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20 Mar 11:16

Role of Hot Electrons and Metal–Oxide Interfaces in Surface Chemistry and Catalytic Reactions

by Jeong Young Park, L. Robert Baker and Gabor A. Somorjai

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Chemical Reviews
DOI: 10.1021/cr400311p
20 Mar 17:29

Activation and Deactivation of a Robust Immobilized Cp*Ir-Transfer Hydrogenation Catalyst: A Multielement in Situ X-ray Absorption Spectroscopy Study

by Grant J. Sherborne, Michael R. Chapman, A. John Blacker, Richard A. Bourne, Thomas W. Chamberlain, Benjamin D. Crossley, Stephanie J. Lucas, Patrick C. McGowan, Mark A. Newton, Thomas E. O Screen, Paul Thompson, Charlotte E. Willans and Bao N. Nguyen

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Journal of the American Chemical Society
DOI: 10.1021/ja512868a
20 Mar 22:30

Mesoporous Carbon Nitride-Tungsten Oxide Composites for Enhanced Photocatalytic Hydrogen Evolution

by Kamalakannan Kailasam, Anna Fischer, Guigang Zhang, Jinshui Zhang, Michael Schwarze, Marc Schröder, Xinchen Wang, Reinhard Schomäcker, Arne Thomas

Abstract

Composites of mesoporous polymeric carbon nitride and tungsten(VI) oxide show very high photocatalytic activity for the evolution of hydrogen from water under visible light and in the presence of sacrificial electron donors. Already addition of very small amounts of WO3 yields up to a twofold increase in the efficiency when compared to bulk carbon nitrides and their composites and more notably even to the best reported mesoporous carbon nitride-based photocatalytic materials. The higher activity can be attributed to the high surface area and synergetic effect of the carbon nitrides and the WO3 resulting in improved charge separation through a photocatalytic solid-state Z-scheme mechanism.

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CN/WO3 composites for enhanced H2 evolution: Mesoporous CN/WO3 composites prepared by a simple dispersion method are efficient photocatalysts for enhanced hydrogen production from water. Compared to other nonporous composites based on carbon nitrides, a twofold increase in activity is observed, which is attributed to the high surface area and efficient solid-state Z-scheme-induced charge separation in these composites.

20 Mar 16:10

Air-Stable (CAAC)CuCl and (CAAC)CuBH4 Complexes as Catalysts for the Hydrolytic Dehydrogenation of BH3NH3

by Xingbang Hu, Michèle Soleilhavoup, Mohand Melaimi, Jiaxiang Chu, Guy Bertrand

Abstract

The first stable copper borohydride complex [(CAAC)CuBH4] [CAAC=cyclic(alkyl)(amino)carbene] bearing a single monodentate ligand was prepared by addition of NaBH4 or BH3NH3 to the corresponding [(CAAC)CuCl] complex. Both complexes are air-stable and promote the catalytic hydrolytic dehydrogenation of ammonia borane. The amount of hydrogen released reaches 2.8 H2/BH3NH3 with a turnover frequency of 8400 molinline image molcat−1 h−1 at 25 °C. In a fifteen-cycle experiment, the catalyst was reused without any loss of efficiency.

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Copper works! [(CAAC)CuCl] reacts with both NaBH4 and BH3NH3 to afford [(CAAC)CuBH4] as a thermally and air-stable complex. Both complexes efficiently promote the hydrolytic dehydrogenation of ammonia borane at room temperature, with a turnover frequency of up to 8400 molinline image molcat−1 h−1. In addition, these air-stable catalysts are readily recyclable. CAAC=cyclic (alkyl)(amino)carbene.

