Bond-Breaking Reactions

No Reactions Bond breaking-off First atom Second atom Calculation Experiment... 

The most straightforward explanation for the observed second-order kinetics is a concerted reaction—bond breaking and bond making occur at the same time, as shown in Mechanism 7.1. 

In chemical reactions, bonds break in the reactants and new bonds form in the products. In homolytic bond cleavage, the bonding electrons are evenly divided among the two parting atoms neutral free radicals are the result. In heterolytic bond cleavage, the bonding electrons are unevenly... 

At a certain stage in the progress of a reaction, bond breaking and bond making are of equal importance. In other words, the energy necessary for bond breaking... 

There are two main manifestations of the anomeric effect concerning energy (Section IV.A) and concerning structure (Section IV.B). In this section, however, the energies of ground states are not considered further since they are an essential part of the definition of the anomeric effect. We shall deal here only with energies of transition states, in particular with transition states of chemical reactions (bond breaking) and transition states for rotation about bonds to an anomeric atom. 

In radical reactions, bonds break homolytically with one electron going one way and one the other. The radicals that are formed have an odd number of electrons, one of which must be unpaired. This makes them very reactive and they are not usually isolated. Even strong bonds can break into ions provided they are polarized, but to make radicals we need weak symmetrical bonds such as 0-0, Br-Br or I-I. Dibenzoyl peroxide, the Ph(C02)2 catalyst in this reaction, readily undergoes homolysis like this—the one-electron movements are represented by fish-hook arrows having one barb and odd electrons on atoms are represented by dots. 

Bond enthalpy data can be used to calculate the enthalpy change for this reaction. Bond breaking ... 

In some reactions, bond breaking and bond formation occur simultaneously in a single step. Such processes are concerted reactions. The description of such a reaction mechanism resembles that of an ordinary chemical equation however, we will see later that a considerable amount of complexity often underlies the apparendy simple nature of a concerted reaction. 

MD/MM Available for large systems fast and cheap Disable in chemical reaction (bond breaking/ forming) Empirical potentials are used which leads to low accuracy... 

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