High selectivity for l-cysteine residue at axial solvated site of trigonal-bipyramidal palladium(II) complex with tripodal tetradentate phosphine

High selectivity for the thiolate sulfur atom in l-cysteinate was observed at the solvated coordination site in the trigonal-bipyramidal palladium(II) complex, [Pd(pp3)(CH3CN)]2+ (pp3 = tris[2-(diphenylphosphino)ethyl]phosphine). The selectivity was applied to extractions of l-cysteinate from a mixture of amino acids and the reduced form of glutathionate from a mixture of the reduced and oxidized forms of glutathione.