Microsolvation of Anions by Molecules Forming CH∙∙X- Hydrogen Bonds

Authors

Steve Scheiner, Utah State University
Binod Nepal, Utah State University

Document Type

Article

Journal/Book Title

Chemical Physics

Publication Date

12-16-2015

Publisher

Elsevier

Volume

463

First Page

137

Last Page

144

Abstract

Various anions were surrounded by n molecules of CF₃H, which was used as a prototype CH donor solvent, and the structures and energies studied by M06-2X calculations with a 6-31+G∗∗ basis set. Anions considered included the halides F^-, Cl^-, Br^- and I^-, as well as those with multiple proton acceptor sites: CN^-, NO₃ ^-, HCOO^-, CH₃COO^-, HSO₄ ^-, H₂PO₄ ^-, and anions with higher charges SO₄ ^2-, HPO₄ ^2- and PO₄ ^3-. Well structured cages were formed and the average H-bond energy decreases steadily as the number of surrounding solvent molecules rises, even when n exceeds 6 and the CF₃H molecules begin to interact with one another rather than with the central anion. Total binding energies are very nearly proportional to the magnitude of the negative charge on the anion. The free energy of complexation becomes more negative for larger n initially, but then reaches a minimum and begins to rise for larger values of n. © 2015 Elsevier B.V.

Recommended Citation

Nepal B., Scheiner S. Microsolvation of anions by molecules forming CH··X- hydrogen bonds (2015) Chemical Physics, 463, pp. 137-144. http://www.scopus.com/inward/record.url?eid=2-s2.0-84946728509&partnerID=40&md5=e47be8b4244d6be09e17edd0022f6124