Magnitude and directionality of the interaction energy of the aliphatic CH/π interaction: Significant difference from hydrogen bond

Seiji Tsuzuki, Kazumasa Honda, Tadafumi Uchimaru, Masuhiro Mikami, Asuka Fujii

Research output: Contribution to journalArticlepeer-review

108 Citations (Scopus)

Abstract

The CCSD(T) level interaction energies of CH/π complexes at the basis set limit were estimated. The estimated interaction energies of the benzene complexes with CH4, CH3CH3, CH 2CH2, CHCH, CH3NH2, CH 3OH, CH3OCH3, CH3F, CH 3Cl, CH3ClNH2, CH3ClOH, CH 2Cl2, CH2FCl, CH2F2, CHCl3, and CH3F3 are -1.45, -1.82, -2.06, -2.83, -1.94, -1.98, -2.06, -2.31, -2.99, -3.57, -3.71, -4.54, -3.88, -3.22, -5.64, and -4.18 kcal/mol, respectively. Dispersion is the major source of attraction, even if substituents are attached to the carbon atom of the C-H bond. The dispersion interaction between benzene and chlorine atoms, which is not the CH/π interaction, is the cause of the very large interaction energy of the CHCl3 complex. Activated CH/π interaction (acetylene and substituted methanes with two or three electron-withdrawing groups) is not very weak. The nature of the activated CH/π interaction may be similar to the hydrogen bond. On the other hand, the nature of other typical (nonactivated) CH/π interactions is completely different from that of the hydrogen bond. The typical CH/π interaction is significantly weaker than the hydrogen bond. Dispersion interaction is mainly responsible for the attraction in the CH/π interaction, whereas electrostatic interaction is the major source of attraction in the hydrogen bond. The orientation dependence of the interaction energy of the typical CH/π interaction energy is very small, whereas the hydrogen bond has strong directionality. The weak directionality suggests that the hydrogen atom of the interacting C-H bond is not essential for the attraction and that the typical CH/π interaction does not play critical roles in determining the molecular orientation in molecular assemblies.

Original languageEnglish
Pages (from-to)10163-10168
Number of pages6
JournalJournal of Physical Chemistry A
Volume110
Issue number33
DOIs
Publication statusPublished - 2006 Aug 24

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Fingerprint Dive into the research topics of 'Magnitude and directionality of the interaction energy of the aliphatic CH/π interaction: Significant difference from hydrogen bond'. Together they form a unique fingerprint.

Cite this