The photochemical generation of novel neutral mononuclear ruthenium complexes and their reactivity

Article abstract of DOI:10.1016/0022-328X(95)05440-Z

The room-temperature photolysis of Ru3(CO)12 (1) in dichloromethane under a flow of ethylene affords the highly reactive complex Ru(CO)4(C2H4) (2) in a quantitative yield.The addition of MeCN to the reaction mixture, while the photolytic conditions and the ethylene flow are maintained, gives Ru(CO)3(C2H4)(NCMe) (3).If the irradiation is continued but the ethylene flow stopped, a different product, namely Ru(CO)3(NCMe)2 (4) is obtained.The addition of an excess of triphenylphosphine to a dichloromethane solution of 2 in the absence of ethylene and of light gives two phosphine-substituted products: Ru(CO)4(PPh3) (5) and Ru(CO)3(PPh3)2 (6).Under similar conditions, 3 affords 6 and the trinuclear cluster Ru3(CO)9(PPh3)3 (7) while, if MeCN is added instead of PPh3, the reactive cluster Ru3(CO)9(NCMe)3 (8) is obtained.If an excess of acrylonitrile is used instead of ethylene, the photolysis of 1 in dichloromethane yields Ru(CO)4(NCCH=CH2) (9) which reacts under photolytic conditions but in the absence of an excess of acrylonitrile with MeCN to give Ru(CO)3(NCCH=CH2)(MeCN) (10) and this product reacts with a second equivalent of acrylonitrile to afford Ru(CO)3(NCCH=CH2)2 (11).All the products have been characterized by IR spectroscopy and their structures established from symmetry considerations.Keywords: Ruthenium; Carbonyl; Nitrile; Photochemical synthesis