HETEROGENEOUS, PLATINUM-CATALYZED HYDROGENATIONS OF (DIOLEFIN)DIALKYLPLATINUM(II) COMPLEXES

The heterogeneous hydrogenation of olefins is perhaps the most extensively studied reaction in heterogeneous catalysis.2 Despite intense scrutiny, the mechanism by which this reaction proceeds has not been unambiguously characterized. In 1934, Horiuti and Polanyi proposed the first plausible mechanism (Scheme I).3 This basic scheme still has wide support, although the individual steps are more complex than those depicted in this simple representation. Questions concerning the structures and reactions of the surface alkyls (e.g., A and B in Scheme I) are particularly complicated. Recent reviews summarize the structures of the many proposed intermediates and the pathways leading to them.4. © 1992, American Chemical Society. All rights reserved.