pinecone/core-2020-05-10-deduplication huggingface dataset:
Fast High-Responsivity Few-Layer MoTe2 Photodetectors

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.The Transition Metal Dichalcogenide MoTe2 is fabricated via mechanical exfoliation into few-layer Field Effect Transistors (FETs) having a hole mobility of 2.04 V/cm2/s. Four-layer MoTe2 FETs show a high photoresponsivity of 6 A/W and a response time, at around 160 μs, over 100 times faster than previously reported for MoTe2. Few-layer MoTe2 thus appears as a strong candidate for high speed and high sensitivity photodetection applications.CDW would like to acknowledge funding via EPSRC grants EP/M015173/1 and EP/M015130/1. TJO acknowledges funding from the EPSRC Centre for Doctoral Training in Metamaterials, grant number EP/L015331/
Upconversion nanocrystal-doped glass: a new paradigm for photonic materials

Version of Record online: 30 MAY 2016The integration of novel luminescent nanomaterials into glassy matrix can lead to new hybrid materials and photonic devices with promising material performance and device functions. Lanthanide-containing upconversion nanocrystals have become unique candidates for sensing, bioimaging, photon energy management, volumetric displays, and other photonic applications. Here, a versatile direct-doping approach is developed to integrate bright upconversion nanocrystals in tellurite glass with tailored nanoscale properties. Following our two-temperature glass-melting technique, the doping temperature window of 550–625 °C and a 5 min dwell time at 577 °C are determined as the key to success, which balances the survival and dispersion of upconversion nanocrystals in glass. It is identified that the fine spectra of upconversion emissions can be used to diagnose the survival and dissolution fraction of doped nanocrystals in the glass. Moreover, 3D dispersion of nanocrystals in the glass is visualized by upconversion scanning confocal microscopy. It is further demonstrated that a low-loss fiber, drawn from the highly transparent nanocrystals-doped glass retains the distinct optical properties of upconversion nanocrystals. These results suggest a robust strategy for fabrication of high-quality upconversion nanocrystal-doped glasses. The new class of hybrid glasses allows for fiber-based devices to be developed for photonic applications or as a useful tool for tailoring light–nanoparticles interactions study.Jiangbo Zhao, Xianlin Zheng, Erik P. Schartner, Paul Ionescu, Run Zhang, Tich-Lam Nguyen, Dayong Jin, and Heike Ebendorff-Heideprie
Nanoassembly of Polydisperse Photonic Crystals Based on Binary and Ternary Polymer Opal Alloys

This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/adom.201600328Ordered binary and ternary photonic crystals, composed of different sized polymer-composite spheres with diameter ratios up to 120%, are generated using bending-induced oscillatory shearing. This viscoelastic system creates polydisperse equilibrium structures, producing mixed opaline colored films with greatly reduced requirements for particle monodispersity, and very different sphere size ratios compared to other methods of nanoassembly.authorsversionPeer reviewe
Nonvolatile All-Optical 1 × 2 Switch for Chipscale Photonic Networks

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Integrated chip-level photonics has the potential to revolutionize future computer systems by eliminating the “von-Neumann information bottleneck” and the power losses resulting from the use of electrical interconnects. Yet, the need for optical-to-electrical conversion has so far hindered the implementation of chip-level all-optical routing schemes, which remain operational without continuous power consumption. Here, a crucial component to successful implementation of such all-photonic networks is demonstrated – an effective, practicable all-optical nonvolatile switch. Current integrated all-optical switches require constant bias power to operate, and lose their state when it is removed. By contrast, our switch is entirely nonvolatile, with the direction of light flow altered by switching the phase state of an embedded phase-change cell using 1 ps optical pulses. High on/off switching contrast devices are achieved that are fully integrated and compatible with existing photonic circuits. It is shown that individual switching events occur with transition times below 200 ps and thus hold promise for ultrafast light routing on chip. The approach offers a reliable and simple route toward hybrid reconfigurable photonic devices without the need for electrical contacting.Funded by:
DFG. Grant Numbers: PE 1832/1-1, PE 1832/2-1;
EPSRC. Grant Numbers: EP/J018783/1, EP/M015173/1, EP/M015130/1;
Clarendon Fun
Strong coupling in fully tunable microcavities filled with biologically-produced fluorescent proteins

