Anisotropy of the 1H and 13C shielding tensors in chloroform

The anisotropies, Δ σ, of the 1H and 13C nuclear shielding tensors of chloroform were determined experimentally and theoretically. The liquid crystal NMR ENEMIX method gives ΔσC = −51.8 to −51.4 ppm in excellent agreement with ab initio GIAO SCF/MCSCF calculations resulting in −51 ppm, preferring the ENEMIX results for C to the ones based on spin-lattice relaxation. A theoretical model and further experiments imply that the deviation of the ENEMIX ΔσH value from the calculated 7 ppm is caused by hydrogen bonding between CHCl3 and the CN groups of the liquid crystal ZLI 1167, which is usually considered an inert solvent.