Solid-gas hydrogenation of hex-3-yne and 1,4-cyclohexadiene in the presence of the clusters Ru-3(CO)(12), H4Ru4(CO)(12), H2Ru4(CO)(13), and H2FeRu3(CO)(13) supported on inorganic materials. Infrared evidence for surface organometallic reactions

The clusters Ru-3(CO)(12) (1), H4Ru4(CO)(12) (2), H2Ru4(CO)(13) (3). and H2 FeRu3(CO)(13) (4) supported on pyrex borosilicate glass behave as catalysts for solid-gas hydrogenation reactions of hex-3-yne and 1,4-cyclohexadiene. Their activity and selectivity are discussed. Ru-3(CO)(12) (1) was also su pported on inorganic oxides, normally used as chromatographic materials or supports for heterogeneous catalysis and characterized by different aciditi es and surface areas. The observed activities depend on the nature of the i norganic supports; the presence of water also has some influence. Some of t hese materials were characterized by HRTEM microscopy. Organometallic produ cts have been collected after the catalytic runs both when pyrex and inorga nic oxides were used as supports. In particular, the "surface organometalli c reactions" of Ru-3(CO)(12) and H4Ru4(CO)(12) supported on silica have bee n followed by IR spectroscopy. The nature and role of the arising organomet allic compounds are discussed. Our solid-gas results are in good agreement with the mechanisms previously proposed for the hydrogenation of comparable substrates under homogeneous conditions.