Cooperatively assembling donor-acceptor superstructures direct energy into an emergent charge separated state.

A novel supramolecular system composed of diketopyrrolopyrrole electron donors and perylene derived bisimide (PDI) electron acceptors forms superstructures that undergo fast photoinduced charge separation following assembly. This bioinspired route toward functional hierarchical structures, whereby assembly and electronic properties are closely coupled, could lead to new materials for artificial photosynthesis and organic electronics.

Electrochemical determination of heme-linked pKa values and the importance of using fluoride binding in heme proteins.

The ultraviolet-visible (UV-vis) spectroelectrochemical measurements of heme proteins in the presence of a heme-bound fluoride ion can be used as a probe for heme-linked ionizations of acid-base groups in the heme pocket. A detailed study of the pH dependence of the midpoint potential of skeletal horse myoglobin (Mb) with a heme-bound fluoride ion (Mb-F) reveals how protonation of the distal histidine (H64) changes the redox properties of the protein with a determined pKa of 5.3. In addition, fluoride binding in myoglobin provides a stabilization of -1.9 kcal/mol of the ferric Mb-F relative to ferric Mb without fluoride.