Bismuth(III) 5-sulfosalicylate complexes: structure, solubility and activity against Helicobacter pylori

Treatment of 5-sulfosalicylic acid (H(3)Ssal) with BiPh3 results in the formation of the first dianionic carboxylate-sulfonate bismuth complex, [PhBi(HSsal)H2O](infinity) 1a, and its ethanol analogue [PhBi(HSsal) EtOH](infinity) 1b (space group P2(1)/c), while Bi(OAc)(3) gives the mixed monoanionic and dianionic complex, {[Bi(HSsal)(H(2)Ssal)(H2O)(3)](2)center dot 2H(2)O}(infinity) 2 (space group P (1) over bar). The three complexes are all polymeric in the solid state as determined by single crystal X-ray diffraction, with extended frameworks constructed from dimeric [Bi(HSsal)] 2, 1a and 1b, or from [Bi(HSsal)(H(2)Ssal)](2) units, 2. The heteroleptic bismuth complexes 1a and 2 display remarkable aqueous solubility, 10 and 2.5 mg ml(-1) respectively, resulting in a clear solution of pH 1.5. In contrast, 1b is essentially insoluble in aqueous environments. All three complexes show significant activity against the bacterium Helicobacter pylori of < 6.25 mu g ml(-1).