Access to Novel Ruthenium−Amidinate Complexes, (η6-arene)Ru(η2-amidinate)X and [Ru(η2-amidinate)(MeCN)4]+PF6- by Photochemical Displacement of the Benzene Ligand in (η6-C6H6)Ru(η2-amidinate)X

Novel ruthenium−amidinate complexes, (η6-C6H5R)Ru(η2-amidinate)X (R = Me, OMe, F) (4) and [Ru(η2-amidinate)(MeCN)4]+PF6- (5) are synthesized by photochemical displacement of the benzene ligand in (η6-C6H6)Ru(η2-amidinate)X (3) by arenes or MeCN. The acetonitrile ligands of 5 are easily replaceable by other σ-donor ligands (L) such as pyridines, phosphines, and isocyanides to afford the corresponding derivatives, [Ru(η2-amidinate)(MeCN)n(L)4-n+]PF6- (n = 1 or 2).