Cleavage, heterolytic calculations

In order to clarify the implementation of the LD model in VB calculations, it is useful to apply this model to the heterolytic bond cleavage of... 

In a polar solvent, heterolytic cleavage leading to proton abstraction is usually facilitated because of the favorable solvation energy of the proton, and cation radicals are ordinarily much more acidic than the corresponding neutral compounds. Table 1-5 combines acidity constants of organic compounds (AH) and their cation radicals (AH+ ) calculated for their solutions in dimethylsulfoxide (DMSO, a very polar solvent) at 25°C. 

Fan HJ, Hall MB. A capable bridging ligand for Fe-only hydrogenase density functional calculations of a low-energy route for heterolytic cleavage and formation of dihydrogen. J Am Chem Soc. 2001 123(16) 3828-9. 

To explain this degradation, two different reaction pathways have been proposed (Scheme 29). The reaction may proceed by concerted reductive elimination or alternatively by migratory insertion, giving the intermediate (175) and subsequent heterolytic cleavage. Kinetic studies and DFT calculations supported the second proposed pathway. An... 

A rough estimate of the free energy of heterolytic cleavage of the H20— H+ bond of H30+ in aqueous solution is obtained from a simple Born-type calculation and gives [132] AG = 70 kcal. mole-1). If corrected for a statistical factor of 3, it follows that V = 70.65 kcal. mole-1 for a three-center system with X = H20, or V2 - 70.65 kcal. mole-1 if Y = H20, respectively. If the pK of the base X or Y is known, the corresponding value of V can be calculated from... 

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