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Hexahelicenophanes and Their Racemization
Author(s) -
Meier Herbert,
Schwertel Manfred,
Schollmeyer Dieter
Publication year - 1998
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/(sici)1521-3773(19980817)37:15<2110::aid-anie2110>3.0.co;2-k
Subject(s) - racemization , steric effects , helicene , chemistry , ground state , stereochemistry , molecule , organic chemistry , physics , quantum mechanics
A drastic increase in the rate of racemization is found for the bridged hexahelicenophanes 1 ( n =8, 10) relative to the unsubstituted parent [6]helicene. This unexpected result occurs from steric interactions between the polymethylenedioxy chains and the terminal rings, which causes the energy of the ground state to be raised and that of the transition state to be lowered.