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The highly active ruthenium‐based water oxidation catalyst [RuX(mcbp)(OHn)(py)2] [mcbp2−=2,6‐bis(1‐methyl‐4‐(carboxylate)benzimidazol‐2‐yl)pyridine; n=2, 1, and 0 for X=II, III, and IV, respectively], can be generated in a mixture of RuIII and RuIV states from either [RuII(mcbp)(py)2] or [RuIII(Hmcbp)(py)2]2+ precursors. The precursor complexes are isolated and characterized by single‐crystal X‐ray analysis, NMR, UV/Vis, EPR, and FTIR spectroscopy, ESI‐HRMS, and elemental analysis, and their redox properties are studied in detail by electrochemical and spectroscopic methods. Unlike the parent catalyst [Ru(tda) (py)2] (tda2−=[2,2′:6′,2′′‐terpyridine]‐6,6′′‐dicarboxylate), for which full transformation into the catalytically active species [RuIV(tda)(O)(py)2] could not be carried out, stoichiometric generation of the catalytically active Ru–aqua complex [RuX(mcbp)(OHn)(py)2] from the RuII precursor was achieved under mild conditions (pH 7.0) and short reaction times. The redox properties of the catalyst were studied and its activity for electrocatalytic water oxidation was evaluated, reaching a maximum turnover frequency (TOFmax) of around 40 000 s−1 at pH 9.0 (from foot‐of‐the‐wave analysis), which is comparable to the activity of the state‐of‐the‐art catalyst [RuIV(tda)(O)(py)2]. [ABSTRACT FROM AUTHOR]

Conventional methods for carrying out carbon–hydrogen functionalization and carbon–nitrogen bond formation are typically conducted at elevated temperatures, and rely on expensive catalysts as well as the use of stoichiometric, and perhaps toxic, oxidants. In this regard, electrochemical synthesis has recently been recognized as a sustainable and scalable strategy for the construction of challenging carbon–carbon and carbon–heteroatom bonds. Here, electrosynthesis has proven to be an environmentally benign, highly effective and versatile platform for achieving a wide range of nonclassical bond disconnections via generation of radical intermediates under mild reaction conditions. This review provides an overview on the use of anodic electrochemical methods for expediting the development of carbon–hydrogen functionalization and carbon–nitrogen bond formation strategies. Emphasis is placed on methodology development and mechanistic insight and aims to provide inspiration for future synthetic applications in the field of electrosynthesis. [ABSTRACT FROM AUTHOR]

The production of clean and sustainable energy is considered as one of the most urgent issues for our society. Mastering the oxidation of water to dioxygen is essential for the production of solar fuels. A study of the influence of the substituents on the catalytic activity of a series of mononuclear Ru complexes ( 2 a- e) based on a tetradentate ligand framework is presented. At neutral pH, using [Ru(bpy)3](PF6)3 (bpy=2,2'-bipyridine) as the terminal oxidant, a good correlation between the turnover frequency (TOF) and the Hammett σmeta parameters was obtained. Additionally, a general pathway for the deactivation of Ru-based catalysts 2 a- e during the catalytic oxidation of water through poisoning by carbon monoxide was demonstrated. These results highlight the importance of ligand design for fine-tuning the catalytic activity of water oxidation catalysts. [ABSTRACT FROM AUTHOR]

Photocatalytic water oxidation represents a key process in conversion of solar energy into fuels and can be facilitated by the use of molecular transition metal-based catalysts. A novel straightforward approach for covalent linking of the catalytic units to other moieties is demonstrated by preparation of a dinuclear complex containing two [Ru(pdc)(pic)3]-derived units (pdc = 2,6-pyridinedicarboxylate, pic = 4-picoline). The activity of this complex towards chemical and photochemical oxidation of water was evaluated and a detailed insight is given into the interactions between the catalyst and acetonitrile, a common co-solvent employed to increase solubility of water oxidation catalysts. The solvent-induced transformations were studied by electrochemical and spectroscopic techniques and the relevant quantitative parameters were extracted. [ABSTRACT FROM AUTHOR]

Herein is described the preparation of a dinuclear molecular Ru catalyst for H2O oxidation. The prepared catalyst mediates the photochemical oxidation of H2O with an efficiency comparable to state-of-the-art catalysts. [ABSTRACT FROM AUTHOR]

The development of catalysts for the oxidation of water using ligands with a non ‐ innocent character could potentially be employed for the rational design of efficient water ‐ oxidation catalysts. In their Full Paper on page 10039 ff., B. Åkermark, M. D. Kärkäs, R. ‐ Z. Liao and co ‐ workers explore the mechanistic details associated with a dinuclear Ru ‐ based water ‐ oxidation catalyst. Combining experimental studies and quantum chemical calculations provides insight into the fundamental principles controlling the reactivity of the catalyst, in which metal – ligand cooperation is a vital part. [ABSTRACT FROM AUTHOR]