pinecone/core-2020-05-10-deduplication huggingface dataset:
Theory and Practice: Bulk Synthesis of C3B and its H2- and Li-Storage Capacity

Previous theoretical studies of C3B have suggested that boron-doped graphite is a promising H2- and Li-storage material, with large maximum capacities. These characteristics could lead to exciting applications as a lightweight H2-storage material for automotive engines and as an anode in a new generation of batteries. However, for these applications to be realized a synthetic route to bulk C3B must be developed. Here we show the thermolysis of a single-source precursor (1,3-(BBr2)2C6H4) to produce graphitic C3B, thus allowing the characteristics of this elusive material to be tested for the first time. C3B was found to be compositionally uniform but turbostratically disordered. Contrary to theoretical expectations, the H2- and Li-storage capacities are lower than anticipated, results that can partially be explained by the disordered nature of the material. This work suggests that to model the properties of graphitic materials more realistically, the possibility of disorder must be considered.We thank the ERC (Advance Investigator awards for D.S.W., C.P.G.), the EPSRC (T.C.K., P.D.M., H.G., J.C.), and the Spanish Ministerio de Economia y Competitividad (under grants ENE2011-24-412 and IPT-2011-1553-420000). We thank John Bulmer for Raman spectroscopy and Keith Parmenter for glass blowing. We thank the Schlumberger Gould Research Centre for XPS analysis.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/anie.20141220
Easy access to modified cyclodextrins by an intramolecular radical approach

A simple method to modify the primary face of cyclodextrins (CDs) is described. The 6I-O-yl radical of a-, b-, and g-CDs regioselectively abstracts the H5II, located in the adjacent d-glucose unit, by an intramolecular 1,8-hydrogenatom-transfer reaction through a geometrically restricted ninemembered transition state to give a stable 1,3,5-trioxocane ring. The reaction has been extended to the 1,4-diols of a- and b-CD to give the corresponding bis(trioxocane)s. The C2-symmetric bis(trioxocane) corresponding to the a-CD is a stable crystalline solid whose structure was confirmed by X-ray diffraction analysis. The calculated geometric parameters confirm that the primary face is severely distorted toward a narrower elliptical shape for this rim
A concise and scalable strategy for the total synthesis of dictyodendrin B based on sequential C–H functionalization

A sequential C-H functionalization strategy for the synthesis of the marine alkaloid dictyodendrin B is reported. Our synthesis begins from commercially available 4-bromoindole and involves six direct functionalizations around the heteroarene core as part of a gram-scale strategy towards the natural product.We are grateful to AstraZeneca, Pfizer, and EPSRC (A.K.P., F.O.
and R.H.S.) and the ERC and EPSRC for fellowships (M.J.G.).This is the author accepted manuscript. The final version is available from Wiley at http://onlinelibrary.wiley.com/doi/10.1002/anie.201500067/abstract
A Signal-Passing DNA-Strand-Exchange Mechanism for Active Self-Assembly of DNA Nanostructures

DNA nanostructured tiles play an active role in their own self-assembly in the system described herein whereby they initiate a binding event that produces a cascading assembly process. We present DNA tiles that have a simple but powerful property: they respond to a binding event at one end of the tile by passing a signal across the tile to activate a binding site at the other end. This action allows sequential, virtually irreversible self-assembly of tiles and enables local communication during the self-assembly process. This localized signal-passing mechanism provides a new element of control for autonomous self-assembly of DNA nanostructures
Targeted Detection of G-Quadruplexes in Cellular RNAs

The G-quadruplex (G4) is a non-canonical nucleic acid structure which regulates important cellular processes. RNA G4s have recently been shown to exist in human cells and be biologically significant. Described herein is a new approach to detect and map RNA G4s in cellular transcripts. This method exploits the specific control of RNA G4–cation and RNA G4–ligand interactions during reverse transcription, by using a selective reverse transcriptase to monitor RNA G4-mediated reverse transcriptase stalling (RTS) events. Importantly, a ligation-amplification strategy is coupled with RTS, and enables detection and mapping of G4s in important, low-abundance cellular RNAs. Strong evidence is provided for G4 formation in full-length cellular human telomerase RNA, offering important insights into its cellular function.This study is supported by a European Research Council Advanced grant to S.B. and supports C.K.K., and the Croucher Foundation for a fellowship to C.K.K. We thank Dr. M. Di Antonio, V. Chambers, and G. Mclnroy for providing comments on the manuscript.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/anie.20150089
High-fidelity noncovalent synthesis of hydrogen-bonded macrocyclic assemblies

