Tetra-Antimony(III)-Bridged 18-Tungsto-2-Arsenates(V), [(LSbIII)4(A‑α-AsVW9O34)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), [(LSbIII)4(A-α-AsVW9O34)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.