We thank C. Schneider for fruitful discussions and A. Clemens and K. Ostermann (TU Dresden, Germany) for technical support with protein preparation. We acknowledge financial support from the European Research Council (ERC StG ABLASE, 640012), the Scottish Funding Council (via SUPA), the European Union Marie Curie Career Integration Grant (PCIG12-GA-2012-334407) and the EPSRC Hybrid Polaritonics program grant (EP/M025330/1). M.S. acknowledges funding from the German Science Foundation (DFG) through a Research Fellowship (SCHU 3003/1-1) and from the European Commission for a Marie Sklodowska-Curie Individual Fellowship (659213). S.H. gratefully acknowledges support by the Royal Society and the Wolfson Foundation.Strong coupling between cavity photons and excited states of biologically produced recombinant fluorescent proteins in fully tunable optical microcavities is demonstrated. Natural thickness and concentration gradients in blends of two different proteins allow precise adjustment of the spectral position of polariton states and of the effective coupling strength, thus providing control of the photonic and excitonic components of the system.Publisher PDFPeer reviewe
Design and Realization of a Novel Optically Disordered Material: A Demonstration of a Mie Glass

Herein, a diffusive material presenting optical disorder is introduced, which represents an example of a Mie glass. Comprising spherical crystalline TiO nanoparticles randomly dispersed in a mesoporous TiO matrix, it is proved that the scattering of light in this inhomogeneous solid can be predicted in an unprecedented manner from single-particle considerations employing Mie theory. To that aim, a study of the dependence of the key parameters employed is performed to describe light propagation in random media, i.e., the scattering mean free path and the transport mean free path, as a function of the size and concentration of the spherical inclusions based on a comparison between experimental results and analytical calculations. It is also demonstrated that Mie glasses enable enhanced fluorescence intensity due to a combined absorptance enhancement of the excitation light combined with an improved outcoupling of the emitted light. The method offers the possibility to perform a deterministic design for the realization of a light diffuser with tailor-made scattering properties.Peer Reviewe
Solution-processable thermally activated delayed fluorescence white OLEDs based on dual-emission polymers with tunable emission colors and aggregation enhanced emission properties.

Thermally activated delayed fluorescence (TADF) white organic light-emitting diodes (WOLEDs) have drawn tremendous interest and have been extensively studied because of harvesting both triplet and singlet excitons without heavy metals. However, single white-light-emitting polymers are currently limited and few strategies exist to design these materials. Herein, a new strategy is proposed to develop the polymers with tunable emission colors by combining fluorescence and TADF based on aggregation-enhanced emission (AEE) characteristics. The polymers containing different ratios of pendant 2-(10H-phenothiazin-10-yl)dibenzothiophene-S,S-dioxide units with yellow TADF emission and dibenzothiophene units with blue fluorophor emission, which display both TADF and AEE characteristics, are synthesized successfully. Among them, the emission color of P3 in different tetrahydrofuran/water mixtures changes from greenish-blue to white or yellow. Moreover, P3 displays white emission in the solid state dispersing by poly(methyl methacrylate). In addition, electroluminescent device of P3 achieve white light emission with high color rending indexes (CRI) and low turn-on voltages (V on ). P3 OLEDs show two-color warm-white emission with high CRI of 77, low V on of 2.9 V, CEmax of 23.0 cd A−1, PEmax of 32.8 lm W−1, external quantum efficiency (EQE)max of 10.4% with Commission Internationale de l'Eclairage coordinates of (0.37, 0.38) at 5 V. Moreover, EQE of 2.6%, CE of 5.7 cd/A, PE of 4.7 lm W−1 at 100 cd m−2 are obtained. To the best of our knowledge, this work reports the first example of warm-white TADF polymer OLEDs
Optical detection and spatial modulation of mid‐infrared surface plasmon polaritons in a highly doped semiconductor

Highly doped semiconductors (HDSCs) are promising candidates for plasmonic applications in the mid‐infrared (MIR) spectral range. This work examines a recent addition to the HDSC family, the dilute nitride alloy In(AsN). Postgrowth hydrogenation of In(AsN) creates a highly conducting channel near the surface and a surface plasmon polariton detected by attenuated total reflection techniques. The suppression of plasmonic effects following a photoannealing of the semiconductor is attributed to the dissociation of the NH bond. This offers new routes for direct patterning of MIR plasmonic structures by laser writing
Supported ionic liquids. New recyclable materials for the L-proline-catalyzed aldol reaction

