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Sterically Strained Porphyrins—Influence of Core Protonation and Peripheral Substitution on the Conformation of Tetra‐ meso ‐, Octa‐β‐, and Dodeca‐Substituted Porphyrin Dications
Author(s) -
Senge Mathias O.,
Forsyth Timothy P.,
Nguyen Liem T.,
Smith Kevin M.
Publication year - 1995
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.199424851
Subject(s) - porphyrin , pyrrole , planarity testing , protonation , chemistry , steric effects , ring (chemistry) , crystal structure , crystallography , tetra , photochemistry , stereochemistry , medicinal chemistry , ion , organic chemistry
The saddle‐shaped porphyrin with the largest deviation from planarity observed to date is found in the crystal structure of [H 4 obrtpp][CF 3 COO] 2 · 0.5 CHCl 3 (H 2 obrtpp = octabromotetraphenylporphyrin). The pyrrole rings in the porphyrin are twisted by 62° with respect to each other, and the β‐pyrrole C atoms are displaced by over 1.5 Å from the mean plane of the porphyrin ring. This extreme distortion is caused by the bulky peripheral substituents on the porphyrin ring and the four protons at the core of the structure.