Macromolecular stereochemistry. The first observations of cholesteric polyisocyanates; searching for expected preferred chiral conformations induced by cholesteric liquid crystals in otherwise optically inactive substances

We have discovered an extreme sensitivity of the helix sense ratio in wormlike polyisocyanates to chiral perturbations from the side chain. In the situation of a homogenious chiral influence the cooperation responsible for this effect can be treated by statistical thermodynamics which can reveal the exact responsible energy terms. This analysis predicts that even tiny fractions of a calorie per mole of residues can cause a measureable, by optical activity, excess of one helical sense.