New derivatives of PCP-type pincer complexes of nickel.
The pincer-type complexes (PC(sp3)P(i-Pr))NiR (PC(sp3)P(i-Pr) = (i-Pr(2)PCH(2)CH(2))(2)CH) react with HBF(4) (R = C[triple bond]CMe, Ph, Me) or AgBF(4) (R = Br) to give (PC(sp3)P(i-Pr))Ni(BF(4)), 1, which was found to involve fluxional Ni-F-BF(3) interactions. Competition experiments revealed that the relative ease of protonation of the Ni-hydrocarbyl moiety follows the order Ni-Me > Ni-C[triple bond]CMe > Ni-Ph. Complex 1 reacts with water to give [(PC(sp3)P(i-Pr))Ni(H(2)O)][BF(4)], 2, that in turn undergoes H(2)O exchange with CH(3)CN, i-PrNH(2), and CO to give the corresponding cationic adducts 3, 4, and 5; alternatively, 3-5 can also be obtained directly from the reaction of 1 with CH(3)CN, i-PrNH(2), and CO, respectively. Deprotonation of complex 2 gives the neutral hydroxo complex (PC(sp3)P(i-Pr))Ni(OH), 6. All complexes have been characterized by NMR spectroscopy and, in the case of 2-6, by X-ray crystallography.
Castonguay
Annie
A
Département de Chimie, Université de Montréal, Montréal, Québec H3C 3J7, Canada.
Beauchamp
André L
AL
Zargarian
Davit
D