bluuebunny/crossref_metadata_2025_split huggingface dataset:
A General Approach to Site‐Specific, Intramolecular C−H Functionalization Using Dithiocarbamates
Authors: Na Christina G. , Alexanian Erik J. 
Published: August 2018

AbstractIntramolecular hydrogen atom transfer is an established approach for the site‐specific functionalization of unactivated, aliphatic C−H bonds. Transformations using this strategy typically require unstable intermediates formed using strong oxidants and have mainly targeted C−H halogenations or intramolecular aminations. Herein, we report a site‐specific C−H functionalization that significantly increases the synthetic scope and convergency of reactions proceeding via intramolecular hydrogen atom transfer. Stable, isolable N‐dithiocarbamates are used as precursors to amidyl radicals formed via either light or radical initiation to efficiently deliver highly versatile alkyl dithiocarbamates across a wide range of complex structures.
Efficient Synthesis of (−)‐Corynoline by Enantioselective Palladium‐Catalyzed α‐Arylation with Sterically Hindered Substrates
Authors: Rao Xiaofeng , Li Naikai , Bai Heng , Dai Chaodi , Wang Zheng , Tang Wenjun 
Published: August 2018

AbstractSterically hindered substrates can be employed in an enantioselective palladium‐catalyzed α‐arylation with the chiral monophosphorus ligand BI‐DIME. This process enabled an efficient synthesis of the antidepressant (S)‐nafenodone, a four‐step enantioselective synthesis of the Sceletium alkaloid (+)‐sceletium A‐4, a concise five‐step enantioselective synthesis of (−)‐corynoline, as well as a three‐step preparation of (−)‐DeN‐corynoline.
Dramatically Enhanced Solubility of Halide‐Containing Organometallic Species in Diiodomethane: The Role of Solvent⋅⋅⋅Complex Halogen Bonding
Authors: Kinzhalov Mikhail A. , Kashina Mariya V. , Mikherdov Alexander S. , Mozheeva Ekaterina A. , Novikov Alexander S. , Smirnov Andrey S. , Ivanov Daniil M. , Kryukova Mariya A. , Ivanov Aleksandr Yu. , Smirnov Sergej N. , Kukushkin Vadim Yu. , Luzyanin Konstantin V. 
Published: August 2018

AbstractIn the current study, we evaluated the solubility of a number of organometallic species and showed that it is noticeably improved in diiodomethane when compared to other haloalkane solvents. The better solvation properties of CH2I2 were associated with the substantially better σ‐hole‐donating ability of this solvent, which results in the formation of uniquely strong solvent–(metal complex) halogen bonding. The strength of the halogen bonding is attenuated by the introduction of additional halogen atoms in the organometallic species owing to the competitive formation of more favourable intermolecular complex–complex halogen bonding. The exceptional solvation properties of diiodomethane and its inertness towards organometallic species make this solvent a good candidate for NMR studies, in particular, for the acquisition of spectra of insensitive spins.
Local Activities of Hydroxide and Water Determine the Operation of Silver‐Based Oxygen Depolarized Cathodes
Authors: Botz Alexander , Clausmeyer Jan , Öhl Denis , Tarnev Tsvetan , Franzen David , Turek Thomas , Schuhmann Wolfgang 
Published: August 2018

AbstractLocal ion activity changes in close proximity to the surface of an oxygen depolarized cathode (ODC) were measured by scanning electrochemical microscopy (SECM). While the operating ODC produces OH− ions and consumes O2 and H2O through the electrocatalytic oxygen reduction reaction (ORR), local changes in the activity of OH− ions and H2O are detected by means of a positioned Pt microelectrode serving as an SECM tip. Sensing at the Pt tip is based on the pH‐dependent reduction of PtO and obviates the need for prior electrode modification steps. It can be used to evaluate the coordination numbers of OH− ions and H2O, and the method was exploited as a novel approach of catalyst activity assessment. We show that the electrochemical reaction on highly active catalysts can have a drastic influence on the reaction environment.
Thermodynamically Stable, Photoreversible Pharmacology in Neurons with One‐ and Two‐Photon Excitation
Authors: Passlick Stefan , Richers Matthew T. , Ellis‐Davies Graham C. R. 
Published: August 2018

