Synthesis, spectroscopic characterization and comparative DNA binding studies of Schiff base complexes derived from l-leucine and glyoxal

The mononuclear Schiff base complexes of the type, [ML(CH3OH)2] [M = Co(II), Ni(II), Cu(II) and Zn(II)] have been synthesized by template condensation of l-leucine and glyoxal. The complexes have been characterized on the basis of the results of the elemental analysis, molar conductance, magnetic susceptibility measurements and spectroscopic studies viz, FT-IR, Mass, 1H NMR and 13C NMR spectra. The UV–vis and magnetic moment data revealed an octahedral geometry around Co(II), Ni(II) ion with distortion around Cu(II) ion complex confirmed by EPR data. The conductivity data show a non-electrolytic nature of the complexes. Absorption and fluorescence spectroscopic studies support that all the complexes exhibit a significant binding to calf thymus DNA.

Graphical abstractThe mononuclear Schiff base complexes of the type, [ML(CH3OH)2] [M = Co(II), Ni(II), Cu(II) and Zn(II)] have been synthesized by template condensation of l-leucine and glyoxal. The complexes have been characterized on the basis of the results of the elemental analysis, molar conductance, magnetic susceptibility measurements and spectroscopic studies viz, FT-IR, Mass, 1H NMR and 13C NMR spectra. The UV–vis and magnetic moment data revealed a octahedral geometry around Co(II), Ni(II) ion with distortion around Cu(II) ion complex confirmed by EPR data. Absorption and fluorescence spectroscopic studies support that all the complexes exhibit a significant binding to calf thymus DNA.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights• We report synthesis of complexes, derived from the template condensation reaction between glyoxal and l-leucine. • The UV–vis and magnetic moment data revealed a octahedral geometry around Co(II), Ni(II) ion with distortion around Cu(II) ion complex confirmed by EPR data. • Absorption and fluorescence spectroscopic studies support that all the complexes exhibit a significant binding to calf thymus DNA. • In the present study, copper complex of l-leucine based Schiff base has higher binding affinity towards DNA as compared to Co(II), Ni(II) and Zn(II) complexes.