Syntheses, crystal structures and antimicrobial activities of polymeric silver(i) complexes with three amino-acids [aspartic acid (H2asp), glycine (Hgly) and asparagine (Hasn)]Note: For ease of reference during discussion of their anions, H2asp, Hgly and Hasn have been used as the abbreviations for the neutral amino-acids, rather than the conventional Asp, Gly and Asn, respectively.