Abstract Stability and structure of complexes between silver (I) l -methionine (L) deduced from potentiometric 1 H NMR measurements allow to assume the prevailing several protonated species. The experimental data are compatible with formation following complexes: AgL, AgL 2 , AgH L, L 3 4 . coordination sites obtained by spectra, showing that only bond methylthioether sulfur atom is responsible...