Anion‐Receptive Triazine‐Centered Azobenzene Trimers

Chem. Eur. J.  2026, e70669.

Triazine-centered C₃-symmetric azobenzene trimers were synthesized using complementary azo-forming strategies, providing a versatile platform for multiresponsive molecular photoswitches. Relative to the isoelectronic benzonitrile monomer, incorporation of the triazine core induces an intrinsic bathochromic shift of the azobenzene absorption bands. The thiomethoxy-substituted derivative exhibits negative photochromism, enabling efficient trans–cis photoisomerization with wavelengths up to 525 nm. Combined temperature-dependent operando UV/vis spectroscopy and DFT calculations reveal thermal cis–trans isomerization kinetics consistent with a triplet-assisted rotational pathway. Evaluation of transmission coefficients exposes pronounced solvent-friction effects, demonstrating that substituent-controlled solute–solvent coupling governs thermal half-lives beyond barrier heights. In addition, the electron-deficient triazine core enables anion binding that induces intramolecular charge-transfer absorption and modulates thermal relaxation, introducing triazine-centered azobenzenes as supramolecular multistimuli-responsive photoswitches.