Preparation and structure of hetero- and homoleptic thiomethyl nickel complexes.

Thiomethyl Ni complexes [Ni(CH2SR)2(PBu3)2] (R = Me (1a), tert-Bu (1b), Ph (1c)) and the homoleptic derivs. [{Li(Et2O)}2Ni(CH2SBu-tert)4] (2), [Li2Ni(CH2SMe)4].xTHF (3a) and [Li2Ni(CH2SPh)4].xEt2O (3b) were synthesized by the reaction of Ni halide phosphine complexes with the appropriate thiomethyl Li compds. LiCH2SR in a molar ratio of 1:2 and 1:4, resp. The mol. structures (x-ray) of the diamagnetic heteroleptic deriv. 1 were characterized by microanal. and by NMR spectroscopy. The tert-butylthiomethyl complex 2 is stable at room temp. (Tdec. .apprx. 60-66 Deg) whereas the Me- and phenylthiomethyl complexes 3a and 3b are decompd. already at -10 to -20 Deg. The mol. structure (x-ray) of 2 shows a slightly distorted planar arrangement of the four methylene C atoms and Ni (d(Ni-C) = 1.944(3) .ANG.). The Li atoms are distorted tetrahedrally coordinated by two S atoms, one O atom (Et2O) and one methylene C atom. The short Li-S distances (2.461(6)-2.535(5) .ANG.) indicate strong Li-S interactions.