As model compounds for silver(i)â protein interactions, silver(i) complexes with three amino-acid ligands, i.e. aspartic acid (H2asp), glycine (Hgly) and asparagine (Hasn), were prepared, characterized by elemental analysis, FTIR, TG/DTA, solution (¹H and ¹³C) and solid-state (¹³C and ¹⁵N) NMR, and X-ray crystallography. Such complexes showed a wide spectrum of effective antimicrobial activities against Gram-negative (E. coli, P. aeruginosa) and -positive (B. subtilis and S. aureus) bacteria, yeasts (C. albicans and S. cerevisiae) and more than 11 tested molds. The crystal structures of four silver(i) complexes, {[Ag2(d-Hasp)(l-Hasp)]·1.5H2O}n 1, {[Ag(gly)]2·H2O}n 2, [Ag(l-asn)]n 3 and [Ag(d-asn)]n 4, were determined. The bonding modes of the silver(i) center were different for each complex, and different to those of the two recently reported silver(i) histidinates with only Agâ N bonds, i.e. water-soluble powder [{[Ag(Hhis)]·0.2EtOH}2]n 6 and water-insoluble crystals [Ag(Hhis)]n 7. Silver(i) complexes formed by amino-acids with N and O donor atoms and without an S atom can be classified into four types (Iâ IV) based on the bonding modes of the silver(i) center. Complex 1 belongs to type I which contains only Agâ O bonds, complex 2 belongs to type II, in which the two-coordinate Oâ Agâ O and Nâ Agâ N bonding units are alternately repeated, complexes 3 and 4 belong to type III, in which the two-coordinate Nâ Agâ O bonding units are repeated, and complexes that contain only Agâ N bonds, as recently found in the two silver(i) histidinates 6 and 7, belong to type IV.