Synthesis, characterization and biological activity of some new VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) complexes of chromone based NNO Schiff base derived from 2-aminothiazole

Coordination compounds of VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) with the Schiff base obtained through the condensation of 2-aminothiazole with 3-formyl chromone were synthesized. The compounds were characterized by 1H, 13C NMR, UV–Vis, IR, Mass, EPR, molar conductance and magnetic susceptibility measurements. The Cu(II) complex possesses tetrahedrally distorted square planar geometry whereas Co(II), Ni(II), and Zn(II) show distorted tetrahedral geometry. The VO(IV) complex shows square pyramidal geometry. The cyclic voltammogram of Cu (II) complex showed a well defined redox couple Cu(II)/Cu(I) with quasireversible nature. The antimicrobial activity against the species Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albigans and Aspergillus niger was screened and compared to the activity of the ligand. Emission spectrum was recorded for the ligand and the metal(II) complexes. The second harmonic generation (SHG) efficiency was measured and found to have one fourth of the activity of urea. The SEM image of the copper(II) complex implies that the size of the particles is 2 μm.

Graphical abstractCoordination compounds of VO(IV), Co(II), Ni(II), Cu(II) and Zn(II) with Schiff base obtained through the condensation of 2-aminothiazole with 3-folmulchromone were synthesized. The compounds were characterized by 1H, 13C NMR, UV–Vis, IR, Mass, EPR, molar conductance and magnetic susceptibility measurements. Pharmacological activity of the ligand and its complexes was tested. The second harmonic generation (SHG) efficiency was measured and found to have one fourth of the activity of urea.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Addition of ethanolat anion to 3-formylchromone was confirmed by NMR and mass spectrum. ► Participation of endocyclic nitrogen atom (thiazole ring) in coordination was observed. ► Cu(II) complex shows tetrahedrally distorted square planar geometry. ► The synthesized compounds show strong antimicrobial activity. ► The Schiff base exhibits second harmonic generation (SHG) efficiency.