HRh4 as a hydrogenation and isomerization catalyst

Article abstract of DOI:10.1016/0022-328X(95)05454-W

The preparation and reactions of 4> (2) have been investigated.The metallation product <(PhO)2(C6H4OP)Rh3> (4) has been characterized by 31P NMR spectroscopy.Catalytic hydrogenation of alkenes with 2 depends strongly on the amount of extra ligand added and the substrate (1-hexene, Z,E-2-hexene and allylbenzene).Without added phosphite, traces of <(HRh2)2> are the actual catalyst.Under these conditions the reaction is zero order in substrate.The kinetics are completely different when extra triphenyl phosphite is present.Complex 2 behaves as a catalyst with a character in between that of ClRh(PPh3)3 and cationic Rh(diphosphine)⁺. Keywords: Rhodium; Hydrogenation catalyst; Isomerization catalyst