bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of Thioether Oxidation over Di‐ and Tetrameric Ti Centres: Kinetic and DFT Studies Based on Model Ti‐Containing Polyoxometalates
Authors: Skobelev Igor Y. , Zalomaeva Olga V. , Kholdeeva Oxana A. , Poblet Josep M. , Carbó Jorge J. 
Published: August 2015

AbstractThe oxidation of thioethers by the green oxidant aqueous H2O2 catalysed by the tetratitanium‐substituted Polyoxometalate (POM) (Bu4N)8[{γ‐SiTi2W10O36(OH)2}2(μ‐O)2], as a model catalyst comprising tetrameric titanium centres, was investigated by kinetic modelling and DFT calculations. Several mechanisms of sulfoxidation were evaluated by using methyl phenyl sulfide (PhSMe) as a model substrate in the experiments and dimethyl sulfide in the calculations. The first mechanism assumes that the active hydroperoxo species forms directly through interaction of the Ti2(μ‐OH)2 group in [{γ‐SiTi2W10O36(OH)2}2(μ‐O)2]8− (1 D) with H2O2. The second mechanism includes hydrolysis of Ti‐O‐Ti bonds linking two γ‐Keggin units in structure 1 D to produce the monomer [(γ‐SiW10Ti2O38H2)(OH)2]4− (1 M), followed by the formation of an active hydroperoxo species upon interaction of the Ti hydroxo group with H2O2. Both kinetic modelling and DFT calculations support the mechanism through the monomeric species that involves the hydrolysis step. According to the DFT studies the activation of H2O2 by compound 1 M is preferred by 6.5 kcal mol−1 with respect to anion 1 D due to the more flexible Ti environment of the terminal Ti hydroxo group in 1 M. The calculations also indicate that for the „monomeric“ mechanism two pathways are operative: the mono‐ and the multinuclear pathway. In the mononuclear mechanism, the active group is the terminal TiOH group, whereas in the multinuclear path the active group is the bridging Ti2(μ‐OH) moiety. Moreover, unlike previous studies, the sulfoxidation is preferred through a β‐oxygen atom transfer from the Ti hydroperoxo group because the α‐oxygen atom transfer leads to an unfavourable seven‐fold coordinated Ti environment in the transition state. Finally, we have generalised these results to other Ti‐containing POMs: the Ti‐monosubstituted α‐Keggin ion [α‐PTi(OH)W11O39]4− and the dititanium‐substituted sandwich‐type ion [Ti2(OH)2As2W19O67]8−.
Rearrangement Reactions of Tritylcarbenes: Surprising Ring Expansion and Computational Investigation
Authors: Banert Klaus , Hagedorn Manfred , Pester Tom , Siebert Nicole , Staude Cornelius , Tchernook Ivan , Rathmann Katharina , Hollóczki Oldamur , Friedrich Joachim 
Published: August 2015

AbstractAs a rule, acetylides and sulfonyl azides do not undergo electrophilic azide transfer because 1,2,3‐triazoles are usually formed. We show now that treatment of tritylethyne with butyllithium followed by exposure to 2,4,6‐triisopropylbenzenesulfonyl azide leads to products that are easily explained through the generation of short‐lived tritylethynyl azide and its secondary product cyanotritylcarbene. Furthermore, it is demonstrated that tritylcarbenes generally do not produce triphenylethenes exclusively, as was stated in the literature. Instead, these carbenes always yielded also (diphenylmethylidene)cycloheptatrienes (heptafulvenes) as side products. This result is supported by static DFT, coupled cluster, and ab initio molecular dynamics calculations. From these investigations, the fused bicyclobutane intermediate was found to be essential for heptafulvene formation. Although the bicyclobutane is also capable of rearranging to the triphenylethene product, only the heptafulvene pathway is reasonable from the energetics. The ethene is formed straight from cyanotritylcarbene.
An Efficient p–n Heterojunction Photocatalyst Constructed from a Coordination Polymer Nanoplate and a Partically Reduced Graphene Oxide for Visible‐Light Hydrogen Production
Authors: Xu Xinxin , Lu Tingting , Liu Xiaoxia , Wang Xiuli 
Published: August 2015

