bluuebunny/crossref_metadata_2025_split huggingface dataset:
An All Solid‐State Zinc−Air Battery with a Corrosion‐Resistant Air Electrode
Authors: Devendrachari Mruthyunjayachari Chattanahalli , Basappa Chidananda , Thimmappa Ravikumar , Bhat Zahid Manzoor , Kotresh Harish Makri Nimbegondi , Kottaichamy Alagar Raja , Varhade Swapnil , Khaire Siddhi , Reddy Kallam Ramareddy Venugopala , Thotiyl Musthafa Ottakam 
Published: March 2018

AbstractWe illustrate an all solid‐state Zn−air battery by utilizing the ability of a titanium‐nitride‐functionalized molecular catalyst to mediate the oxygen reduction reaction by avoiding the parasitic corrosion chemistry and the hydroxide‐holding capacity of the Zirfon membrane. The efficient ionic communication between the half‐cell electrodes provided by the Zirfon membrane in combination with the chemical/electrochemical stability of the TiN‐based air electrode ultimately led to an all solid‐state and air‐breathing battery possessing high durability and stability.
Flexible Versus Rigid G‐Quadruplex DNA Ligands: Synthesis of Two Series of Bis‐indole Derivatives and Comparison of Their Interactions with G‐Quadruplex DNA
Authors: Prasad Bagineni , Jamroskovic Jan , Bhowmik Sudipta , Kumar Rajendra , Romell Tajanena , Sabouri Nasim , Chorell Erik 
Published: March 2018

AbstractSmall molecules that target G‐quadruplex (G4) DNA structures are not only valuable to study G4 biology but also for their potential as therapeutics. This work centers around how different design features of small molecules can affect the interactions with G4 DNA structures, exemplified by the development of synthetic methods to bis‐indole scaffolds. Our synthesized series of bis‐indole scaffolds are structurally very similar but differ greatly in the flexibility of their core structures. The flexibility of the molecules proved to be an advantage compared to locking the compounds in the presumed bioactive G4 conformation. The flexible derivatives demonstrated similar or even improved G4 binding and stabilization in several orthogonal assays even though their entropic penalty of binding is higher. In addition, molecular dynamics simulations with the c‐MYC G4 structure showed that the flexible compounds adapt better to the surrounding. This was reflected by an increased number of both stacking and polar interactions with both the residues in the G4 DNA structure and the DNA residues just upstream of the G4 structure.
Synthesis of α‐Chlorolactams by Cyanoborohydride‐Mediated Radical Cyclization of Trichloroacetamides
Authors: Coussanes Guilhem , Jakobi Harald , Lindell Stephen , Bonjoch Josep 
Published: March 2018

AbstractA cyanoborohydride‐promoted radical cyclization methodology has been developed to access α‐chlorolactams in a simple and efficient way using NaBH3CN and trichloroacetamides easily available from allylic and homoallylic secondary amines. This methodology allowed the synthesis of a library of α‐chlorolactams (mono‐ and bicyclic), which were tested for herbicidal activity, trans‐3‐chloro‐4‐methyl‐1‐(3‐trifluoromethyl)phenyl‐2‐pyrrolidinone being the most active.
Chemoenzymatic Synthesis of Asymmetrical Multi‐Antennary N‐Glycans to Dissect Glycan‐Mediated Interactions between Human Sperm and Oocytes
Authors: Chinoy Zoeisha S. , Friscourt Frédéric , Capicciotti Chantelle J. , Chiu Philip , Boons Geert‐Jan 
Published: March 2018

