We report the solution and structural chemistry of nickel(ii) complexes of the phosphine-oxime Ph2PC6H4-2-CHNOH (PCHNOH). PCHNOH invariably binds in a bidentate manner as illustrated by cis-Ni(PCHNOH)2Cl2 and cis-[Ni(PCHNOH)2]2+ (as its BF4- salt). Treatment of PCHNOH with Ni(OAc)2(H2O)4 gave charge-neutral trans-[Ni(PCHNO)2]0. Treatment of trans-[Ni(PCHNO)2]0 with BF3 gave [Ni(PCHNO)2BF2]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(PCHNOH)Cl2]2 and [Ni(C6F5)(PCHNO)]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 [Ni3(PCHNO)3O]+. One feature of the PCHNOH ligand is its wide bite angle combined with its protic OH center. These aspects are manifested in the structures of Ni(PCHNOH)2Cl2 and [Ni(PCHNOH)Cl2]2, which show intramolecular hydrogen bonding to terminal chloride ligands.
ASJC Scopus subject areas
- Inorganic Chemistry