Selective Substitution of One of the Substituents on Germanium in Coordinatively Unsaturated Ruthenium Germyl Complexes

Abstract

The coordinatively unsaturated tri-p-tolylgermyl complex RuCl(Ge[p-tolyl]3)(CO)(PPh3)2 (1) is obtained in good yield through the reaction between HGe(p-tolyl)3 and RuCl(Ph)(CO)(PPh3)2. On treatment of 1 with 1 equiv of NaS2CNR′2 (R′ = Et, Me), the chloride ligand is displaced and the corresponding coordinatively saturated complexes Ru(κ2-S2CNR′2)(Ge[p-tolyl]3)(CO)(PPh3)2 (2a, R′ = Et; 2b, R′ = Me) are formed. One of the PPh3 ligands in 2a is labile and undergoes substitution readily on addition of CO to give the cis-dicarbonyl complex Ru(κ2-S2CNEt2)(Ge[p-tolyl]3)(CO)2(PPh3) (3). On addition of NaS2CNMe2 to 2b, a PPh3 ligand is displaced by one sulfur atom while the other sulfur atom displaces one of the p-tolyl groups on germanium to give Ru(κ2(Ge,S)-Ge[p-tolyl]2S2CNMe2)(κ2-S2CNMe2)(CO)(PPh3) (4). Complex 4 is also formed on addition of excess NaS2CNMe2 to 1. Treatment of 1 with pyridine and ethanol under ambient conditions also results in cleavage of one of the germyl p-tolyl groups, and the product formed is the coordinatively unsaturated, ethoxy-substituted germyl complex RuCl(Ge[OEt][p-tolyl]2)(CO)(PPh3)2 (5). The ethoxy group in 5 is labile, and on contact with n-propanol in solution, alkoxy group exchange slowly occurs to give RuCl(Ge[OnPr][p-tolyl]2)(CO)(PPh3)2 (6). This reaction is reversible, and treatment of 6 with ethanol returns 5. In a related reaction, treatment of 5 with water gives the hydroxy–germyl analogue RuCl(Ge[OH][p-tolyl]2)(CO)(PPh3)2 (7). The single-crystal X-ray structures of 1, 2a, 3, and 4 are presented.