Abstract: Compounds of formulae I: (DIP)IrX.sub.q Y.sub.r (Z), Ia: (DIP)IrX.sub.s Y.sub.t (Z).sub.2 and Ib: (DIP)Ir(Z).sub.3 or mixtures of at least two of those compounds, wherein DIP is a ditertiary diphosphine, the two phosphine groups of which are bonded to a C.sub.2 -, C.sub.3 - or C.sub.4 -carbon chain, with the result that the diphosphine forms a 5- to 7-membered ring together with the Ir atom, X is Cl, Br or I, Y is a hydrogen atom, q and r are 0, 1 or 2 and the sum of q+r is 2, s and t are 0 or 1 and the sum of s+t is 1, and Z is the anion of an organic oxy acid that contains a group C(.dbd.O), S(.dbd.O)O or P(.dbd.O)O in the anion. The compounds are excellent catalysts for the hydrogenation of imines, especially for the enantioselective hydrogenation of prochiral imines.

Abstract: A process for the preparation of primary or secondary amines by hydrogenation of imines with hydrogen at elevated pressure and in the presence of a dinuclear Ir(III) complex having ditertiary diphosphine ligands, halide bridges, halide and hydride ligands, or an Ir(III) halide complex salt containing ditertiary diphosphine ligands, as catalyst, wherein the catalyst corresponds to formula I or Ia or to mixtures of at least two compounds of formula I, at least two compounds of formulae I and Ia, or at least two compounds of formula Ia[(DIP)IrX.sub.q Y.sub.r ].sub.2 (I),[(DIP)X.sub.4 ].sup..crclbar. Me.sup..sym. (Ia),whereinDIP is the ditertiary diphosphine ligand of a ferrocenyldiphosphine the phosphine groups of which are either bonded directly or via a bridge group --CR.sub.v R.sub.w -- to the ortho positions of a cyclopentadienyl ring or are each bonded to a cyclopentadienyl ring of a ferrocenyl, so that a 5-, 6- or 7-membered ring is formed together with the Ir atom;R.sub.v and R.sub.