AbstractPhotoswitchable bioprobes enable bidirectional control of cell physiology with different wavelengths of light. Many current photoswitches use cytotoxic UV light and are limited by the need for constant illumination owing to thermal relaxation in the dark. Now a photoswitchable tetrafluoroazobenzene(4FAB)‐based ion channel antagonist has been developed that can be efficiently isomerized in two separate optical channels with visible light. Importantly, the metastable cis configuration showed very high stability in the dark over the course of days at room temperature. In neurons, the 4FAB antagonist reversibly blocks voltage‐gated ion channels with violet and green light. Furthermore, photoswitching could also be achieved with two‐photon excitation yielding high spatial resolution. 4FAB probes have the potential to enable long‐term biological studies where both ON and OFF states can be maintained in the absence of irradiation.
Enantio‐ and Diastereoselective Synthesis of Chiral Allenes by Palladium‐Catalyzed Asymmetric [3+2] Cycloaddition Reactions
Authors: Trost Barry M. , Zell Daniel , Hohn Christoph , Mata Guillaume , Maruniak Autumn 
Published: August 2018

AbstractA protocol for the asymmetric synthesis of highly substituted chiral allenes with control of point and axial chirality has been developed. A palladium‐catalyzed [3+2] cycloaddition using readily available racemic allenes gives access to densely functionalized chiral allenes with excellent yields and functional group tolerance. The catalytic asymmetric protocol utilizes a broad range of allenyl TMM (trimethylenemethane) donors to form cyclopentanes, pyrrolidines, and spirocycles with very good control of regio‐, enantio‐, and diastereoselectivity. The chiral allene moiety is shown to be a valuable functional group for rapid elaboration towards complex targets.
Enhancement of soot oxidation activity of manganese oxide (Mn2O3) through doping by the formation of Mn1.9M0.1O3–δ (M = Co, Cu, and Ni)
Authors: Neelapala Satya Deepika , Patnaik Harsh , Dasari Harshini 
Published: August 2018

AbstractThe current work describes the catalytic soot oxidation activity of metal‐doped manganese oxide (Mn1.9M0.1O3–δ; M = Co, Cu, and Ni) materials, synthesized by coprecipitation method. All the fabricated materials were characterized using X‐ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Brunauer–Emmett–Teller surface area analysis, and X‐ray photoelectron spectroscopy (XPS). XRD analysis confirmed the formation of solid solution Mn1.9M0.1O3–δ (M = Co, Cu, and Ni). M‐doped samples exhibited different morphology when compared with pure Mn2O3 as evidenced by FESEM analysis, and Co‐doped Mn2O3 possessed the highest specific surface area. XPS analysis revealed the presence of multiple oxidation states of Mn (+4, +3, and +2) and Co (+2 and +3). Soot oxidation activity tests, performed using thermogravimetric analysis, showed that Mn1.9Co0.1O3–δ exhibited better catalytic performance (T50 = 390°C) when compared with pure Mn2O3 (T50 = 490°C). The incorporation of dopants greatly enhanced the oxygen vacancies and redox properties of Mn2O3.
Molecular self‐assembly and morphology induction in high‐performance aromatic phosphonated block copolymers
Authors: Kumar Avneesh , Pisula Wojciech , Müllen Klaus 
Published: August 2018

ABSTRACTWell‐defined morphology induction in new block copolymers based on high‐performance individual blocks is presented here. Rod‐ and coil‐like polymers such as poly(phenylene oxide) and poly(vinybenzyl phosphonic acid), respectively, contribute to the origin of self‐assembly via phase separation between chemically dissimilar regions. Individual blocks of homopolymer are oriented in a cooperative manner leading to a controlled stacking of macromolecules and evolution of microspheres with a size up to 200 nm in solution. Growth of ordered phase in poly(p‐phenylene oxide) chains are recorded as a result of molecular reorganization guided by poly(vinybenzyl phosphonic acid) segment. The stacking of macromolecules is noticed under atomic force microscope. Influence of the size of poly(phenylene oxide) block on self‐assembly is also examined. Scattering patterns from two‐dimensional wide angle X‐ray scattering verifies the crystalline domains in copolymers. Further end to end and side by side orientations of macromolecules are confirmed by X‐ray experiments. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46750.
Development of starch‐furcellaran‐gelatin films containing tea tree essential oil
Authors: Jamróz Ewelina , Juszczak Lesław , Kucharek Mateusz 
Published: August 2018

