The invention relates to N'-substituted N-acylamidine transition metal complexes of the general formula (I), wherein M represents a transition metal, selected from the group of metals including Ni, Cu, Ru, Rh, Pd, Os, Ir and Pt, X represents Cl, Br, triflate, methane sulfonate or p-toluol sulfonate, m is 0, 1 or 2, n is 1, 2 or 3 and the radicals have the following meanings: R.sup.1, R.sup.2 is a straight-chain or branched, cyclic hydrocarbon group with 1 to 20 carbon atoms which can be mono or poly-unsaturated, an aromatic group with 3 to 6 chain members, which is linked directly or via a C.sub.1 to C.sub.6 alkyl or C.sub.2 to C.sub.6 alkylene group, whereby the mentioned groups can carry one or more substituents. Ar represents C.sub.6 to C.sub.10 aryl or hetaryl with 5 to 10 ring members, whereby the mentioned groups can be substituted by C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.4 halogenalkyl, NR.sup.10R.sup.11, COOR.sup.6, Si(R.sup.7).sub.3Si(R.sup.7).sub.2R.sup.8, OR.sup.3 and/or halogen. The invention also relates to a method for producing this new class of metal transition complexes and their use as catalysts ##STR00001##