from first principles PP-I-1

PP-II-1New Bis(imino)pyridine Nickel Catalysts: Polymerization of Norborneneand Investigation of the Active SpeciesAntonov A.A. 1 , Semikolenova N.V. 2 , Zakharov V.A. 2 , Zhang W. 3 , Wang Y. 3 , Sun W.-H. 3Talsi E.P. 2 , Bryliakov K.P. 21 Novosibirsk State University, Novosibirsk, Russia2 Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia3 Institute of Chemistry CAS, Beijing, Chinaarrant90@gmail.comBis(imino)pyridine complexes of iron(II) and cobalt(II) have captured attention in the last twodecades due to their ability to polymerize ethylene into linear PE with high activities [1].However, these complexes have been applied in polymerization of norbornene with only alimited success, while bis(imino)pyridine nickel(II) complexes with electron-donatingsubstituents were shown to be highly active in vinyl polymerization of norbornene [2].In the present work, a series of bis(imino)pyridine nickel(II) dichloride complexes containingelectron-withdrawing substituents (F, Cl, Br, CF 3 ) in aryl moieties have been examined innorbornene polymerization, using methylaluminoxane (MAO) as co-catalyst. All complexesdisplay high activities (up to 1.16*10 7 g PNB*(mol Ni) -1 *h -1 ) and yielded high-molecularweightpolynorbornene (M w up to 4.5*10 6 ). The catalytic activity has been found to correlatewith the number and position of the electron-withdrawing substituents [3].Formation of ion-pair intermediates of the type [LNiMe] + [MeMAO] - or [LNiMe] + [B(C 6 F 5 ) 4 ] -(where L – bis(imino)pyridyl ligand) has been documented by NMR spectroscopy upon theinteraction of nickel pre-catalysts LNiCl 2 with MAO or AlMe 3 /[CPh 3 ][B(C 6 F 5 ) 4 ]. Themechanism of polymerization is discussed.FNClNNiClNFMAOThis work was supported by Russian Foundation for Basic Research, grant 12-03-91159.References:[1] a) B.L. Small, M. Brookhart, A.M.A. Benett, J. Am. Chem. Soc. 120 (1998) 4049; b) K.P.Tellmann, V.C. Gibson, A.J.P. White, D.J. Williams, Organometallics 24 (2005) 280.[2] M.C. Sacchi, M. Sonzogni, S. Losio, F. Forlini, P. Locatelli, L. Tritto, M. Licchelli, Macromol.Chem. Phys. 202 (2001) 2052; b) Y. Huang, J. Chen, L. Chi, C. Wei, Z. Zhang, Z. Li, A. Li, L. Zhang,J. Appl. Polym. Sci. 112 (2009) 1486.[3] A.A. Antonov, N.V. Semikolenova, V.A. Zakharov, W. Zhang, Y. Wang, W-H. Sun, E.P. Talsi,K.P. Bryliakov, Organometallics 31 (2012) 1143.131n