Light-induced formation of dibenzochalcogenophenes - From novel luminescent structural motifs to applications in materials science

• Applicant: Professor Dr. Jens Voskuhl
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 566015618

The planned project involves the investigation of light-induced cyclization of ether-based (E = S, Se, Te) organic compounds to phosphorescent dibenzochalcogenophenes. The formation of these molecules is achievable without the addition of additives and can also be induced in polymeric materials. After an extensive study concerning the scope of starting materials, we will mainly focus on potential applications.The high compatibility of the ethers with 3D-printing enables the investigation of cyclization processes in polymeric materials. In this context numerous questions will be addressed. Besides the use of this photocyclization as a UV-light detector as proof for light promoted disinfection of surfaces, aging phenomena of polymers by light will be also investigated. The formation of dibenzoalcogenophenes can be investigated directly by changing the photophysical properties (emission wavelength, emission lifetime and photoluminescence quantum yield). Since the dibenzoalcogenophenes are able to show phosphorescence emission and are hence excellent indicators for triplet oxygen. This enables the use as detection tool for materials weakening within polymeric materials by a change in emission lifetime due to oxygen diffusion and associated triplet-triplet annihilation.In addition, the incorporation of mainly chiral ethers (dopands) into liquid crystalline host systems enables a modulation of the mesophase properties after irradiation with light and the associated formation of the dibenzoalcogenophenes, which is due to a change in the geometry of the dopands and the associated change in the helical pitch. As a final goal, the photocyclization in polymer nanoparticles will be investigated, which should enable the stabilization of phosphorescence emission by shielding triplet oxygen in aqueous media, which should ultimately find application in biological imaging using phosphorescence lifetime microscopy after surface functionalization with bioligands.

• DFG Programme: Research Grants