Bond activation quantum-chemical view

During this, the electrons of the partial X—Z multiple bond are used. Experiments show that the ester can be further active in the polymerization. Its reactivity, however, is reduced in comparison with ion pairs. From a mechanistical point of view, the chain propagation should proceed in the manner of a SN2 reaction, that is with the monomer as nucleophile and the ester as substrate. With the assistance of quantum chemical calculations using the CNDO/2 method, the differences between covalent species and free ions should be examined. The following contains the three types of anions used ... 

TS is a state in the course of reaction when one bond breaks and a new bond forms. This state is imaginary which carmot be isolated. TS cannot be found in an experiment as it is short lived, so it is not possible to view how the TS looks like experimentally. In quantum chemical reaction modelling detailed information about the geometry of TS and other physical properties associated with the TS can be foimd and also activation energy and activation entropy can be calculated which tells us that the energy of TS is more than the reactant. 

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