Azobenzene Macrocycles: Synthesis of a Z-Stable Azobenzenophane

Abstract Azobenzenes have attracted increasing attention in the past years due to their application as molecular switches. In this report, we present a macrocyclic bisazobenzene that exists as the stable Z -isomer. The synthetic efforts as well as the successful strategy are discussed. Final ring closure under continuous irradiation gave the ( Z , Z )-bisazobenzenophane. This Z -azobenzene does not show any isomerization under either heating or prolonged irradiation. The thermal stability of the Z -form has also been supported by computations. The prepared bisazobenzenophane represents one of the few azobenzenes in which the Z -isomer is more stable than the E -isomer.