20 Mar 16:50

Semiconductor Photocatalysis: Principles and Applications. By Horst Kisch

by Horst Hennig
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Wiley-VCH, Weinheim 2015. 264 pp., € 126.00.—ISBN 978-3527335534

20 Mar 16:50

Widening Synthesis Bottlenecks: Realization of Ultrafast and Continuous-Flow Synthesis of High-Silica Zeolite SSZ-13 for NOx Removal

by Zhendong Liu, Toru Wakihara, Kazunori Oshima, Daisuke Nishioka, Yuusuke Hotta, Shanmugam P. Elangovan, Yutaka Yanaba, Takeshi Yoshikawa, Watcharop Chaikittisilp, Takeshi Matsuo, Takahiko Takewaki, Tatsuya Okubo

Abstract

Characteristics of zeolite formation, such as being kinetically slow and thermodynamically metastable, are the main bottlenecks that obstruct a fast zeolite synthesis. We present an ultrafast route, the first of its kind, to synthesize high-silica zeolite SSZ-13 in 10 min, instead of the several days usually required. Fast heating in a tubular reactor helps avoid thermal lag, and the synergistic effect of addition of a SSZ-13 seed, choice of the proper aluminum source, and employment of high temperature prompted the crystallization. Thanks to the ultra-short period of synthesis, we established a continuous-flow preparation of SSZ-13. The fast-synthesized SSZ-13, after copper-ion exchange, exhibits outstanding performance in the ammonia selective catalytic reduction (NH3-SCR) of nitrogen oxides (NOx), showing it to be a superior catalyst for NOx removal. Our results indicate that the formation of high-silica zeolites can be extremely fast if bottlenecks are effectively widened.

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Bottle opener: SSZ-13 is a zeolite commercialized as a catalyst to remove nitrogen oxides (NOx). However, its long synthesis time is one of the biggest barriers to large-scale production. An ultrafast synthesis route now allows SSZ-13 to be synthesized in 10 min and thus facilitates continuous preparation of SSZ-13. The fast-synthesized SSZ-13 exhibits outstanding performance for the NOx removal.

20 Mar 22:30

SBA-15-Oxynitrides as a Solid-Base Catalyst: Effect of Nitridation Temperature on Catalytic Activity

by Baljeet Singh, Kaustubh R. Mote, C. S. Gopinath, P. K. Madhu, Vivek Polshettiwar

Abstract

Solid bases, such as SBA-15-oxynitrides, have attracted considerable interest for potential applications as catalysts in important industrial processes. Reported herein is that by simply tuning the temperature of nitridation (ammonolysis), the catalytic activity of these solid bases can be enhanced. Solid-state NMR spectroscopy and XPS studies provided the reasoning behind this change in activity.

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Oxynitride solid: Solid bases, such as SBA-15-oxynitrides, have attracted considerable interest for potential applications as catalysts in important industrial processes. Reported here is that tuning the temperature of nitridation (ammonolysis) leads to enhanced catalytic activity of these solid bases. Detailed studies are discussed to explain this change in activity.

20 Mar 00:00

Transfer hydrogenation catalysis in cells as a new approach to anticancer drug design

by Joan J. Soldevila-Barreda

Article

Organometallic complexes are effective hydrogenation catalysts for organic reactions. Here the authors report for the first time that transfer hydrogenation catalysis can take place inside the cell and could be used as a novel anticancer strategy.

Nature Communications doi: 10.1038/ncomms7582

Authors: Joan J. Soldevila-Barreda, Isolda Romero-Canelón, Abraha Habtemariam, Peter J. Sadler

23 Mar 00:00

Efficient hole-blocking layer-free planar halide perovskite thin-film solar cells

by Weijun Ke

Article

Lead halide perovskite solar cells use hole-blocking layers to allow a separate collection of positive and negative charge carriers and to achieve high-operation voltages. Here, the authors demonstrate efficient lead halide perovskite solar cells that avoid using this extra layer.