AbstractComplex N‐glycans of glycoproteins of the zona pellucida (ZP) of human oocytes have been implicated in the binding of spermatozoa. The termini of these unusual bi‐, tri‐, and tetra‐antennary N‐glycans consist of the tetrasaccharide sialyl‐Lewisx (SLex), which was previously identified as the minimal epitope for sperm binding. We describe here the chemoenzymatic synthesis of highly complex triantennary N‐glycans derived from ZP carrying SLex moieties at the C‐2 and C‐2′ arm and a sialyl‐Lewisx‐Lewisx (SLex–Lex) residue at the C‐6 antenna and two closely related analogues. The compounds were examined for their ability to inhibit the interaction of human sperm to ZP. It was found that the SLex–Lex moiety is critical for inhibitory activity, whereas the other SLex moieties exerted minimal effect. Further studies with SLex–Lex and SLex showed that the extended structure is the more potent inhibitor. In addition, trivalent SLex–Lex and SLex were prepared which showed greater inhibitory activity compared to their monovalent counterparts. Our studies show that although SLex can inhibit the binding of spermatozoa, presenting this epitope in the context of a complex N‐glycan results in a loss of inhibitory potential, and in this context only SLex–Lex can make productive interactions. It is not the multivalent display of SLex on a multi‐antennary glycan but the presentation of multiple SLex–Lex on the various glycosylation sites of ZP that accounts for high avidity binding.
Trans‐Metal‐Trapping: Concealed Crossover Complexes En Route to Transmetallation?
Authors: Uzelac Marina , Mulvey Robert E. 
Published: March 2018

AbstractDefined as the transfer of ligands from one metal to another, transmetallation is a common reaction in organometallic chemistry. Its chemical celebrity stems from its role in important catalytic cycles of cross‐coupling reactions such as those of Negishi, Sonogashira, Stille, or Suzuki. This article focuses on trans‐metal‐trapping (TMT), which could be construed as partially complete transmetallations. On mixing two distinct organometallic compounds, of for example lithium with aluminium or gallium, the two metals meet in a crossover co‐complex, but the reaction ceases at that point and full transmetallation is not reached. Though in its infancy, trans‐metal‐trapping shows promise in transforming failed lithiations into successful lithiations and in stabilising sensitive carbanions through cooperative bimetallic effects making them more amenable to onward reactivity.
Anion Recognition by a Bioactive Diureidodecalin Anionophore: Solid‐State, Solution, and Computational Studies
Authors: Jurček Ondřej , Valkenier Hennie , Puttreddy Rakesh , Novák Martin , Sparkes Hazel A. , Marek Radek , Rissanen Kari , Davis Anthony P. 
Published: March 2018

AbstractRecent work has identified a bis‐(p‐nitrophenyl)ureidodecalin anion carrier as a promising candidate for biomedical applications, showing good activity for chloride transport in cells yet almost no cytotoxicity. To underpin further development of this and related compounds, a detailed structural and binding investigation is reported. Crystal structures of the transporter as five solvates confirm the diaxial positioning of urea groups while revealing a degree of conformational flexibility. Structures of complexes with Cl−, Br−, NO3−, SO42− and AcO−, supported by computational studies, show how the binding site can adapt to accommodate these anions. 1H NMR binding studies revealed exceptionally high affinities for anions in DMSO, decreasing in the order SO42−>H2PO4−≈HCO3−≈AcO−≫HSO4−>Cl−>Br−>NO3−>I−. Analysis of the binding results suggests that selectivity is determined mainly by the H‐bond acceptor strength of different anions, but is also modulated by receptor geometry.
Cell‐Penetrating Peptides Containing Fluorescent d‐Cysteines
Authors: Navo Claudio D. , Asín Alicia , Gómez‐Orte Eva , Gutiérrez‐Jiménez Marta I. , Compañón Ismael , Ezcurra Begoña , Avenoza Alberto , Busto Jesús H. , Corzana Francisco , Zurbano María M. , Jiménez‐Osés Gonzalo , Cabello Juan , Peregrina Jesús M. 
Published: March 2018

AbstractA series of fluorescent d‐cysteines (Cys) has been synthesized and their optical properties were studied. The key synthetic step is the highly diastereoselective 1,4‐conjugate addition of aryl thiols to a chiral bicyclic dehydroalanine recently developed by our group. This reaction is fast at room temperature and proceeds with total chemo‐ and stereoselectivity. The Michael adducts were easily transformed into the corresponding amino acids to study their optical properties and, in some selected cases, into the corresponding N‐Fmoc‐d‐cysteine derivatives to be used in solid‐phase peptide synthesis (SPPS). To further demonstrate the utility of these non‐natural Cys‐derived fluorescent amino acids, the coumaryl and dansyl derivatives were incorporated into cell‐penetrating peptide sequences through standard SPPS and their optical properties were studied in different cell lines. The internalization of these fluorescent peptides was monitored by fluorescence microscopy.
Manganese‐Based Nanozymes: Multienzyme Redox Activity and Effect on the Nitric Oxide Produced by Endothelial Nitric Oxide Synthase
Authors: Singh Namrata , Geethika Motika , Eswarappa Sandeep M. , Mugesh Govindasamy 
Published: March 2018

