Tetra-Antimony(III)-Bridged 18-Tungsto-2-Arsenates(V), [(LSb(III))4(A-α-As(V)W9O34)2](10-) (L = Ph, OH): Turning Bioactivity On and Off by Ligand Substitution.

Two tetra-antimony(III)-bridged, sandwich-type 18-tungsto-2-arsenates(V), [(LSb(III))4(A-α-As(V)W9O34)2](10-) (L = Ph (1), OH (2)), were prepared and fully characterized in the solid state and in solution. Both polyanions are stable in aqueous physiological medium for at least 24 h (at concentrations ≥2.5 × 10(-6) M). Despite the presence of an isostructural tetra-antimony(III) motif in 1 and 2, distinctly different antibacterial activity was observed for both polyanions. The minimum inhibitory concentrations (MIC) of 1 (7.8-62.5 μg/mL) is lower than for any other organoantimony(III)-containing polyoxometalate reported to date.