Stimuli-responsive phenothiazine-based materials: Multicolor emission, mechanochromism, and anticounterfeiting applications

The development of stimuli responsive materials has advanced rapidly owing to their fascinating colour switching properties and wide range of applications in optoelectronics. In this contribution, we have designed and synthesized four benzothiazole based phenothiazine derivatives PTZ, CHO, CN, and BT by the Suzuki cross-coupling reaction. The solvatochromic, aggregation induced emission (AIE), mechanochromism, acidochromism and anticounterfeiting applications have been explored. The compounds PTZ and CHO shows significant AIE properties with enhanced emission upon nanoaggregates formation, confirmed by dynamic light scattering (DLS) and scanning electron microscopy (SEM). All the compounds (PTZ, CHO, CN, and BT) are highly emissive in their solid-state, and exhibit bathochromic shift in the emission wavelength in response to external mechanical grinding. These compounds exhibit rapid and reversible solid state acid base responsiveness, demonstrating the potential for sensor applications. The compound PTZ owing to its strong fluorescence and high thermal stability shows potential for anticounterfeiting applications.  

Ramakant S Gavale is currently a PhD student at the Indian Institute of Technology (IIT) Indore, working under the supervision of Prof. Rajneesh Misra. He has completed his Bachelor of Science (BSc) in 2016 and Master of Science (MSc) in 2018, North Maharashtra University, Jalgaon. His research at IIT Indore focuses on the design and synthesis of organic mechanochromic luminogens.