학술논문

Aliphatic C—H⋯Anion Hydrogen Bonds: Weak Contacts or Strong Interactions?
Document Type
Article
Source
Journal of Organic Chemistry. 3/20/2009, Vol. 74 Issue 6, p2554-2560. 7p. 5 Diagrams, 3 Charts, 2 Graphs.
Subject
*ALIPHATIC compounds
*ANIONS
*HYDROGEN bonding
*ELECTRONS
*CHEMISTRY
Language
ISSN
0022-3263
Abstract
Electronic structure calculations, MP2/aug-cc-pVDZ, are used to determine C-H⋯Cl- hydrogen bond energies for a series of XCH3 donor groups in which the electron-withdrawing ability of X is varied over a wide range of values. When attached to polarizing substituents, aliphatic CH groups are moderate-to-strong hydrogen bond donors, exhibiting interaction energies comparable to those obtained with O-H and N-H groups. The results explain why aliphatic C-H donors are observed to function as competitive binding sites in solution and suggest that such C-Hߪ anion contacts should be considered as possible contributors when evaluating the denticity of an anion receptor. [ABSTRACT FROM AUTHOR]