New materials for l-proline recycling have been developed. These materials have been applied to the l-proline-catalyzed aldol reaction between acetone and several aldehydes. The l-proline has been supported on the surface of modified silica gels with a monolayer of covalently attached ionic liquid with or without additional adsorbed ionic liquid. Good yields and ee values, comparable with those obtained under homogeneous conditions, have been obtained especially with imidazolinium-modified and 4-methylpyridinium-modified silica gels. Moreover, these materials have been easily recovered by simple filtration and studies about their reuse have been carried out. These studies showed that these materials can be used at least up to seven times. Finally, in the case of imidazolinium-modified silica gel, investigations showed that this support can be regenerated giving again a recyclable material with high isolated yields and reproducible ee values up to 13 cycles
New simple hydrophobic proline derivatives as highly active and stereoselective catalysts for the direct asymmetric aldol reaction in aqueous medium

New 4-substituted acyloxyproline derivatives with different hydrophobic properties of the acyl group were easily synthesized and used as catalysts in the direct asymmetric aldol reaction between cyclic ketones (cyclohexanone and cyclopentanone) and several substituted benzaldehydes. Reactions were carried out using water, this being the best reaction medium examined. Screening of these catalysts showed that compounds bearing the most hydrophobic acyl chains [4-phenylbutanoate and 4-(pyren-1-yl)butanoate] provided better results. The latter catalysts were successfully used in only 2 mol% at room temperature without additives to give aldol products in excellent stereoselectivities. These results demonstrate that derivatization of the proline moiety with the proper simple hydrophobic substituent in the 4-position can furnish highly active and stereoselective catalysts without the need of additional chiral backbones in the molecule. Finally, an explanation of the observed stereoselectivities in the presence of water is provided
Water versus solvent-free conditions for the enantioselective inter- and intramolecular aldol reaction employing L-prolinamides and L-prolinethioamides as organocatalysts

Organocatalysts 1, derived from L-proline and (1S,2R)-cis-1-aminoindan-2-ol or (R)-1-aminoindane, are evaluated as promoters in the direct asymmetric aldol reaction between ketones and aromatic aldehydes in the presence of water and under solvent-free reaction conditions. L-Prolinethioamides 1c and 1d exhibited higher enantioselectivity than the corresponding prolinamides 1a and 1b in the model aldol reaction between cyclohexanone and 4-nitrobenzaldehyde in the presence of 4-nitrobenzoic acid as cocatalyst. In particular, L-prolinethioamide 1d (5 mol%), derived from L-proline and (R)-1-aminoindane, is shown as the most efficient organocatalyst studied promoting the direct aldol reaction of cycloalkyl, alkyl, and α-functionalized ketones with aromatic aldehydes in the presence of water and under solvent-free reaction conditions employing only 2 equivalents of nucleophile. Generally, anti-aldol products are obtained in high yields and excellent diastereo- and enantioselectivities (up to >98/2 anti/syn, up to 98% ee). Solvent-free conditions give slightly higher dr and ee than using water as solvent. In addition, organocatalyst 1d can be easily recovered by extractive work-up and reused. Prolinethioamide 1d (5 mol%) in combination with 4-NO2C6H4CO2H (5 mol%) is also a very effective organocatalytic system for the asymmetric solvent-free intramolecular Hajos-Parrish-Eder-Sauer-Wiechert reaction with comparable or higher levels of enantioselectivity (up to 88% ee) to other reported catalysts in organic solvents.Financial support from the MEC (Projects CTQ2004-00808/BQU, CTQ2007–62771/BQU and Consolider INGENIO 2010 CSD2007-00006), from the Generalitat Valenciana (GRUPOS05/11, GV05/144, GV/2007/142) and the University of Alicante
Activated α, β-Unsaturated Aldehydes as Substrate of Dihydroxyacetone Phosphate (DHAP)-Dependent Aldolases in the Context of a Multienzyme System

