[(CF3)3BCP]− and [(CF3)3BCAs]−: Thermally Stable Phosphaethynyl and Arsaethynyl Complexes

Make mine a triple: The tetraphenyl phosphonium salts of [(CF3)3BCX]− (X=P, As) are stable even well above room temperature. The synthesis of these first phospha- and arsaethynyl complexes of boron from (CF3)3BCO is carried out in two steps (see scheme). The complex [(CF3)3BCAs]− is the first stable anionic arsaalkyne.