Title

Deuterium Nuclear Quadrupole Resonance Spectra of Nonlinear Hydrogen Bonds

Document Type

Article

Publication Date

1-1-1982

Abstract

The 2H NQR spectra of several compounds having nonlinear hydrogen bonds (OH⋯O angle of less than 150°) have been obtained at 77 K by a field-cycling double-resonance method: 1,3-diphenyl-1,3-propanedione, salicylamide, 1,4-dihydroxyanthraquinone, tropolone, salicyclic acid, 2-nitrophenol, 1-hydroxy-9-fluorenone, 3-hydroxy-2-naphthoic acid, and 1-hydroxy-2-naphthoic acid. The values obtained for the quadrupole coupling constants are higher than those found in a linear hydrogen bond of the same O⋯O distance. A single-crystal NMR study of 1,3-diphenyl-1,3-propanedione has been carried out at room temperature by a rotating-frame double-resonance experiment. The results show that the principal (z) axis of the deuterium electric field gradient tensor lies nearly along the OH bond direction. Additional 2H NQR spectra for several linear hydrogen-bonded systems in the crystalline benzoic acid, 4-chlorobenzoic acid, 2-bromobenzoic acid, 3-hydroxybenzoic acid, potassium acid phthalate, salicylamide, 3-hydroxy-2-naphthoic acid, and 1-hydroxy-2-naphthoic acid, have also been obtained. In addition, an X-ray structural study of 1-hydroxy-9-fluorenone has provided structural data to test for enhancement of the 2H quadrupole coupling constant for the case of a relatively long nonlinear hydrogen bond. © 1982, American Chemical Society. All rights reserved.

Publication Source (Journal or Book title)

Journal of the American Chemical Society

First Page

1172

Last Page

1177

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