Published in: Advanced Synthesis & Catalysis, Volume 351, Issue 17, Date: November 2009, Pages: 2967-2975.The utility for carbon-carbon bond formation of a multienzyme system composed of recombinant dihydroxyacetone kinase (DHAK) from Citrobacter freundii, the fructose bisphosphate aldolase from rabbit muscle (RAMA) and acetate kinase (AK) for adenosine triphosphate (ATP) regeneration has been studied. Several aldehydes with great structural diversity, including three ,-unsaturated aldehydes, have been analysed as acceptor substrates. It was found that ,-unsaturated aldehydes bearing an electron-withdrawing group in the  position to the double bond with a trans configuration are good acceptors for RAMA in this multienzyme system. The aldol reaction proceeds with excellent D-threo enantioselectivity and the aldol adduct is obtained in good overall yield. The L-threo and D-erythro enantiomers are also accessible from rhamnulose 1-phosphate aldolase (Rha-1PA) and fuculose 1-phosphate aldolase (Fuc-1PA) catalysed reactions, respectively.Funded by: Spanish Ministerio de Ciencia e Innovación; Grant Number: CTQ2007-67403/BQU\ud
Comunidad de MadridPeer reviewe
Nonafluorobutanesulfonyl Azide: A Shelf-Stable Diazo Transfer Reagent for the Synthesis of Azides from Primary Amines

6 páginas, 2 esquemas, 2 tablasNonafluorobutanesulfonyl azide is an efficient, shelf-stable and cost-effective diazo transfer reagent for the synthesis of azides from primary amines. The reagent can also be successfully applied to the one-pot regioselective synthesis of 1,2,3-triazoles from primary amines by a sequential diazo transfer and azide–alkyne 1,3-dipolar cycloaddition process catalyzed by copper. The cycloaddition step can be conducted in an inter- or intramolecular way to afford 1,4- or 1,5-disubstituted triazoles, respectively. The atypical 1,5-regioselectivity under copper catalysis is a consequence of geometrical constraints of the amino-alkyne substrates used in the intramolecular version. Nonafluorobutanesulfonyl azide offers an advantageous alternative to the better known and most commonly used trifluoromethanesulfonyl azide.We thank the Spanish Ministerio de Ciencia e Innovación\ud
(projects CTQ-2006-15515-C02-02/BQU and CTQ2009-\ud
14551-C02-02) and Comunidad de Madrid (project S2009/\ud
PPQ-1634 “AVANCAT”) for financial support. We also\ud
thank Ministerio de Ciencia e Innovación for a FPU predoctoral\ud
fellowship to B. T. and C.S.I.C. for a JAE-Doc contract\ud
to J. R. S., a JAE-Predoc fellowship to M. E. P.-O., and a\ud
JAE-Intro fellowship to R. M.-B.Peer reviewe
Multicomponent synthesis of 1,2,3-triazoles in water catalyzed by copper nanoparticles on activated carbon

Copper nanoparticles on activated carbon have been found to effectively catalyze the multicomponent synthesis of 1,2,3-triazoles from different azide precursors, such as organic halides, diazonium salts, anilines and epoxides in water. The first one-pot transformation of an olefin into a triazole is also described. The catalyst is easy to prepare, very versatile and reusable at a low copper loading.This work was generously supported by the Spanish Ministerio de Ciencia e Innovación (MICINN; CTQ2007-65218 and Consolider Ingenio 2010-CSD2007-00006), the Generalitat Valenciana (GV; PROMETEO/2009/039)
An Easy, Stereoselective Synthesis of Hexahydroisoindol-4-ones under Phosphine Catalysis

International audienceA new synthetic approach to hexahydroisoindol-4-ones is reported, based on the formal [3+2] cyclization reaction between N-arylsulfonylimines and cyclic conjugated dienes, under phosphine catalysis. Key substrates are 3-vinylcyclohex-2-enones with electron-withdrawing substituents (ester, amido, cyano, phosphoryl and keto groups) on the exocyclic double bond, which afford the three atom synthons for the construction of the pyrroline ring. Total syn stereoselectivity is observed in these annulations. The scope of the reaction has been demonstrated and mechanistic issues are considered, based on deuteration experiments and DFT calculations
Polytopic oxazoline-based chiral ligands for cyclopropanation reactions: A new strategy to prepare highly recyclable catalysts

El pdf del artículo es la versión post-print.New polytopic chiral copper complexes based on azabis(oxazoline) moieties have been synthesized and applied in cyclopropanation reactions of several alkenes. Excellent enantioselectivities have been obtained in all cases and additionally, the catalysts have been recovered in up to 14 cycles without noticeable loss of activity and selectivity. Analysis of the copper complexes by mass spectrometry suggests the formation of coordination polymers, representing the resting state of the catalysts.This work was supported by the Ministerio de Ciencia e Innovación (projects CTQ2008-05138 and Consolider Ingenio 2010 CSD2006-0003), the Aragon Government, the European Commission (European Regional Development Funds), the and the Deutsche Forschungsgemeinschaft (RE 948–8/1 “GLOBUCAT”).Peer Reviewe
A New Step Towards Solid Base Catalysis: Azidoproazaphosphatranes Immobilized in Nanopores of Mesoporous Silica

