Zur Energiedelle von Diradikalen, IV [1] . 2‐Methylen‐1,4‐cyclohexadiyl

The Energy‐Well of Diradicals, IV [1] . – 2‐Methylene‐1,4‐cyclohexadiyl The energy surface of the title compound 2 is derived from the kinetics of its precursors 5, 6, 7 , and 8 , the oxygen dependance of its trapping rate, and heat of hydrogenation measurements of 5, 6, 7 , and 15 . These data lead to a heat of formation for the diradical 2 of 69.8 kcal/mol and an energy well of 8.2 kcal mol –1 . From the Curie plot of the ESR spectrum and oxygen trapping experiments a singlet‐triplet splitting of 1.4 kcal mol –1 is indicated, with the triplet being the ground state.