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Efficient Synthesis of Arylenedioxy‐Bridged Porphyrin Dimers through Catalyst‐Free Nucleophilic Aromatic Substitution
Author(s) -
Yamashita Kenichi,
Kuramochi Narumi,
Pham Qui Van Hang,
Furutani Kazuhiro,
Ogawa Takuji,
Sugiura Kenichi
Publication year - 2020
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201900670
Subject(s) - porphyrin , steric effects , chemistry , dimer , monomer , nucleophilic substitution , photochemistry , catalysis , stereochemistry , crystallography , medicinal chemistry , organic chemistry , polymer
Abstract A series of porphyrin dimers bridged by one or two rigid arylenedioxy linkers was successfully synthesized by catalyst‐free meso ‐aryloxylation involving nucleophilic aromatic substitution. The orientational freedom and conformation of the two porphyrin macrocycles in the mono‐bridged dimers depended on the steric hindrance between the macrocycles and substituents on the arylenedioxy linkers. On the other hand, the bis‐bridged dimers exhibited a highly rigid cofacial conformation with a distinct interplanar distance. The fluorescence quantum yields of the bis‐bridged dimers ( Φ fl =0.094 and 0.096) were quite similar to those of the monomers ( Φ fl =0.13). Owing to their high rigidities, the nonradiative deactivation of the photoexcited states associated with dimerization, which are observed for reported dimers, are mostly suppressed, thus suggesting that those dimers have highest rigidities among the cofacial porphyrin dimers exploring emission properties. Cyclic voltammetry revealed the electronic communication between the porphyrin macrocycles in the closely stacked bis‐bridged dimer.