[NIL(2)X(2)] OR [HL][NILX(3)] - REACTION OF STERICALLY DEMANDING TRIALKYLPHOSPHINES-L WITH NIX(2) (X=CL, BR) IN ETHANOL

The reaction of some sterically demanding trialkylphosphines L = PR(2) R' (R = Pr-i, R' = (t)Bu; R = (t)Bu, R' = Pr-i, Me) with NiX(2) (X = C l, Pr) in ethanol affords instead of the expected non-electrolytes [Ni L(2)X(2)] tertiary phosphonium nickelates [HL][NiLX(3)] due to partici pation of the solvent. In case of the less bulky P(t)Bu(2)Me both comp lex types were obtained. [Ni(P(t)Bu(2)Me)(2)Cl-2] is tetrahedral and t herefore one of the two examples of paramagnetic bis(trialkylphosphine )dihalogenonickel(II) complexes known so far. In solution the latter c ompound undergoes an equilibrium of tetrahedral (paramagnetic) and pla nar (diamagnetic) conformer. Vis spectra as well as the results of mag netic measurements and H-1 and P-31 NMR investigations are reported.