Some new cadmium complexes: Antibacterial/antifungal activity and thermal behavior

Four new cadmium(II) Schiff base complexes formulated as CdLX2 (X = Cl−, Br−, I−, SCN− and L = bis (3(4-dimethylaminophenyl)-allylidene)-1,2-diaminoethane) were synthesized. All novel compounds were identified by spectroscopic techniques including FT-IR, 1H and 13C NMR, UV–vis spectra and physico-chemical methods such as molar conductivity, elemental analysis and melting point. Based on the physical and spectral evidences, the pseudo-tetrahedral geometry was proposed for all complexes. The in vitro antibacterial/antifungal activity of each compound was screened against four bacterial strains such as Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa as well as two fungal pathogens such as Candida albicans and Aspergillus niger. The biological testing data showed that all compounds were antimicrobial active against both Gram-positive and Gram-negative bacteria and two fungal strains. The bactericidal/fungicidal properties of compounds showed that the cadmium complexes were more bioactive than the parent ligand. Furthermore, the thermal behavior of all compounds was studied. The ligand was completely destructed through three temperature stages. Among the cadmium complexes, the CdL(NCS)2was found as the most stable while the CdLCl2 showed the least thermal stability. Besides some activation thermodynamic parameters such as E*, ΔH*, ΔS*, ΔG* were calculated using thermo-grams data by Coats–Redfern equation.