Synthesis, spectro-analytical, computational and biological studies of novel 6-methyl-3-(1-(4-oxo-2-phenylquinazolin-3(4H)-ylimino) ethyl)-2H-pyran-2, 4(3H)-dione and its Co (II), Cu (II) and Hg (II) metal complexes

Abstract

A novel 6-methyl-3-(1-(4-oxo-2-phenylquinazolin-3(4H)-ylimino) ethyl)-2H-pyran-2, 4(3H)-dione (MOPQIEP) was prepared and characterized on the basis of Mass, IR, UV-Vis and 1 H-NMR spectral data. The solid metal complexes of the title compound were synthesized with chlorides of Co (II), Cu (II) and Hg (II) salts and characterized by Mass, IR, TGA, DTA, SEM, EDX and Magnetic Susceptibility measurements. The HyperChem.7.5 software was used for quantum chemical calculations using semi empirical method. The IR data and the energies of frontier orbitals and their corresponding contour maps of HOMO and LUMO for title compound were computed by means of single point PM3 method. 1 H NMR data is generated by TANDO 1 method. The IR and NMR data computed were in good agreement with the experimentally recorded values. The pKa value was computed by employing ChemAxon software. The computed pKa value and contour maps of frontier orbitals for the compound under study envisaged potential binding sites for metal ion coordination. The spectro-analytical analyses of its metal complexes, revealed oxygen of carbonyl group from quinazolinone and enol oxygen of pyran through deprotonation and 'N' from azomethine group as donor sites. Further the title compound and its metal complexes were tested for biological activity. The studies revealed more pronounced antimicrobial activity in mercury complex compared to the candidate compound, while with copper and cobalt complexes the activity is not significant. The experimental studies on super coiled plasmid PBR 322 DNA carried out with the title compound and its complexes inferred that only Cu (II) metal complex has the cleavage activity.