| Abstract
| - A series of (arylimido)vanadium(V) complexes containing phenoxyimine ligands of the type V(NAr)Cl2[O-2-R-6-{(2,6-iPr2C6H3)NCH}C6H3] have been prepared, and their structures (rather distorted square pyramidal) were determined by X-ray crystallography. These complexes (especially 1c) exhibited notable catalytic activities for ethylene polymerization in the presence of MAO, and the ortho substituent in the aryloxo ligand strongly affected the catalytic activity. The reaction of 1.1 equiv of 2-Me-6-{(2,6-iPr2C6H3)NCH}C6H3OH with V(NAr)Me(NCtBu2)2 afforded another methyl complex, and a unique reactivity of the methyl complex with phenol was thus observed.
- A series of (arylimido)vanadium(V) complexes containing phenoxyimine ligands of the type V(NAr)Cl2[O-2-R-6-{(2,6-iPr2C6H3)NCH}C6H3] [Ar = 2,6-Me2C6H3; R = H (1a), Me (1b), tBu (1c)] have been prepared in 64−78% yields from V(NAr)Cl3 with LiO-2-R-6-[(2,6-iPr2C6H3)NCH]C6H3. The structures for 1a−c determined by X-ray crystallography indicate that these complexes have distorted square-pyramidal structures around vanadium, consisting of the arylimido ligands in the apical site of a distorted square-pyramid and the N,O-chelate ligand, which forms a plane including both the aryloxo ring and the imino nitrogen. The Cl−V−Cl bond angle for 1c [90.49(2)°] is apparently smaller than those in 1a,b [91.97(7)°, 91.25(2)°, respectively], and the V−N(imine) bond distance in 1c [2.203(2) Å] is shorter than those in 1b,c [2.216(4), 2.2165(17) Å, respectively]. These complexes (especially 1c) exhibited notable catalytic activities for ethylene polymerization in the presence of MAO, and the ortho substituent in the aryloxo ligand strongly affected the catalytic activity; the activity of the tBu analogue (1c) was higher than that of the reported V(NAr)Cl2(O-2,6-Me2C6H3) under the same conditions. The reaction of 1.1 equiv of 2-Me-6-{(2,6-iPr2C6H3)NCH}C6H3OH with V(NAr)Me(NCtBu2)2 afforded another methyl complex without reaction with the methyl group occurring; unique reactivity of the methyl complex with phenol could thus be observed.
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