Structural dependence of heterolytic bond dissociation energy of carbon–carbon σ bonds in hydrocarbons

✍ Scribed by Toshikazu Kitagawa; Ken'ichi Takeuchi

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 314 KB
• Volume: 11
• Category: Article
• ISSN: 0894-3230
• DOI: 10.1002/(sici)1099-1395(199803)11:3<157::aid-poc994>3.0.co;2-#

✦ Synopsis

The coordination of a resonance-stabilized hydrocarbon cation and anion yielded a series of unprecedented hydrocarbons, which are susceptible to thermal heterolytic cleavage of carbon-carbon s bonds in polar media, generating the original ions under reversible conditions. When the component ions were sufficiently stabilized, some ion pairs were even isolated as solids, thus providing the first examples of hydrocarbon salts. The direct observation of the heterolysis by means of spectroscopy permitted reliable thermodynamic treatments of the observed degree of ionic dissociation. Correlation of the free energy of heterolysis with solvent dielectric constants and parameters of ion stabilities such as pK HA , pK R and redox potentials revealed the importance of the thermodynamic stabilities of ions, the degree of solvation and steric congestion in the starting molecule as major controlling factors in the heterolysis.