Knowledge Bank

Vibrational circular dichroism (VCD) measurements using FTIR techniques were reported recently. In these measurements, the VCD spectra are obtained by subtracting the VCD measured for the two enantiomers of a chiral molecule. This is necessary to eliminate the base line artifacts and to determine the zero line of VCD spectra. This procedure however cannot be used when for a given optically active sample, (a). both enantiomers are not resolved (b). the enantiomers are not of same optical purity. Carbohydrates are one series of molecules for which both enantiomers are not available. We present a procedure to determine the zero line in such cases and discuss the experimental results. We also present the first VCD measurements below $900cm-1$. $\mathrm{<mrow\; data-mjx-texclass="ORD">1</mrow>}$E. D Lipp, C. Zimba and L. A. Nafic, Chem. Phys. Lett., 90. 1(1982).