This is the accepted version of the following article: Angewandte Chemie International Edition 54.23 (2015): 6780-6784, which has been published in final form at http://dx.doi.org/10.1002/anie.201501321A hydrogen-bonded cyclic tetramer is assembled with remarkably high effective molarities from a properly designed dinucleoside monomer. This self-assembled species exhibits an impressive thermodynamic and kinetic stability and is formed with high fidelities within a broad concentration
rangeFunding from MINECO (CTQ2011-23659) and the E.U. (ERC-Starting Grant 279548) is gratefully acknowledge
Single-Walled Carbon Nanotube/Metalloporphyrin Composites for the Chemiresistive Detection of Amines and Meat Spoilage

Chemiresistive detectors for amine vapors were made from single-walled carbon nanotubes by noncovalent modification with cobalt meso-arylporphyrin complexes. We show that through changes in the oxidation state of the metal, the electron-withdrawing character of the porphyrinato ligand, and the counteranion, the magnitude of the chemiresistive response to ammonia could be improved. The devices exhibited sub-ppm sensitivity and high selectivity toward amines as well as good stability to air, moisture, and time. The application of these chemiresistors in the detection of various biogenic amines (i.e. putrescine, cadaverine) and in the monitoring of spoilage in raw meat and fish samples (chicken, pork, salmon, cod) over several days was also demonstrated.National Science Foundation (U.S.) (DMR-1410718)National Science Foundation (U.S.). Graduate Research Fellowship (Grant 1122374)Massachusetts Institute of Technology. Institute for Soldier Nanotechnologie
Far-Red and Near-IR AIE-Active Fluorescent Organic Nanoprobes with Enhanced Tumor-Targeting Efficacy:Shape-Specific Effects

The rational design of high-performance fluorescent materials for cancer targeting in vivo is still challenging. A unique molecular design strategy is presented that involves tailoring aggregation-induced emission (AIE)-active organic molecules to realize preferable far-red and NIR fluorescence, well-controlled morphology (from rod-like to spherical), and also tumor-targeted bioimaging. The shape-tailored organic quinoline-malononitrile (QM) nanoprobes are biocompatible and highly desirable for cell-tracking applications. Impressively, the spherical shape of QM-5 nanoaggregates exhibits excellent tumor-targeted bioimaging performance after intravenously injection into mice, but not the rod-like aggregates of QM-2
Combining electron-accepting phthalocyanines and nanorod-like CuO electrodes for p-type dye-sensitized solar cells

This is the peer reviewed version of the following article: Angewandte Chemie - International Edition 54.26 (2015): 7688-7692, which has been published in final form at http://dx.doi.org/10.1002/anie.201501550]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingA route is reported for the synthesis of two electron-accepting phthalocyanines featuring linkers with different lengths as sensitizers for p-type dye-sensitized solar cells (DSSCs). Importantly, our devices based on novel nanorod-like CuO photocathodes showed high efficiencies of up to 0.191%: the highest value reported to date for CuO-based DSSCs. The longer the better: Novel electron-accepting zinc phthalocyanines with different linker lengths performed well in combination with nanorod-like CuO electrodes in p-type dye-sensitized solar cells. A particularly high efficiency of 0.191% was observed with a photosensitizer containing a carboxyethynyl anchor (see picture; R is a branched alkyl group)The authors thank the German Science Council (DFG) for the financial support in the framework of the Cluster of Engineering of Advanced Materials (EAM), the MINECO Spain (CTQ2014- 52869/BQU), the Comunidad de Madrid Spain (FOTOCARBON, S2013/MIT-2841), and the European Union within the FP7-ENERGY-2012-1 nr. 309194-2, GLOBALSO
Determination of enantiomeric excess in amine derivatives with molecular self-assemblies

We report the first fluorescence-based assay for the rapid determination of the ee value of amines, amino alcohols, and amino acid esters. The method uses the self-assembly of 2-formylphenylboronic acid with a chiral diol and a chiral amine or derivatives (of unknown chirality) to produce two diastereomeric iminoboronates that differ in their fluorescence intensity and polarization. The approach allows for the accurate determination of the ee value of chiral amines with errors of just 1-2%. We believe that this application of orthogonal dynamic covalent self-assembly in the determination of the enantioselectivity will lead to the development of high-throughput procedures for the determination of chirality
Aplysiasecosterol A: A 9,11-Secosteroid with an Unprecedented Tricyclic γ-Diketone Structure from the Sea Hare Aplysia kurodai

