Reaction of a Germylene, Stannylene, or Plumbylene with Trimethylaluminum and Trimethylgallium: Insertion into Al-C or Ga-C Bonds, a Reversible Metal Carbon Insertion Equilibrium, and a New Route to Diplumbenes

The reaction of the tetrylenes Ge(Ar(Me)6)(2), Sn(Ar(Me)6)(2), and Pb(Ar(Me)6)(2) [Ar(Me)6 = C6H3-2,6-(C6H2-2,4,6-(CH3)(3))(2)] with the group 13 metal alkyls trimethylaluminum and trimethylgallium afforded (Ar(Me)6)2Ge(Me)Al(Me)2 (1), (Ar(Me)6)(2)Ge((Me))Ga(Me)2 (2), and (ArMe6)2Sn(Me)Ga-2(Me) (3) in good yields via insertion reaction routes. In contrast, the reaction of AlMe3 with Sn(ArMe6)(2) afforded the [1.1.1]propellane analogue Sn-2{Sn(Me)ArMe6}(3) (5) in low yield, and the reaction of AlMe3 or GaMe3 with Pb(Ar(Me)6)(2) resulted in the formation of the diplumbene {Pb(Me)Ar(Me)6}(2) (6) and AlAr(Me)6Me(2) (7) or GaAr(Me)6Me(2) (8) via metathesis. The reaction of Sn(Ar(Me)6)(2) with gallium trialkyls was found to be reversible under ambient conditions and analyzed through the reaction of Sn(Ar(Me)6)(2) with GaEt3 to form (Ar(Me)6)(2)Sn(Et)GaEt2 (4), which displayed a dissociation constant Kdiss and Gdiss of 8.09(6) x 10(3) and 11.8(9) kJ mol(1) at 296 degrees C. The new compounds were characterized by X-ray crystallography, NMR (H-1, C-13, Sn-119, and (20)7Pb), IR, and UV vis spectroscopies.