Spectro-electrochemical toolbox for monitoring and controlling quinone-mediated redox-driven molecular gripping

The control of molecular systems by electrical charge or light is a prerequisite for their application in nanoelectronics. Such potential has been uniquely exploited in quinone-based resorcin[4]arene cavitands that can act as molecular grippers, reversibly expanding and contracting in response to electrical or electromagnetic stimuli. The development of such redox- and photoredox-driven gripper systems required employing a set of electrochemical, spectroscopic, and spectroelectrochemical techniques that have been applied to control and monitor the redox state and the geometry of grippers. Here, we provide a systematic overview of this spectro-electrochemical toolbox in the context of the quinone redox chemistry and molecular gripping, from cyclic and rotating disc voltammetry, through square-wave voltammetry and UV–Vis spectroelectrochemistry, to NMR, EPR, and ENDOR spectroscopy. The understanding of the molecular gripping process revealed through the lens of these techniques paves the way for more advanced molecular design and sets the basis for extending the utility of molecular grippers in the future.