AbstractA new p–n heterojunction photocatalyst has been synthesized successfully through chemical‐bond‐mediated combination of coordination polymer nanoplates (CPNPs) and partially reduced graphene oxide (PRGO) with a simple colloidal blending process. Photocatalytic H2 production by the p–n heterojunction photocatalyst PRGO/CPNP was investigated under visible‐light irradiation, which illustrates that PRGO/CPNP exhibits a much higher photocatalytic H2 production rate than neat the CPNPs. The improvement of this photocatalytic property can be attributed to the inner electrical field formed in the p–n heterojunction, which impedes recombination of photogenerated electrons and holes. In PRGO/CPNP, the existence of the p–n heterojunction has been confirmed by electrochemical methods clearly. For PRGO/CPNP, the reductive degree of the PRGO has a great influence on the H2 production rate and an ideal condition to get a PRGO/CPNP photocatalyst with higher performance has been obtained.
Bamboo‐Like Nitrogen‐Doped Carbon Nanotubes with Co Nanoparticles Encapsulated at the Tips: Uniform and Large‐Scale Synthesis and High‐Performance Electrocatalysts for Oxygen Reduction
Authors: Cao Tai , Wang Dingsheng , Zhang Jiatao , Cao Chuanbao , Li Yadong 
Published: August 2015

AbstractIn recent years, various non‐precious metal electrocatalysts for the oxygen reduction reaction (ORR) have been extensively investigated. The development of an efficient and simple method to synthesize non‐precious metal catalysts with ORR activity superior to that of Pt is extremely significant for large‐scale applications of fuel cells. Here, we develop a facile, low‐cost, and large‐scale synthesis method for uniform nitrogen‐doped (N‐doped) bamboo‐like CNTs (NBCNT) with Co nanoparticles encapsulated at the tips by annealing a mixture of cobalt acetate and melamine. The uniform NBCNT shows better ORR catalytic activity and higher stability in alkaline solutions as compared with commercial Pt/C and comparable catalytic activity to Pt/C in acidic media. NBCNTs exhibit outstanding ORR catalytic activity due to high defect density, uniform bamboo‐like structure, and the synergistic effect between the Co nanoparticles and protective graphitic layers. This facile method to synthesize catalysts, which is amenable to the large‐scale commercialization of fuel cells, will open a new avenue for the development of low‐cost and high‐performance ORR catalysts to replace Pt‐based catalysts for applications in energy conversion.
Fluorogenic Strain‐Promoted Alkyne–Diazo Cycloadditions
Authors: Friscourt Frédéric , Fahrni Christoph J. , Boons Geert‐Jan 
Published: August 2015

AbstractFluorogenic reactions, in which non‐ or weakly fluorescent reagents produce highly fluorescent products, are attractive for detecting a broad range of compounds in the fields of bioconjugation and material sciences. Herein, we report that a dibenzocyclooctyne derivative modified with a cyclopropenone moiety (Fl‐DIBO) can undergo fast strain‐promoted cycloaddition reactions under catalyst‐free conditions with azides, nitrones, nitrile oxides, as well as mono‐ and disubstituted diazo‐derivatives. Although the reaction with nitrile oxides, nitrones, and disubstituted diazo compounds gave cycloadducts with low quantum yield, monosubstituted diazo reagents produced 1H‐pyrazole derivatives that exhibited an approximately 160‐fold fluorescence enhancement over Fl‐DIBO combined with a greater than 10 000‐fold increase in brightness. Concluding from quantum chemical calculations, fluorescence quenching of 3H‐pyrazoles, which are formed by reaction with disubstituted diazo‐derivatives, is likely due to the presence of energetically low‐lying (n,π*) states. The fluorogenic probe Fl‐DIBO was successfully employed for the labeling of diazo‐tagged proteins without detectable background signal. Diazo‐derivatives are emerging as attractive reporters for the labeling of biomolecules, and the studies presented herein demonstrate that Fl‐DIBO can be employed for visualizing such biomolecules without the need for probe washout.
Short Access to Belt Compounds with Spatially Close CC Bonds and Their Transannular Reactions
Authors: Camps Pelayo , Gómez Tània , Otermin Ane , Font‐Bardia Mercè , Estarellas Carolina , Luque Francisco Javier 
Published: August 2015

AbstractTwo domino Diels–Alder adducts were obtained from 3,7‐bis(cyclopenta‐2,4‐dien‐1‐ylidene)‐cis‐bicyclo[3.3.0]octane and dimethyl acetylenedicarboxylate or N‐methylmaleimide under microwave irradiation. From the first adduct, a C20H24 diene with C2v symmetry was obtained by Zn/AcOH reduction, hydrolysis, oxidative decarboxylation, and selective hydrogenation. Photochemical [2+2] cycloaddition of this diene gave a thermally unstable cyclobutane derivative, which reverts to the diene. However, both the diene and the cyclobutane derivatives could be identified by X‐ray diffraction analysis upon irradiation of the diene crystal. New six‐membered rings are formed upon the transannular addition of bromine or iodine to the diene. The N‐type selectivity of the addition was examined by theoretical calculations, which revealed the distinct susceptibility of the doubly bonded carbon atoms to the bromine attack.
An N‐Acetyl Cysteine Ruthenium Tricarbonyl Conjugate Enables Simultaneous Release of CO and Ablation of Reactive Oxygen Species
Authors: Seixas João D. , Chaves‐Ferreira Miguel , Montes‐Grajales Diana , Gonçalves Ana M. , Marques Ana R. , Saraiva Lígia M. , Olivero‐Verbel Jesus , Romão Carlos C. , Bernardes Gonçalo J. L. 
Published: August 2015