AbstractNanomaterials having enzyme‐like activity (nanozymes) make them suitable candidates for various biomedical applications. In this study, we demonstrate the morphology‐dependent enzyme mimetic activity of Mn3O4 nanoparticles. It is found that Mn3O4 nanoparticles mimic the functions of all three cellular antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Interestingly, the nanozyme activity of Mn3O4 depends on various factors including size, morphology, surface area, and the redox properties of the metal ions. The Mn3O4 nanoflowers exhibited remarkably high activity in all three enzyme systems and the order of multienzyme activity of different morphologies was: flowers ≫ flakes > hexagonal plates≈polyhedrons≈cubes. Interestingly, all five nanoforms are taken up by the mammalian cells and were found to be biocompatible, with very low cytotoxicity. The activity of the most active nanoflowers was studied in primary human umbilical vein endothelial cells (HUVEC) and human pulmonary microvascular endothelial cells (hPMEC) and it was found that Mn3O4 does not reduce the level of nitric oxide (NO). This is in contrast to the effect of some of the Mn‐porphyrin‐based SOD mimetics, which are known to scavenge NO in endothelial cells.
Direct Electrochemistry of Bilirubin Oxidase from Magnaporthe orizae on Covalently‐Functionalized MWCNT for the Design of High‐Performance Oxygen‐Reducing Biocathodes
Authors: Gentil Solène , Carrière Marie , Cosnier Serge , Gounel Sébastien , Mano Nicolas , Le Goff Alan 
Published: March 2018

AbstractHerein, the direct electrochemistry of bilirubin oxidase from Magnaporthe orizae (MoBOD) was studied on CNTs functionalized by electrografting several types of diazonium salts. The functionalization induces favorable or unfavorable orientation of MoBOD, the latter being compared to the well‐known BOD from Myrothecium verrucaria (MvBOD). On the same nanostructured electrodes, MoBOD can surpass MvBOD in terms of both current densities and minimal overpotentials. Added to the fact that MoBOD is also highly active at the gas‐diffusion electrode (GDE), these findings make MoBOD one of the MCOs with the highest catalytic activity towards the oxygen reduction reaction (ORR).
Enantio‐ and Diastereoselective Synthesis of Latanoprost using an Organocatalyst
Authors: Kawauchi Genki , Umemiya Shigenobu , Taniguchi Tohru , Monde Kenji , Hayashi Yujiro 
Published: March 2018

AbstractAn enantioselective total synthesis of latanoprost was achieved. Its chiral cyclopentane core structure was constructed through an organocatalyst‐mediated [3+2]‐cycloaddition reaction, and chirality in the ω‐side chain was generated by prolinate‐anion‐mediated α‐aminoxylation of an aldehyde. Highly diastereoselective domino acetalization and an oxy‐Michael reaction were key steps for the generation of C9 chirality.
Light‐Controlled Simultaneous “On Demand” Release of Cytotoxic Combinations for Bimodal Killing of Cancer Cells
Authors: Tessaro André Luiz , Fraix Aurore , Failla Mariacristina , Cardile Venera , Graziano Adriana C. E. , Estevão Bianca Martins , Rescifina Antonio , Sortino Salvatore 
Published: March 2018

