Cd(II), Hg(II) and Pt(II) complexes of 1-ethyl-3-(4-methylthiazol-2-yl)thiourea: Synthesis, X-ray crystal structure, DFT studies, antimicrobial and antioxidant applications

H2EMT has been separated into divalent cadmium, mercury, and platinum complexes. The structures of the complexes were identified by various physico-chemical and spectroscopic techniques (UV-vis., IR, Mass Spectrometry and NMR). The FTIR results show that H2EMT exists as a mono-basic NS donor in all complexes. In [Cd(HEMT)Cl(H2O)]·2H2O and [Hg(HEMT)Cl(H2O)]·3H2O, only one deprotonatedH2EMT molecule was attached to the metal forming 4-coordinated distorted tetrahedral geometries. In [Pt(HEMT)2], two deprotonatedH2EMT were found to be forming a one-dimensional square-planar complex and its crystal structure was determined using X-ray diffraction. Using geometry optimization for isolated compounds, different descriptors were calculated. Density functional theory calculates were used for the estimation of hypothetical frequencies for all studied compounds and the correlation of the measured (solution) and hypothetical (gas) 1H & and 13C NMR spectra of H2EMT. Antimicrobial studies showed that H2EMT exhibited the highest activity against S. aureus and C. albicans followed by [Cd(HEMT)(H2O)Cl]·2H2O. However, [Cd(HEMT)(H2O)Cl]·2H2O showed the highest antibacterial activity against E. coli. H2EMT and [Cd(HEMT)(H2O)Cl]·2H2O revealed the highest DPPH scavenging activity (IC50 values equal 38.1 and 43.6 μg/mL, respectively).