Improving the photoinduced charge separation parameters in corrole-perylene carboximide dyads by tuning the redox and spectroscopic properties of the components.

ABSTRACT

A couple of corrole-perylene carboximide dyads (C2-PIa and C2-PIx) have been synthesized and their photoreactivity has been evaluated. We aimed at obtaining better performances for photoinduced charge separation, both in terms of efficiency and in terms of lifetime, with respect to formerly studied systems. The energy level of the charge-separated state was tuned by selecting perylene and corrole components with diverse redox and spectroscopic properties. High spectroscopic energy levels of the perylene carboximide derivatives (PIs) allow a fast charge separation to be maintained in competition with an energy-transfer process from the PI to the corrole unit. Yields and lifetimes of charge separation in toluene are, respectively, 75% and 2.5 µs for C2-PIa and 65% and 24 ns for C2-PIx. The results and the effect of solvent polarity are discussed in the framework of current energy- and electron-transfer theories.