The Coumarin-Based Silver(I) Complex Showed Enhanced Antitumor and Antimicrobial Activity than Ligand Itself

In this study, a novel silver(I) complex [Ag(HL1)2]NO3 (AgHL1) with coumarin derivative (3E)-3-(1-{[(pyridin-2-yl)methyl]amino}ethylidene)-3,4-dihydro-2H-benzopyran-2,4-dione (HL1) was prepared. The compounds HL1 and AgHL1 were characterized by IR and NMR spectroscopy, elemental analysis, and single crystal X-ray structural analysis. Specifically, the single crystal X-ray analysis determined the structures of both compounds HL1 and AgHL1 in their solid state, while NMR spectroscopy was used for structural determination in a solution. The HL1 proved to be a monodentate ligand and is coordinated to the Ag(I) atom through a nitrogen atom from the 2-picolylamine fragment. In the complex AgHL1, two molecules of neutral HL1 are coordinated forming a nearly linear N-Ag-N arrangement. An uncoordinated nitrate anion balances the positive charge of the complex cation. NMR spectroscopy also confirmed the stability of AgHL1 in DMSO-d6 for 3 days. In vitro cytotoxicity of HL1 and AgHL1 was performed over two cancerous cell lines A549 and HT-29 and their selectivity was verified on a healthy CCD-18Co cell line. AgHL1 exhibited low anticancer nonselective activity while the ligand was inactive. Also, the complex shows better antimicrobial activity than the positive controls on the Pseudomonas aeruginosa standard and clinical strain as well as on the tested molds.