<sup>1</sup>H and <sup>2</sup>H NMR Spectroscopic Characterization of Heterobinuclear Ion Pairs Formed upon the Activation of Bis(imino)pyridine Vanadium(III) Precatalysts with AlMe<sub>3</sub>/[Ph<sub>3</sub>C]<sup>+</sup>[B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>]<sup>−</sup> and MAO
作者:Igor E. Soshnikov、Nina V. Semikolenova、Artem A. Antonov、Konstantin P. Bryliakov、Vladimir A. Zakharov、Evgenii P. Talsi
DOI:10.1021/om500267e
日期:2014.5.27
Until recently, attempts to characterize vanadium(III) species formed upon the activation of vanadium(III) alpha-olefin polymerization precatalysts with AlMe3/[Ph3C][B(C6F5)](4)(-) or MAO were unsuccessful. In this contribution, H-1 and H-2 NMR spectroscopy was used to study the activation of bis(imino)pyridine vanadium(III) chloride (LVCl3)-Cl-III L = [2,6(ArN=CMe)(2)C5H3N], Ar = 2,6-(Pr2C6H3)-Pr-i; 2,6-Me2C6H3; 2,4,6Me(3)C(6)H(2); 3,5-F2C6H3} with AlMe3/[Ph3C][B(C6F5)](4)(-) or MAO. Formation of heterobinuclear ion pairs of the type [L(R)VIII(mu-R)(2)AlMe2](+)[A](-) ([A](-) = [B(C6F5)](4)(-) or [MeMAO](-), R = Me or Cl) was observed, which are the most likely direct precursors of active sites of ethylene polymerization.