Heterolytic cleavage heterolysis

Breaking a bond by unequally dividing the electrons between the two atoms in the bond is called heterolysis or heterolytic cleavage. Heterolysis of a bond between A and B can give either A or B the two electrons in the bond. When A and B have different electronegativities, the electrons end up on the more electronegative atom. 

The first two stages (oxidation of Viv to Vv and complex formation) were proved but the third stage predicting the heterolysis of the O—O bond with the addition of OH+ at the double bond is speculative. Heterolysis of this type is doubtful because of the very high energy of the heterolytic cleavage of RO—OH to RO- and OH+. 

H—F. In the crudest approximation, one may say that the orbitals of C, N, O, and F are all approximately the same size and therefore the interaction matrix element hab will be approximately the same size for any A- pair. The dominant factor determining the heterolysis energy therefore is the difference in orbital energies in the denominator, and one has directly the prediction (Figure 4.2) that ease of heterolytic cleavage for C—X is in the order C > N > > F. The C—C bond is least likely to dissociate heterolytically and the C—F bond the most likely. In an absolute sense, of course, heterolytic cleavage is not a likely process for any of these bonds in the absence of other factors, as discussed below. 

Intramolecular heterolytic cleavage of H2 is one of the oldest reactions of H2 and is among the first homogeneous catalytic conversions. r 2-H2 can protonate a counteranion or a basic ancillary ligand, either at the M-L bond or at a ligand lone pair. Intramolecular heterolysis of H H is most likely an essential step in many diverse systems ranging from industrial processes to the function of metallo enzymes such as... 

In polar reactions, heterolytic (unsymmetrical) bond cleavage (heterolysis) and bond formation occur, while homolytic (symmetrical) bond cleavage (homolysis) and bond formation occur in radical reactions as shown below (Scheme a). 

The D2/H+ exchange reaction requires a heterolytic cleavage of the D2 molecule into D+ and D species and, vice versa, of H2 into H+ and H-. When such a H2 heterolysis takes place at [MS] sites, plausible intermediates are metal hydride thiol species forming according to Eq. 46. 

Usually attack of the EPD occurs at the more positive, and attack of the EPA at the more negative part of the molecule. In both cases, coordination leads to an increase in polarity of the bond A +—B and finally to heterolysis with formation of stabilized cations or of stabilized anions 18, 19). It may be anticipated that a homolytic cleavage of A +—B is rather unlikely A" " acts as a much stronger EPA than A ", and B acts as a stronger EPD than B , so that maximum stabilization is usually achieved by heterolytic cleavage of the A +—B - bond. 

There are two ways of breaking a covalent bond. The unsymmetrical cleavage is called heterolytic cleavage (or heterolysis), and this leads to the formation of ions (cations and anions). The symmetrical cleavage is called homolytic cleavage (or homolysis), and this leads to the formation of radicals. 

Fe-O-Fe also.75 An electropMic cationic system would favor rapid heterolytic cleavage of the C-H bond (see Section 12.4.3), but there is no evidence for interaction of CH4 with the Fe atoms or a heterolysis of C-H. Carbocation-like... 

The problem of participation of higher energy reactive conformers is not limited to derivatives of heteroanes. In particular, heterolytic cleavage of the C—OX (X = alkyl, acyl) bond in 1-arylethanol derivatives 152 (Scheme 41) to produce a cation 153 could serve as a good example. As was shown by Kirby s group (314), this heterolysis must be accompanied by an increase in the stabilizing interaction which may occur independently (Scheme... 

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