ExStaCaT

Nowadays, smart molecular photoswitches able to toggle between, at least, two states with different physical responses are still receiving an increasing attention. So far, photoswitch principles are always based on the same elementary photochemical processes such as Intramolecular Charge Transfer (ICT) or Excited State Proton Transfer (ESPT). In this project, we propose to design a new class of photoswitches based on Excited State Cation Transfer (ESCT). However, even though numerous cation photoejection-based systems have been developed during the last three decades, molecular photoswitches based on ion translocation between two binding sites remains largely unexplored. The ExStaCaT project proposes to design and to study well-structured molecular architecture, to provide an efficient ESCT photoswitch, composed of different photo-active and complexing units linked to a cation photoejector in order to control the position and the movement of the cation within the system, thus triggering specific and trackable spectroscopic responses. The first step will be to develop a proof of concept ESCT system, followed, in second step, by the conception of smart ESCT photoswitches (bistable). To explore this new field of photo-organic switching chemistry, this project relies on the development of innovative molecular design strategies supported by a consortium that combines organic synthesis (PPSM), molecular design and (TD-)DFT calculations (IRCP) and time-resolved spectroscopy to rationalize and then control the basic photoinduced processes (LASIR). Several systems will be designed with a strategy based on well-known and convergent organic chemistry and coupling reactions supported by in-silico molecular design. Moreover, in order to track the ESCT reactions, the development of a two-color dual-pump laser flash spectroscopy will be required. The ExStaCaT project thus aims to explore a new field of organic photochemistry and pave the way towards advanced systems with potential applications as memory storage or logic gate.