Tetraammineruthenium(II) and -ruthenium(III) Complexes of o-Benzoquinone Diimine and Their Redox Series.

The complexes [Ru(NH(3))(4)(4,5-R(2)-bqdi)](n)(+) where bqdi is o-benzoquinone diimine, R = H, Cl, or OMe, and n = 2 or 3 have been characterized by elemental analysis, optical spectroscopy, electrochemistry, spectroelectrochemistry, and electron paramagnetic and nuclear magnetic resonance spectroscopies. ZINDO/S calculations provide a very detailed picture of the degree of mixing existing between metal and ligand orbitals. Both pi back-donation and ligand pi-d mixing are important such that these compounds are considered to be extensively delocalized.