E‐Diazocine in Chemical Education: Synthesis, Structure, Photochromism and Thermal Stability

Abstract

Z‐diazocine, synthesized as described by Tellkamp, has been photochemically converted into E‐diazocine by irradiation of its solution at λ=365 nm. After purification, single crystals of E‐diazocine were obtained by recrystallization at −18 °C from n‐pentane. The title compound was characterized by NMR spectroscopy and X‐ray crystallography. For its thermal isomerization into the more stable Z‐isomer, the thermal half‐life was determined by UV/Vis absorption studies. Furthermore, the photochemical behaviour of the compound in the solid state has been investigated.

Light-Powered Dissipative Assembly of Diazocine Coordination Cages

“…The Pd···Pd distance was measured as 17.0 Å, significantly longer than that found in the cis -Ring (10.9 Å), the latter showing a more folded conformation. To the best of our knowledge, only two examples of crystal structures for a trans -diazocine have been reported so far, 49 , 50 none of them carrying any substituents.…”

Teaching Photochemistry: Experimental Approaches and Digital Media

“…In this sense, we have been exploring experimental approaches and developing teaching materials for more than 20 years [2–13] . Some of them have been presented in about ten editions of the Central European Photochemistry Conference CECP in Bad Hofgastein (Austria), and most of our experiments and teaching materials have been digitalized and made available in German and English as open access on our website [14] .…”

Fabrication of Diazocine-Based Photochromic Organic Thin Films via Initiated Chemical Vapor Deposition

“…In our work, the photoswitchable compound of choice is represented by a functional diazocine. Diazocine represents an azobenzene-related compound with an eight-membered heterocyclic ring as the central unit, which results in higher stiffness and more efficient power transmission to the environment, which is an advantage in materials science. − In contrast to azobenzene, diazocines are thermodynamically more stable in their Z configuration, which is a further advantage in actuator and mechanophore applications. Upon irradiation with violet light (385–400 nm), the bent Z configuration converts to the extended E isomer (Figure ).…”

“…In contrast to azobenzenes the Z isomer is more stable than the E isomer. Photoinduced motion results in expansion/contraction of the chromophore, making it an interesting candidate for future mechanistic studies. − …”

“…Moreover, both isomers of diazocine in bulk crystalline form or dissolved in solution can be distinguished by their specific color: The Z isomer has a yellow color, whereas the E isomer exhibits a red color, and the color change can be observed with the bare eye. The absorption bands of the two isomers are well separated from each other, making them excellent candidates for optical and mechanical sensing. − …”