A new 9,11-secosteroid having an unprecedented tricyclic γ-diketone structure, aplysiasecosterol A (1), was isolated from the sea hare Aplysia kurodai. The structure was determined by one- and two-dimensional NMR spectroscopic analysis, molecular modeling studies, a comparison of experimental and calculated ECD spectra, and a modified Mosher′s method. Aplysiasecosterol A (1) exhibited cytotoxicity against human myelocytic leukemia HL-60 cells. A biosynthetic pathway for 1 from a known cholesterol was proposed and includes twice α-ketol rearrangements and an intramolecular acetalization
Palladium-assisted "aromatic metamorphosis" of dibenzothiophenes into triphenylenes.

Two new palladium-catalyzed reactions of aromatic sulfur compounds enabled the conversion of dibenzothiophenes into triphenylenes in four steps. This transformation of one aromatic framework into another consists of 1) 4-chlorobutylation of the dibenzothiophene to form the corresponding sulfonium salt, 2) palladium-catalyzed arylative ring opening of the sulfonium salt with a sodium tetraarylborate, 3) an intramolecular S(N)2 reaction to form a teraryl sulfonium salt, and 4) palladium-catalyzed intramolecular C-S/C-H coupling through electrophilic palladation. Symmetrical as well as unsymmetrical triphenylenes of interest were synthesized in a tailor-made fashion in satisfactory overall yields
Copper catalysed oxy-alkenylation of homoallylic alcohols to functional syn-1,3-diol derivatives

A novel method for the synthesis of a wide range of functionalized 1,3-diol derivatives is reported. Employing a copper-catalyzed oxy-alkenylation strategy, a range of readily available, substituted homoallylic alcohol derivatives and alkenyl(aryl) iodonium salts combine to form syn-1,3-carbonates in excellent yield and with high selectivity. Furthermore, the products formed are amenable to an iterative reaction sequence, thus affording highly complex polyketide-like fragments.We are grateful to the EPSRC (D.H.) for a studentship and the ERC and EPSRC for fellowships (M.J.G.).This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/anie.20150199
Exceedingly facile Ph−X activation (X=Cl, Br, I) with ruthenium(II) : Arresting kinetics, autocatalysis, and mechanisms

The ICIQ Foundation and The Spanish Government (Grant CTQ2011-25418 and the Severo Ochoa Excellence Accreditation 2014-2018 SEV-2013-0319) are thankfully acknowledged for support of this work. F.M.M. is grateful to the Government of Spain (MICINN) for the FPI Ph.D. Scholarship (BES-2012-054922). S.A.M. and D.M. thank the EPSRC for support through award EP/J010677/1.[(Ph3P)3Ru(L)(H)2] (where L=H2 (1) in the presence of styrene, Ph3P (3), and N2 (4)) cleave the Ph[BOND]X bond (X=Cl, Br, I) at RT to give [(Ph3P)3RuH(X)] (2) and PhH. A combined experimental and DFT study points to [(Ph3P)3Ru(H)2] as the reactive species generated upon spontaneous loss of L from 3 and 4. The reaction of 3 with excess PhI displays striking kinetics which initially appears zeroth order in Ru. However mechanistic studies reveal that this is due to autocatalysis comprising two factors: 1) complex 2, originating from the initial PhI activation with 3, is roughly as reactive toward PhI as 3 itself; and 2) the Ph[BOND]I bond cleavage with the just-produced 2 gives rise to [(Ph3P)2RuI2], which quickly comproportionates with the still-present 3 to recover 2. Both the initial and onward activation reactions involve PPh3 dissociation, PhI coordination to Ru through I, rearrangement to a η2-PhI intermediate, and Ph[BOND]I oxidative addition.Publisher PDFPeer reviewe
Titanium trisulfide monolayer: A new direct-gap semiconductor with high
  and anisotropic carrier mobility