International audienceHeterogeneous basic catalysts derived from proazaphosphatranes, known as Verkade’s superbases, were prepared for the first time by covalent immobilization onto SBA-15 silica. In order to introduce the tether to the surface, three siloxane-containing azido derivatives of the proazaphosphatranes were first synthesized (2a–c) which after post-synthetic grafting onto silica support led to the formation of hybrid materials of different basicity and steric properties, 2a–c@SBA-15. These latter were fully characterized using a wide variety of molecular and solid-state techniques to determine their structural and textural properties. These new solid base catalysts were then evaluated in the Diels–Alder reactions of anthrone and 3-hydroxy-2-pyrone with two electron-deficient dienophiles, N-methylmaleimide and dimethyl fumarate. In general, high activity and selectivity were obtained depending on the catalytic species, the performance decreasing in the order methoxybenzyl>neopentyl>methyl azidophosphatrane. Catalyst recycling was studied for the best catalyst, the methoxybenzyl derivative, 2c@SBA-15, and it was shown that the catalyst could be re-used up to 3 cycles before any loss of activity could be detected
Dehydration of Benzyl Alcohols in Phosphonium Ionic Liquids: Synthesis of Ethers and Alkenes

Dehydration of benzylic alcohols has been studied in several phosphonium ionic liquids in the absence of any metal catalysts. Benzyl ethers and alkenes were obtained from primary and secondary benzylic alcohols in good to excellent yields for these reactions. Commercially available hydrophobic phosphonium ionic liquids containing the trihexyl(tetradecyl)phosphonium cation paired with six different anions were used for the reactions under microwave irradiation. The interaction of the substrate with the ionic liquid was investigated using different NMR techniques, such as NOESY NMR. The effects of cation and anions on the behaviour of these ionic liquids in the reactions were studied in order to understand the mechanism. A catalytic cycle is proposed involving activation of the benzyl alcohol by the phosphonium cation
Pinacol as a new green reducing agent: molybdenum-catalyzed chemoselective reduction of sulfoxides and nitroaromatics

Pinacol is disclosed as a new chemoselective and environmentally benign reducing agent for sulfoxides and nitroaromatics assisted by readily available dichlorodioxomolybdenum(VI) complexes as catalysts. A wide range of substrates including those bearing challenging functional groups has been efficiently and selectively reduced with acetone and water being the only by-products of these reactionsMinisterio de Ciencia e Innovacion (MICINN) and FEDER (CTQ2010-15358 and CTQ2009-09949/BQU) and Junta de Castilla y Leon (BU021 A09 and GR-172) for financial support. P.G.-G. and M.A.F.-R. thank MICINN for "Juan de la Cierva" and "Ramon y Cajal" contractsThis is the peer reviewed version of the following article:García, N., García-García, P., Fernández-Rodríguez, M. A., Rubio, R., Pedrosa, M. R., Arnáiz, F. J. and Sanz, R. (2012), Pinacol as a New Green Reducing Agent: Molybdenum- Catalyzed Chemoselective Reduction of Sulfoxides and Nitroaromatics. Adv. Synth. Catal., 354: 321–327. doi: 10.1002/adsc.201100877 , which has been published in final form at 10.1002/adsc.201100877. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archivin
One-pot cascade reactions using fructose-6-phosphate aldolase: Efficient synthesis of D-arabinose 5-phosphate, D-fructose 6-phosphate and analogues

One-pot multienzymatic reactions have been performed for the synthesis of 1-deoxy-D-fructose 6-phosphate, 1,2-dideoxy-D-arabino-hept-3-ulose 7-phosphate, D-fructose 6-phosphate and D-arabinose 5-phosphate. The whole synthetic strategy is based on an aldol addition reaction catalysed by fructose-6-phosphate aldolase (FSA) as a key step of a three or four enzymes-catalysed cascade reaction. The four known donors for FSA - dihydroxyacetone (DHA), hydroxyacetone (HA), 1-hydroxy-2-butanone (HB) and glycolaldehyde (GA) - were used with D-glyceraldehyde 3-phosphate as acceptor substrate. The target phosphorylated sugars were obtained in good to excellent yields and high purity. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Peer Reviewe