pH-dependent displacement of [Bi(citrate)]− with cysteine: Synthesis, spectroscopic and X-ray crystallographic characterization of Bi(cysteine)3

The compound Bi(cys)3 · H2O (cys = L-cysteine) has been obtained from the displacement reaction of [Bi(cit)]− (cit = citrate) with cys in aqueous solution, and characterized by X-ray crystallography for the first time. It crystallizes in orthorhombic system with the space group P212121, a = 5.135(3) Å, b = 11.841(7) Å, c = 28.120(16) Å, V = 1709.8(17) Å3. The displacement reaction between bismuth citrate with cysteine in aqueous solution has been found to be pH-dependent and the complete displacement of the bound citrate with cysteine occurs at physiological pH value.