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meso ‐Aryl Substituted Rubyrin and Its Higher Homologues: Structural Characterization and Chemical Properties
Author(s) -
Shimizu Soji,
Cho WonSeob,
Sessler Jonathan L.,
Shinokubo Hiroshi,
Osuka Atsuhiro
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200701909
Subject(s) - antiaromaticity , intramolecular force , chemistry , aromaticity , aryl , crystal structure , crystallography , stereochemistry , molecule , organic chemistry , alkyl
meso ‐Aryl substituted rubyrin ([26]hexaphyrin(1.1.0.1.1.0)) 2 and a series of rubyrin‐type large expanded porphyrins were obtained from a facile one‐pot oxidative coupling reaction of meso ‐pentafluorophenyl substituted tripyrrane 1 . The structures of two of the resulting products were determined by single‐crystal X‐ray diffraction analysis. Whereas [52]dodecaphyrin(1.1.0.1.1.0.1.1.0.1.1.0) 4 takes a symmetric helical conformation, the larger species, [62]pentadecaphyrin(1.1.0.1.1.0.1.1.0.1.1.0.1.1.0) 5 , adopts a nonsymmetric distorted conformation in the solid state that contains an intramolecular helical structure. The ability of rubyrin 2 to act as an anion receptor in its diprotonated form ( 2 ⋅2H + ) was demonstrated in methanolic solutions. Oxidation of 2 with MnO 2 gave [24]rubyrin 6 , a species that displays antiaromatic characteristics. [26]Rubyrin 2 and [24]rubyrin 6 both underwent metallation when reacted with Zn(OAc) 2 to give the corresponding bis‐zinc(II) complexes 7 and 8 quantitatively without engendering a change in the oxidation state of the ligands. As a result, complexes 7 and 8 exhibit aromatic and antiaromatic character, respectively. NICS calculation on these compounds also supported aromaticity of 2 and 7 , and antiaromaticity of 6 and 8 .