BICYCLO[4.4.0]DECA-1,6-DIENE-2,7-DIYL - A 1,4-DIDEHYDROBUTADIENE DERIVATIVE

From the NO- and O-2-dependence of the trapping rate of 1,6-cyclodecad iyne (3) in the gas phase and in supercritical CO2 in the temperature range 160-290 degrees C, the enthalpy profile for the equilibrium 3 re versible arrow 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).