Surface organometallic chemistry: reaction of alkyne vapours with [Ru3(CO)12] supported on inorganic oxides

The reactions described herein represent new examples of surface organometallic chemistry aimed at preparing alkyne-substituted clusters in the absence of solvents. We report that the reaction of [Ru3(CO)12], deposited on pyrex glass, silica, alumina or zinc oxide, with the gaseous alkynes tert-butyl acetylene (TBA) and 2-methyl-1-butyn-3-ol (MBO) or with solid 3-phenyl-1-butyn-3-ol (PBO), leads to medium/high yields of the corresponding trinuclear acetylido- or acetylene-substituted clusters, under mild conditions. Factors effecting the reaction rates and yields (such as alkyne vapour pressure, the nature of the oxides and addition of additives) are discussed. It is shown that the triruthenium dodecacarbonyl starting material, which is initially deposited on the supports at room temperature, undergoes modification upon thermolysis leading to the formation of active species, the natures of which were probed using IR and Raman spectroscopy. In order to determine whether the active intermediates are anionic complexes, comparison of the reaction products with those obtained from addition of the same alkynes to [Ru3(CO)12] in methanol–KOH solution are made. Finally, electron microscopy studies suggest that small metal particles are formed during some of the solid–gas reactions.