Virtual enantiomers as the solution of optical activity's deterministic offset problem
Virtual enantiomers as the solution of optical activity's deterministic offset problem
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DOI：
10.1366/000370203321165142
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发表时间：
2003-01-01
影响因子：
3.5
通讯作者：
Hug, W
中科院分区：
文献类型：
--
作者：
Hug, W
确定性偏移一直是光学活动中最棘手的问题之一。在某种程度上，它们产生的机制不依赖于样品的热学性质，它们可以通过减去对两种对映体的测量值来消除。我们表明，有可能通过纯光学手段，仅使用半波延迟器，创建手性分子的光学对映体，测量分子及其光学产生的对映体的手性特性，并通过减去测量值来恢复物理存在的对映体的无偏移数据。此外，我们还表明，有可能以一种方式进行测量，以消除由于两个对跖点的不同热带性质的影响而可能发生的偏移。这个过程可以重复，通过这样做，可以达到几乎任意高的精度。该方法通过在所谓的散射圆偏振模式下测量的无偏移拉曼光活度后向散射光谱来证明，这是迄今为止光学活度的主要测量问题之一。这样的测量现在可以用2毫克的物质，在一次性毛细管细胞中，在密封在圆柱形小瓶中的化合物上进行。
Deterministic offsets have remained one of optical activity's most intractable problems. To the extent that the mechanisms by which they are produced do not depend on the chiroptical properties of the sample, they can be eliminated by the subtraction of measurements done on both enantiomers. We show that it is possible to create, by purely optical means, by the sole use of half-wave retarders, the optical antipode of a chiral molecule, to measure the chiroptical properties of the molecule and of its optically generated antipode, and to recover, by subtracting the measurements, the offset-free data of the enantiomer which is physically present. We moreover show that it is possible to do the measurements in a way that eliminates offsets that might occur through the influence of the differing chiroptical properties of the two antipodes. The procedure can be repeated, and by doing so, an almost arbitrarily high precision can be reached. The method is demonstrated by offset-free Raman optical activity back-scattering spectra measured in the so-called scattered circular polarization mode, one of optical activity's so far largely unsolved measurement problems. Such measurements can now be done with 2 mg of substance, in throw-away capillary cells, and on compounds sealed in cylindrical vials.