ABSTRACTTea tree essential oil (TEO) was added in different concentrations (2%, 4%, and 6%) to starch/furcellaran/gelatin (S/F/G) films. Film solubility of S/F/G film significantly decreased when containing 6% TEO (P ≤ 0.05). Referring to the control sample (without TEO), water content decreased with increasing concentration of oil. Films with 4% and 6% TEO exhibited a significant decrease (P ≤ 0.05) in tensile strength, and Young's modulus. The amounts of TEO had no significant on the elongation at break (P ≤ 0.05). Analysis obtained by Fourier transform infrared spectroscopy exhibited some insights on the possible interactions between polysaccharides, protein, and essential oil. The thermal stability of the film was decreased by TEO addition. The antioxidant properties proved to be significantly enhanced with addition of TEO into films. S/F/G films incorporated with TEO showed antimicrobial activity against Staphylococcus aureus and Escherichia coli, with inhibition zone diameters of 27.8 ± 0.29 mm and 18.4 ± 0.20 mm, respectively. Our results suggested that the S/F/G films containing TEO could be used as an active film which enhances microbial safety and the shelf‐life of foods due to its good in vitro antioxidant and antimicrobial properties for food packaging applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46754.
Porous aromatic networks with amine linkers for adsorption of hydroxylated aromatic hydrocarbons
Authors: Li Q. , Mu X. , Xiao S. , Wang C. , Chen Y. , Yuan X. 
Published: August 2018

ABSTRACTThe porous covalent organic polymers (COPs) are valuable materials in various fields such as gas storage, adsorption or separation, luminescent detection, catalysis, and sensors. Two thermally stable COPs with aromatic skeleton linked by amine groups were prepared by Buchwald–Hartwig protocol. The COPs with respective Brunauer–Emmett–Teller surface area of 204 and 178 m2/g were employed for adsorption of hydroxylated aromatic hydrocarbons (HAHs) due to expected strong π–π stacking and hydrogen‐bond interactions between COPs and HAH. In adsorption of phenol from water, COP2 showed far better capacity than COP1, silica, basic alumina, and macroporous resin (D101). In adsorption of 2‐naphthol COP1 and COP2 displayed similar capacity, being 2.8, 5.4, and 7.4 times high as those for macroporous resin (D101), basic alumina, and silica, respectively. COP1 and COP2 are useful for efficient separation of 2‐naphthol or other HAHs from waste water. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46919.
Enhanced ion conductivity of poly(ethylene oxide)‐based single ion conductors with lithium 1,2,3‐triazolate end groups
Authors: Hoffmann Justus Friedrich , Pulst Martin , Kressler Jörg 
Published: August 2018

ABSTRACTPoly(ethylene oxide) (PEO)‐based single ion conductors (SICs) are of great interest for applications in modern lithium ion batteries. They have several advantages over other common electrolytes such as high cation transference numbers, low toxicity, and nonflammability, but their major disadvantage is the low ion conductivity. Here, linear PEO‐based SICs with lithium 1,2,3‐triazolate (TrLi) end groups are synthesized and studied in terms of crystallinity by differential scanning calorimetry, and with respect to ion conductivity by impedance spectroscopy. Introduction of TrLi end groups to PEO chains reduces its crystallinity and melting temperature as well as an enhancement of the ion conductivity up to 8.0·10−6 S cm−1 at 70°C is observed. The increased ion conductivity is a direct result of the Tr rings, which can actively contribute to the conduction mechanism. In comparison with conductivities of other PEO‐based SICs reached so far (σ0 ≤ 10−6 S cm−1), the results of this study show that the introduction of TrLi end groups is a new approach to enhance the Li+‐ion conductivity of PEO‐based SICs that have also a good electrochemical stability versus lithium electrodes as revealed by linear sweep voltammetry. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46949.
A biomimetic cellulose‐based composite material that incorporates the antimicrobial metal‐organic framework HKUST‐1
Authors: Rickhoff T. A. , Sullivan E. , Werth L. K. , Kissel D. S. , Keleher J. J. 
Published: August 2018

ABSTRACTThe synthesis and characterization of a biomimetic composite material composed of cellulose acetate embedded with a copper‐based metal‐organic framework, MOF‐199 (HKUST‐1), is reported and has been investigated for use as an adsorbent material in water remediation. Incorporation of MOF‐199 into cellulose acetate enhances the stability of the metal‐organic framework in water allowing for a flexible and tunable polymeric material. The adsorption of methylene blue to the cellulose‐MOF199 composite was tracked spectroscopically over time and is best described by a mixed Langmuir–Freundlich isotherm adsorption model. The total remediation of methylene blue to the cellulose‐MOF199 composite is comparable to that of pure cellulose, however, it is shown herein that incorporation of MOF‐199 into cellulose acetate inhibits the growth of the Gram‐negative bacterium Escherichia coli. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 46978.
Ancient DNA and its contribution to understanding the human history of the Pacific Islands
Authors: BEDFORD STUART , BLUST ROBERT , BURLEY DAVID V. , COX MURRAY , KIRCH PATRICK V. , MATISOO‐SMITH ELIZABETH , NÆSS ÅSHILD , PAWLEY ANDREW , SAND CHRISTOPHE , SHEPPARD PETER 
Published: August 2018

