The 13C spin-lattice relaxation times for carbon tetrachloride have been measured in the presence of various paramagnetic chromium (111) chelates (PAR&). The TI values were compared with those of an inert standard, cyclohexane. A specific PARR. carbon tetrachloride interaction was clearly indicated, which is less obvious for bulky ligands or ligands having electron-withdrawing substituents. The electron-nuclear relaxation model and the quantitative description of outer-sphere complexation is briefly discussed.