Electric field effects on nuclear spin-spin coupling tensors and chiral discrimination via NMR spectroscopy.

Nuclear magnetic resonance spectrometers presently available are unable to recognize the two mirror-image forms of a chiral molecule, because in the absence of a chiral solvent, the NMR spectral parameters (chemical shifts and spin-spin coupling constants) are identical for the two enantiomers. This paper discusses how chirality may nevertheless, at least in theory, be recognized in liquid-state NMR spectroscopy by applying strong d.c. electric fields and measuring a pseudoscalar contribution to nuclear spin-spin coupling polarizability. Calculations are reported for medium-size chiral molecules, (2R)- N-methyloxaziridine, ( R)-1,3-dimethylallene, and (2R)-2-methyloxirane. The very small contributions provided by the pseudoscalar of nuclear spin-spin coupling polarizability seem rather difficult to detect via NMR experiments in disordered phase. [ABSTRACT FROM AUTHOR]