ABSTRACTTwo recent papers, by Lipson et al. and Posth et al., have challenged current interpretations of the initial settlement of Remote Oceania. We invited Stuart Bedford, who is an author on both papers, to outline their importance, and a number of scholars in various disciplines to comment on their findings.
Design and evaluation of biological activities of 1,3‐oxazolidinone derivatives bearing amide, sulfonamide, and thiourea moieties
Authors: Karaman Nurcan , Adil Zainel Rabeah , Kapkaç Handan A. , Karaca Gençer Hülya , Ilgın Sinem , Karaduman A. Burak , Karaküçük‐İyidoğan Ayşegül , Oruç‐Emre Emine E. , Koçyiğit‐Kaymakçıoğlu Bedia 
Published: August 2018

Abstract1,3‐Oxazolidine‐2‐one is an important heterocyclic ring participating in the chemical structure of many drugs. In this research, 22 new amide/sulfonamide/thiourea derivatives (1–22) were obtained by the reaction of (S)‐4‐(4‐aminobenzyl)‐2(1H)‐1,3‐oxazolidinone with 4‐substituted benzoyl chlorides, 4‐substituted benzene sulfonyl chlorides, and 4‐substituted phenyl isothiocyanates. The structures of all synthesized compounds were clarified by FT‐IR, NMR, and mass spectroscopic and elemental analysis techniques. The synthesized compounds were screened for their antimicrobial activity. Antimicrobial susceptibility and cellular physiology were evaluated using the microbroth dilution assay and the flow cytometry method. As a result, it was determined that compound 16 displayed better antimicrobial activity than chloramphenicol against Gram‐positive bacteria, especially Staphylococcus aureus. In order to understand the mechanism of effect of the compounds on the cell membrane, fluorescence microscopy was used. Cell membrane damage of the Gram positive bacteria treated with compound 16 was observed as a result of intense staining with propidium iodide. In addition, genotoxicity, cytotoxicity, and absorption, distribution, metabolism, and excretion (ADME) parameters of compound 16 were examined and it was found as non‐mutagenic and non‐cytotoxic at the concentration at which it showed antimicrobial activity. According to the calculated ADME parameters and drug likeness scores, the compounds can be good drug candidates, especially compound 16.
Synthesis of novel sulfamides incorporating phenethylamines and determination of their inhibition profiles against some metabolic enzymes
Authors: Aksu Kadir , Akıncıoğlu Hülya , Akıncıoğlu Akın , Göksu Süleyman , Tümer Ferhan , Gülçin İlhami 
Published: August 2018

AbstractA series of sulfamides were synthesized and evaluated for their acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and carbonic anhydrase inhibition properties. The synthesis of sulfamides was achieved by the reactions of phenethylamines with N,N‐dimethylsulfamoyl chloride in the presence of Et3N. The methoxylated sulfamides were converted into their phenolic derivatives with BBr3 for structure–activity relationships. The synthesized sulfamide/phenolic sulfamide derivatives were investigated as cholinesterase inhibitors and their relative role in AChE versus BChE inhibition was defined. Sulfamide/phenolic sulfamide derivatives are known as important carbonic anhydrase inhibitors; therefore, the synthesized compounds were investigated for inhibitory effects on both carbonic anhydrase isoenzymes. Additionally, we evaluated four different enzymes, which were inhibited in the low nanomolar range by these compounds. According to the present studies, for AChE, BChE, and carbonic anhydrase I and II, the ranges of results are recorded as 0.027–0.076 nM, 0.075–0.327 nM, 0.123–0.678 nM, and 0.024–0.688 nM, respectively.
Efficacy and Safety of Febuxostat Extended and Immediate Release in Patients With Gout and Renal Impairment: A Phase III Placebo‐Controlled Study
Authors: Saag Kenneth G. , Becker Michael A. , Whelton Andrew , Hunt Barbara , Castillo Majin , Kisfalvi Krisztina , Gunawardhana Lhanoo 
Published: August 2018

