✦ LIBER ✦

Site charge models for molecular electrostatic potentials of cycloalkanes and tetrahedrane

✍ Scribed by Williams, Donald E.; Abraha, Aron

Publisher: John Wiley and Sons
Year: 1999
Tongue: English
Weight: 158 KB
Volume: 20
Category: Article
ISSN: 0192-8651
DOI: 10.1002/(sici)1096-987x(19990430)20:6<579::aid-jcc3>3.0.co;2-e

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✦ Synopsis

The molecular structures of cycloalkanes from cyclopropane to . cyclodecane and tetrahedrane were optimized at the Hartree᎐Fockr6᎐31G** Ž . 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 C-C bonds.

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