Circularly polarised luminescence CPL

Consequently, an attractive complementary tool is the use of Ln(III) luminescence spectroscopy, and especially circularly polarised luminescence (CPL) spectroscopy, the... 

Since the complete details of the CPL theory have been the subject of numerous reviews [36-42], only a brief overview of the theoretical principles is highlighted here. CPL spectroscopy allows one to measure the difference in the luminescence intensity (A/) of left circularly polarised light (I ) versus right circularly polarised light (/ ). By convention this difference is defined as... 

One unique aspect of the CPL spectroscopy is that it can identify whether a Ln(Ill) complex solution contains a mixture of diastereomeric/enantiomeric species or whether this complex solution is a racemic mixture. If only one emitting species contributes to the luminescence observed in the sample, then the CPL results should be independent of excitation polarisation. Variation of the excitation polarisation from left to right circular polarisation will produce an oppositely signed CPL result of equal magnitude for a racemic... 

Unlike CD, the measurement of CPL is still mainly dependent on the use of custom-made instruments that have been designed, developed and improved by a limited number of research groups around the world over the last three decades [36,38,41,42,45,52,59-63]. However, the growing interest in developing chiral luminescent probes, and in particular Ln(in)-based systems, has resulted in the advertising and some availability of commercial instrumentation. The first commercial CPL spectrometer, which essentially consists of two CD spectrometers with the second one used as the emission spectrometer, was manufactured by JASCO Inc., the JASCO CPL-200. More recently, the company OLIS Inc. developed its Polarisation Toolbox to support fluorescence, polarisation of fluorescence, anisotropy, CPL, CD, and FDCD (fluorescence detected circular dichroism) measurements for its CD instrumentation. As of Febmary 2012, only CPL-related studies using the JASCO CPL-200 instrument have appeared in the hterature [64-67]. 

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