Syntheses, Crystal Structures and Catalytic Performance of 2,6-Bis(imino) pyridyl Manganese Complexes

Reactions of equalinolar ratios of MnCl(2)4H(2)O and the tridentate ligands 2,6-bis[1-(2,6-dimethyl-phenylimino)ethyl]pyridine(L(1)), 2, 6-bis [1-(2, 6-diethy phenylimino) ethyl] pyridine (L(2)), and 2, 6-bis [1-(2,6-dimethylphenylimino)ethyl] pyridine (L(3)) in acetonitrile afforded the five-coordinated complexes L(1)Mn (II)Cl(2) CH(3)CN (1), L(2)Mn (II) Cl(2) CH(3)CN (2) and L(3)Mn (II) Cl(2) CH(3)CN (3), respectively. The three complexes were characterized using elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Crystallographic studies on complexes 1-3 reveal the pentacoordinate with geometries that can be best described as distorted trigonal bipyramidal. Complex 1 crystallizes in the monoclinic system, space group P2(1)/n, with a = 1.3304 (3) nm, b = 1.4864 (3) nm, c = 1.4423 (3) nm; beta = 108.41 (3)degrees, V = 2.7063(9) nm(3), Z = 4, F(000) = 1116, R(1) = 0. 0465; complex 2 belongs to monoclinic system with space group P2(1)/c, with a = 1.2919 (1) nm, b = 1.5283 (1) nm, c = 1.6362 (1) nm; beta = 99.27 (1), V = 3.1883(3) nm(3), Z = 4, F(000) =1244, R(1) = 0.0599; complex 3 belongs to monoclinic system with space group P2(1)/a, with a = 1.4542 (3) nm, b = 1.5083 (3) nm, c = 1.4646 (3) nm; beta = 112.56 (3)degrees, V = 2.9667(10) nm(3), Z = 4, F(000) = 1180, R(1) = 0.0627. Complexes 1-3 exhibit lower catalytic activities for ethylene polymerization after activation with cocatalysts of [Ph(3)C] (+) [B(C(6)F(5))(4)](-).