Nature Communications doi: 10.1038/ncomms7700

Authors: Weijun Ke, Guojia Fang, Jiawei Wan, Hong Tao, Qin Liu, Liangbin Xiong, Pingli Qin, Jing Wang, Hongwei Lei, Guang Yang, Minchao Qin, Xingzhong Zhao, Yanfa Yan

16 Mar 14:02

Base-Free Methanol Dehydrogenation Using a Pincer-Supported Iron Compound and Lewis Acid Co-catalyst

by Elizabeth A. Bielinski, Moritz Förster, Yuanyuan Zhang, Wesley H. Bernskoetter, Nilay Hazari and Max C. Holthausen

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ACS Catalysis
DOI: 10.1021/acscatal.5b00137
16 Mar 14:02

Combining Low-Pressure CO2 Capture and Hydrogenation To Form Methanol

by Julia R. Khusnutdinova, Jai Anand Garg and David Milstein

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ACS Catalysis
DOI: 10.1021/acscatal.5b00194
17 Mar 14:43

BODIPY-Derived Photoremovable Protecting Groups Unmasked with Green Light

by Pratik P. Goswami, Aleem Syed, Christie L. Beck, Toshia R. Albright, Kaitlyn M. Mahoney, Ryan Unash, Emily A. Smith and Arthur H. Winter

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Journal of the American Chemical Society
DOI: 10.1021/jacs.5b01297
17 Mar 20:20

Tunable Photochromism in the Robust Dithienylethene-Containing Phospholes: Design, Synthesis, Characterization, Electrochemistry, Photophysics, and Photochromic Studies

by Jacky Chi-Hung Chan, Hok-Lai Wong, Wing-Tak Wong, Vivian Wing-Wah Yam

Abstract

A series of dithienylethene-containing phosphole derivatives has been designed, synthesized and characterized. One of the compounds has been characterized by X-ray crystallography. Upon photoexcitation, the compounds exhibit drastic color changes, ascribed to the reversible photochromic behavior. Their photochromic, photophysical and electrochemical properties have been studied. They show photochromic reactivities with high photocyclization quantum yields. Their photophysical and photochromic properties are found to be facilely tuned in this system by substitution at the phosphole backbone, as well as variation on the extent of π-conjugation of the phosphole backbone. Some selected compounds have been demonstrated to exhibit photochromic properties in polymethylmethacrylate (PMMA) films.

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Robust photoswitch: A new series of robust dithienylethene-containing phosphole derivatives has been synthesized (see figure); their photophysical and photochromic properties are found to be readily tuned by simple modifications at the phosphorus center, substitution at the phosphole backbone, as well as variation on the extent of π-conjugation of the phosphole backbone. Both the open and closed forms of the phosphole compounds have good thermal stability in benzene solution and in PMMA film.

18 Mar 10:07

Frontispiece: A Simple Iridicycle Catalyst for Efficient Transfer Hydrogenation of N-Heterocycles in Water

by Dinesh Talwar, Ho Yin Li, Emma Durham, Jianliang Xiao
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Transfer hydrogenation Transfer hydrogenation is a simple safe way for reduction reactions and using water as a solvent has the additional benefit of being “green”. In their Full paper on page 5370 ff., J. Xiao et al. report that a cyclometalated iridium complex catalyzes the transfer hydrogenation of various nitrogen heterocycles in an aqueous solution of formate under mild conditions. The catalyst shows excellent functional-group compatibility and high turnover number, with loadings as low as 0.01 mol % being feasible. A mechanistic study of quinoline reduction suggests that the reaction proceeds via both 1,2- and 1,4-addition pathways, with the catalytic turnover limited by hydride transfer.

