title: Facile synthesis of dibenzopentalene dianions and their application as new π-extended ligands.
abstract: Reduction of phenyl(silyl)ethynes with potassium followed by quenching with iodine gave dibenzopentalenes in moderate yields. The intermediates of the reactions, dipotassium dibenzopentalenides, were isolated. The first dibenzopentalene-transition-metal complex was successfully synthesized. The ruthenium atoms are located above the six-membered rings. However, X-ray diffraction analysis and theoretical calculations revealed that the aromatic nature of the five-membered rings was retained. The cyclic voltammetry of the Ru complex revealed two oxidation waves with relatively large separation.
authors.affiliation: Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Shimo-okubo, Sakura-ku, Saitama, 338-8570 (Japan), Fax: (+81) 48-858-3700.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kuwabara
authors.forename: Kazuya
authors.initials: K
authors.lastname: Ishimura
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sasamori
authors.forename: Norihiro
authors.initials: N
authors.lastname: Tokitoh
authors.forename: Masaichi
authors.initials: M
authors.lastname: Saito
keywords: coordination modes; cyclization; potassium; reduction; ruthenium