Detection and localization of solvent effects on the structure of molecules with C₃ or C_2v symmetries derived from NMR spectra in anisotropic solvents

Abstract

Methods are suggested that aUow the detection and localization of solvent effects on direct coupling constants, i.e. molecular structure. Results are presented for the methyl cyanide and ethylene molecules.

NMR Studies of 13C-Iodomethane: Different Behavior in Thermotropic and Lyotropic Liquid Crystals

“…For molecules of high symmetry (with C 3 or higher), the dipolar couplings between nuclei μ and ν in a solvent n can be expressed as in which p h , p d ( n ) , and g denote a correction factor for harmonic vibration, another correction factor for the correlated deformation in a solvent n , and a function of the equilibrium molecular geometry, respectively. Applying this to the case of halomethane gives where ( g CH / g HH ) is the “ideal” analytic expression with the equilibrium molecular geometry, and ξ is the empirical scaling factor required to get the correct molecular geometry.…”