19 Mar 12:42

Electrochemical and Spectroelectrochemical Studies of Diphosphorylated Metalloporphyrins. Generation of a Phlorin Anion Product

by Yuanyuan Fang, Yulia G. Gorbunova, Ping Chen, Xiaoqin Jiang, Machima Manowong, Anna A. Sinelshchikova, Yulia Yu. Enakieva, Alexander G. Martynov, Aslan Yu. Tsivadze, Alla Bessmertnykh-Lemeune, Christine Stern, Roger Guilard and Karl M. Kadish

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Inorganic Chemistry
DOI: 10.1021/acs.inorgchem.5b00067
19 Mar 13:24

Hydroboration of Carbon Dioxide Using Ambiphilic Phosphine–Borane Catalysts: On the Role of the Formaldehyde Adduct

by Richard Declercq, Ghenwa Bouhadir, Didier Bourissou, Marc-André Légaré, Marc-André Courtemanche, Karine Syrine Nahi, Nicolas Bouchard, Frédéric-Georges Fontaine and Laurent Maron

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ACS Catalysis
DOI: 10.1021/acscatal.5b00189
19 Mar 14:09

Chemoenzymatic Dynamic Kinetic Resolution: A Powerful Tool for the Preparation of Enantiomerically Pure Alcohols and Amines

by Oscar Verho and Jan-E. Bäckvall

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Journal of the American Chemical Society
DOI: 10.1021/jacs.5b01031
19 Mar 19:33

Ancillary Ligand Control of Electronic Structure in o-Benzoquinonediimine-Ruthenium Complex Redox Series: Structures, Electron Paramagnetic Resonance (EPR), and Ultraviolet−Visible−Near-Infrared (UV-vis-NIR) Spectroelectrochemistry

by Ankita Das, Prabir Ghosh, Sebastian Plebst, Brigitte Schwederski, Shaikh M. Mobin, Wolfgang Kaim and Goutam Kumar Lahiri

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Inorganic Chemistry
DOI: 10.1021/ic503070j
19 Mar 18:54

In Situ Formation of Cobalt Oxide Nanocubanes as Efficient Oxygen Evolution Catalysts

by Gregory S. Hutchings, Yan Zhang, Jian Li, Bryan T. Yonemoto, Xinggui Zhou, Kake Zhu and Feng Jiao

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Journal of the American Chemical Society
DOI: 10.1021/jacs.5b01006
19 Mar 19:53

[Editors' Choice] Silver's salty twist on water splitting

by Jake Yeston
Author: Jake Yeston
17 Mar 20:50

Progress on All Ends for Carbon–Carbon Bond Formation through Photoredox Catalysis

by Miguel Peña-López, Alonso Rosas-Hernández, Matthias Beller
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Dual role for catalysts: Novel protocols for the generation of asymmetric stereocenters using photoredox catalysis were recently developed. Different chiral catalytic systems allowed to form new C[BOND]C bonds in good yields and enantioselectivities using a mild methodology in which light is used as energy source.

11 Mar 00:00

Sustainability science: Exploiting the synergies

by David Griggs

Sustainability science: Exploiting the synergies

Nature 519, 7542 (2015). doi:10.1038/519156a

Author: David Griggs

Dave Griggs relishes Jeffrey Sachs's analysis of the policy and practice key to a viable future for people and planet.

16 Mar 14:13

Reductive photocatalysis and smart inks

Chem. Soc. Rev., 2015, Advance Article
DOI: 10.1039/C4CS00279B, Tutorial Review
Andrew Mills, Nathan Wells
Examples of reductive photocatalysis and smart ink.
To cite this article before page numbers are assigned, use the DOI form of citation above.
The content of this RSS Feed (c) The Royal Society of Chemistry
16 Mar 22:20

Inside Cover: Efficient Access to Titanaaziridines by CH Activation of N-Methylanilines at Ambient Temperature (Angew. Chem. Int. Ed. 14/2015)

by Manfred Manßen, Nicolai Lauterbach, Jaika Dörfler, Marc Schmidtmann, Wolfgang Saak, Sven Doye, Rüdiger Beckhaus
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Killing two birds with one stoneIn the presence of a bis(η51-pentafulvene) titanium complex, N-methylanilines undergo two bond activation reactions to directly give titanaaziridines. Based on this transformation, S. Doye, R. Beckhaus, et al. report in their Communication on page 4383 ff. the isolation and investigation of all key intermediates of the titanium-catalyzed hydroaminoalkylation of alkenes. The results represent the first experimental proof of the suggested reaction mechanism of this industrially promising reaction.

