bluuebunny/crossref_metadata_2025_split huggingface dataset:
Discrete Rectangles, Prisms, and Heterometallic Cages from a Conjugated Cp*Rh‐Based Building Block
Authors: Shen Xu‐Yu , Zhang Ying‐Ying , Zhang Long , Lin Yue‐Jian , Jin Guo‐Xin 
Published: October 2015

AbstractBy carefully selecting an existing synthetic strategy and suitable coordination subunits, constructing desired coordination geometries is no longer that difficult to accomplish. Herein, a new strategy to construct a series of unprecedented structures by using conjugated Cp*Rh‐based complex BN‐OTf (Cp*=η5‐C5Me5) as the building block is proposed. DFT calculations revealed extensive delocalized π bonds in the subunit. With BN‐OTf, rectangular macrocycles TN‐bpy and TN‐bpe were controllably synthesized. Single‐crystal XRD studies confirmed one‐dimensional stacking channels for the tetranuclear structure. Notably, the starting ligand imidazole‐4,5‐dicarboxylate was found to act not only as a tetradentate but also as a hexadentate ligand that can coordinate to further metal ions. Subsequently, [4 Rh+1 M] heterometallic complexes HMZ (M=Cu and Zn) were accessed by chelating borderline hard/soft Lewis acids. With TN‐Linker or HMZ, two routes resulted in the [8 Rh+2 M] heterometallic cages HMC (M=Cu and Zn) with excellent crystallinity and stability. Surprisingly, when BN‐OTf bonded to rhodium itself, triangular prisms TP‐Linker were obtained with high solubility after being linked by bipyridine linkers. Both the X‐ray structure and 1H NMR spectrum confirmed the novel isomerization of the triangular structures. All of the compounds were obtained in high yields and were fully characterized by 1H NMR spectroscopy, elemental analysis, IR spectroscopy, and in most cases single‐crystal X‐ray structure determination.
Synthesis of Upconverting Hydrogel Nanocomposites Using Thiol‐Ene Click Chemistry: Template for the Formation of Dendrimer‐Like Gold Nanoparticle Assemblies
Authors: Meesaragandla Brahmaiah , Mahalingam Venkataramanan 
Published: October 2015

AbstractThe synthesis of upconverting hydrogel nanocomposites by base‐catalyzed thiol‐ene click reaction between 10‐undecenoic acid capped Yb3+/Er3+‐doped NaYF4 nanoparticles and pentaerythritol tetrakis(3‐mercaptopropionate) (PETMP) as tetrathiol monomer is reported. This synthetic strategy for nanocomposite gels is quite different from works where usually the preformed gels are mixed with the nanoparticles. Developing nanocomposites by surface modification of capping ligands would allow tuning and controlling of the separation of the nanoparticles inside the gel network. The hydrogel nanocomposites prepared by thiol‐ene click reaction show strong enhancement in luminescence intensity compared to 10‐undecenoic acid‐capped Yb3+/Er3+‐doped NaYF4 nanoparticles through the upconversion process (under 980 nm laser excitation). The hydrogel nanocomposites display strong swelling characteristics in water resulting in porous structures. Interestingly, the resulting nanocomposite gels act as templates for the synthesis of dendrimer‐like Au nanostructures when HAuCl4 is reduced in the presence of the nanocomposite gels.
Site Covalent Modification of Methionyl Peptides for the Production of FRET Complexes
Authors: Jadhav Pramodkumar D. , Shen Jianheng , Sammynaiken Ramaswami , Reaney Martin J. T. 
Published: October 2015

AbstractFlax cyclic peptides (orbitides, linusorbs (LOs)) [1–8‐NαC],[1‐MetO2]‐linusorb B1 ([MetO2]‐LO1) and [1–9‐NαC],[1‐MetO2]‐linusorb B2 ([MetO2]‐LO2) are biologically active. These LOs lack active nuclei commonly used in peptide modification. We have developed reactions to activate methionine methyl sulphide to produce stable derivatives. In these reactions, LOs are converted to sulfonium intermediates and subsequently to derivatives containing active nuclei while preserving their fundamental structures. The reaction conditions preserved cyclic peptide fundamental structure and organic solvent solubility. [Met]‐LO1 and [Met]‐LO2 analogues containing activated groups (CN, COOEt, and NH2) in the form of methionine, methionine (S)‐oxide, and methionine (S,S)‐dioxide amino acids were synthesized and characterized by LCMS and 1D and 2D NMR spectroscopy. Coumarin orbitide complexes produced in this manner bind Eu3+ yielding FRET compounds that absorb energy through coumarin antennae and emit photons at lanthanide wavelengths.
Experimental and Theoretical Study of an Intramolecular CF3‐Group Shift in the Reactions of α‐Bromoenones with 1,2‐Diamines
Authors: Muzalevskiy Vasily M. , Ustynyuk Yury A. , Gloriozov Igor P. , Chertkov Vyacheslav A. , Rulev Alexander Yu. , Kondrashov Evgeniy V. , Ushakov Igor A. , Romanov Alexey R. , Nenajdenko Valentine G. 
Published: October 2015

