Water-Soluble Silver(I) Complexes Featuring the Hemilabile 3,7-Dimethyl-1,3,5-triaza-7-phosphabicyclo[3.3.1]nonane Ligand: Synthesis, Characterization, and Antimicrobial Activity

A series of bis- and tris-ligated 3,7-dimethyl-1,3,5-triaza-7-phosphabicyclo[3.3.1]nonane (PTN(Me)) silver(I) complexes featuring different types of counterions, including the antibiotic triclosan, were synthesized and fully characterized. For comparison, the bis-PTN(Me) gold species was re-prepared. Density functional theory modeling revealed strong Ag-P bonding and negligible Ag-N interactions. All complexes were assessed for antimicrobial activity against Gram-negative and Gram-positive bacteria, and fungi. The highest activity was against the Gram-negative Escherichia coli bacteria, particularly by complexes featuring the triclosan counterion.