Diazirines Beyond Photoaffinity Labeling: A Comprehensive Overview of Applications in Biological Sciences, Materials Chemistry, and NMR-Spectroscopy.

Diazirines are well-known for their role in photoaffinity labeling (PAL) probes, acting as reactive groups to fish out proteins for drug target identification or tag installation. Their key asset lies in the precise activation through UV light, heat, or voltage, and in the ability to covalently bind to organic materials. However, the versatility of diazirines extends beyond this application. It was demonstrated that diazirines act as diverse entities, functioning as bridging units to connect different materials or reinforce polymers for applications such as bulletproof armor. Some facilitate blending of non-mixable polymers, allowing the disassembly for recycling. Others serve as glues, aiding wound healing, or immobilize molecules on surfaces, creating new material and surface properties. Some contribute to the fabrication of elastic electronic materials, and others function as magnetic resonance imaging (MRI) biolabels without the need for a "conventional hook function." This review intends to showcase diazirines beyond PAL and provide an overview of these applications, often combined across different fields. In this regard, the chemistry of diazirines demonstrates how different disciplines draw inspiration from one another, disclosing exciting new methodologies. This review intends to inspire the development of further innovative methods and applications.