The chiral asymmetry revealed by the Raman differential bond polarizability of (2R, 3R)-(-)- 2, 3-butanediol

Abstract

The Raman optical activity (ROA) of (2R, 3R)-2, 3-butanediol is investigated through the intensities of Raman spectrum and ROA spectrum, bond polarizability and differential bond polarizability. In view of the two possible optimized structures, i.e., C1 and C2 group, we obtain the conclusion that ample information concerning the physical pictures of this chiral system does not depend on the two variant structures.Based on the analysis of bond polarizabilities, the charge moves from the periphery to the skeleton structure in the Raman relaxation process. The analysis of differential bond polarizabilities shows that the signs of differential bond polarizabilities on the both sides of the plane associated with the asymmetric C and H atoms are opposite. This means that the chiral asymmetry of this molecule is rather complete.Also, it is observed that bond polarizabilities for the symmetric modes are larger than for the antisymmetric modes, while for the differential bond polarizabilities, the situation is just reverse.