An open and shut case: The competition between charge separation and recombination in artificial photosynthetic systems can be controlled by using photochromic dynamic bridge. The photoinduced opening and closing of the bridge mediates the electronic coupling between donor (D) and acceptor (A).

The effect of the in-backbone presence of charge-assisted hydrogen bonds (CAHBs) in the conductance of single-molecule junctions has been studied by the scanning tunneling microscope break junction technique. In particular, two amidinium−carboxylate supramolecular complexes of different lengths have been tested. We observed that the ionic character that gives extra stability to the CAHB is a hindrance toward the electron transport through the complexes. Theoretical calculations using the DFT + Σ method indicate that both the highest occupied molecular orbital and lowest unoccupied molecular orbital of the complexes are fully localized in only one of the moieties of the complex explaining the low singlemolecular conductance of the compounds.

Kopplung mit Schalter: Die Konkurrenz zwischen Ladungstrennung und ‐rekombination in künstlichen Photosynthesesystemen kann durch Verwendung einer photochromen dynamischen Brücke kontrolliert werden. Das lichtinduzierte Öffnen und Schließen der Brücke vermittelt die elektronischen Kopplung in Donor(D)‐Akzeptor(A)‐Paaren.

The thermoelectric properties of molecular junctions consisting of a metal Pt electrode contacting [60]fullerene derivatives covalently bound to a graphene electrode have been studied by using a conducting-probe atomic force microscope (c-AFM). The [60]fullerene derivatives are covalently linked to the graphene via two meta-connected phenyl rings, two para-connected phenyl rings, or a single phenyl ring. We find that the magnitude of the Seebeck coefficient is up to nine times larger than that of Au−C 60 −Pt molecular junctions. Moreover, the sign of the thermopower can be either positive or negative depending on the details of the binding geometry and on the local value of the Fermi energy. Our results demonstrate the potential of using graphene electrodes for controlling and enhancing the thermoelectric properties of molecular junctions and confirm the outstanding performance of [60]fullerene derivatives.