Isolation and Structures of Two New Organozinc Anions from Solutions Rich in Halide Ions

The organometallic dianions diethyltetrachlorodizincate, [Et(Cl)Zn(mu-Cl)(2)Zn(Cl)Et], and ethyltribromozincate, [EtZnBr(3)], have been isolated from reaction mixtures containing diethylzinc and a tetraphenylphosphonium halide (X = Cl or Br). Evidence for these anions had previously been reported using mass spectrometry. The ions may have importance in the solution structure of organozinc reagents used extensively in organic synthesis.