Synthesis, characterization and DNA-binding properties of four Zn(II) complexes with bis(pyrrol-2-yl-methyleneamine) ligands

A novel series of bis(pyrrol-2-yl-methyleneamine) ligands H2Ln (n = 1–4) were synthesized via condensation of diamines with two equivalents of 2-formyl-pyrrole (2). Their Zn(II) complexes were characterized by elemental analyses, mass spectra and IR spectra. The crystal structures of [ZnL1]2 and [ZnL4]2 obtained from ethanol solution was determined by X-ray diffraction analysis, each of them possesses a double-stranded helical geometry. In addition, the DNA-binding properties of the compounds have been fully investigated by absorption, fluorescence and viscosity measurements.