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Critical distance model for the energy of activation of the Bergman cyclization of enediynes
Author(s) -
Gaffney Shan M.,
Capitani Joseph F.,
Castaldo Lyana,
Mitra Abhijit
Publication year - 2003
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.10689
Subject(s) - singlet state , function (biology) , critical point (mathematics) , density functional theory , energy (signal processing) , zero point energy , polynomial , chemistry , computational chemistry , physics , quantum mechanics , atomic physics , mathematical analysis , mathematics , excited state , evolutionary biology , biology
The reaction profile of the Bergman cyclization of enediynes is written as a cubic polynomial expansion about the critical distance. Using the “simple sewing” approximation, a relationship is derived that expresses the energy of activation as a function of the critical distance, with the effect of other geometric and electronic factors accounted for in the expansion coefficients. A training set of 10 representative enediynes were selected and input parameters were calculated by density functional theory at the B3LYP/6‐311G* level of theory. All calculations were corrected for zero‐point energy. All singlet biradical calculations were also checked for wave function stability. Calibration curves were then constructed that correlate the activation energy of cyclization of the molecules in the test set with the critical distance parameter. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003