The invention relates to a method for producing 1,2-diimine compounds of general formula (I) in which the symbols have the following meanings: R?1 and R2¿, independent of one another, represent alkyl radicals, aryl radicals or metallocenyl radicals; and R3, R4, independent of one another, represent H, alkyl radicals or aryl radicals; or R3, R4 form a cyclic radical together so that, including both imine carbon atoms, a 5- to 8-member ring is formed which can be saturated and unsaturated or arbitrarily substituted with hydrocarbon radicals. The inventive compounds are produced by reacting 1,2-dicarbonyl compounds with primary amines, whereby the amines are activated with trialkylaluminum compounds before being reacted with the 1,2-dicarbonyl compounds. The invention also relates to 1,2-diimine compounds of general formula (I), wherein R?1 and R2¿, independent of one another, are metallocenyl radicals. Finally, the invention relates to metal complexes comprised of compounds of formula (I) and to the use of these metal complexes as catalysts in a method for polymerizing unsaturated compounds.