Grant for Exploratory Research: Laser NMR Spectroscopy

Warren教授得到了实验物理化学项目探索性研究的资助，研究方法将利用一种新观察到的现象，即用圆偏振光照射样品会导致手性分子的核磁共振谱线发生频率偏移。由于每个核磁共振核，取决于其相对于发色团的位置，将经历不同的符号和幅度的频移，这种现象有可能能够在拥挤的光谱中区分靠近发色团的质子。通过左圆偏振光与右圆偏振光的差谱，可以消除大多数非手性分子的所有信号，以便观察少数手性物种。由于许多重要的分子具有光学活性，这种现象可能有非常强大的应用。有可能将该技术纳入复杂系统的多维核磁共振波谱，在一个维度上的激光。这个探索性的研究项目将利用刚刚发现的对核磁共振（NMR）信号的影响，这些核位于具有手性（旋光性）的分子的发色团附近，在用激光圆偏振可见光照射下。有可能完全消除样品中所有其他非光学活性分子的核磁共振光谱中的所有信号。如果成功，这项技术将对含有生物分子的样品的核磁共振光谱产生重大影响。

Professor Warren is supported by a grant for exploratory research from the Experimental Physical Chemistry Program to develop the methods that will take advantage of a newly observed phenomenon in which irradiation of samples with circularly polarized light causes frequency shifts in the NMR spectral lines of a chiral molecule. Since each NMR nucleus, depending on its location relative to the chromophore, will experience a different sign and magnitude of frequency shift, this phenomenon has the potential of being able to distinguish among the protons located close to the chromophore in a congested spectrum. It is possible to eliminate all signals from achiral molecules in the majority, in order to observe minority chiral species by taking a difference spectrum for left vs. right circularly polarized light. Since many important molecules are optically active, this phenomenon could have very powerful applications. There are possibilities of incorporating this technique into multidimensional NMR spectroscopy of complex systems, with the laser on in one dimension. %%% This exploratory research project will make use of the just discovered effect on the nuclear magnetic resonance (NMR) signals of nuclei that are located close to the chromophore group of a molecule possessing handedness (optically active) upon irradiation with circularly polarized visible light using a laser. It is possible to eliminate entirely all signals in the NMR spectrum from all other non-optically active molecules in the sample. If successful, this technique could have a great impact on the NMR spectroscopy of samples containing biological molecules.