Oxidation of (AsPh(2))(2)E (E=O or S); Supramolecular hydrogen-bonded self-assembly of an unusual tetranuclear adduct and crystal structure of [AsPh(2)(O)OH center dot AsPh(2)(S)OH](2)

Oxidation of (AsPh(2))(2)E(E = O or S) with tert-butyl hydroperoxide and sulfur in the ratios 1:1 and 1:2 has been investigated in an attempt to produce compounds of the type AsPh(2)(E)-E-AsPh(2) and [AsPh(2)(E)](2)E. Although it has been possible to isolate all four compounds of the type AsPh(2)(E)-E-AsPh(2), where E = O or S, the dioxidation products are less stable and recrystallisation of the products from oxidation of (AsPh(2))(2)O with sulfur and (AsPh(2))(2)S with tert-butyl hydroperoxide leads to a mixed arsinic acid-monothioarsinic acid [AsPh(2)(O)OH . AsPh(2)(S)OH](2). This compound has an unusual tetranuclear structure, arising from simultaneous intermolecular hydrogen bond formation between the OH groups of the constituent acids and the oxygen of a centrosymmetrically related diphenylarsinic acid molecule.