ISSN 1070-3284, Russian Journal of Coordination Chemistry, 2006, Vol. 32, No. 3, pp. 199–207. © Pleiades Publishing, Inc., 2006. Original Russian Text © M.B. Bushuev, V.P. Krivopalov, N.V. Semikolenova, E.V. Peresypkina, A.V. Virovets, L.A. Sheludyakova, L.G. Lavrenova, V.A. Zakharov, S.V. Larionov, 2006, published in Koordinatsionnaya Khimiya, 2006, Vol. 32, No. 3, pp. 208–216. 199 A search for and study of new catalytic systems that can be used in the target synthesis of polymers with the required properties make an urgent task for researchers [1–4]. Recently, a series of new Fe, Co, Ni, and V com- plexes with the nitrogen-containing organic ligands were used in combination with cocatalysts (methylalu- minoxane (MAO) or trialkylaluminium compounds) as efficient catalysts in ethylene polymerization [5–10]. Nevertheless, the development of novel complexes of the transition 3d metals that can be used as catalysts in olefin polymerization reactions is still of interest today. The authors of [11] reported lately the catalytic activity of the Fe(II) and Co(II) complexes with 2,6-di(pyr- azole-1-yl)- and 2,6-di(pyrazole-1-ylmethyl)pyridines in ethylene polymerization in the presence of MAO. Also, the first Cu catalysts of ethylene polymerization were reported (the CuCl 2 complexes with bidentate α-diamine [12] and bis(benzimidazole) [13] ligands). N N N N M Cl Cl n [ ] n [ ] N Cu N R R R R Cl Cl N N N N X Cu Cl Cl R R R = H, Me; M = Co, Fe; n = 0, 1 [11] R = Ph, iso-Pr [12] R = alkyl; X = C(OMe)Me, CEt 2 , 2,2'-C 6 H 4 –C 6 H 4 [13] R R n n The structural aspects of the Cu(I) and Cu(II) com- plexes with the nitrogen-containing ligands, which are usually used in the radical atom-transfer polymeriza- tion are discussed in [14]. In this connection, the synthesis of new Cu com- plexes with the nitrogen-containing ligands incorporat- ing heterocycles with several N atoms and the study of their structures and catalytic activity in reactions of ole- fin polymerization are of unquestionable interest. The aim of this work was to synthesize the Cu(II) and Cu(I) complexes with a new nitrogen-containing heterocyclic ligand, namely, 2-(3,5-diphenyl-1H-pyr- Cu(II) and Cu(I) Complexes with 2-(3,5-Diphenyl-1H–pyrazole-1-yl)-4,6-diphenylpyrimidine: Synthesis and Structure. Catalytic Activity of Cu(II) Compounds in Reaction of Ethylene Polymerization M. B. Bushuev*, V. P. Krivopalov**, N. V. Semikolenova***, E. V. Peresypkina*, A. V. Virovets*, L. A. Sheludyakova*, L. G. Lavrenova*, V. A. Zakharov***, and S. V. Larionov* *Nikolaev Institute of Inorganic Chemistry, Siberian Division, Russian Academy of Sciences, pr. Akademika Lavrent’eva 3, Novosibirsk, 630090 Russia **Novosibirsk Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences, Novosibirsk, Russia ***Boreskov Institute of Catalysis, Siberian Division, Russian Academy of Sciences, pr. Akademika Lavrent’eva 3, Novosibirsk, 630090 Russia Received June 21, 2005 Abstract—The Cu(II) and Cu(I) complexes with 2-(3,5-diphenyl-1H-pyrazole-1-yl)-4,6-diphenylpyrimidine (L) of the composition CuLX 2 (X = Cl, Br) and CuL(MeCN)Br are synthesized. According to X-ray diffraction data, the complexes have molecular structures. The molecules L are coordinated to the copper atom in biden- tate-cyclic mode, i.e., through the N 2 atom of pyrazole and N 1 atom of pyrimidine rings. The coordination poly- hedron of the Cu 2+ ion in CuLX 2 compounds is completed to a distorted tetrahedron with halide ions, that of the Cu + ion in CuL(MeCN)Br compounds, with the bromide ion and the nitrogen atom of acetonitrile molecule. The CuLX 2 complexes (X = Cl, Br) in combination with cocatalysts (methylaluminoxane and triisobutylalu- minium) exhibit catalytic activity in ethylene polymerization. DOI: 10.1134/S1070328406030067