Organoarsonate Functionalization of Heteropolyoxotungstates

[Image: see text] Functionalization of the {P(8)W(48)} polyoxotungstate (POT) archetype with aromatic organoarsonates results in the first homometallic {P(8)W(48)} derivatives, with the general formula [(RAs(V)O)(4)P(V)(8)W(VI)(48)O(184)](32−) [R = C(6)H(5) (1) or p-(H(2)N)C(6)H(4) (2)]. Short As−O bonds here induce unusual bending of the otherwise rigid {P(8)W(48)} macrocycle, breaking its D(4h) symmetry. The obtained species also represent the first lacunary POTs functionalized with organoarsonates and can potentially act as polyoxometalate precursors themselves. We elaborate solution stability in different aqueous media using (1)H and (31)P NMR spectroscopy and possible pathways for subsequent transformations in aqueous solutions of the functionalized polyanions. Recrystallization of the K(+)/Li(+)/dimethylammonium salt of 2 from 4 M LiCl solution yielded a further functionalized POT, [(H(3)NC(6)H(4)AsO)(3)P(8)W(48)O(184)H(x){WO(2)(H(2)O)(2)}(0.4)]((30.2−x)−) (3), revealing dissociation of the organoarsonate fragments in slightly acidic aqueous solutions followed by their rearrangement within the inner POT cavity.