Photoequilibration of 2-naphthylcarbene and 2,3-benzobicyclo[4.1.0]hepta-2,4,6-triene

Irradiation (λ>300 nm or λ=480±6 nm) of 2-naphthyldiazomethane (4), matrix-isolated in argon at 10 K, gives a mixture of 2-naphthylcarbene (1) and 2,3-benzobicyclo[4.1.0]hepta-2,4,6-triene (2). 2-Naphthylcarbene (1) is characterized by infrared, UV/visible, and ESR spectroscopy and by chemical trapping with CO. 2,3-Benzobicyclo[4.1.0]hepta-2,4,6-triene (2) is characterized by infrared and UV/visible spectroscopy. A photoequilibrium exists between carbene 1 and bicyclic compound 2. Photolysis (λ=290±6 nm) of bicyclic compound 2 results exclusively in ring-opening to carbene 1