Abstract: A compound having catalytic properties which is a .sigma. or .pi. organic complex of a transition metal represented by the general formula: M (A).sub.n (L-C) (L).sub.m, wherein M is Ir or Re; L is a member of the group consisting of alkyl and aryl phosphines; (L-C) is (a) an alkyl or aryl phosphine ligand wherein a C-H bond is reacted with the central M atom to which the ligand is coordinated, and a metal-carbon bond is formed, or (b) a .pi.-allyl radical; A is a linear monoolefin having from 2 to 5 carbon atoms or a cyclic monoolefin having from 6 to 8 carbon atoms; n is a number in the range of 0 to 2 and is always zero when L-C is a .pi.-allyl radical; and m is a number from 1 to 3 which satisfies the valence of M, is prepared by reacting a hydride complex represented by the general formula: MHLn.sub.1 wherein M and L have the meaning given above, x is in the range from 5 to 7 and n.sub.