A single chiroptical spectroscopic method may not be able to establish the absolute configurations of diastereomers: dimethylesters of hibiscus and garcinia acids.

Prasad L Polavarapu, Emily A Donahue, Ganesh Shanmugam, Giovanni Scalmani, Edward K Hawkins, Carmelo Rizzo, Ibrahim Ibnusaud, Grace Thomas, Deenamma Habel, Dellamol Sebastian

The journal of physical chemistry. A 2011 Jun 09

filter terms:

Electronic circular dichroism (ECD), optical rotatory dispersion (ORD), and vibrational circular dichroism (VCD) spectra of hibiscus acid dimethyl ester have been measured and analyzed in combination with quantum chemical calculations of corresponding spectra. These results, along with those reported previously for garcinia acid dimethyl ester, reveal that none of these three (ECD, ORD, or VCD) spectroscopic methods, in isolation, can unequivocally establish the absolute configurations of diastereomers. This deficiency is eliminated when a combined spectral analysis of either ECD and VCD or ORD and VCD methods is used. It is also found that the ambiguities in the assignment of absolute configurations of diastereomers may also be overcome when unpolarized vibrational absorption is included in the spectral analysis.

Citation

Prasad L Polavarapu, Emily A Donahue, Ganesh Shanmugam, Giovanni Scalmani, Edward K Hawkins, Carmelo Rizzo, Ibrahim Ibnusaud, Grace Thomas, Deenamma Habel, Dellamol Sebastian. A single chiroptical spectroscopic method may not be able to establish the absolute configurations of diastereomers: dimethylesters of hibiscus and garcinia acids. The journal of physical chemistry. A. 2011 Jun 09;115(22):5665-73