The synthesis and redox behaviors of binuclear ruthenocene derivatives bridged by an aromatic moiety

• Published in: Journal of organometallic chemistry 2002-08, Vol.655 (1), p.23-30
• Main Authors: Sato, Masaru, Maruyama, Genta, Tanemura, Atsushi
• Format: Article
• Language: English
• Subjects: Binuclear ruthenocene derivatives; Dioxaborolane; Redox behavior; Suzuki–Miyaura coupling reaction
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/S0022-328X(02)01407-9

2-Ruthenocenyl-4,4,5,5-tetramethyl-1,3-dioxa-2-borolane was prepared by the boration and the subsequent reaction with dilithium pinacolate as the starting material of the Suzuki–Miyaura coupling reaction. The dioxaborolane was heated with 1,4-dibromobenzene, 1,2-diiodobenzene, 4,4′-dibromobiphenyl, 1,4-dibromonaphthalene, and 2,6-dibromonaphthalene in the presence of (dppf)PdCl 2–aqueous NaOH in DME to give the corresponding bis(ruthenocenyl) derivatives in moderate yields. The reaction of the dioxaborolane with 2,2′-diiodobiphenyl and 1,8-diiodo-naphthalene in the presence of Pd(PPh 3) 4–Cs 2(CO) 3 in N, N-dimethylformamide (DMF) produced ruthenoceno[l]phenanthrene and ruthenocenyl[a]acenaphthylene in low yield, respectively. The result of the cyclic voltammetry suggests that there is weak electronic interaction between the two metal sites in the two-electron oxidized species of the binuclear ruthenocene derivatives with an aromatic bridge. 2-Ruthenocenyl-4,4,5,5-tetramethyl-1,3-dioxa-2-borolane was prepared as the starting material of the Suzuki–Miyaura coupling reaction. The reaction of the dioxaborolane with 1,4-dibromobenzene, 1,2-diiodobenzene, 4,4′-dibromobiphenyl, 1,4-dibromonaphthalene, 2,6-dibromonaphthalene gave the corresponding bis(ruthenocenyl) derivatives in moderate yields. The cyclic voltammetry suggests that there is little electronic interaction in their two-electron oxidized species.