Silver(I) complexes with halo-substituted cyanoanilines: synthesis, characterization and antibacterial activity

Four Ag(I) complexes, [Ag(L-1)(2)](NO3) (1), [Ag(L-2)(NO3)] (2), [Ag(L-3)(3)](NO3) (3), and [Ag(L-4)(2)](NO3) (4), with ligands derived from halo-containing cyanoanilines (L-1=4-amino-3fluorobenzonitrile, L-2=4-amino-3-chlorobenzonitrile, L-3=4-amino-3-bromobenzonitrile, L-4=4-amino-2-bromobenzonitrile) were synthesized and characterized by C, H, and N elemental analysis, IR and H-1 NMR spectroscopy and single crystal X-ray diffraction. Complexes 1-4 crystallized in the triclinic space group C2/c, P2(1)/n, P-1 and C2/c, respectively. In 1 and 4, Ag+ is four-coordinate with L-1 or L-4 to form 1-D {[Ag(L-1/L-4)(2)](+)} polymeric cations. In 2, Ag+ is three-coordinate by two L-2 ligands and one NO3- ligand to form a 1-D {[Ag(L-2)(NO3)]} zigzag chain. In 3, Ag+ is four-coordinate by L-3 to form a dinuclear [Ag(L-3)(3)](+) cation. The NO3- is a 4-connector bridging group in 1 and 3 and a 5-connector bridging group in 2 and 4. The intermolecular hydrogen bonds and AgO weak interactions play important roles in forming 3-D networks of 1-4. The antibacterial activities for 1-4 were evaluated against Bacillussubtilis, Staphylococcus aureus and Escherichia coli with MTT method. The antibacterial results indicated that 2 showed the best inhibitory activity against the test bacterial strains, and was as potent as chloramphenicol. [GRAPHICS] .