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Site charge models for molecular electrostatic potentials of cycloalkanes and tetrahedrane
Author(s) -
Williams Donald E.,
Abraha Aron
Publication year - 1999
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/(sici)1096-987x(19990430)20:6<579::aid-jcc3>3.0.co;2-e
Subject(s) - cyclopropane , chemistry , charge (physics) , atomic charge , computational chemistry , bond length , charge density , molecule , ring (chemistry) , physics , quantum mechanics , organic chemistry
The molecular structures of cycloalkanes (from cyclopropane to cyclodecane) and tetrahedrane were optimized at the Hartree–Fock/6–31G** level and their molecular electric potentials (MEPs) were calculated using a geodesic grid. The MEPs were fitted using net atomic charges and several site charge models. The net atomic charge model gave very poor fits to the MEPs in every case. A model with additional methylene bisector charge sites, similar to one successfully used previously for linear alkanes, greatly improved the fits to the MEPs of these cycloalkanes. The MEPs of the highly strained molecules cyclopropane and tetrahedrane were further studied using ring center and displaced bond charge sites. The fitting of the MEP of cyclopropane was consistent with a banana bond model with asymmetrically displaced electron density in the CC bonds. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 579–585, 1999