Limiting Molecular Twisting: Upgrading a Donor-Acceptor Dye to Drive H Evolution.

The donor-acceptor (D-A) dye 4-(bis-4-(5-(2,2-dicyano-vinyl)-thiophene-2-yl)-phenyl-amino)-benzoic acid (P1) has been frequently used to functionalize NiO photocathodes and induce photoelectrochemical reduction of protons when coupled to a suitable catalyst. Photoinduced twisting of the P1 dye is steered on NiO by co-adsorption of tetradecanoic acid (C, myristic acid (MA)). Density Functional Theory and time-resolved photoluminescence studies confirm that twisting lowers the energy levels of the photoexcited D-A dye.

Slow hole diffusion limits the efficiency of p-type dye-sensitized solar cells based on the P1 dye.

NiO electrodes are widely applied in p-type dye-sensitized solar cells (DSSCs) and photoelectrochemical cells, but due to excessive charge recombination, the efficiencies of these devices are still too low for commercial applications. To understand which factors induce charge recombination, we studied electrodes with a varying number of NiO layers in benchmark P1 p-DSSCs. We obtained the most efficient DSSCs with four layers of NiO (0.

Mechanistic Insights into Electrocatalytic Hydrogen Evolution by an Exceptionally Stable Cobalt Complex.

Co(aPPy) is one of the most stable and active molecular first-row transition-metal catalysts for proton reduction reported to date. Understanding the origin of its high performance via mechanistic studies could aid in developing even better catalysts. In this work, the catalytic mechanism of Co(aPPy) was electrochemically probed, in both organic solvents and water.

Formate Over-Oxidation Limits Industrialization of Glycerol Oxidation Paired with Carbon Dioxide Reduction to Formate.

Electrocatalytic CO reduction processes are generally coupled with the oxidation of water. Process economics can greatly improve by replacing the water oxidation with a more valuable oxidation reaction, a process called paired electrolysis. Here we report the feasibility of pairing CO reduction with the oxidation of glycerol on Ni S /NF anodes to produce formate at both anode and cathode.

Parallels between Metal-Ligand Cooperativity and Frustrated Lewis Pairs.

Metal ligand cooperativity (MLC) and frustrated Lewis pair (FLP) chemistry both feature the cooperative action of a Lewis acidic and a Lewis basic site on a substrate. A lot of work has been carried out in the field of FLPs to prevent Lewis adduct formation, which often reduces the FLP reactivity. Parallels are drawn between the two systems by looking at their reactivity with CO, and we explore the role of steric bulk in preventing dimer formation in MLC systems.

Relevance of Orbital Interactions and Pauli Repulsion in the Metal-Metal Bond of Coinage Metals.

The importance of relativity and dispersion in metallophilicity has been discussed in numerous studies. The existence of hybridization in the bonding between closed shell d-d metal atoms has also been speculated, but the presence of attractive MO interaction in the metal-metal bond is still a matter of an ongoing debate. In this comparative study, a quantitative molecular orbital analysis and energy decomposition is carried out on the metallophilic interaction in atomic dimers (M···M) and molecular perpendicular [HP-M-X] (where M = Cu, Ag, and Au; X = F, Cl, Br, and I).