AbstractIn this contribution, we report a novel entirely photocontrolled nanoplatform comprising a binary mixture of pluronic copolymers capable of self‐assembling into core–shell micelles and co‐entrapping two photoactivatable components: a benzoporphyrin photosensitizer for photodynamic therapy (PDT) and coumarin‐photocaged chemotherapeutic agent Chlorambucil (CAB). The resulting supramolecular micellar assembly is about 30 nm in diameter with a polydispersity index <0.1, stable for more than 72 h, and exhibits excellent preservation of the photochemical properties of the two photoresponsive components, even though they are confined within the same host nanocarrier. Appropriate regulation of the relative concentrations of these components makes them capable of absorbing visible light in comparable amounts, leading to effective simultaneous photogeneration of singlet oxygen and photo‐triggered release of CAB. This “on demand” release of cytotoxic combinations results in amplified anticancer activity against MCF‐7 human breast adenocarcinoma cells.
Pathway Diversity Leads to 2D‐Nanostructure in Photo‐triggered Supramolecular Assembly
Authors: Pal Deep Sankar , Ghosh Suhrit 
Published: March 2018

AbstractThis Communication reports photo‐triggered supramolecular assembly of a naphthalene‐diimide (NDI) derivative, appended with a photo‐labile ortho‐nitrobenzyl (ONB)‐ester protected carboxylic acid. Photo‐irradiation produces the free COOH group which facilitates H‐bonding‐driven face‐to‐face stacking of the NDI chromophores producing an ultra‐thin (height <2.0 nm) two‐dimensional (2D) nanosheet. In contrast, spontaneous supramolecular assembly of the same active monomer exhibits entirely different features such as uncontrolled growth, J‐aggregation and fibrillar morphology. A completely different pathway for photo‐triggered assembly is attributed to the dual function of the photo‐caged pro‐monomer in i) producing the carboxylic acid in controlled manner and ii) simultaneously inhibiting the spontaneous J‐aggregation of the photo‐generated monomers by ester‐carboxylic acid H‐bonding and in turn directing a distinct growth mechanism.
Regioisomeric Tandem Triblock Shape Amphiphiles Based on Polyhedral Oligomeric Silsesquioxanes
Authors: Shao Yu , Yin Hang , Jin Peng‐Fei , Jiang Yu‐Sheng , Yang Shuguang , Zhang Wen‐Bin 
Published: March 2018

AbstractWe report the design, synthesis and self‐assembly of a series of tandem triblock shape amphiphile regioisomers composed of one rod‐like fluorinated polyhedral oligomeric silsesquioxane (FPOSS) cage tethered with two spherical tert‐butyl‐POSS (tBPOSS) cages in para‐, meta‐, and ortho‐configurations. Precision syntheses are achieved through sequential “click” reactions and the compounds are thoroughly characterized by combined techniques of NMR, FT‐IR and MALDI‐TOF MS spectroscopy. Only the ortho‐isomer forms an ordered lamellae structure induced by the crystallization of perfluoroalkyl‐chains and the other two remain amorphous due to frustrated packing by unfavorable regio‐configuration. The distinct assembly behaviors of these three regioisomers reflect the delicate influence of a minute structural difference on precision macromolecular assembly.
Deciphering the Mechanism of Human Carbonic Anhydrases Inhibition with Sulfocoumarins: Computational and Experimental Studies
Authors: Nocentini Alessio , Carta Fabrizio , Tanc Muhammet , Selleri Silvia , Supuran Claudiu T. , Bazzicalupi Carla , Gratteri Paola 
Published: March 2018

AbstractThe reaction mechanism of the carbonic anhydrase‐mediated hydrolysis of sulfocoumarins to sulfonic acids has been investigated on an enzyme cluster model using the B3LYP hybrid density functional theory (DFT) and the QST procedure for the Transition State (TS) search. A multistep process was highlighted, with the rate‐determining step identified in the initial dual nucleophilic/acidic attack of the zinc‐bound hydroxide ion to the sulfocoumarin sulfur atom and to the C3=C4 double bond. The reported multi‐step process, combined to SAR analysis on a new set of derivatives, highlighted unprecedented mechanistic aspects of the CA‐mediated prodrug activation, which in turn possess relevant consequences to the isoforms‐selective inhibition profiles reported by such a class of compounds.
Chemically Tunable Formation of Different Discrete, Oligomeric, and Polymeric Self‐Assembled Structures from Digold Metallotweezers
Authors: Ibáñez Susana , Peris Eduardo 
Published: March 2018

