Cation controlled assembly and transformation of mono- and bi-sulfite templated dawson-type polyoxotungstates.

The Dawson-like polyoxometalate clusters (TEAH)(6)[H(2)W(18)O(57)(SO(3))] (1) and (DMAH)(8)[W(18)O(56)(SO(3))(2)(H(2)O)(2)] (2) were synthesized under similar reaction conditions by employing triethanolammonium (TEAH(+)) and dimethylammonium (DMAH(+)) as cations, respectively. Crystallographic studies revealed that compound 1 has a compressed, peanut-like {W(18)} cage containing a single sufilte anion where each cage metal atom supports one terminal oxo-based ligand whereas compound 2 also has a {W(18)} cage, but four of the eighteen cage metal atoms support two terminal oxo-based ligands with two sulfite anions embedded in the cluster.