Motional dynamics in liquid 1,2,3,4-tetrahydro-5,6-dimethyl-1,4-methanonaph-thalene. Part 1. A new model compound for the investigation of anisotropic rotational diffusion and internal rotations by 13C spin–lattice relaxation data

Abstract

The hydrocarbon 1,2,3,4-tetrahydro-5,6-dimethyl-1,4-methanonaphthalene (1) was synthesized and characterized. The molecular structure of (1) is rigid and asymmetric. The molecules of (1) have at least one hindered rotating methyl group and a sufficient number of non-parallel C–H vectors. The ¹³C spin–lattice relaxation times and n.O.e. factors of (1) were measured and assigned to the corresponding carbon atoms. The dipolar ¹³C spin–lattice relaxation times n(T₁^DD) of non-methyl carbon atoms bearing directly attached protons (n is the number of these protons) are significantly different from each other, thus indicating the anisotropy of the molecular reorientation.