QUANTUM-CHEMICAL CHARACTERISTICS OF CATIONIC ACTIVE-SITES FORMING IN THE BCL3-ALPHA,OMEGA-DICHLOROALKYL SYSTEMS

Taking as examples the cyclic halonium (1) and linear carbenium (II) m odel cations of equal composition, viz. [Cl(CH2)4]+, and products of p ropene addition to them (V and VI), the energetic characteristics of t hese structures were estimated by the MNDO(a)) method. The energetic p reference of I with respect to II was found to be much higher than tha t of V with respect to VI (ca. 97 and ca. 11 kJ/mole, respectively). T his difference is suggested to reflect the decrease in the tendency of linear Cl-containing carbenium ions to cyclization into halonium ions with an increase in the length of the linear hydrocarbon chain. The r esults obtained are applied to the discussion of the mechanism of poly merization in the methylpropene-BCl3-2,5-dichloro-2,5-dimethylhexane s ystem.