Antimicrobial and genotoxic activity of 2,6-diacetylpyridine bis(acylhydrazones) and their complexes with some first transition series metal ions. X-ray crystal structure of a dinuclear copper(II) complex.

The antibacterial and antifungal properties of five 2,6-diacetylpyridine bis(acylhydrazones) (acyl:benzoyl, H2dapb; 2-aminobenzoyl, H2dapab; salicyloyl, H2daps; picolinoyl, H2dappc; 2-thenoyl, H2dapt) and of a series of metal complexes were investigated. The x-ray crystal structure of the [Cu(dapt)]2 complex was also determined. It consists of dimeric units in which both copper atoms have sixfold coordination. The evaluation of in vitro antimicrobial properties showed some compounds to exhibit good activity against Gram positive bacteria. In most cases, complexes showed a similar or reduced activity as compared to the ligand itself. Only the iron complexes were found to be more active than the chelating agent involved. None of the compounds showed any significant antifungal activity. The genotoxicity of the compounds described was studied in vitro with Bacillus subtilis rec-assay and Salmonella-microsome reversion assay. No DNA-damaging activity was detected in the Bacillus subtilis rec-assay. H2dapb, H2dapb, and H2dappc were active in the Salmonella test. In several cases, the genotoxic properties of the ligands disappeared in the complexes.