Ni(II) complexes of the phosphine-oxime Ph2PC6H4-2-CH=NOH

摘要

We report the solution and structural chemistry of nickel(ii) complexes of the phosphine-oxime Ph2PC6H4-2-CH?NOH (PCH?NOH). PCH?NOH invariably binds in a bidentate manner as illustrated by cis-Ni(PCH?NOH)(2)Cl-2 and cis-[Ni(PCH?NOH)(2)](2+) (as its BF4- salt). Treatment of PCH?NOH with Ni(OAc)(2)(H2O)(4) gave charge-neutral trans-[Ni(PCH?NO)(2)](0). Treatment of trans-[Ni(PCH?NO)(2)](0) with BF3 gave [Ni(PCH?NO)(2)BF2]BF4. The cation features a planar NiP2N2 center wherein the pair of oximate groups are linked by the difluoroboryl center. The 1:1 complexes of the oxime and the oximate are illustrated by [Ni(PCH?NOH)Cl-2](2) and [Ni(C6F5)(PCH?NO)](2), which feature five- and four-coordinate Ni(ii) centers, respectively. All complexes in this series hydrolyze to give the trinickel oxo-phosphine-oximate complex [Ni-3(PCH?NO)(3)O](+). One feature of the PCH?NOH ligand is its wide bite angle combined with its protic OH center. These aspects are manifested in the structures of Ni(PCH?NOH)(2)Cl-2 and [Ni(PCH?NOH)Cl-2](2), which show intramolecular hydrogen bonding to terminal chloride ligands.