Taking advantage of Co(ii) induced enhanced VCD for the fast and sensitive determination of enantiomeric excess

Co(II) induces a large VCD signal enhancement, which overcomes the low sensitivity of VCD and opens new perspectives in quantitative VCD. We used a stereodynamic system, where the analyte determines the chirality of the Co(II) coordination sphere. The strong VCD signals stand out the baseline, which allows for their rapid and accurate quantitation. This lends itself to the first general method for the ee determination of α-amino acids based on vibrational circular dichroism and constitutes a model for the design of sensitive quantitative assays based on VCD.