AbstractThe reactions of trifluoromethylated 2‐bromoenones andN,N′‐dialkyl‐1,2‐diamines have been studied. Depending on the structures of the starting compounds, the formation of 2‐trifluoroacetylpiperazine or 3‐trifluoromethylpiperazine‐2‐ones was observed. The mechanism of the reaction is discussed in terms of multistep processes involving sequential substitution of bromine in the starting α‐bromoenones and intramolecular cyclization of the captodative aminoenones as key intermediates to form the target heterocycles. The results of theoretical calculations are in perfect agreement with the experimental data. The unique role of the trifluoromethyl group in this reaction is demonstrated.
Enhancement of Solar Fuel Production Schemes by Using a Ru,Rh,Ru Supramolecular Photocatalyst Containing Hydroxide Labile Ligands
Authors: Rogers Hannah Mallalieu , Arachchige Shamindri M. , Brewer Karen J. 
Published: October 2015

AbstractPolyazine‐bridged RuIIRhIIIRuII complexes with two halide ligands, Cl− or Br−, bound to the catalytically active Rh center are efficient single‐component photocatalysts for H2O reduction to H2 fuel, with the coordination environment on Rh impacting photocatalysis. Herein reported is a new, halide‐free RuIIRhIIIRuII photocatalyst with OH− ligands bound to Rh, further enhancing the photocatalytic reactivity of the structural motif. H2 production experiments using the photocatalyst bearing OH− ligands at Rh relative to the analogues bearing halides at Rh in solvents of varying polarity (DMF, CH3CN, and H2O) suggest that ion pairing with halides deactivates photocatalyst function, representing an exciting phenomenon to exploit in the development of catalysts for solar H2 production schemes.
Transition‐Metal‐Free N‐Arylation of Pyrazoles with Diaryliodonium Salts
Authors: Gonda Zsombor , Novák Zoltán 
Published: October 2015

AbstractA new synthetic method was developed for the N‐arylation of pyrazoles using diaryliodonium salts. The transformation does not require any transition‐metal catalyst and provides the desired N‐arylpyrazoles rapidly under mild reaction condition in the presence of aqueous ammonia solution as a mild base without the use of inert atmosphere. The chemoselectivity of unsymmetric diaryliodonium salts was also explored with large number of examples.
Mechanistic Insight into the Facilitation of β‐Lactam Fragmentation through Metal Assistance
Authors: Casarrubios Luis , Esteruelas Miguel A. , Larramona Carmen , Lledós Agustí , Muntaner Jaime G. , Oñate Enrique , Ortuño Manuel A. , Sierra Miguel A. 
Published: October 2015

AbstractThe mechanism of OsH6(PiPr3)2‐mediated fragmentation of a 4‐(2 pyridyl)‐2‐azetidinone has been investigated by DFT calculations. The addition of the C4H bond of the substrate to OsH2(PiPr3)2 allows the active participation of an osmium lone pair in the B‐type β‐lactam fragmentation process. This new mechanism makes the N1C4/C2C3 fragmentation of the lactamic core thermally accessible through a stepwise process.
Iron‐Catalyzed Decarboxylation of Trifluoroacetate and Its Application to the Synthesis of Trifluoromethyl Thioethers
Authors: Exner Benjamin , Bayarmagnai Bilguun , Jia Fan , Goossen Lukas J. 
Published: October 2015

AbstractNucleophilic CF3 has been generated by decarboxylation of potassium trifluoroacetate, arguably the most easy‐to‐handle, inexpensive, and sustainable source of trifluoromethyl groups. Simple iron(II) chloride catalyzes the decarboxylation as well as a subsequent trifluoromethylation of organothiocyanates, resulting in a straightforward synthesis of trifluoromethyl thioethers. The KCN byproduct is absorbed by iron(II) with formation of nontoxic potassium hexacyanoferrate. An analogous trifluoromethylation of aldehydes with trifluoroacetate underlines the synthetic potential of such iron‐catalyzed decarboxylative trifluoromethylations.
Helical Polybissilsesquioxane Bundles Prepared Using a Self‐Templating Approach
Authors: Wang Qingfeng , Lin Shuwei , Qin Jiaming , Li Yi , Li Baozong , Yang Yonggang 
Published: October 2015