ObjectiveTo assess the efficacy and safety of febuxostat extended release (XR) and immediate release (IR) in patients with gout and normal or impaired renal function.MethodsThis was a 3‐month, phase III, multicenter, double‐blind, placebo‐controlled study. Patients (n = 1,790) with a history of gout and normal or impaired (mild‐to‐severe) renal function were randomized to receive placebo, febuxostat IR 40 or 80 mg, or febuxostat XR 40 or 80 mg once daily (1:1:1:1:1 ratio). End points included proportions of patients with a serum urate (UA) level of <5.0 mg/dl at month 3 (primary end point), a serum UA level of <6.0 mg/dl at month 3, and ≥1 gout flare requiring treatment over 3 months (secondary end points).ResultsBoth febuxostat formulations led to significantly greater proportions of patients achieving a serum UA level of <5.0 mg/dl or <6.0 mg/dl at month 3 (P < 0.001 for all comparisons versus placebo). Equivalent doses of febuxostat XR and IR had similar treatment effects on serum UA level end points; however, a significantly greater proportion of patients achieved a serum UA level of <5.0 mg/dl with XR 40 mg versus IR 40 mg. Similar proportions of patients experienced ≥1 gout flare across treatment groups. Rates of treatment‐emergent adverse events were low and evenly distributed between treatment arms. A preplanned subgroup analysis demonstrated that febuxostat formulations were well tolerated and generally effective on serum UA level end points (versus placebo) across all renal function subgroups.ConclusionBoth formulations of febuxostat (XR and IR) were well tolerated and effective in patients with gout and normal or impaired renal function, including patients with severe renal impairment.
Asymmetric “Acetylenic” [3+2] Cycloaddition of Nitrones Catalyzed by Cationic Chiral PdII Lewis Acid
Authors: Honda Kazuya , Mikami Koichi 
Published: August 2018

AbstractHighly enantioselective [3+2] cycloaddition of ynones and nitrones has been developed. Very bulky ligand, DTBM‐SEGPHOS, was used for an effective asymmetric induction over distal reaction centers on the linear ynone dipolarophile and for prevention of PdII catalyst deactivation by coordination of the nitrones. The reaction has wide scope of substrates in both ynones and nitrones.
Diruthenium Complexes of p‐Benzoquinone–Imidazole Hybrid Ligands: Innocent or Noninnocent Behavior of the Quinone Moiety
Authors: Ansari Mohd. Asif , Beyer Katharina , Schwederski Brigitte , Kaim Wolfgang , Lahiri Goutam Kumar 
Published: August 2018

AbstractAfter double deprotonation, 2,6‐diaryl‐p‐benzoquinonodiimidazoles (aryl=4‐tolyl (I) or 2‐pyridyl (II)) were shown to bridge two [Ru(bpy)2]2+ (bpy=2,2′‐bipyridine) complex fragments through the imidazolate N and p‐quinone O (I→12+) or through the imidazolate N and pyridyl N donor atoms (II→22+). Characterization by crystal structure analysis, 1H/13C NMR spectroscopy, cyclic and differential pulse voltammetry, and spectroelectrochemistry (UV/Vis/NIR, IR, EPR) in combination with TD‐DFT calculations revealed surprisingly different electronic structures for redox systems 1n and 2n. Whereas 12+ is reduced to a radical complex with considerable semiquinone character, the reduction of 22+ with its exclusive N coordination exhibits little spin on the now redox‐innocent quinone moiety, compared with the electron uptake by the pyridyl–imidazolate chelating site. The first of two close‐lying oxidation processes occurs at the bridging heteroquinone ligand, whereas the second oxidation is partly (14+) or predominantly (24+) centered on the metal atoms.
Geometrically (Q, S, R)‐Incremental Dissipativity and Incremental Stability for Switched Time‐Varying Nonlinear Discrete‐Time Systems
Authors: Ren Yuanhong , Wang Weiqun , Wang Yixiang 
Published: August 2018

AbstractThis paper investigates geometrically (Q,S,R)‐incremental dissipativity and incremental stability for switched time‐varying nonlinear discrete‐time systems. A geometrically (Q,S,R)‐incremental dissipativity concept is proposed for switched nonlinear discrete‐time systems by using multiple storage functions and multiple incremental supply rate. Furthermore, the sufficient conditions of geometrically (Q,S,R)‐incremental dissipativity are given under the design of state‐dependent switching law. The incremental stability conditions are derived for geometrically (Q,S,R)‐incrementally dissipative switched systems. By designing of a composite state‐dependent switching law, the feedback interconnected switched systems are ensured to be geometrically (Q,S,R)‐incrementally dissipative. A numerical example is given to illustrate the validity of the proposed approach.