An unusual binary phosphorus-tellurium anion and its seleno- and thio- analogues: P(4)Ch(2)(2-) (Ch = S, Se, Te)

We present an unusual discrete P-Te anion, P(4)Te(2)(2-), which is readily obtained by the oxidation of white phosphorus with Te(2)(2-) in N-methyl imidazole at ambient temperature. According to the (31)P and (125)Te NMR spectra, the anion P(4)Te(2)(2-) had a bicyclo[1.1.0]tetraphosphane ("butterfly") structure with the tellurium atoms in the exo positions. The anion was remarkably stable at ambient temperature and disproportionated only slowly with the formation of elemental tellurium. P(4)Te(2)(2-) is the first P-Te anion with a bicyclo[1.1.0]tetraphosphane structure. When Se(2)(2-) or S(2)(2-) was reacted with white phosphorus, the analogous seleno- and thiophosphate anions P(4)Se(2)(2-) and P(4)S(2)(2-) were formed, thus completing the series of phosphorus-chalcogen anions P(4)Ch(2)(2-) (Ch = S, Se, Te). The synthesis of P(4)Te(2)(2-) demonstrated that binary P-Te anions do exist as stable species in solution.