AbstractDigold metallotweezers whose complex supramolecular landscape is controlled by adding a series of metal cations are described. The metallotweezers have a strong tendency to form interesting supramolecular structures on addition of Tl+, Ag+, and Cu+. The choice of the cation can be used to direct the formation of a designated molecular architecture. The addition of thallium facilitates the formation of a self‐aggregated duplex structure in which the cation occupies the cavity of the dimer. The same type of structure is formed when Cu+ is added, and the resulting duplex inclusion complex shows interesting vapochromic properties. This copper‐encapsulating system evolves in solution to a 1D helical supramolecular polymer showing multiple aurophilic and Au⋅⋅⋅Cu interactions, in which the copper cation is bound to several alkynyl ligands of the tweezer. The addition of a small amount of silver cations to the digold tweezer yields a similar type of inclusion dimer complex, but adding an excess of the cation produces new discrete molecules presumably exhibiting multiple Au⋅⋅⋅Au, Au⋅⋅⋅Ag, and Ag⋅⋅⋅Ag metallophilic interactions. The differences in the supramolecular structures formed are ascribed to the different tendencies of the metal cations to exhibit interactions with the gold atoms and to coordinate to the alkynyl ligands of the tweezer.
Synthesis of Highly Substituted 1,2‐Diazetidin‐3‐ones, Small‐Ring Scaffolds for Drug Discovery
Authors: Santos Marilia S. , Nortcliffe Andrew , Lewis William , Bradshaw Tracey D. , Moody Christopher J. 
Published: March 2018

Abstract1,2‐Diazetidin‐3‐ones are readily accessible, small ring scaffolds that upon functionalization have the potential to produce diverse 3‐dimensional structures for drug discovery. Thus, treatment of diazo hydrazides, obtained from simple hydrazides and malonyl half ester derivatives, followed by diazo transfer, with catalytic amounts of rhodium(II) acetate dimer results in intramolecular carbenoid N−H insertion to give 1,2‐diazetidin‐3‐ones. Although subsequent functionalization reactions could be hampered by the lability of the 4‐membered ring, a wide range of new derivatives was available by deprotection at N‐1, and subsequent amide or urea formation. The structures of four four‐membered rings was confirmed by X‐ray crystallography; the compounds showed modest growth inhibitory activity in mammary carcinoma cells.
34S: A New Opportunity for the Efficient Synthesis of Stable Isotope Labeled Compounds
Authors: Ren Sumei , Fier Patrick S. , Ren Hong , Hoover Andrew J. , Hesk David , Marques Rosemary , Mergelsberg Ingrid 
Published: March 2018

AbstractThe synthesis of stable isotope labeled (SIL) complex drug molecules with a ≥3 mass unit increase from the parent compound is essential for drug discovery and development. Typical approaches that rely on 2H, 13C, and 15N isotopes can be very challenging or even intractable, and can delay the drug development process. This work introduces a new concept for the synthesis of labeled compounds that relies on the use of 34S. The synthetic utility of 34S was demonstrated with the efficient synthesis of [34S]phosphorothioates [34S2]‐PS‐ODNs‐TTT and [13C, 15N, 34S]‐ceftolozane. In addition, a procedure for the direct oxidation of phosphites to [34S]phosphorothioates using elemental 34S without isotope dilution was developed.
A Versatile Colorimetric Probe based on Thiosemicarbazide–Amine Proton Transfer
Authors: Calvino Céline , Piechowicz Marek , Rowan Stuart J. , Schrettl Stephen , Weder Christoph 
Published: March 2018

AbstractThere is significant interest in the rapid and efficient detection of amines, which are widely used in different industries and also serve as markers in many biological processes. This work reports that the coupling of a thiosemicarbazide binding motif and a naphthalimide‐based chromophore affords highly sensitive sensor molecules, which can indicate the presence of amines with a pronounced and readily visible color change. It was demonstrated that the binding mechanism involves a proton transfer from the thiosemicarbazide to the analyte. This process renders the mechanism highly sensitive and broadly exploitable. The potential usefulness of the sensor is demonstrated by fabricating an indicator paper, which allows for the detection of volatile amines at concentrations as low as ca. 10 ppm.
Dismantling‐Free and Gentle Mechanical Cleaning of Industrial Heat Exchangers and Cooling Circuits
Authors: Kuschnerow Jan , Klein Norbert , Schlüter Florian , Augustin Wolfgang , Scholl Stephan , Strathmann Martin , Schaule Gabriela , Hammann Hans‐Gerd 
Published: March 2018

