Photocatalytic and photosensitized water splitting: A plea for well-defined and commonly accepted protocol
Publication date: Available online 8 May 2018Source: Comptes Rendus ChimieAuthor(s): Arindam Indra, Prashanth W. Menezes, Matthias DriessAbstractThe amount of “free” energy provided by the sun in 1 h is more than what currently mankind uses from fossil fuels and other renewable energy sources. Water covers 71% of the earth surface, making it easily available and one of the cheapest natural resources. Therefore, the concept of sunlight-driven water splitting (oxygen and hydrogen evolution) by converting the solar energy into chemical energy could be a cheap substitute for fuels and thus is of paramount interest. Moreov...
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
High activity heterogeneous catalysts by plasma-enhanced chemical vapor deposition of volatile palladium complexes on biomorphic carbon
Publication date: Available online 10 May 2018Source: Comptes Rendus ChimieAuthor(s): Lisa Czympiel, Michael Frank, Andreas Mettenbörger, Sven-Martin Hühne, Sanjay MathurAbstractSix new palladium complexes based on allyl and alkenolate ligands were synthesized and structurally characterized. Combination of delocalized allylic sp2-hybridized carbon centers and a strongly binding NˆO chelating unit (e.g., 3,3,3-trifluoro(pyridin-2-yl)propen-2-ol) offered a promising combination of high volatility and thermal lability not commonly observed in noble metal precursors. Application of the new Pd compounds in thermal metal–or...
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
Challenges in chemical synthesis at the border of solution-based and solid-state chemistry—Synthesis and structure of [CH3CH2Ge9{Si(SiMe3)3}]2−
We present a synthetic method for a stepwise ligand exchange reaction at a Zintl ion. Herein, we functionalized the [Ge9{Si(SiMe3)3}2]2− cluster with an ethyl group by a reaction with bromoethane. The obtained anion [CH3CH2Ge9{Si(SiMe3)3}2]− was characterized by NMR spectroscopy and mass spectrometry. After addition of 2,2,2-crypt an abstraction of one silyl ligand was observed resulting in the crystallization of [K(2,2,2-crypt)]2[CH3CH2Ge9{Si(SiMe3)3}] representing the first monosilylated Ge9 Zintl cluster, which carries an additional ethyl group. The latter compound was characterized by single crystal X-ray crystallo...
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
Macroscopic methods: Magnetic, optical, and calorimetric techniques
In this study, we will focus on the basis and the evolution of three critical macroscopic tools, i.e. the optical, magnetic, and calorimetric characterization methods. (Source: Comptes Rendus Chimie)
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
Materials from binary tetrahedral main group element units
Publication date: Available online 23 May 2018Source: Comptes Rendus ChimieAuthor(s): Stefanie DehnenAbstractSynthetic approaches to new materials are as various as the nature of the materials themselves. Here, we report on one synthetic concept that was used during the recent past to address a variety of different families of compounds from superionic conductors and supersphere cages for molecular trapping to new white-light generators and reactive multimetallic clusters. The use of small binary molecules comprising atoms of two main group elements is the base of all of the presented methodologies, which lead to the named...
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
Zeolite nanoparticles (H-ZSM5) as a highly efficient, green, and reusable heterogeneous catalyst for selective oxidation of sulfides to sulfoxides under mild conditions
Publication date: Available online 9 June 2018Source: Comptes Rendus ChimieAuthor(s): Amin Rostami, Noosheen Saedmocheshi, Zeinab ShirvandiAbstractH-ZSM5 is applied as an efficient, highly reusable, and heterogeneous catalyst for the oxidation of sulfides to sulfoxides using 30% H2O2 under solvent-free conditions at room temperature. A variety of aromatic and aliphatic sulfides with different functional groups were successfully oxidized with good to excellent yields in short reaction times. The catalyst can be easily recovered by simple filtration and recycled for several consecutive runs without any significant loss of it...
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
Tris-hydroxymethylaminomethane (THAM): An efficient organocatalyst in diversity-oriented and environmentally benign synthesis of spirochromenes
Publication date: Available online 10 June 2018Source: Comptes Rendus ChimieAuthor(s): Supriya S. Khot, Prashant V. Anbhule, Uday V. Desai, Prakash P. WadgaonkarAbstractTris-hydroxymethylaminomethane has been demonstrated to be an efficient organocatalyst in diversity-oriented synthesis of medicinally prevalent spirochromenes by one-pot, three-component reactions between isatins, malononitrile, and enolizable CH acids like dimedone, 4-hydroxycoumarin, 4-hydroxy-N-methylquinolin-2-one, or in situ generated 2-methylpyrazolon-2-one. Biodegradability and extremely low cost of the catalyst are the noteworthy features of this ch...
