Hyperconjugative effects in π‐hydrogen bonding: Theory and experiment. Issue 10 (8th November 2017)

• Record Type: Journal Article
• Authors: Galabov, Boris; Nikolova, Valia; Cheshmedzhieva, Diana; Hadjieva, Boriana; Schaefer, Henry F.
• Other Names: Gadre Shridhar R. guestEditor.; Suresh C. H. guestEditor.
• Is Part Of: Journal of computational chemistry. Volume 39:Issue 10(2018)
• Page Start: 527
• Page End: 534
• Publication Date: 2017-11-08
• Subjects: π‐hydrogen bonding -- hexamethylbenzene -- substituted phenols -- OH stretching frequency -- hyperconjugation -- density functional theory computations; Chemistry -- Data processing -- Periodicals; 542.85
• DOI: 10.1002/jcc.25088
• Languages: English
• ISSNs: 0192-8651

Abstract

Abstract : Density functional theory computations with the B3LYP/6‐311++G(2df, 2p) method and IR spectroscopy are employed in investigating the properties of twenty π‐hydrogen bonded complexes between substituted phenols and hexamethylbenzene. All complexes possess T‐shaped structures. The methyl hyperconjugative effects on interactions energies and OH stretching frequencies are estimated via comparisons with previously reported theoretical and experimental results for analogous phenol complexes with benzene. The theoretical computations provide excellent quantitative predictions of the OH stretching frequency shifts (Δ ν OH ) resulting from the hydrogen bonding. The Δ ν OH shifts in the hexamethylbenzene complexes are approximately twice as large as the corresponding shifts for the benzene complexes. Hirshfeld charges, electrostatic potential at nuclei values, and molecular electrostatic potential maps are employed in gaining insights into the mechanisms of methyl hyperconjugative effects on complex formation. © 2017 Wiley Periodicals, Inc. Abstract : Infrared spectroscopy and density functional theory computations at B3LYP/6‐311++G(2df, 2p) are employed in characterizing the methyl hyperconjugative effects on the π‐hydrogen bonding between hexamethylbenzene and substituted phenols. Comparisons with analogous theoretical and experimental data for the complexes of phenols with benzene provide a quantitative measure of the hyperconjugation influence on interaction energies and OH frequency shifts. Molecular electrostatic potential characteristics explain well the spectroscopic features and the variations of hydrogen bonding energies.