AbstractDas COMPREX®‐Verfahren ist ein geeignetes mechanisches Reinigungsverfahren für Rohrleitungen und Wärmeübertrager. Impulsweise zu laminar einfließendem Wasser dosierte Druckluft erzeugt Luft‐ und Wasserblöcke, die sich in großer Geschwindigkeit durch die Anlage bewegen. Es arbeitet ohne Demontage der Apparate und ermöglicht kurze Stillstandszeiten. Es erfordert keinen Einsatz von Chemikalien und ist materialschonend. Mobile Technikeinheiten ermöglichen den Einsatz an beliebigen Standorten. Gegenüber anderen Verfahren erlaubt es kürzere Reinigungszyklen und dadurch eine höhere Verfügbarkeit der Anlage.
Close‐to‐Practice Investigations of Heterogeneously Catalyzed Syngas Conversions in Slurry and Fixed‐Bed Reactor Systems
Authors: Girod Kai , Breitkreuz Klaas , Gerstner Andrea , Marzi Thomas , Schulzke Tim , Kaluza Stefan 
Published: March 2018

AbstractIn der Grundlagenforschung wird die Testung heterogener Katalysatoren normalerweise mit sehr kleinen Probenmengen durchgeführt. Eine Übertragung der ermittelten Ergebnisse hinsichtlich Produktivität und Standzeit auf den technischen Maßstab ist nur sehr eingeschränkt möglich. Es wurde ein neues praxisnahes Testsystem für heterogene Katalysatoren entwickelt. Es kann sowohl in Festbett‐Fahrweise als auch in Slurry‐Fahrweise in einem weiten Temperatur‐ und Druckbereich betrieben werden. Das System wurde für die Synthese höherer Alkohole und die einstufige Dimethylether‐Synthese erfolgreich eingesetzt.
Catalyst Deactivation During Photocatalytic Degradation of Methylene Blue with TiO2
Authors: Robert Johannes , Jüstel Thomas , Ulber Roland , Jordan Volkmar 
Published: March 2018

AbstractNeben hohen Umsatzraten ist die Langlebigkeit eines Katalysators von entscheidender Bedeutung. Im Rahmen des photochemischen Abbaus von Methylenblau an aktiviertem TiO2 entsteht CO2, das mit Ca2+ und Mg2+ im alkalischen unlösliche Carbonatsalze bildet, die ihrerseits Verkrustungen auf der Katalysatoroberfläche erzeugen und den Reaktanden dadurch den Zugang zu den aktiven Zentren verwehren. Durch den Vergleich des beobachtbaren Reaktionskoeffizienten erster Ordnung bei unterschiedlichen pH‐Werten konnte gezeigt werden, dass es sich um einen Dual‐site‐Mechanismus handelt. Durch EDX‐Elementmapping konnte gezeigt werden, dass die Verringerung der Reaktionsgeschwindigkeiten mit wiederverwendetem Katalysator in CaCl2‐ und MgCl2‐Lösungen durch Verkrustungen der Erdalkalimetallcarbonate hervorgerufen wird.
Additive Manufacturing of Al2O3‐Based Carriers for Heterogeneous Catalysis
Authors: Ludwig Theresa , von Seckendorff Jennie , Troll Carsten , Fischer Richard , Tonigold Markus , Rieger Bernhard , Hinrichsen Olaf 
Published: March 2018

AbstractAdditive manufacturing techniques are known for their impressive possibilities in shaping complex structures, which would be beneficial in the production of alumina‐based catalyst shaped bodies. 3D printing of dense ceramics, especially Al2O3, is known for various printing systems. However, only little effort was done to produce pure alumina parts with increased BET surface areas and sufficient mechanical strength to be used as catalyst carriers. The applicability of four different printing techniques is evaluated and discussed to determine possibilities, strategies and limitations of each technique.