| Abstract |
Two novel semicarbazide [HL1,1, 1-((4-nitrophenyl)(phenyl)methylene)semicarbazide] and thiosemicarbazide [HL2,2, 1-((4-nitrophenyl)(phenyl)methylene)thiosemicarbazide] ligands were generated from 4-nitrobenzophenone and the corresponding (thio)semicarbazide precursors. Compounds1and2were fully characterized and their X-ray crystal structures were established. These organic derivatives were further applied as bioactive building blocks for the self-assembly synthesis of silver(i) coordination compounds. The reactions of silver(i) nitrate with HL1/HL(2)in the presence of aqueous NH4OH resulted in new silver(i) coordination compounds formulated as [Ag(HL1)(NO3)]center dot H2O (3) and [Ag-6(mu(3)-L-2)(6)] (4). These complexes were characterized by standard methods (FT-IR, NMR, ESI-MS, and elemental analysis) as well as single-crystal X-ray diffraction. The structure of3features a two-coordinate silver(i) center with a distorted linear \AgNO\ geometry, wherein an unusual coordination of HL(1)through the nitrogen atom of the amine group is realized. The structure of4reveals a discrete Ag(6)cluster composed of two joined trisilver(i) rings, wherein the three-coordinate Ag(i) centers adopt an \AgNS2\ environment. The antimicrobial activity of1-4was screened against Gram-positive (S. epidermidisandS. aureus) and Gram-negative (P. aeruginosaandE. coli) bacteria. Compound4presented antimicrobial activity against Gram-positive bacteria, including the ability to impair biofilm formation. This study thus contributes to a still limited research area on the development of new silver coordination compounds with potential antibiofilm activity. |
