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Updated: Mar 18, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Azulenylcarbenes: Rearrangements on the C11 H8 Potential Energy Surface
Stefan Henkel1, Corina H Pollok1, Tim Schleif1
1Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, 44780, Bochum, Germany.
Abstract:
Four isomeric azulenylcarbenes were synthesized in argon matrices by photolysis of the corresponding diazo precursors, and the photochemistry of these carbenes was studied. The carbenes and their rearranged products were characterized by IR, UV/Vis, and EPR spectroscopy, and the experimental data were compared to results from DFT calculations. While 2-, 5- and 6-azulenylcarbene show triplet ground states, 1-azulenylcarbene exhibits a singlet ground state, in accord with theoretical predictions. The rearrangements of the azulenylcarbenes give access to a number of unusual C11 H8 isomers, such as other carbenes and strained allenes.
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