Photochemistry of surface-confined mononuclear and trinuclear ruthenium carbonyl complexes. Direct evidence for the ability to isolate photogenerated intermediates from each other on high surface area silica

Photoactivation of homogeneous organometallic catalysts by light-induced extrusion of 2-electron donor ligands or metal-metal bond cleavage has been demonstrated. A problem that has arisen is that the reactive solution species can recombine with the extruded ligand or can react with each other to form inactive clusters. We now report the synthesis and photochemical behavior of LRu(CO)4 and L3Ru3(CO)9 confined to the surface of high surface area silica. The results illustrates that immobilization of precursors to coordinatively unsaturated species prevents cluster formation, when the surface coverage is sufficiently low. Further, photodeclusterification of anchored L3Ru3(CO)9 is reversible due to the immobilization of the fragments.