Preparation, spectroscopic characterisation, electrochemical and photochemical properties of cis-bis(2,2′-bipyridyl)carbonylruthenium(II) complexes

Abstract

The preparation of a series of cis-[Ru^II(L–L)₂(CO)L]ⁿ⁺ complexes [L–L-2,2′-bipyridyl (bipy), n= 1, L = H, Cl, or NCS; n= 2, L = H₂O, MeCN, CO, pyridine (py), 4-vinylpyridine (vpy), or 4-methylpyridine (Mepy); L–L = 4,4′-dimethyl-2,2′-bipyridyl (Me₂bipy), n= 1, L = H or Cl; n= 2, L = H₂O or CO] is reported. The CO stretching frequency, the energy of the d–π* metal to ligand charge-transfer absorption bands, and the oxidation and reduction potentials of the complexes are found to depend markedly on the σ- and the π-donor abilities of the ligands. In complexes [Ru(L–L)₂(CO)(H₂O)]²⁺ and [Ru(L–L)₂(CO)Cl]⁺ the water and Cl^– ligands are thermally substitution labile. On u.v. irradiation all complexes except [Ru(L–L)₂(CO)H]⁺ are efficiently decarbonylated.