A new two-dimensional (2D) layered material, namely, titanium trisulfide
(TiS$_3$) monolayer sheet, is predicted to possess desired electronic
properties for nanoelectronic applications. On basis of the first-principles
calculations within the framework of density functional theory and deformation
theory, we show that the TiS$_3$ 2D crystal is a direct gap semiconductor with
a band gap of 1.06 eV and high carrier mobility. More remarkably, the in-plane
electron mobility of the 2D TiS$_3$ is highly anisotropic, amounting to
$\sim$10,000 cm$^2$V$^{-1}$s$^{-1}$ in the \emph{b} direction, which is higher
than that of the MoS$_2$ monolayer. Meanwhile, the hole mobility is about two
orders of magnitude lower. We also find that bulk TiS$_3$ possesses lower
cleavage energy than graphite, indicating high possibility of exfoliation for
TiS$_3$ monolayers or multilayers. Both dynamical and thermal stability of the
TiS$_3$ monolayer is examined via phonon-spectrum calculation and
Born-Oppenheimer molecular dynamics simulation in \emph{NPT} ensemble. The
predicted novel electronic properties render the TiS$_3$ monolayer an
attractive 2D material for applications in future nanoelectronics.Comment: 4 figure
A small molecule walks along a surface between porphyrin fences that are assembled In situ

An on-surface bimolecular system is described, comprising a simple divalent bis(imidazolyl) molecule that is shown to “walk” at room temperature via an inchworm mechanism along a specific pathway terminated at each end by oligomeric “fences” constructed on a monocrystalline copper surface. Scanning tunneling microscopy shows that the motion of the walker occurs along the [1equation image0] direction of the Cu surface with remarkably high selectivity and is effectively confined by the orthogonal construction of covalent porphyrin oligomers along the [001] surface direction, which serve as barriers. Density functional theory shows that the mobile molecule walks by attaching and detaching the nitrogen atoms in its imidazolyl “legs” to and from the protruding close-packed rows of the metal surface and that it can transit between two energetically equivalent extended and contracted conformations by overcoming a small energy barrier
Synthesis of Meso-Substituted Subphthalocyanine-Subporphyrin Hybrids: Boron SubTriBenzoDiAzaPorphyrins (SubTBDAPs)

The first syntheses of hybrid structures that lie between SubPhthalocyanines and SubPorphyrins are reported. The versatile, single-step synthetic protocol uses a preformed aminoisoindolene to provide the bridging methine unit and its substituent, while trialkoxyborates simultaneously act as Lewis acid/template and provider of the apical substituent. Selection of each component therefore allows controlled formation of diverse, differentially functionalised systems. The new hybrids are isolated as robust, pure materials that display intense absorption and emission in the mid-visible region. They are further characterised in solution and solid state by variable temperature NMR spectroscopy and X-ray crystallography respectivel
Deciphering the Non-Equivalence of Serine and Threonine O-Glycosylation Points: Implications for Molecular Recognition of the Tn Antigen by an anti-MUC1 Antibody

© 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. The structural features of MUC1-like glycopeptides bearing the Tn antigen (α-O-GalNAc-Ser/Thr) in complex with an anti MUC-1 antibody are reported at atomic resolution. For the α-O-GalNAc-Ser derivative, the glycosidic linkage adopts a high-energy conformation, barely populated in the free state. This unusual structure (also observed in an α-S-GalNAc-Cys mimic) is stabilized by hydrogen bonds between the peptidic fragment and the sugar. The selection of a particular peptide structure by the antibody is thus propagated to the carbohydrate through carbohydrate/peptide contacts, which force a change in the orientation of the sugar moiety. This seems to be unfeasible in the α-O-GalNAc-Thr glycopeptide owing to the more limited flexibility of the side chain imposed by the methyl group. Our data demonstrate the non-equivalence of Ser and Thr O-glycosylation points in molecular recognition processes. These features provide insight into the occurrence in nature of the APDTRP epitope for anti-MUC1 antibodies.Peer Reviewe
Deciphering the Non-Equivalence of Serine and Threonine O-Glycosylation Points: Implications for Molecular Recognition of the Tn Antigen by an anti-MUC1 Antibody

