Conformational Studies by Dynamic NMR. 99. Experimental and Computed Determination of Rotation Barriers in the Crystalline State: The Case of Naphthylphenylsulfoxide

The 13C NMR CP-MAS spectrum of 2-naphthylphenylsulfoxide in the solid state displays line broadening effects due to the restricted rotation about the Ph-S bond. Line shape simulation of the temperature-dependent traces allowed the corresponding barrier to be determined in the solids (14.7 kcal mol-1). By making use of the information obtained from single-crystal X-ray diffraction, this barrier could be satisfactorily reproduced by theoretical calculations (14.5 kcal mol-1) that take into account the correlated phenyl motion involving a large set of molecules in the crystalline state.