A molecular orbital approach to conformational study of the polyisocyanates

A conformational study of poly(alkyl isocyanates) with both non-chiral and chiral side groups (R) is presented. For this purpose the conformational preferences of model compounds CH₃ - (CONR)_m - CH₃, where m is the number of monomers, were investigated by means of quantum mechanical methods. The influence of the number of monomers and the side chain conformation on the relative stability of the different helical minima has been systematically studied. Finally, the influence of the solvent chloroform has been examined by using a self-consistent reaction-field. The results provide a detailed picture of the modulation exerted by these factors on the helical preferences of these compounds.