Solvent effects on chiroptical properties of carbonyl functional group molecules

Solvent effects on Optical Rotatory Dispersion (ORD) and Circular Dichroism CD of carvone enantiomers and $R$-(+)-3-methylcyclopentanone ($R$3MCP) are studied for 35 common solvents. Solvent effects are significantly attributed to the solute-solvent electrostatic and Van der waals interactions. Hartree-Fock and Density Function theoretical calculations of $R$3MCP CD and ORD in solvation are also employed to support the experimental findings and observed to have good agreement with experimental results. Enantiomers ($R$,$S)$ of chiral molecules are known to exhibit optical activity effects which are equal in magnitude and opposite in sign. For some carbonyl molecules (possessing C=O) the equatorial and axial conformers also exhibit CD and ORD of opposite sign but not necessarily the same absolute magnitude for the $n\to \pi $* ($n\to $3s) molecular transition. Temperature dependent variations of CD and Raman spectra are shown to be a useful technique to study the conformer's populations and energy difference of $R$3MCP. Thermodynamic constants of $R$3MCP in 35 solvents, will be presented and related to solvent polarity parameters.