Calculations on the polymerization process of some 1,1-disubstituted cyclopropanes: I. The initiation step

Ab initio calculations on the initial steps of the polymerization process of 1,1-dicyano-, -difluoro- and -dimethyl-substituted cyclopropanes are presented. Polymerization enthalpies determined by model calculations show the thermodynamic feasibility of the process. The reaction mechanism of the first step is further discussed by considering initiation by various species such as H-q, OHq, and CH3q (q = +, 0, -). Transition structures and energy barriers are obtained for all species, allowing discussion of the reaction mechanism and an estimation of the kinetic feasibility. The Hartree-Fock structures at the 6-31+G(d,p) level have been fully optimized and electron correlation has been introduced at the MP2 level for some selected reaction mechanisms.