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).