FIELD: chemistry of polymers. SUBSTANCE: described are organometallic complexes which are soluble in aliphatic, cycloaliphatic and aromatic solvents used for reaction of polymerization of unsaturated monomers of general formula: Me(Ar)(AlX3R)3, wherein Me is metal having atomic number of 39, 59, 60 and 64; Ar is benzene or benzene substituted by 1-4 alkyl groups containing from 1 to 10 carbon atoms; X is halogen atom; R is linear or branched alkyl containing from 1 to 12 carbon atoms. Also described are method of preparing said complexes and method of polymerizing alpha-olefin and diolefin monomers in the presence of catalyst system based on said complexes. EFFECT: improved properties of the organomethallic complex. 15 cl, 3 dwg, 33 ex, 3 tbl
