Selective excitation and detection of maximum quantum coherence of a group of scalar coupled protons in chiral molecules: an NMR experiment for enantiodiscrimination

Chiral discrimination of secondary alcohols and carboxylic acids by NMR spectroscopy

“…Many a times, the discrimination achieved may get completely masked because of severe spectral overlap. In order to circumvent such problems, earlier, we have reported the utility of two‐dimensional J ‐resolved, selective ω 1 ‐decoupled, z‐cosy and spin‐selective higher quantum experiments . These two‐dimensional NMR techniques are extremely useful to determine the accurate chemical shift difference between the discriminated peaks, especially when there is severe overlap as a result of complex spectral multiplicity.…”

A One-Dimensional Phase-Modulated (PM) NMR Experiment for Differentiating Spin Systems in Small Molecules Mixtures: With Application to Chiral Discrimination and Bicomponent Organic Systems

“…NMR spectroscopy, although blind to discriminate enantiomers, has been employed for their visualization by introducing a chiral environment, using one of the chiral auxiliaries such as a chiral solvating agent (CSA), a chiral derivatizing agent (CDA), and a chiral lanthanide shift reagent (CLSR). − Often one encounters a complicated situation in the identification of spin systems from the discriminated peaks due to severe overlap, because of poor chemical shift dispersion, excessive line broadening, and insufficient baseline resolution. − The baseline resolution is achieved by enhancing the interaction between chiral analytes and the chiral auxiliary either by decreasing the temperature or by adopting the strategy of employing a third ingredient. , When CLSR is chosen as a chiral auxiliary, the higher concentrations of the auxiliary yield better discrimination but with an excessive broadening of the peaks . This problem has been addressed by detecting the higher quantum transitions, which are both experimentally demanding and time-consuming . The pure shift approaches also aid in simplifying the spectral complexity for enantiodiscrimination .…”

“…21 This problem has been addressed by detecting the higher quantum transitions, which are both experimentally demanding and time-consuming. 22 The pure shift approaches also aid in simplifying the spectral complexity for enantiodiscrimination. 23 Also, a spectral editing technique known as the chemical shift selective filtration (CSSF) method has also been proposed earlier, which is used for the identification of spin systems.…”