Ab initio theoretical optical rotations of small molecules

Abstract

Abstract Optical rotations of small chiral molecules have been calculated ab initio to evaluate the role of substituents and of conformations. The optical rotations of oxaziridines provide a nice correlation between the sign of optical rotation and absolute configuration. Such correlation is not obvious in the case of diaziridines and tetrahydrofurans. The optical rotations obtained for different conformers of 3-butyn-2-ol suggested a possible predominant conformation in liquid solutions. The prediction of optical rotations, as a function of dihedral angle, for H 2 O 2 and H 2 S 2 reveal that the sign of optical rotation is negative for counter-clockwise dihedral angles (M-helicity) and the magnitude is maximum at a dihedral angle of 90° (in H 2 O 2 ) or 110° (in H 2 S 2 ).