Minimizing the Reorganization Energy of Cobalt Redox Mediators Maximizes Charge Transfer Rates from Quantum Dots.

Light-induced charge separation is at the very heart of many solar harvesting technologies. The reduction of energetic barriers to charge separation and transfer increases the rate of separation and the overall efficiency of these technologies. Here we report that the internal reorganization energy of the redox acceptor, the movement of the atoms with changing charge, has a profound effect on the charge transfer rates from donor quantum dots.

Cobalt cage complexes as mediators of protein electron transfer.

A selection of cobalt (III)/(II) macrobicyclic 'sarcophagine' (sar) cage complexes with NS mixed donor sets but differing in a single apical substituent has been chosen to span a redox potential range of +150 to -150 mV vs the normal hydrogen electrode and thus acts as redox buffers in protein spectroelectrochemistry and redox potentiometry. The cobalt(III) cage complexes are all based on the same parent structure [Co(XMeNSsar)], where X, the variable apical substituent, is -NO, -Cl, -OH, -NH or -NMe , and a methyl group occupies the opposite apical position. The X-ray crystal structures of selected members of this series are reported.