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[40]π Fused and Nonfused Core‐Modified Nonaphyrins: Syntheses and Structural Diversity
Author(s) -
Ghosh Arindam,
Srinivasan A.,
Suresh Cherumuttathu H.,
Chandrashekar Tavarekere K.
Publication year - 2016
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.201602245
Subject(s) - antiaromaticity , protonation , chemistry , stereochemistry , core (optical fiber) , ring (chemistry) , crystallography , molecule , aromaticity , materials science , organic chemistry , ion , composite material
Abstract The synthesis of fused and nonfused core‐modified 40π nonaphyrins are reported. Spectroscopic and X‐ray structural studies reveal a twisted figure‐eight conformation in the freebase form that is nonaromatic. Structural changes occur, from figure‐eight to open extended conformation, upon protonation, thereby adopting 4nπ Hückel antiaromatic character, which is reflected in spectroscopic and theoretical studies. Such a structural change also induces ring inversions of specific heterocyclic rings by 180°.