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The reaction of the tetrahydroxyborate ion, B(OH);, with 31 polyols and carbohydrates in aqueous solution has been studied by complementary investigations involving polarimetry and llB and 13C n.m.r. spectroscopy. The calculation of equilibrium constants for the complexation of the carbohydrates with B(0H); from the polarimetry results, using a previously derived equation, was only partially successful owing to the presence of multiple equilibria in a number of cases. The presence of several complexed species in these reactions is demonstrated by llB n.m.r. studies. A calibration method devised to relate peak area in llB n.m.r. spectra with concentration has been used to calculate equilibrium constants for the various equilibria present, and an attempt has been made to rationalise the equilibrium constants with the molecular structures of the substrates. In the majority of cases the 13C n.m.r. spectra confirm the polarimetric and llB n.m.r. studies, and in most cases allow a more specific identification of the reaction sites in the polyols/carbohydrates to be made.

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