Relative Thermodynamic Stabilities of 1,6-Methanoannulene, Dinorcaradiene, and the1,6-Methanoannulene Anion Radical

Article abstract of DOI:10.1021/j100228a039

The enthalpies of reaction of both the solvated and solid salts of potasssium 1,6-metano<10>annulene (M10) anion radical were measured with calorimetric techniques.These measurements show that anion radical of M10 has suprising degree of thermodynamic stability.The heat of formation of K⁺M10^-*_(s) from gas-phase potassium and gas-phase hydrocarbon (-61.9 kcal/mol) is about 16 kcal/mol more negative than that for the solid potassium salt of the naphthalene anion radical.Combustion experiments were used to show that the open form of M10 is about 5.7 kcal/mol lower in energy than dinorcaradiene.