Buckingham A David
Department of Chemistry,Cambridge University,Cambridge CB2 1EW,UK.
Q Rev Biophys. 2015 Nov;48(4):421-3. doi: 10.1017/S0033583515000074.
Nuclear magnetic resonance is the most important form of molecular spectroscopy in chemistry and biochemistry but it is normally blind to chirality. It was predicted in 2004 that precessing nuclear spins in chiral molecules in a liquid in a strong magnetic field induce a rotating electric polarization that is of opposite sign for enantiomers. This polarization arises from the distortion of the electronic structure by the nuclear magnetic moment in the presence of the strong magnetic field and is equivalent to the linear effect of an electric field on the nuclear shielding tensor. The polarization is strongly enhanced in dipolar molecules through the partial orientation of the permanent dipole through the antisymmetric part of the nuclear magnetic shielding tensor. Alternatively, an applied electric field will induce a chirally sensitive magnetization perpendicular to the field and to the nuclear spin. Progress towards the experimental realization of chiral discrimination by NMR is assessed.
核磁共振是化学和生物化学中最重要的分子光谱形式,但它通常对手性不敏感。2004年有人预测,在强磁场中液体里的手性分子中进动的核自旋会诱导出一种旋转的电极化,对映体的这种极化具有相反的符号。这种极化源于强磁场存在时核磁矩对电子结构的扭曲,等同于电场对核屏蔽张量的线性效应。在偶极分子中,通过核磁屏蔽张量反对称部分使永久偶极部分取向,这种极化会大大增强。另外,外加电场会诱导出垂直于电场和核自旋的手性敏感磁化。评估了通过核磁共振实现手性鉴别实验的进展情况。