How long are Ga⇆Ga double bonds and Ga-Ga single bonds in dicationic gallium dimers?

Abstract

Syntheses and characterization of two salts [(L)GaGa(L)][pf]2 ([pf]− = [Al(ORF)4]−; RF = C(CF3)3) are reported. They include the first dicationic digallene [(L)Ga⇆Ga(L)]2+ (L = CDPPh = C(PPh3)2) and a digallane [(L)Ga-Ga(L)]2+ (L = [NacNacMes]−). The CDPPh-supported digallene dication includes a trans-bent [L-GaGa-L]2+ bond that is analogous to neutral R-GaGa-R molecules and related to Robinson's famous “Digallyne” [R-GaGa-R]2−. The dicationic digallane [(L)Ga-Ga(L)]2+ is analogous to the widely used “Jones magnesium dimer”, but includes a very short GaII-GaII single bond.