炭化水素塩ならびにイオン解離性炭化水素の合成と性質

概要

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Two novel classes of hydrocarbons, i.e. hydrocarbon salts and ionically dissociative covalent hydrocarbons, were prepared from Kuhns carbanion (5-) and various cyclopropenylium and tropylium ions. The ionic structures of the hydrocarbon salts were evidenced by IR spectra (solid state), UV-vis spectra (DMSO), and electric conductivity measurements (DMSO) The salt obtained from 5- and tricyclopropylcyclopropenylium ion formed a unique covalent compound in chloroform which can exist only in solution. The salt of 5- and tricyclopropyltropylium ion was found to undergo both coordination and single-electron transfer in THF, affording a yet unknown type of equilibrium system, in which the ionic, radical, and covalent species coexist. Studies on the free energies of heterolysis of the newly synthesized covalent hydrocarbons revealed the importance of the steric effect in the heterolytic cleavage of σ carbon-carbon a bond. It was also found that a slight difference in the cation stability differentiates the product, either ionic or covalent, of the reaction with a carbanion.