Synthesis and X-ray characterization of helical polymer complexes [Ag(1,2,3-L)(PPh3)2]n and [Ag(1,2,4-L)(PPh3)2]n (HL = triazole) and their antimicrobial activities

Two novel polymeric silver(I)-triphenylphosphine complexes with nitrogen-containing heterocycles, [Ag(1,2,3-L)(PPh3)(2)](n) 3 and [Ag(1,2,4-L)(PPh3)(2)](n) 4 (HL = triazole) were synthesized from reactions of polymeric precursors [Ag(1,2,3-L)](n) 1 and [Ag(1,2,4-L)](n) 2 with 3 equivalents of PPh3 in CH2Cl2, respectively. The polymeric precursors 1 and 2 have been obtained as non-crystalline, colorless powder-solids: 2 showed a wide spectrum of excellent antibacterial activities, but 1 did not. The antimicrobial activities of the complexes 1-4, evaluated by minimum inhibitory concentration, were compared and key factors affecting them discussed. The crystal structures of the complexes 3 and 4 were determined by single-crystal X-ray diffraction. The complexes 3 and 4 in the solid state were helical polymers consisting of AgN2P2 cores formed by bridging triazolate anions and two PPh3 ligands. The complexes 3 and 4 were also fully characterized by elemental analyses, TG/DTA and FT-IR in the solid state and by various solution NMR (P-31, Ag-109, H-1 and C-13) spectroscopies and molecular weight measurements in solution.