Quantum chemical characteristics of cationic active sites forming in the Bcl₃‐α,ω‐dichloroalkyl systems

Abstract

SUMMARY:Taking as examples the cyclic halonium (I) and linear carbenium (11) model cations of equal composition, viz. [Cl(CH,),]+, and products of propene addition to them (V and VI), the energetic characteristics of these structures were estimated by the MNDO a) method. The energetic preference of I with respect to I1 was found to be much higher than that of V with respect to VI (ca. 97 and ca. 11 kJ/mole, respectively). This difference is suggested to reflect the decrease in the tendency of linear C1-containing carbenium ions to cyclization into halonium ions with an increase in the length of the linear hydrocarbon chain. The results obtained are applied to the discussion of the mechanism of polymerization in the 2-methylpr0pene-BC1~-2,5-dichloro-2,5-dimethylhexane system.

Models of macromolecular chains based on Classical and Quantum Mechanics: comparison with Gaussian models

“…where H hsYin is the classical Hamiltonian given in Eq. (30). Upon performing the Gaussian integrations over all momenta, one gets:…”

“…[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] as samples of recent studies, not based upon Quantum Mechanics and to ref. [30][31][32][33][34][35][36][37][38][39][40] as examples of quantum mechanical ones. For a full variety of cases in Polymer Science, it may be not easy or, even, extremely difficult, to set up quantum-mechanical formulations: then, the probabilistic or Classical Mechanics approaches may well be the only available tools, in practice.…”

Hindered macromolecular chains: A quantum mechanical model

“…We shall omit the resulting lengthy expression for Hi, and replace it into Eq (29),. in order to, subsequently, carry through the integrations over the variables pjj+l, in the high frequency limit.…”