Group 2 and 12 metal gallyl complexes containing unsupported Ga-M covalent bonds (M = Mg, Ca, Sr, Ba, Zn, Cd)

Reactions of the anionic gallium(I) heterocycle [:Ga(DAB)]a?? (DAB = N(Dip)C(H) 2, Dip = C6H3Pri2-2,6) with several group 2 and 12 metal halide complexes are reported. Treatment of in situ generated [MI2(tmeda)n] (M = Ca, Sr, Ba; tmeda = N,N,Na??,Na??-tetramethylethylenediamine) with 2 equiv of [K(tmeda)][:Ga(DAB)] leads to salt elimination and formation of the neutral metal gallyl complexes trans-[M Ga(DAB) 2(tmeda)2]. Reaction of [(Nacnac)MgI(OEt2)] (Nanac = N(Dip)C(Me) 2CH) with [K(tmeda)][:Ga(DAB)] gives [(Nacnac)(I?1-tmeda)Mg Ga(DAB) . All complexes were crystallographically characterized and display isomerism in solution, which for the latter compound has been investigated by variable-temperature NMR spectroscopy. The 1:1 reactions of [K(tmeda)][:Ga(DAB)] with [MX2(tmeda)] (M = Zn, X = Br; M = Cd, X = I) yield [(tmeda)MX Ga(DAB) , the cadmium example of which is the first molecular complex bearing a Gaa??Cd bond. Attempts to reduce these compounds to low-valent species, e.g. [ (DAB)Ga MM Ga(DAB) , were unsuccessful. Treating [(Nacnac)Zn(I?-Br)2Li(OEt2)2] with [K(tmeda)][:Ga(DAB)] gave [(Nacnac)Zn Ga(DAB) , the X-ray crystal structure of which is reported.