Characterization of some new Mg(II) complexes with heterocyclic N-donor ligands and their antimicrobial effects

Synthesis, analytical data, IR spectra, as well as antimicrobial activities of 14 Mg(II) compounds are presented. Antimicrobial activities of 4 free l igands were also tested. By means of IR spectral analysis the stereochemist ry around Mg(II) atom in the complexes had been studied. Methyl (3-pyridyl) carbamate (mpc), 3-(hydroxymethyl)pyridine (ron), and caffeine (caf) were c oordinated to Mg(II) through the nitrogen atom of the respective heterocycl ic ring. IR data suggest a unidentate coordination of carboxylate ions to M g(II). The antimicrobial effects have been tested on various strains of fil amentous fungi. A significant morphological change of Botrytis cinerea was observed with the compounds Mg(SCN)(2)(mpc)(2) . 3H(2)O and Mg(SCN)(2)(caf) (2) . 7H(2)O. The highest antimicrobial effects were manifested by the comp ound Mg(pc) H2O (pc = pyridine-2,6-dicarboxylate), especially against filam entous fungi R. oryzae and dermatophytic fungi Microsporum gypseum (IC50 = 320 mu g cm(-3) and 537 mu g cm(-3), respectively). Antimicrobial effect of the compounds is decreased in the sequence: Microsporum gypseum, Botrytis cinerea, Rhizopus oryzae, Fusarium nivale, and Alternaria alternata.