Premium
Outstanding Enhancement in the Axial Coordination Ability of the Highly Rigid Cofacial Cyclic Metalloporphyrin Dimer
Author(s) -
Yamashita Kenichi,
Furutani Kazuhiro,
Ogawa Takuji
Publication year - 2021
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.202100186
Subject(s) - chemistry , dabco , porphyrin , dimer , molecule , crystallography , denticity , coordination sphere , ligand (biochemistry) , coordination complex , octane , metal , stereochemistry , photochemistry , crystal structure , organic chemistry , biochemistry , receptor
Copper‐ and nickel−porphyrin complexes show extremely weak axial coordination ability without any electron‐withdrawing groups. Herein, we report axial ligation on Cu II ‐ and Ni II −porphyrins in a highly rigid cofacial porphyrin dimer with a bidentate ligand, 1,4‐diazabicyclo[2.2.2]octane (DABCO). To the best of our knowledge, this is the first report on the use of Cu II ‐ and Ni II −porphyrins for coordination‐induced guest binding of porphyrin‐based host molecules without the help of other metal ions. The high rigidity of the dimer induces guest binding through the cooperative effect of weak axial ligation. The results showed that Cu II ‐ and Zn II ‐complexes bind one DABCO molecule inside their cavities, whereas the Ni II ‐complex binds two additional DABCO molecules outside to form a stable 6‐coordinate paramagnetic Ni II ‐complexes. The binding constants were determined by the UV/vis titration experiments.