Hemipiperazines for light-triggered molecular machines and responsive systems

• Applicant: Privatdozent Dr. Zbigniev Pianowski
• Subject Area: Organic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 563876067

Inclusion complexes of cavitands found numerous applications ranging from supramolecular materials and molecular machines, to food and fragrance industry, or drug delivery. Combination of the complexes with molecular photoswitches enable formation of light-triggered materials, which largely expand their application range. Yet, the majority of such systems has been demonstrated with azobenzene switches that has limited stability and biocompatibility. My group has recently discovered peptide-derived molecular photoswitches – hemipiperazines – with largely increased thermal and biological stability, as well as the activity as anticancer agents. In this application, we want to explore the formation of inclusion complexes of cyclodextrins and cucurbiturils with hemipiperazines. On the side of basic research, we aim at understanding the nature of interactions, as well as the scope of their photomodulation, including modulation of fluorescent properties under confinement. Regarding the practical applications, we want to test a system for solubilization and light-induced anticancer drug release, a system for optical detection of anabolic steroids and pesticides, or multistimuli-responsive supramolecular hydrogels triggered with light and pH changes. Overall, we want to propose a complementary design to the already existing photoswitchable inclusion complexes, which can find a number of novel applications, particularly in biological systems, therapeutic setups, or biocompatible materials. Moreover, we want to explore the applicability of hemipiperazines to construct molecular machines – in particular a biocompatible molecular motor as stand-alone entity, or combined with photomodulation (gearing) of the unidirectional motion. Hemipiperazines as dual switches operational under aqueous conditions are particularly suitable for realization of such systems, and may find future applications in complex light-propelled molecular machines operational inside living systems or human body.

• DFG Programme: Research Grants
• International Connection: Sweden, USA
• Cooperation Partners: Stefano Crespi, Ph.D.; Professor Dr. Eric Masson