Synthesis, characterization and electrochemistry of dipyrrinato nickel(II) complexes with different aromatic rings to meso-position

Abstract Three kinds of dipyrrinato nickel(II) complexes with different aromatic substituted groups on meso -carbon position have been synthesized while their properties have been studied. The aromatic substituents of investigated compounds are phenyl ( 2a ), 2-naphthyl ( 2b ) and 4-carbazolylphenyl ( 2c ), respectively. All compounds were characterized by 1 H and 13 C NMR spectra, MS and UV–Vis absorption spectra. These compounds were also investigated by electrochemistry in dichloromethane containing 0.1 M tetra-n-butylammonium perchlorate (TBAP). Each compound undergoes two reversible reductions along with one irreversible oxidation and 2c shows another two quasi-reversible oxidations. The redox potentials of 2a-c are consistent with the optical spectroscopy data and the relatively narrow HOMO–LUMO gaps that are predicted in DFT calculation. The X-ray crystal structure of 5-(4-carbazolylphenyl) nickel(II) dipyrrinato complex ( 2c ) was also reported.