The structural features of MUC1-like glycopeptides bearing the Tn antigen (α-O-GalNAc-Ser/Thr) in complex with an anti MUC-1 antibody are reported at atomic resolution. For the α-O-GalNAc-Ser derivative, the glycosidic linkage adopts a high-energy conformation, barely populated in the free state. This unusual structure (also observed in an α-S-GalNAc-Cys mimic) is stabilized by hydrogen bonds between the peptidic fragment and the sugar. The selection of a particular peptide structure by the antibody is thus propagated to the carbohydrate through carbohydrate/peptide contacts, which force a change in the orientation of the sugar moiety. This seems to be unfeasible in the α-O-GalNAc-Thr glycopeptide owing to the more limited flexibility of the side chain imposed by the methyl group. Our data demonstrate the non-equivalence of Ser and Thr O-glycosylation points in molecular recognition processes. These features provide insight into the occurrence in nature of the APDTRP epitope for anti-MUC1 antibodies.We thank the Ministerio de Econom a y Competitividad/FEDER
(project CTQ2012-36365, CTQ2012-32065, BFU2010-19504,
CTQ2013-44367-C2-2-P, UNLR13-4E-1931 and grant I.C.) and DGA
(B89) for financial support. N.M.-S. and D.M. thank Universidad de
La Rioja for FPI grants. We thank Katherine Stott (Department of
Biochemistry, Cambridge University) for technical help with the BLI
experiments. G.J.L.B. thanks financial support from the EPSRC.
G.J.L.B. is a Royal Society University Research Fellow. M.S. thanks
the Generalitat de Catalunya and Universitat Rovira i Virgili for
financial support.This is the published version. It first appeared at http://onlinelibrary.wiley.com/doi/10.1002/anie.201502813/abstract
Ag2 and Ag3 Clusters: Synthesis, Characterization, and Interaction with DNA

Subnanometric samples, containing exclusively Ag2 and Ag3 clusters, were synthesized for the first time by kinetic control using an electrochemical technique without the use of surfactants or capping agents. By combination of thermodynamic and kinetic measurements and theoretical calculations, we show herein that Ag3 clusters interact with DNA through intercalation, inducing significant structural distortion to the DNA. The lifetime of Ag3 clusters in the intercalated position is two to three orders of magnitude longer than for classical organic intercalators, such as ethidium bromide or proflavine.Fil: Buceta, David. Universidad de Santiago de Compostela; EspañaFil: Busto, Natalia. Universidad de Burgos; EspañaFil: Barone, Giampaolo. Università di Palermo; ItaliaFil: Leal, José M.. Universidad de Burgos; EspañaFil: Domínguez, Fernando. Universidad de Santiago de Compostela; EspañaFil: Giovanetti, Lisandro Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de la Plata; ArgentinaFil: Requejo, Felix Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico la Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentina. Universidad Nacional de la Plata; ArgentinaFil: García, Begoña. Universidad de Burgos; EspañaFil: López-Quintela, M. Arturo. Universidad de Santiago de Compostela; Españ
Tropolone as a High-Performance Robust Anchoring Group for Dye-Sensitized Solar Cells.

Article first published online: 16 JUN 2015A tropolone group has been employed for the first time as an anchoring group for dye-sensitized solar cells (DSSCs). The DSSC based on a porphyrin, YD2-o-C8T, with a tropolone moiety exhibited a power-conversion efficiency of 7.7 %, which is only slightly lower than that observed for a reference porphyrin, YD2-o-C8, with a conventional carboxylic group. More importantly, YD2-o-C8T was found to be superior to YD2-o-C8 with respect to DSSC durability and binding ability to TiO2 . These results unambiguously demonstrate that tropolone is a highly promising dye-anchoring group for DSSCs in terms of device durability as well as photovoltaic performance
Spectroscopic and crystal field consequences of fluoride binding by [Yb⋅DTMA](3+) in aqueous solution.

Yb⋅DTMA forms a ternary complex with fluoride in aqueous solution by displacement of a bound solvent molecule from the lanthanide ion. [Yb⋅DTMA⋅F]2+ and [Yb⋅DTMA⋅OH2]3+ are in slow exchange on the relevant NMR timescale (<2000 s−1), and profound differences are observed in their respective NMR and EPR spectra of these species. The observed differences can be explained by drastic modification of the ligand field states due to the fluoride binding. This changes the magnetic anisotropy of the YbIII ground state from easy-axis to easy-plane type, and this change is easily detected in the observed magnetic anisotropy despite thermal population of more than just the ground state. The spectroscopic consequences of such drastic changes to the ligand field represent important new opportunities in developing fluoride-responsive complexes and contrast agents