SURFACE ORGANOMETALLIC CHEMISTRY - REDUCTIVE CARBONYLATION OF SILICA-SUPPORTED RUCL3.3H2O

The reductive carbonylation of silica-supported RuCl3 · 3H2O was investigated. This physisorbed salt reacts with CO at 25-50°C to form the silica-bound species [Ru(CO)2Cl2(HOSi{A figure is presented})2], which is converted into the silica-bound tricarbonyl species [Ru(CO)3 Cl2(HOSi{A figure is presented})] when the temperature is raised to 100°C. The surface species may be extracted with suitable donor solvents at room temperature. With [Ru(CO)3Cl2(HOSi{A figure is presented})], extraction using acetone followed by recrystallization from dichloroethane/ pentane affords [Ru(CO)3Cl2]2 in high yield. The dimer sublimes directly from the surface upon carbonylation at 180°C. Liberated HCl probably inhibits further reduction. However, starting from physisorbed [{Ru(CO)3Cl2}2], the species [Ru2(CO)6Cl 4(H2O)] is formed on the surface in the presence of CO + H2O at 100°C. Only traces of [{Ru(CO)3Cl2}2] and clusters such as [Ru3(CO)10Cl2] and [Ru3(CO)12] sublime under these conditions.