AbstractWe have designed and synthesised a [Ru(CO)3Cl2(NAC)] pro‐drug that features an N‐acetyl cysteine (NAC) ligand. This NAC carbon monoxide releasing molecule (CORM) conjugate is able to simultaneously release biologically active CO and to ablate the concurrent formation of reactive oxygen species (ROS). Complexes of the general formulae [Ru(CO)3(L)3]2+, including [Ru(CO)3Cl(glycinate)] (CORM‐3), have been shown to produce ROS through a water–gas shift reaction, which contributes significantly, for example, to their antibacterial activity. In contrast, NAC‐CORM conjugates do not produce ROS or possess antibacterial activity. In addition, we demonstrate the synergistic effect of CO and NAC both for the inhibition of nitric oxide (formation) and in the expression of tumour‐necrosis factor (TNF)‐α. This work highlights the advantages of combining a CO‐releasing scaffold with the anti‐oxidant and anti‐inflammatory drug NAC in a unique pro‐drug.
Photolithographic Encoding of Metal Complexes
Authors: Lang Christiane , Bestgen Sebastian , Welle Alexander , Müller Rouven , Roesky Peter W. , Barner‐Kowollik Christopher 
Published: August 2015

AbstractA platform technology for the creation of spatially resolved surfaces encoded with a monolayer consisting of different metal complexes was developed. The concept entails the light‐triggered activation of a self‐ assembled monolayer (SAM) of UV‐labile anchors, that is, phenacylsulfides, and the subsequent cycloaddition of selected diene‐functionalized metal complexes at defined areas on the surface. The synthesis and characterization of the metal complexes for the UV‐light assisted anchoring on the surface and a detailed study of a short‐chain oligomer model system in solution confirm the high efficiency of the photoreaction. The hybrid materials obtained by this concept can potentially be utilized for the design of highly valuable catalytic or (opto‐)electronic devices.
Divergent Gold(I)‐Catalyzed Skeletal Rearrangements of 1,7‐Enynes
Authors: Meiß Rebecca , Kumar Kamal , Waldmann Herbert 
Published: August 2015

AbstractThe gold(I) complex catalyzed cycloisomerization and skeletal rearrangement of 1,n‐enynes (n=5–7) is a powerful methodology for the efficient synthesis of complex molecular architectures. In contrast to 1,6‐enynes, readily accessible homologous 1,7‐enynes are largely unexplored in such transformations. Here, the divergent skeletal rearrangement of all‐carbon 1,7‐enynes by catalysis with a cationic gold(I) complex is reported. Depending on electronic and steric factors, differently substituted 1,7‐enynes react via different carbocations formed from a common gold carbene intermediate to yield on the one hand novel exocyclic allenes and on the other hand tricyclic hexahydro‐anthracenes through a novel dehydrogenative Diels–Alder reaction.
Membrane‐Active Small Molecules: Designs Inspired by Antimicrobial Peptides
Authors: Ghosh Chandradhish , Haldar Jayanta 
Published: August 2015

AbstractInfectious diseases continue to be one of the major contributors to human morbidity. The rapid rate at which pathogenic microorganisms have developed resistance against frontline antimicrobials has compelled scientists to look for new alternatives. Given their vast antimicrobial repertoire, substantial research effort has been dedicated toward the development of antimicrobial peptides (AMPs) as alternative drugs. However, inherent limitations of AMPs have driven substantial efforts worldwide to develop synthetic mimics of AMPs. This review focuses on the progress that has been made toward the development of small molecules that emulate the properties of AMPs, both in terms of design and biological activity. Herein we provide an extensive discussion of the structural features of various designs and we examine biological properties that have been exploited. Furthermore, we raise a number of questions for which the field has yet to provide solutions and discuss possible future research directions that remain either unexploited or underexploited.
Particle transport in the human respiratory tract: formulation of a nodal inverse distance weighted Eulerian–Lagrangian transport and implementation of the Wind–Kessel algorithm for an oral delivery
Authors: Kannan Ravishekar , Guo Peng , Przekwas Andrzej 
Published: August 2015

