BASE HYDROLYSIS OF ACETONITRILE COORDINATED TO A RUTHENIUM(II) POLYPYRIDINE COMPLEX

On coordination to Ru(terpy)(bipy)(2+) (terpy = 2,2': 6',2 ''-terpyrid ine, bipy = 2,2'-bipyridine), acetonitrile is converted to acetamide i n aqueous basic solution, through hydroxide attack with a catalytic fa ctor of ca 3 x 10(3) (k(OH) = 4.6 X 10(-3) M(-1) s(-1)). This is a rem arkable effect for a d(6) transition metal in the (II) oxidation state , and can be ascribed to pi backbonding from the metal to the polypyri dyl ligands, which makes the ruthenium(II) centre more electropositive than ruthenium(II) in the Ru(NH3)(5)(2+) moiety. The final hydrolysis product is the [Ru(terpy)(bipy)(OH)](+) complex, since amides, being poor pi-acceptor ligands, are rapidly released from the coordination s phere of ruthenium(II). (C) 1997 Elsevier Science Ltd.