Synthesis, Characterization, and Antimicrobial Activity of Silver(I) and Copper(II) Complexes of Phosphate Derivatives of Pyridine And Benzimidazole

Abstract Two silver(I) complexes—{[Ag(4‐pmOpe)]NO 3 } n and [Ag(2‐bimOpe) 2 ]NO 3 —and three copper(II) complexes—[Cu 4 Cl 6 O(2‐bimOpe) 4 ], [CuCl 2 (4‐pmOpe) 2 ], and [CuCl 2 (2‐bis(pm)Ope]—were synthesized by reaction of silver(I) nitrate or copper(II) chloride with phosphate derivatives of pyridine and benzimidazole, namely diethyl (pyridin‐4‐ylmethyl)phosphate (4‐pmOpe), 1 H ‐benzimidazol‐2‐ylmethyl diethyl phosphate (2‐bimOpe), and ethyl bis(pyridin‐2‐ylmethyl)phosphate (2‐bis(pm)Ope). These compounds were characterized by 1 H, 13 C, and 31 P NMR as well as IR spectroscopy, elemental analysis, and ESIMS spectrometry. Additionally, molecular and crystal structures of {[Ag(4‐pmOpe)]NO 3 } n and [Cu 4 Cl 6 O(2‐bimOpe) 4 ] were determined by single‐crystal X‐ray diffraction analysis. The antimicrobial profiles of synthesized complexes and free ligands against test organisms from the ATCC and clinical sources were determined. Silver(I) complexes showed good antimicrobial activities against Candida albicans strains (MIC values of ∼19 μ M ). [Ag(2‐bimOpe) 2 ]NO 3 was particularly active against Pseudomonas aeruginosa and methicillin‐resistant Staphylococcus epidermidis , with MIC values of ∼5 and ∼10 μ M , respectively. Neither copper(II) complexes nor the free ligands inhibited the growth of test organisms at concentrations below 500 μg mL −1 .