SummaryThis paper is the first in a series wherein efficient computational methods are developed and implemented to accurately quantify the transport, deposition, and clearance of the microsized particles (range of interest: 2 to 10 µm) in the human respiratory tract. In particular, this paper (part I) deals with (i) development of a detailed 3D computational finite volume mesh comprising of the NOPL (nasal, oral, pharyngeal and larynx), trachea and several airway generations; (ii) use of CFD Research Corporation's finite volume Computational Biology (CoBi) flow solver to obtain the flow physics for an oral inhalation simulation; (iii) implement a novel and accurate nodal inverse distance weighted Eulerian–Lagrangian formulation to accurately obtain the deposition, and (iv) development of Wind–Kessel boundary condition algorithm. This new Wind–Kessel boundary condition algorithm allows the ‘escaped’ particles to reenter the airway through the outlets, thereby to an extent accounting for the drawbacks of having a finite number of lung generations in the computational mesh. The deposition rates in the NOPL, trachea, the first and second bifurcation were computed, and they were in reasonable accord with the Typical Path Length model. The quantitatively validated results indicate that these developments will be useful for (i) obtaining depositions in diseased lungs (because of asthma and COPD), for which there are no empirical models, and (ii) obtaining the secondary clearance (mucociliary clearance) of the deposited particles. Copyright © 2015 John Wiley & Sons, Ltd.
Multiple‐Site SO2‐Capture Ionic Liquids with Nearly Uniform Site Performance
Authors: Tang Huarong , Lu Dongmei 
Published: August 2015

AbstractWe propose a series of azolium poly(azolyl)borate ionic liquids (ILs) for reversible SO2 capture. Density functional calculations demonstrate that the designed borate anions can strongly bond to SO2 at multiple sites with nearly uniform binding energies. Thus, as well as high overall uptakes, the ILs can achieve much higher effective uptakes (the uptake difference between absorption and desorption conditions) than existing SO2‐capture reagents. The larger size of the borate anions, the evenly distributed negative charge among the azolyl rings, and the blocking of the conjugation by the tetrahedral boron concertedly reduce absorbate–absorbate repulsion, which leads to a large disparity among binding sites in other multiple‐site SO2 sorbents.
Bournonite PbCuSbS3: Stereochemically Active Lone‐Pair Electrons that Induce Low Thermal Conductivity
Authors: Dong Yongkwan , Khabibullin Artem R. , Wei Kaya , Salvador James R. , Nolas George S. , Woods Lilia M. 
Published: August 2015

AbstractAn understanding of the structural features and bonding of a particular material, and the properties these features impart on its physical characteristics, is essential in the search for new systems that are of technological interest. For several relevant applications, the design or discovery of low thermal conductivity materials is of great importance. We report on the synthesis, crystal structure, thermal conductivity, and electronic‐structure calculations of one such material, PbCuSbS3. Our analysis is presented in terms of a comparative study with Sb2S3, from which PbCuSbS3 can be derived through cation substitution. The measured low thermal conductivity of PbCuSbS3 is explained by the distortive environment of the Pb and Sb atoms from the stereochemically active lone‐pair s2 electrons and their pronounced repulsive interaction. Our investigation suggests a general approach for the design of materials for phase‐change‐memory, thermal‐barrier, thermal‐rectification and thermoelectric applications, as well as other functions for which low thermal conductivity is purposefully sought.
Sonochemical Synthesis of Layered Copper Hydroxy Nitrate Nanosheets
Authors: Anandan Sambandam , Wu Jerry J. , Ashokkumar Muthupandian 
Published: August 2015

AbstractSonochemical reduction of copper nitrate, using 20 kHz ultrasound in aqueous solutions in the presence of urea, led to the formation of layered copper hydroxy nitrate nanosheets, as evidenced by scanning and transmission electron microscopy images. Fourier‐transform infrared, X‐ray diffraction, and X‐ray photoelectron spectroscopy analyses were used to characterize layered Cu2(OH)3NO3 nanosheets. The ultrasound‐assisted progressive hydrolysis of urea and in situ formation of Cu(0) through the sonochemical reduction process induced homogeneous nucleation and crystallization of layered Cu2(OH)3NO3 nanosheets.
Immobilization of a Molecular Ruthenium Catalyst on Hematite Nanorod Arrays for Water Oxidation with Stable Photocurrent
Authors: Fan Ke , Li Fusheng , Wang Lei , Daniel Quentin , Chen Hong , Gabrielsson Erik , Sun Junliang , Sun Licheng 
Published: August 2015

