Phenazine-bridged Ni(II) porphyrin dimers and its oxidative fusion

Abstract

Oxidative fusion reaction of phenazine-bridged dimer 4 with DDQ and Sc(OTf)3 generated half phenazine-fused porphyrin dimer 6 and 10,12-, 18,20-, 10[Formula: see text],12[Formula: see text]- and 18[Formula: see text],20[Formula: see text]-quadruply 3,5-di-tert-butylphenyl-fused porphyrin dimer 7. The structures of 4, 6 and 7 were unambiguously confirmed by the comprehensive results of nuclear magnetic resonance, highresolution mass spectrometry, and X-ray crystallographic analysis. As compared to their precursors, the fused porphyrins exhibit significant change in optical properties due to the extended [Formula: see text]-conjugation, such as a bathochromic shift of absorption and broadening of the Soret band. In addition, NICS(0) calculations were performed to understand the aromaticity variation of porphyrins 4, 6 and 7. Electrochemical properties were determined and DFT calculations were performed to deepen our understanding of the electronic structures and spectral properties of these Ni(II) porphyrin dimers.