Germa- and Stanna-<i>closo</i>-dodecaborate in Reaction with [PdCl₂(Xantphos)]: P–C and B–H Bond Activation

The two nucleophilic heteroborates germa-closo-dodecaborate and stanna-closo-dodecaborate show different reactivity toward the electrophile [PdCl2(Xantphos)]: In the case of the germanium ligand we found straightforward substitution of one chloride ligand and formation of a Ge–Pd bond. The tin ligand also reacts to give the substitution products [PdCl­(SnB11H11)­(Xantphos)]− and [Pd­(SnB11H11)­(Xantphos)], but the complexes exhibit a subsequent reaction under activation of a B–H and P–C bond. A dinuclear Pd­(I)–Pd­(I) complex featuring a P–B bond was characterized, and during its formation the evolution of benzene was detected. The respective germanium derivative does not show an activation reaction even at elevated temperature.