Benzo[ cd ]azulenyl: A Structural Isomer of Phenalenyl—Synthesis and Properties of Its Tri‐ tert ‐butyl‐substituted Derivative and Formation of a Thermal‐ and Photoresponsive σ‐Dimer

The chemistry of nonalternant hydrocarbons has recently experienced a significant resurgence in interest. While extensive research has been conducted on azulenoids, that is, structural isomers of benzenoid polycyclic hydrocarbons, the exploration of doublet open-shell nonalternant systems, that is, isomers of open-shell graphene nanofragments has not yet been undertaken. To clarify the chemical and physical effects of nonhexagonal rings on the unpaired electron in these structures, we focus on b