10 Mar 10:20

Oxidation State, A Long-Standing Issue!

by Pavel Karen
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What is an oxidation state? Oxidation state has defining algorithms but lacks a comprehensive definition. Results of an IUPAC project to find such a definition have recently been published in an extensive Technical Report. A summary in this Essay is illustrated with applications on Lewis, bond-graph, and summary formulas of molecules, ions, or solids, together with the most recent information regarding tricky cases.

10 Mar 10:10

Electrocatalytic Carbon Dioxide Reduction by Using Cationic Pentamethylcyclopentadienyl–Iridium Complexes with Unsymmetrically Substituted Bipyridine Ligands

by Fanni D. Sypaseuth, Corinna Matlachowski, Manuela Weber, Matthias Schwalbe, C. Christoph Tzschucke

Abstract

Eight [Ir(bpy)Cp*Cl]+-type complexes (bpy= bipyridine, Cp*=1,2,3,4,5-pentamethylcyclopentadienyl) containing differently substituted bipyridine ligands were synthesized and characterized. Cyclic voltammetry (CV) of the complexes in Ar-saturated acetonitrile solutions showed that the redox behavior of the complexes could be fine tuned by the electronic properties of the substituted bipyridine ligands. Further CV in CO2-saturated MeCN/H2O (9:1, v/v) solutions showed catalytic currents for CO2 reduction. In controlled potential electrolysis experiments (MeCN/MeOH (1:1, v/v), Eapp=−1.80 V vs Ag/AgCl), all of the complexes showed moderate activity in the electrocatalytic reduction of CO2 with good stability over at least 15 hours. This electrocatalytic process was selective toward formic acid, with only traces of dihydrogen or carbon monoxide and occasionally formaldehyde as byproducts. However, the turnover frequencies and current efficiencies were quite low. No direct correlation between the redox potentials of the complexes and their catalytic activity was observed.

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Promising option: Selective electrocatalytic CO2 reduction was achieved at room temperature under atmospheric CO2 pressure with [Ir(bpy)Cp*Cl]+-type complexes (see picture) in solvent mixtures containing protic solvents. Catalytic activity subtly depended on the electron density of the Ir center, which was influenced by the bipyridine substitution pattern. Turnover frequencies are moderate, but the catalysts show stability over at least 15 hours.

11 Mar 12:44

Inverting Transient Absorption Data to Determine Transfer Rates in Quantum Dot–TiO2 Heterostructures

by Tess R. Senty, Scott K. Cushing, Congjun Wang, Christopher Matranga and Alan D. Bristow

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The Journal of Physical Chemistry C
DOI: 10.1021/jp512500g
11 Mar 15:37

Solvents Effects on Charge Transfer from Quantum Dots

by Jennifer L. Ellis, Daniel D. Hickstein, Kyle J. Schnitzenbaumer, Molly B. Wilker, Brett B. Palm, Jose L. Jimenez, Gordana Dukovic, Henry C. Kapteyn, Margaret M. Murnane and Wei Xiong

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Journal of the American Chemical Society
DOI: 10.1021/jacs.5b00463
11 Mar 19:31

Understanding the Origin of the Photocatalytic CO2 Reduction by Au- and Cu-Loaded TiO2: A Microsecond Transient Absorption Spectroscopy Study

by Herme G. Baldoví, Ştefan Neaţu, Anish Khan, Abdullah M. Asiri, Samia A. Kosa and Hermenegildo Garcia

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The Journal of Physical Chemistry C
DOI: 10.1021/jp5106136
09 Mar 17:29

Iron Catalysis in Organic Synthesis

by Ingmar Bauer and Hans-Joachim Knölker

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Chemical Reviews
DOI: 10.1021/cr500425u