Liquid-phase Dehydrogenation Catalysis for Alkane with Metal Cluster Complexes

钌羰基簇络合物Ru_3(CO)_<12>对环辛烷脱氢表现出均匀的催化作用，在t.o.n = 69时生成环辛烯和二氢，而环己烷即使在沸腾和回流条件下也没有反应，与催化活性的铂或铂-钌复合细颗粒相反。以离子对Cs_2[Pt_3(CO)_6]_5和[Ru(C_6Me_6)_2](BF_4)_2为原料，在碳载体上沉淀制备了Pt-Ru复合催化剂，并对其进行热处理或用钌氢氧羰基配合物H_4Ru_4(CO)_<12>对铂催化剂进行表面改性。这些复合催化剂对乙基环己烷脱氢芳构化反应具有较高的催化活性。用铑和铱的a -框架双核络合物证明了烷烃的光催化脱氢。值得注意的是，RhCl(CO)(PR_3)_2在365 nm处的光活性波段现已扩展到475 nm（双核Rh）和520 nm（双核Ir），这对太阳能利用具有重要意义。

A ruthenium carbonyl cluster complex Ru_3(CO)_<12> exhibited homogeneous catalysis for cyclooctane dehydrogenation, yielding cyclooctene and dihydrogen at T.O.N.= 69, whereas cyclohexanes were unreactive even under boiling and refluxing conditions in contrast to catalytically-active platinum or platinum-ruthenium composite fine particles.Pt-Ru composite catalysts were prepared from an ionic pair of Cs_2[Pt_3(CO)_6]_5 and [Ru(C_6Me_6)_2](BF_4)_2 by precepitation on a carbon support, followed by a heat treatment or from the surface modification of a platinum catalyst with a ruthenium hydrido-carbonyl complex H_4Ru_4(CO)_<12>. These composite catalysts were highly-active for dehydrogeno-aromatization of ethylcyclohexane.Photocatalytic alkane dehydrogenation was demonstrated with the A-frame dinuclear complexed of rhodium and iridium. It is noteworthy that the photoactive band at 365 nm of RhCl(CO)(PR_3)_2 is now extended to 475 nm (dinuclear Rh) and to 520 nm (dinuclear Ir), since it is important from the viewpoint of solar energy utilization.