Pure and Applied Chemistry

Abstract: The macrocyclic cyclodextrins (enzymic conversion products of starch) were discovered in 1891, and the structures were elucidated in the mid-1930s. Their industrial significance become obvious in the 1970s, and by now thousand of tons of the three cyclodextrins (alpha-, beta-, and gamma-CD) and of their chemical derivatives and inclusion complexes are produced industrially. The outer surface of these doughnut-shaped molecules is hydrophilic, but they possess an axial open cavity, which is of hydrophobic character and capable of including other apolar molecules (or their moiety) in case of geometric compatibility. This is the essence of molecular encapsulation by inclusion complex formation.