Photoinduced removal of molecular oxygen from solutions.

We propose a new, simple and efficient procedure of light-driven deoxygenation of solutions based on hydroperoxides formation upon irradiation. Efficient and fast removal of molecular oxygen is caused by photosensitized generation of singlet oxygen, which then reacts with the solvent (2-methyltetrahydrofuran or tetrahydrofuran). Oxygen depletion makes it possible to observe processes normally undetectable in non-degassed liquid samples at room temperature, such as phosphorescence and triplet-triplet annihilation.

Hemiporphycene: A pH-tunable specific probe for Zn and Cu.

Porphyrins and their isomers possess high affinity towards the formation of complexes with metal cations, but their use for the determination of metal cations is rather limited, due to low selectivity. In this study, we have investigated the unsubstituted hemiporphycene, which shows a highly irregular shape of the inner cavity, and very different reactivity with various metal cations in methanol:water solutions. It was found that hemiporphycene can act as a pH-tunable specific probe for the determination of Zn at pH 8.

Tandem Pd-catalyzed annulation/coupling of acetylenic enamines with aryl triflates.

A cascade of 5- intramolecular nucleophilic addition of enamine to terminal alkyne followed by cross coupling has been demonstrated for the first time. Two new C-C bonds are stereoselectively forged by a single Pd-complex capable of catalyzing two mechanistically diverse transformations. Mechanistic investigations identified cyclization as the rate limiting step relying on the facile displacement of OTf, weakly bound to the Pd-center, by the alkyne.

Tautomerization of single asymmetric oxahemiporphycene molecules on Cu(111).

We have studied 22-oxahemiporphycene molecules by a combination of scanning tunneling microscopy at low temperatures and density functional theory calculations. In contrast to other molecular switches with typically two switching states, these molecules can in principle exist in three different tautomers, due to their asymmetry and three inequivalent binding positions of a hydrogen atom in their macrocycle. Different tautomers are identified from the typical appearance on the surface and tunneling electrons can be used to tautomerize single molecules in a controllable way with the highest rates if the STM tip is placed close to the hydrogen binding positions in the cavity.

Piezoelectric Response and Substrate Effect of ZnO Nanowires for Mechanical Energy Harvesting in Internet-of-Things Applications.

Recently, an unprecedented growth in the internet of things (IoT) is being observed, which is becoming the main driver for the entire semiconductor industry. Reliable maintenance and servicing of the IoT is becoming challenging, knowing that the IoT nodes outnumber the human population by a factor of seven. Energy harvesting (EH) can overcome those difficulties, delivering the energyautonomous IoT nodes to the market.