New zinc(II) 3-aminobenzoates with bioactive ligands: Synthesis, thermal, spectral and antimicrobial properties

Zinc(II) 3-aminobenzoate (3-NH2benz) as well as four new coordination compounds containing ligands L (thiourea - tu, nicotinamide - nad; isonicotinamide - inad; N,N-diethylnicotinamide - dnad) with general formula of [Zn(3-NH2benz)2L2] were synthesized and characterized by elemental analysis and IR spectroscopy. Thermoanalytical methods (TG/DTG, DTA) were used in order to compare the thermal decomposition of synthesized compounds with previously prepared 2- and 4-aminobenzoates. The intermediates and the final product of thermal decomposition were proved by spectroscopic methods. The antimicrobial activity of the zinc(II) 3-aminobenzoate complexes against various strains of bacteria, yeasts and filamentous fungi was determined and compared with 2- and 4-aminobenzoates as well. According to obtained results complexes with thiourea and N,N-diethylnicotinamide exhibit activity towards filamentous fungi R. oryzae, and A. Alternata, yeast C. Albicans, as well as bacteria S. aureus.