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
The power of synthesis towards new materials
Publication date: Available online 14 June 2018Source: Comptes Rendus ChimieAuthor(s): Michael Veith, Pierre Braunstein (Source: Comptes Rendus Chimie)
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
Microscopic models of spin crossover
Publication date: Available online 15 June 2018Source: Comptes Rendus ChimieAuthor(s): Ján Pavlik, Jorge LinaresAbstractThe basic model for thermal spin crossover (SCO) is discussed in its microscopic and thermodynamic formulation. Compared to the basic model, its more elaborated forms formulated in course of almost 50 years are briefly reviewed with emphasis on their additional features. A separate section is devoted to the newer developments in the field of modelling of the SCO nanoparticles. The presentation of models is led in a comparative way to provide an accessible outline of the foundations of modern theoretical ...
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
Nanostructured ternary composites of PPy/CNT/NiFe2O4 and PPy/CNT/CoFe2O4: Delineating and improving microwave absorption
Publication date: Available online 19 June 2018Source: Comptes Rendus ChimieAuthor(s): Erfan Ghashghaei, Somayyeh Kheirjou, Sara Asgari, Hanif KazerooniAbstractTwo different ternary nanocomposites, PPy/CNT/CoFe2O4 and PPy/CNT/NiFe2O4, were synthesized by in situ polymerization method. The resulting composites were characterized using Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray diffraction. They were evaluated with the aim of investigating microwave absorption properties. The results showed that the value of microwave refl...
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
Imidazolinone and triazine herbicides in soils in relation to the complexes formed with Cu(II) ions
In conclusion, crops treated with such herbicides in conjunction with Cu(II) salts experience a decrease in its persistence and effectiveness. In addition, the herbicides and the copper ions may pass to the phreatic layer of the soil, increasing the chance of pollution.Graphical abstract (Source: Comptes Rendus Chimie)
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
Hexavalent chromium quantification in solution: Comparing direct UV–visible spectrometry with 1,5-diphenylcarbazide colorimetry
Publication date: Available online 22 June 2018Source: Comptes Rendus ChimieAuthor(s): Arnaud Sanchez-Hachair, Annette HofmannAbstractQuantification of Cr(VI) in an aqueous solution is conducted by direct UV–visible spectrophotometry based on the yellow coloring of the chromate ion. Measurements show that absorption follows the Beer–Lambert law over a wide range of concentrations. At pH below the pKa of 6.4 (HCrO4−/CrO4−2), the absorption maximum lies at 350 nm wavelength and the linear range spans from 0.5 to 100 mg Cr(VI)/L; above the pKa (pH 6.4), the absorption maximum is 373 nm and linearity occurs in the r...
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
Réaction pseudo-multicomposants entre le glutaconate de diméthyle et des aldéhydes aromatiques induite par le bromure de phénylzinc : accès domino à des dihydropyranones 2,3,5-trisubstituées
Publication date: Available online 28 June 2018Source: Comptes Rendus ChimieAuthor(s): Erwan Le Gall, Marc Presset, Éric Léonel, Pascal RetailleauAbstractPhenylzinc bromide enables a pseudo three-component reaction of methyl glutaconate and aromatic aldehydes. Unsaturated trisubstituted δ-valerolactones (dihydropyranones) are obtained in fair to good yields by an aldol/aldol/elimination/lactonization domino process that allows the formation of four new bonds in a single step. A putative reaction mechanism is proposed.RésuméLe bromure de phénylzinc induit une pseudo-réaction à trois composants entre le glutaconate d...
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
Editorial Board - English
Publication date: July 2018Source: Comptes Rendus Chimie, Volume 21, Issue 7Author(s): (Source: Comptes Rendus Chimie)
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
Editorial Board - French
Publication date: July 2018Source: Comptes Rendus Chimie, Volume 21, Issue 7Author(s): (Source: Comptes Rendus Chimie)
Source: Comptes Rendus Chimie - July 11, 2018 Category: Chemistry Source Type: research
