title: Synthesis, structures, and olefin polymerization capability of vanadium(4+) imido compounds with fac-N3 donor ligands.
abstract: One-pot reactions of V(NMe2)4 with a range of primary alkyl- and arylamines RNH2 and Me3SiCl afforded the corresponding five-coordinate vanadium(4+) imido compounds V(NR)Cl2(NHMe2)2 [R = 2,6-C6H3(i)Pr2 (1a, previously reported), 2-C6H4(t)Bu (1b), 2-C6H4CF3 (1c), (t)Bu (1d), Ad (Ad = adamantyl, 1e)]. The crystal structures of 1b (two diamorphic forms) and 1c featured N-H...Cl hydrogen-bonded chains. Reaction of 1a-e with the neutral face-capping, N3 donor ligands TACN (TACN = 1,4,7-trimethyltriazacyclononane) or TPM [TPM = tris(3,5-dimethylpyrazolyl)methane] gave the corresponding six-coordinate complexes V(NR)(TACN)Cl2 (2a-e) and V(NR)(TPM)Cl2 (3a-e). The X-ray structures of 2b, 2c, 2d, 3b, 3c, and 3e were determined. When activated with methylaluminoxane, certain of the complexes V(NR)(TPM)Cl2 (3) formed moderately active ethylene polymerization catalysts, whereas none of the compounds V(NR)(TACN)Cl2 (2) were active.
authors.affiliation: Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.
authors.forename: Helen R
authors.initials: HR
authors.lastname: Bigmore
authors.forename: Martin A
authors.initials: MA
authors.lastname: Zuideveld
authors.forename: Radoslaw M
authors.initials: RM
authors.lastname: Kowalczyk
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Cowley
authors.forename: Mirko
authors.initials: M
authors.lastname: Kranenburg
authors.forename: Eric J L
authors.initials: EJ
authors.lastname: McInnes
authors.forename: Philip
authors.initials: P
authors.lastname: Mountford