Synthesis, spectral and electrochemical redox properties of N-methyl fused nickel(II) porphyrin

Abstract

[Formula: see text]-methyl fused nickel(II) porphyrin was synthesized by a facile synthetic route in excellent yield. The effect of the electron-donating methyl group on spectral and electrochemical redox properties was analyzed by comparing the electrochemistry with that of its precursors. [Formula: see text]-methylated fused nickel(II) porphyrin exhibited a red-shifted absorption spectrum ([Formula: see text] 6–13 nm) and a 180[Formula: see text]mV anodic shift in the first ring oxidation as well as a 210[Formula: see text]mV shift in reduction with respect to its Ni(II)-fused porphyrin precursor (Ni[Formula: see text]-(NH)TPP). However, the absorption spectral features and redox potentials of N-methyl fused nickel(II) porphyrin are marginally shifted as compared to its immediate precursor, [Formula: see text]-formyl Ni(II)-fused porphyrin. Notably, Ni(II)(N-CH[Formula: see text](CHO)TPP exhibited a third oxidation at 1.51[Formula: see text]mV, corresponding to oxidation of Ni(II) to Ni(III) due to the presence of “push–pull” [Formula: see text] substituents.