Access to New Fluorescent Materials

Researchers Access New Fluorescent Materials Fluorescence is a fascinating natural phenomenon. It is based on the fact that certain materials can absorb light at a specific wavelength and then emit light at a different wavelength. Fluorescent materials play an important role in our daily lives, for example in modern displays. Due to high demand for applications, science is constantly trying to produce new and easily accessible molecules with high fluorescence efficiency. Chemist Professor Evamarie Hey-Hawkins from Leipzig University and colleagues have specialized in phospholes, a specific class of fluorescent material. Phospholes consist of hydrocarbon frameworks with a central phosphorus atom. Nils König from Hey-Hawkins' working group accessed new fluorescent materials through experiments with this substance and published his findings in Chemical Science. König explained: "Phospholes can be modified through certain chemical reactions that have a major impact on the color and efficiency of the molecule's fluorescence. Another property of these substances is their butterfly-like structure." When these molecules are dissolved in a solvent and exposed to UV light, they do not emit fluorescence. The absorbed energy is dissipated as rotational motion, causing the molecules to spin like a butterfly within the solvent. In a crystalline state, however, the ability to rotate is severely limited, which causes the substances to fluoresce brightly under UV light. This behavior is known as aggregation-induced emission (AIE). In a recently published article, Nils König and colleagues demonstrated a new reaction on AIE-based phospholes that provides access to a new class of material. Phospholes can be modified under mild conditions by isocyanates, a reactive class of substances composed of nitrogen, oxygen and carbon elements that are inexpensive and widely available, due to their industrial applications in polymers and biochemistry. This reaction, which appears to contradict classical organic chemistry, is characterized by high yields and excellent atom economy. The optical properties of the new materials were investigated in collaboration with the Institute of Surface Engineering (IOM) in Leipzig, the Center for Nanotechnology (CeNTech) and Münster University (WWU). It was found that simple modification significantly increased fluorescence efficiency compared to the original materials. This is due to a unique interaction between parts of the molecular framework that significantly strengthens the molecule in the solid state and leads to stronger fluorescence. Therefore, this new modification method makes a major contribution to understanding the AIE concept and can serve as a tool for the synthesis of efficient new dyes for displays or as markers for biomolecules. Source: https://www.uni-leipzig.de/en/newsdetail/artikel/forschende-finden-zugang-zu-neuen-fluoreszierenden-materialien-2023-03-09 / Created by: Susann Huster / Translation: Matthew Rockey / Original title of the publication in "Chemical Science": "Facile modification of phosphole-based aggregation-induced emission luminogens with sulfonyl isocyanates", doi.org/10.1039/D3SC00308F