Photochemistry using a host-guest charge transfer paradigm: DMABN as a dynamical probe of ground and excited states.

Abstract

Photoexciting charge transfer (CT) transitions arising from host-guest interactions in a confined environment can efficiently yield kinetically trapped radicals. In order to predispose these photogenerated radicals for diffusion limited reactions it becomes imperative to understand the nature of the host-guest CT interactions in the ground and excited states. Here we probe the heterogeneity of guest orientations and the ensuing excited state charge transfer dynamics of an electron-rich molecular probe N,N-dimethylaminobenzonitrile (DMABN) incarcerated inside an electron deficient water-soluble cationic Pd6L412+ nanohost. Using a combination of 1H-NMR, resonance Raman spectrosocopy, and pump-probe spectroscopy we highlight the necessary challenges that need to be addressed in order to use molecular cages as photocatalytic reaction vessels.