Synthesis and redox properties of trinuclear ruthenium-acetylide complexes with tri(ethynylphenyl)amine bridge.
Novel trinuclear ruthenium complexes have been prepared by using tri(4-ethynylphenyl)amine as a bridging ligand. Cyclic voltammetry of the trinuclear ruthenium complexes revealed stepwise quasi-reversible redox behavior of three ruthenium-acetylide species and the central triphenylamine unit, whereas the mononuclear analog showed two sequential quasi-reversible redox waves. The spectroelectrochemical UV-VIS spectral studies suggested that the 1e- oxidized triruthenium species was stable and showed a characteristic absorption at lambda(max) = 505 nm. Chemical oxidation of the triruthenium complex with ferrocenium hexafluorophosphate led to the isolation of the 1e- oxidized complex, the near-IR spectrum of which revealed an intervalence charge transfer band due to the electronic coupling among three ruthenium species. The 1e(-) oxidized triruthenium complexes can be classified as class II mixed-valence compounds.
Onitsuka
Kiyotaka
K
Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka, 567-0047, Japan. onitsuka@sanken.osaka-u.ac.jp
Ohara
Naoko
N
Takei
Fumie
F
Takahashi
Shigetoshi
S