Synthesis and electrochemistry of meso-substitutes dipyrromethene nickel (II) complexes

Abstract Metalation of dipyrromethene (dipyrrin) ( 1a–c ) with Ni(OAc) 2 provides Ni-dipyrrole complexes (NiL 2 ) ( 2a–c ) in 37–47% yields. The complexes were characterized by mass spectrometry and UV–Vis absorption, 1 H NMR spectroscopy and single crystal X-ray. In CH 2 Cl 2, each compound undergoes two reversible one-electron reductions and one irreversible oxidation wave. In DMF, complexes 2a–c also undergoes two reversible one-electron reductions but with three irreversible oxidation waves were observed. The effect of substituents and solvent on redox potentials is discussed.