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Redox‐Driven Symmetry Change for Terbium(III) Bis(porphyrinato) Double‐Decker Complexes by the Azimuthal Rotation of the Porphyrin Macrocycles
Author(s) -
Yamashita Kenichi,
Yamanaka Takayo,
Sakata Naoya,
Ogawa Takuji
Publication year - 2018
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201800324
Subject(s) - porphyrin , chemistry , crystallography , terbium , redox , steric effects , ligand (biochemistry) , photochemistry , ion , stereochemistry , inorganic chemistry , biochemistry , receptor , organic chemistry
Molecular structures for three oxidation forms (anion, radical, and cation) of terbium(III) bis(porphyrinato) double‐decker complexes have been systematically studied. We found that the redox state controls the azimuthal rotation angle ( φ ) between the two porphyrin macrocycles. For [Tb III (tpp) 2 ] n (tpp: tetraphenylporphyrinato, n =−1, 0, and +1), φ decreases at each stage of the oxidation process. The decrease in φ is due to the higher steric repulsion between the phenyl rings on the porphyrin macrocycle and the β hydrogen atoms on the other porphyrin macrocycle, which results from the shorter interfacial distance between the two porphyrin macrocycles. Conversely, φ =45° for both [Tb III (oep) 2 ] −1 and [Tb III (oep) 2 ] 0 (oep: octaethylporphyrinato), but φ =36° for [Tb III (oep) 2 ] +1 . Theoretical calculations suggest that the smaller azimuthal rotation angle of the cation form is due to the electronic interaction in the doubly oxidized ligand system.