title: Polarimetry as a tool for the study of solutions of chiral solutes.
abstract: Optical rotation of aqueous solutions of D-levoglucosan was studied experimentally in the 0.03-4.0 mol L(-1) concentration range and a nonlinear concentration dependence of specific optical rotation (SR) was revealed. Discontinuities observed in the concentration plot of SR (at 0.1, 0.3, 0.5, 1.0, and 2.0 mol L(-1)) are well correlated with those found by static and dynamic light scattering and identify concentration ranges in which different solution domains (supramers) may exist. The average SR experimental value for a D-levoglucosan aqueous solution ([α]D(28) -58.5±8.7 deg dm(-1) cm(-3) g(-1)) was found to be in good agreement with values obtained by theoretical calculation (TD-DFT/GIAO) of SR for 15 different conformers revealed by conformational sampling at the PCM/B3LYP/6-311++G(2d,2p)//B3LYP/6-31+G(d,p) level, which were shown to be strongly affected by the solvation microenvironment (0, 1, 2, and 3 explicit solvent molecules considered) due to local geometrical changes induced in the solute molecule. This exceptionally high sensitivity of SR makes polarimetry a unique method capable of sensing changes in the structure of supramers detected in this study.
authors.affiliation: N. K. Kochetkov Laboratory of Carbohydrate Chemistry, N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky prospect 47, 11991 Moscow (Russian Federation), Fax: (+7) 499-135-5328.
authors.forename: Anna V
authors.initials: AV
authors.lastname: Orlova
authors.forename: Renato R
authors.initials: RR
authors.lastname: Andrade
authors.forename: Clarissa O
authors.initials: CO
authors.lastname: da Silva
authors.forename: Alexander I
authors.initials: AI
authors.lastname: Zinin
authors.forename: Leonid O
authors.initials: LO
authors.lastname: Kononov
keywords: carbohydrates; chirality; light scattering; polarimetry; solution domains