Aroyl‐S,N‐Ketene Acetals: Luminous Renaissance of a Class of Heterocyclic Compounds

• Published in: Chemistry : a European journal Vol. 29; no. 64; pp. e202302067 - n/a
• Main Authors: Biesen, Lukas, Müller, Thomas J. J.
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 16.11.2023
• Subjects: Acetals; aggregation-induced emission; aroyl-S,N-ketene acetals; Chemistry; Dipoles; Dyes; Emission; Fluorescence; heterocycles; Heterocyclic compounds; Organic chemistry
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202302067

Aroyl‐S,N‐ketene acetals represent a peculiar class of heterocyclic merocyanines, compounds bearing pronounced and rather short dipoles with great push‐pull characteristics that define their rich properties. They are accessible via a wide array of synthetic concepts and procedures, ranging from addition‐elimination and condensation procedures up to rearrangement and metal‐mediated reactions. With our work from 2020, aroyl‐S,N‐ketene acetals have been identified as powerful and promising dyes with pronounced and vastly tunable solid‐state emission and aggregation‐induced emission properties. One characteristic trademark of this class of dye molecules is the level of control that could be exerted, and which was thoroughly explored. Based on these results, the field was opened to extend the system to bi‐ and multichromophoric systems by the full toolkit of synthetic organic chemistry thus giving access to even more exciting properties and manifolded substance libraries capitalizing on the AIE properties. This review aims at outlining the reaction‐based principles that allow for a swift and facile access to aroyl‐S,N‐ketene acetals, their methodical and structural evolution and the plethora of fluorescence and aggregation properties. Aroyl‐S,N‐ketene acetals have experienced a renaissance from a synthetic heterocyclic peculiarity as a short dipole with strong push‐pull characteristics to a promising class of dyes with pronounced controllable and tunable solid‐state and aggregation‐induced emission properties, thus allowing for a methodical and synthetical extension of the system.