Over a million turnovers for a molecular WOC

http://onlinelibrary.wiley.com/doi/10.1002/anie.201609167/abstract

A Million Turnover Molecular Anode for Catalytic Water Oxidation

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• First published: 7 November 2016Full publication history
• DOI: 10.1002/anie.201609167View/save citation
• Cited by: 0 articles

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Abstract

Molecular ruthenium-based water oxidation catalyst precursors of general formula [Ru(tda)(Lⁱ)₂] (tda²⁻ is [2,2′:6′,2′′-terpyridine]-6,6′′-dicarboxylato; L¹=4-(pyren-1-yl)-N-(pyridin-4-ylmethyl)butanamide, 1 b; L²=4-(pyren-1-yl)pyridine), 1 c), have been prepared and thoroughly characterized. Both complexes contain a pyrene group allowing ready and efficiently anchoring via π interactions on multi-walled carbon nanotubes (MWCNT). These hybrid solid state materials are exceptionally stable molecular water-oxidation anodes capable of carrying out more than a million turnover numbers (TNs) at pH 7 with an E_app=1.45 V vs. NHE without any sign of degradation. XAS spectroscopy analysis before, during, and after catalysis together with electrochemical techniques allow their unprecedented oxidative ruggedness to be monitored and verified.

Multinuclear copper complexes for mild alkane oxidation

Communication

http://onlinelibrary.wiley.com/doi/10.1002/anie.200500585/abstract

 

Multinuclear Copper Triethanolamine Complexes as Selective Catalysts for the Peroxidative Oxidation of Alkanes under Mild Conditions^†

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• First published: 8 June 2005Full publication history
• DOI: 10.1002/anie.200500585View/save citation
• Cited by: 147 articles
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  This work has been partially supported by the Fundação para a Ciência e a Tecnologia and its POCTI programme (FEDER funded) (project POCTI/QUI/43415/2001), Portugal, and by a Human Resources and Mobility Marie-Curie Research Training Network (AQUACHEM project, CMTN-CT-2003-503864).

Abstract

Rich activity from a few coppers: Di-, tri-, tetra-, and polynuclear copper triethanolamine complexes are easily prepared and are selective and efficient catalysts for alkane peroxidative oxidation under mild conditions (see picture).

C–H Activation on Co,O Sites: Isolated Surface Sites versus Molecular Analogs

http://pubs.acs.org/doi/abs/10.1021/jacs.6b08705
Deven P. Estes,† Georges Siddiqi,† Florian Allouche,† Kirill V. Kovtunov,§,∥ Olga V. Safonova,‡ Alexander L. Trigub,⊥ Igor V. Koptyug,§,∥ and Christophe Coperet ́ *,†

http://pubs.acs.org/doi/abs/10.1021/jacs.6b08705

Abstract

The activation and conversion of hydrocarbons is one of the most important challenges in chemistry. Transition-metal ions (V, Cr, Fe, Co, etc.) isolated on silica surfaces are known to catalyze such processes. The mechanisms of these processes are currently unknown but are thought to involve C–H activation as the rate-determining step. Here, we synthesize well-defined Co(II) ions on a silica surface using a metal siloxide precursor followed by thermal treatment under vacuum at 500 °C. We show that these isolated Co(II) sites are catalysts for a number of hydrocarbon conversion reactions, such as the dehydrogenation of propane, the hydrogenation of propene, and the trimerization of terminal alkynes. We then investigate the mechanisms of these processes using kinetics, kinetic isotope effects, isotopic labeling experiments, parahydrogen induced polarization (PHIP) NMR, and comparison with a molecular analog. The data are consistent with all of these reactions occurring by a common mechanism, involving heterolytic C–H or H–H activation via a 1,2 addition across a Co–O bond.