Water oxidation catalysts are essential components of light-driven water splitting systems, which could convert water to H 2 driven by solar radiation (H 2 O þ hν → 1∕2O 2 þ H 2 ). The oxidation of water (H 2 O → 1∕2O 2 þ 2H þ þ 2e − ) provides protons and electrons for the production of dihydrogen (2H þ þ 2e − → H 2 ), a clean-burning and high-capacity energy carrier. One of the obstacles now is the lack of effective and robust water oxidation catalysts. Aiming at developing robust molecular Ru-bda (H 2 bda ¼ 2,2 0 -bipyridine-6,6′-dicarboxylic acid) water oxidation catalysts, we carried out density functional theory studies, correlated the robustness of catalysts against hydration with the highest occupied molecular orbital levels of a set of ligands, and successfully directed the synthesis of robust Ru-bda water oxidation catalysts. A series of mononuclear ruthenium complexes ½RuðbdaÞL 2 (L ¼ pyridazine, pyrimidine, and phthalazine) were subsequently synthesized and shown to effectively catalyze Ce IV -driven ½Ce IV ¼ CeðNH 4 Þ 2 ðNO 3 Þ 6 water oxidation with high oxygen production rates up to 286 s −1 and high turnover numbers up to 55,400.catalysis | density function theory | seven coordination | photosystem II | solar fuels I n pursuit of sustainable energy systems such as solar fuels, much effort has been spent on water splitting to hydrogen and oxygen since hydrogen is a potential clean energy carrier and water is an abundant and environmentally benign resource (1-5). Water splitting consists of two half reactions: (i) water oxidationIn practice, an overpotential is always present, leading to an even higher applied potential. The former half reaction requires strongly oxidizing conditions and is generally considered as the bottleneck of the whole water-splitting process due to the multiple protonelectron transfers and the formation of the O─O bond. Over the last few years, there has been an increasing development of water oxidation catalysts (WOCs) and many transition metal-based catalysts, including Ru (4, 5), Ir (6-8), Co (9-13), Fe (14,15), and Mn (16-18), have been reported with oxygen production rates (OPRs: mole oxygen produced per mole catalyst per second) ≤5 s −1 . Very recently, we reported a family of highly active Ru-based WOCs ½RuðbdaÞL 2 (H 2 L ¼ 2;2 -bipyridine-6,6′-dicarboxylic acid; L ¼ 4-picoline, A; L ¼ isoquinoline, B) ( Fig. 1) with OPRs up to 300 s −1 (19, 20); a seven-coordinate dimeric Ru IV intermediate (D7Ru IV ) (Fig. 1) is involved in the O─O bond formation step (20,21).A general problem encountered in molecular WOCs is the decomposition of catalysts. Ligand dissociation and oxidative decomposition have been considered as the major deactivation pathways. The groups of Llobet, Meyer, and Sun have demonstrated an improved durability of their catalysts by immobilizing catalysts on the electrode/material surface and thereby dramatically suppressing the intermolecular oxidative decomposition pathway (22-25).For our Ru-bda catalysts, the main deactivation pathway has been found to b...

Dinuclear alkynyl copper(I) complexes exhibit superior reactivity toward organic azides compared to their monomeric analogues. DFT studies indicate that the second copper center facilitates the formation of the cupracycle in the rate-determining step and stabilizes the metallacycle intermediate itself. These findings support the experimentally determined rate law and shed light on the origin of high reactivity of the in situ generated copper acetylides.

Two monomeric ruthenium molecular catalysts for water oxidation have been prepared, and both of them show high activities in pH 1.0 aqueous solutions, with an initial rate of over 1000 turnover s(-1) by complex 1, and a turnover number of more than 100,000 by complex 2.

The use of water as an oxygen and hydrogen source for the paired oxygenation and hydrogenation of organic substrates to produce valuable chemicals is of utmost importance as a means of establishing green chemical syntheses. Inspired by the active Ni 3+ intermediates involved in electrocatalytic water oxidation by nickel‐based materials, we prepared NiB x as a catalyst and used water as the oxygen source for the oxygenation of various organic compounds. NiB x was further employed as both an anode and a cathode in a paired electrosynthesis cell for the respective oxygenation and hydrogenation of organic compounds, with water as both the oxygen and hydrogen source. Conversion efficiency and selectivity of ≥99 % were observed during the oxygenation of 5‐hydroxymethylfurfural to 2,5‐furandicarboxylic acid and the simultaneous hydrogenation of p ‐nitrophenol to p ‐aminophenol. This paired electrosynthesis cell has also been coupled to a solar cell as a stand‐alone reactor in response to sunlight.