Reliability configuration series

We concur with Whitesides (111) that in view of the complexity of lanthanide-solute systems, CLSR correlations are likely to prove neither general nor reliable, and with Mosher (110) in asserting that this technique should not be applied outside a closely related series of compounds. Even when proper precautions are taken, configurations assigned by the CLSR method should not be held above suspicion. 

Second detector confirmation is another compound confirmation technique. Two detectors with selectivity to different functional groups are connected in series to one column or in parallel to two columns. For example, two detectors, a UV/VIS detector and a fluorometer, connected in series to the HPLC column are used in the EPA Method 8310 for analysis of PAH compounds. If the second detector is connected to a second column of a dissimilar polarity, then the confirmation becomes even more reliable. An example of such a configuration is organophosphorus pesticides analysis the samples may be initially analyzed with an NPD, and then confirmed on a different column with an ECD or a FPD. 

The definitive assignments of the H and C NMR spectra of artemisinin 17 and other analogs have been reported. The 7c,h coupling constant was employed as a reliable index of the configuration of the substituents on the 1,2,4-trioxane framework and, by dynamic NMR spectroscopy, the barriers to ring interconversion of various 1,2,4-trioxane derivatives were estimated. In addition, a series of strategies has been developed using one-dimensional (TD) and 2-D NMR spectroscopy for identification of the relative stereochemistry in an assembly of substituted antimalarial... 

Fig. 9.14 Flow sheet and fault tree for a series configuration in the sense of reliability...

The estimation of spin-orbit coupling constants in the third transition series involves much more difficult methods than in the first and seeond series. There are therefore no reliable values available for Cjj in pure 54 configurations. Values for some ions in 5 4 6s and 5 4 6 configurations may be found in the references [121,161]. 

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