Chiroptical Properties of the Crosslinked Polymers

Usually the chiroptical properties of highly crosslinked polymers cannot be measured. The asymmetry of the empty cavities can be analyzed by the excellent racemate resolution ability. By a new method it can now also be directly detected by measuring the optical activity [133], This is measured by suspending the polymer in a solvent which has the same refractive index as the polymer, a technique which was developed for other types of insoluble polymers [141]. The molar optical rotation values thus measured are shown in Table 2-4. 

The optical rotation of these polymers without templates is not caused by individual chiral centers, as is usual, but by the boundaries of the empty imprints as a whole. Their chiral construction and conformation are stabilized by means of the crosslinking of the polymer chains. 

It is unlikely that the chiral configurations of the linear portions of the chains contribute to the asymmetry of the cavity since no asymmetric cyclocopolymerization is possible for the template monomer 7. With other types of template monomers, though, such contributions of backbone chiral portions of the polymer might be expected (see Section 2.2). 

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