Syntheses and Reactivities of New PCsp3P Pincer Complexes of Nickel

Heating Ni(II) halides with 1 equiv of Bu t 2 P(CH 2 ) 5 PBu t 2 gives the PC sp3 P pincer complexes [{(Bu t 2 P(CH 2 ) 2 ) 2 CH}NiX] (X = Cl, 1a; Br, 1b; I, 1c ). These compounds react with MeMgCl or n -BuLi to give, respectively, the methyl species {(Bu t 2 P(CH 2 ) 2 ) 2 CH}NiMe, 2, or the hydride species {(Bu t 2 P(CH 2 ) 2 ) 2 CH}NiH, 3, while reaction with NaBPh 4 in a mixture of benzene/acetonitrile gives the cationic species [{(Bu t 2 P(CH 2 ) 2 ) 2 CH}Ni (N⋮CCH 3 )][BPh 4 ], 4 . Complexes 1 − 3 are inert toward olefins, but react with PhSiH 3 to give (PhSiH) n . The cationic complex 4 is also inert toward most olefins, but its reaction with excess acrylonitrile results in displacement of coordinated acetonitrile to give [{(Bu t 2 P(CH 2 ) 2 ) 2 CH}Ni(N⋮CCH CH 2 )][BPh 4 ], 5 . Complexes 1 − 5 have been characterized by NMR spectroscopy and, in the case of 1, 4, and 5, by X-ray crystallography.