ChemInform Abstract: Bicyclo(4.4.0)deca-1,6-diene-2,7-diyl: A 1,4-Didehydrobutadiene Derivative

From the NO- and O2-dependence of the trapping rate of 1,6-cyclodecadiyne (3) in the gas phase and in supercritical CO2 in the temperature range 160–290°C, the enthalpy profile for the equilibrium 3 ⇌ 4 has been established. For the diradical 4, a heat of formation of 116.2 kcal · mol−1 is obtained, which agrees well with the expectation value derived by the abstraction of two hydrogen atoms from hexahydronaphthalene (5).