1-3 having diarylmethylene units were designed as novel electron donors giving highly colored cationic species upon oxidation. They were prepared along with the dithiane and dithiazine derivatives 4-6 by the reactions of lithiated heterocycles with diaryl ketones followed by dehydration. Voltammetric analyses indicate that a large structural change and/or transannular bonding are induced during their electrochemical oxidation. Mono(diarylmethylene) derivative 1a exhibits electrochromism with vivid change in color from faintly yellow to deep blue with concomitant rotation around the exocyclic bond. Both of the strongly colored salts obtained upon oxidation of 2,4-bis- and 2,4,6-tris(diarylmethylene)-1,3,5-trithianes (2aa and 3) consist of the dications with a 1,2,4-trithiane ring, suggesting the easy skeletal rearrangement of the transannular dications with a trithiabicylo[3.1.0]hexane ring. Upon reduction of these salts were obtained bright yellow 12 and 13, respectively, with high electron-donating properties due to the tetraarylbutadiene-type conjugation, thus giving another class of electrochromic compounds.
authors.affiliation: Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.initials: T
authors.lastname: Suzuki
authors.initials: T
authors.lastname: Yoshino
authors.initials: Ji
authors.lastname: Nishida
authors.initials: M
authors.lastname: Ohkita
authors.initials: T
authors.lastname: Tsuji