Syntheses, structures, and antimicrobial activities of remarkably light-stable and water-soluble silver complexes with amino acid derivatives, silver(I) N-acetylmethioninates.

Reaction of l- and dl-N-acetylmethionine (Hacmet) and Ag2O in water at ambient temperature afforded the remarkably light-stable silver complexes {[Ag(l-acmet)]}n (1) and {[Ag2(d-acmet)(l-acmet)]}n (2), respectively. The color of the solids and aqueous solutions of 1 and 2 did not change for more than 1 month under air without any shields. The light stability of these two silver(I) complexes is much higher than that of silver(I) methioninate {[Ag2(d-met)(l-met)]}n (3) (Hmet = methionine), silver(I) S-methyl-l-cysteinate {[Ag(l-mecys)]}n (4), and silver(I) l-cysteinate {[Ag(l-Hcys)]}n (5). X-ray crystallography of 1 obtained by vapor diffusion revealed that ladder-like coordination polymers with two O- and two S-donor atoms were formed. The acetyl group of acmet– prevents chelate formation of the ligand to the metal center, which is frequently observed in amino acid metal complexes, but allows for formation of hydrogen bonds between the ligands in the crystals of 1. These two silver(I) N-acetylmethioninates...