19-Tungstodiarsenate(III) Functionalized by Organoantimony(III) Groups: Tuning the Structure–Bioactivity Relationship

A family
of three discrete organoantimony­(III)-functionalized heteropolyanions[Na­{2-(Me2HN+CH2)­C6H4SbIII}­AsIII2W19O67(H2O)]10– (1), [{2-(Me2HN+CH2)­C6H4SbIII}2AsIII2W19O67(H2O)]8– (2), and
[{2-(Me2HN+CH2)­C6H4SbIII}­{WO2(H2O)}­{WO­(H2O)}2(B-β-AsIIIW8O30)­(B-α-AsIIIW9O33)2]14– (3)have been prepared by one-pot reactions of the 19-tungstodiarsenate­(III)
precursor [AsIII2W19O67(H2O)]14– with 2-(Me2NCH2)­C6H4SbCl2. The three novel
polyanions crystallized as the hydrated mixed-alkali salts Cs3KNa6[Na­{2-(Me2HN+CH2)­C6H4SbIII}­AsIII2W19O67(H2O)]·43H2O (CsKNa-1), Rb2.5K5.5[{2-(Me2HN+CH2)­C6H4SbIII}2AsIII2W19O67(H2O)]·18H2O·Me2NCH2C6H5 (RbK-2), and
Rb2.5K11.5[{2-(Me2HN+CH2)­C6H4SbIII}­{WO2(H2O)}­{WO­(H2O)}2(B-β-AsIIIW8O30)­(B-α-AsIIIW9O33)2]·52H2O (RbK-3), respectively. The number
of incorporated {2-(Me2HN+CH2)­C6H4SbIII} units could be tuned by careful
control of the experimental parameters. Polyanions 1 and 2 possess a dimeric sandwich-type topology, whereas 3 features a trimeric, wheel-shaped structure, representing
the largest organoantimony-containing polyanion. All three compounds
were fully characterized in the solid state via single-crystal X-ray
diffraction (XRD), infrared (IR) spectroscopy, and thermogravimetric
analysis, and their aqueous solution stability was validated by ultraviolet–visible
light (UV-vis) and multinuclear (1H, 13C, and 183W) nuclear magnetic resonance (NMR) spectroscopy. Effective
inhibition against six different types of bacteria was observed for 1 and 2, and we could extract a structure–bioactivity
relationship for these polyanions.