Magnetic Relaxation Under Fast Internal Rotation in Liquid

Abstract

AbstractThe 13C nuclear spin‐lattice relaxation times for ring and methyl carbons in liquid 3,5‐lutydyne (3,5‐dimethylpyridine, 3,5‐DMP) have been measured as a function of temperature. The results have been analyzed in terms of two relaxation mechanisms: intramolecular dipole‐dipole coupling and spin‐rotation interaction. In order to separate these contributions, also the nuclear Overhauser enhancement factors have been studied. The results have been analyzed in terms of the theory of extended diffusion (ED) model for internal motion of methyl groups with a low barrier to internal rotation.