AbstractPhotoelectrochemical (PEC) cells for light‐driven water splitting are prepared using hematite nanorod arrays on conductive glass as the photoanode. These devices improve the photocurrent of the hematite‐based photoanode for water splitting, owing to fewer surface traps and decreased electron recombination resulting from the one‐dimensional structure. By employing a molecular ruthenium co‐catalyst, which contains a strong 2,6‐pyridine‐dicarboxylic acid anchoring group at the hematite photoanode, the photocurrent of the PEC cell is enhanced with high stability for over 10 000 s in a 1 m KOH solution. This approach can pave a route for combining one‐dimensional nanomaterials and molecular catalysts to split water with high efficiency and stability.
Rational Design of an Electron‐Reservoir PtII Complex for Efficient Photocatalytic Hydrogen Production from Water
Authors: Whang Dong Ryeol , Park Soo Young 
Published: August 2015

AbstractHerein we report a PtII complex containing a 4,4′‐bis[4‐(triphenylsilyl)phenyl]‐2,2′‐bipyridine ligand as a molecular catalyst for water splitting. Systematic studies of the electrochemical and electronic properties of this catalyst, in comparison with two control complexes, reveal electron‐reservoir characteristics upon two‐electron reduction. A turnover number of 510 000 was recorded by employing this complex as a water reduction catalyst in combination with a state‐of‐the‐art photosensitizer and N,N‐dimethylaniline as a sacrificial electron donor, which represents a large improvement over the control complexes that do not contain the tetraphenylsilyl ligand substitution.
Does parental divorce moderate the heritability of body dissatisfaction? An extension of previous gene–environment interaction effects
Authors: O'Connor Shannon M. , Klump Kelly L. , VanHuysse Jessica L. , McGue Matt , Iacono William 
Published: August 2015

ABSTRACTObjectivePrevious research suggests that parental divorce moderates genetic influences on body dissatisfaction. Specifically, the heritability of body dissatisfaction is higher in children of divorced versus intact families, suggesting possible gene–environment interaction effects. However, prior research is limited to a single, self‐reported measure of body dissatisfaction. The primary aim of this study was to examine whether these findings extend to a different dimension of body dissatisfaction: body image perceptions.MethodParticipants were 1,534 female twins from the Minnesota Twin Family Study, aged 16–20 years. The Body Rating Scale (BRS) was used to assess body image perceptions.ResultsAlthough BRS scores were heritable in twins from divorced and intact families, the heritability estimates in the divorced group were not significantly greater than estimates in the intact group. However, there were differences in nonshared environmental effects, where the magnitude of these environmental influences was larger in the divorced as compared with the intact families.DiscussionDifferent dimensions of body dissatisfaction (i.e., negative self‐evaluation versus body image perceptions) may interact with environmental risk, such as parental divorce, in discrete ways. Future research should examine this possibility and explore differential gene–environment interactions using diverse measures. © 2015 Wiley Periodicals, Inc. (Int J Eat Disord 2016; 49:186–190).
Indices for assessing coral reef fish biodiversity: the need for a change in habits
Authors: Loiseau Nicolas , Gaertner Jean‐Claude 
Published: August 2015

AbstractWe present the first representative and quantified overview of the indices used worldwide for assessing the biodiversity of coral reef fishes. On this basis, we discuss the suitability and drawbacks of the indices most widely used in the assessment of coral fish biodiversity. An extensive and systematic survey of the literature focused on coral reef fish biodiversity was conducted from 1990 up to the present. We found that the multicomponent aspect of biodiversity, which is considered as a key feature of biodiversity for numerous terrestrial and marine ecosystems, has been poorly taken into account in coral reef fish studies. Species richness is still strongly dominant while other diversity components, such as functional diversity, are underestimated even when functional information is available. We also demonstrate that the reason for choosing particular indices is often unclear, mainly based on empirical rationales and/or the reproduction of widespread habits, but generally with no clear relevance with regard to the aims of the studies. As a result, the most widely used indices (species richness, Shannon, etc.) would appear to be poorly suited to meeting the main challenges facing the monitoring of coral reef fish biodiversity in the future. Our results clearly show that coral reef scientists should rather take advantage of the multicomponent aspect of biodiversity. To facilitate this approach, we propose general guidelines to serve as a basis for the selection of indices that provide complementary and relevant information for monitoring the response of coral reef fish biodiversity in the face of structuring factors (natural or anthropic). The aim of these guidelines was to achieve a better match between the properties of the selected indices and the context of each study (e.g. expected effect of the main structuring factors, nature of data available).