title: Integration of Paramagnetic Diruthenium Complexes into an Extended Chain by Heterometallic Metal-Metal Bonds with Diplatinum Complexes.
abstract: We successfully obtained a paramagnetic one-dimensional (1D) chain complex [{Ru2(O2CCH3)4}{Pt2(piam)2(NH3)4}2]n(PF6)4n·4nH2O (2; piam = pivalamidate) extended by metal-metal bonds. Compound 2 comprises two types of metal species, ruthenium and platinum, where an acetate-bridged dinuclear ruthenium complex (i.e., [Ru2]) and a pivalamidate-bridged platinum complex (i.e., [Pt2]) are connected by axial metal-metal bonds, forming an attractive quasi-1D infinite chain that can be expressed as -{[Pt2]-[Ru2]-[Pt2]}n-. Such axial metal-metal bonds are attributed to the interaction between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) along the z axis, where both the HOMO in [Pt2(II,II)] and the LUMO in [Ru2(II,II)] are σ* orbitals associated with metal cores. The crystal structure and X-ray photoelectron spectrum for 2 reveal that metal oxidation states are -{[Pt2(II,II)]-[Ru2(II,II)]-[Pt2(II,II)]}n-, where [Ru2(II,II)] can have an electronic configuration of σ(2)π(4)δ(2)δ*(2)π*(2) or σ(2)π(4)δ(2)π*(4). The magnetic susceptibility of 2 has a μeff [∝(χT)(1/2)] value of 2.77 μB per [Pt2(II,II)]-[Ru2(II,II)]-[Pt2(II,II)] unit at 300 K, showing that two unpaired electrons lie on π*(Ru2). Magnetic measurements performed at temperatures of 2-300 K indicate that S = 1 Ru2(II,II) units are weakly antiferromagnetically coupled (zJ = -1.4 cm(-1)) with a large zero-field splitting (D = 221 cm(-1)).
authors.affiliation: Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University , Yanagido 1-1, Gifu 501-1193, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Uemura
authors.affiliation: Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University , Yanagido 1-1, Gifu 501-1193, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Uesugi
authors.affiliation: Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University , Yanagido 1-1, Gifu 501-1193, Japan.
authors.forename: Akina
authors.initials: A
authors.lastname: Matsuyama
authors.affiliation: Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University , Yanagido 1-1, Gifu 501-1193, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ebihara
authors.affiliation: Department of Chemistry and Research Center for Materials Science (RCMS), Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Yoshikawa
authors.affiliation: Department of Chemistry and Research Center for Materials Science (RCMS), Nagoya University , Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Awaga