title: Aliphatic C-H...anion hydrogen bonds: weak contacts or strong interactions?
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-H...anion contacts should be considered as possible contributors when evaluating the denticity of an anion receptor.
authors.affiliation: Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6119, USA.
authors.forename: Lee
authors.initials: L
authors.lastname: Pedzisa
authors.forename: Benjamin P
authors.initials: BP
authors.lastname: Hay