AbstractPolybissilsesquioxanes with single‐handed helical morphologies attracted much attention during the last decade, which could be applied as asymmetric catalysts and chiral stationary phases. Herein, a pair of chiral biphenylene‐bridged bissilsesquioxanes were synthesized. They self‐assembled into helical bundles in ethanol, behavior that was confirmed in field emission scanning electron microscopy images. Circular dichroism analysis indicated that the biphenylene groups twisted in a single‐handed fashion. Single‐handed helical polybissilsesquioxane bundles were prepared via polycondensation of the bissilsesquioxanes, using a self‐templating approach. Because of the shrinkage that occurred during polycondensation, the helical pitches of the bundles were shorter than those of their corresponding organic self‐assemblies. The wide‐angle X‐ray diffraction pattern indicated that there were no π–π interactions among the diphenylene groups. The circular dichroism spectra indicated that the chirality was successfully transferred from the bissilsesquioxane self‐assemblies to the polybissilsesquioxane. The polybissilsesquioxanes displayed a capacity for the adsorption of nitrobenzene and had potential application for enantioseparation. Chirality 28:44–48, 2016. © 2015 Wiley Periodicals, Inc.
Gemeinsames Recycling von Flachbildschirmen und Bleigläsern
Authors: Wolf Robert , Stelter Michael 
Published: October 2015

AbstractDerzeit werden weder Bleigläser noch Flachbildschirme wirtschaftlich recycelt. Kathodenstrahlröhren von Monitoren und alten Fernsehgeräten enthalten Blei, ein Massenmetall mit moderatem Preis. Flachbildschirme enthalten Indium und Zinn in so geringen Konzentrationen, dass ein Recycling unwirtschaftlich ist. Ein neues Verfahren wird präsentiert, das beide Abfälle in einem Prozess recycelt, um alle enthaltenen Metalle sowie Glas zurück zu gewinnen. Ein zusätzlicher Vorteil ist das Zero‐Waste‐Konzept des Verfahrens, da die Endprodukte verwertbares Glas sowie eine Metallphase, die alle Wertmetalle enthält, sind.
Schwermetallentfernung aus Gewässersediment durch Bioleaching im Praxismaßstab
Authors: Görsch Kati , Hoffmann Petra , Schlenker Uwe , Aurich Andreas , Zehnsdorf Andreas 
Published: October 2015

AbstractMit dem Ziel, die Materialeigenschaften zu verbessern und die Schwermetallgehalte von belasteten Gewässersedimenten soweit zu reduzieren, dass eine Verwertung möglich ist, wurde ein kombiniertes Konditionierungs‐ und Bioleaching‐Verfahren in den Praxismaßstab überführt. Am Beispiel eines schwermetallbelasteten Teichsedimentes konnte die Praxistauglichkeit des Verfahrens gezeigt werden. Aus zwei Chargen des Gewässersedimentes wurden Zink und Cadmium entfernt. Das Sediment wurde erfolgreich bei der Renaturierung von Bergbauhalden verwendet. Der bei der Prozesswasseraufbereitung anfallende Fällungsschlamm könnte als Quelle für strategische Elemente genutzt werden.
Effect of nickel promoter on solvent‐free sulphated zirconia catalyst for the esterification of acetic acid with n‐butanol
Authors: Wijayanti Hesti , Duangchan Apinya 
Published: October 2015

AbstractA simple solvent‐free preparation method was used to synthesize sulphated zirconia catalyst with various amounts of nickel promoter. This research investigated the effect of nickel addition to sulphated zirconia on the catalyst performance in esterification of acetic acid (a bio‐oil model) with n‐butanol. The results show that the addition of nickel contributed to the increase of sulphur content that bonded with nickel, the increase of thermal stability of the catalysts, and the formation of additional sulphate groups, and thus resulted in better catalytic performance compared to sulphated zirconia without nickel. More nickel being added resulted in a significant increase of acetic acid conversion; with 0.05 mol/mol nickel amount, the conversion was 97.93  %. This result represents a dramatic increase of about 2 and 3 times compared to the conversions of non‐nickel sulphated zirconia catalyst and non‐catalyst reactions, respectively.
The Distribution of Terrestrial Heat Flow and its Structural Control in the Huainan‐Huaibei Coalfield
Authors: Tao PENG , Ji‐Wen WU , Zi‐Qiang REN , Sheng‐Ping XU , Hai‐Chao ZHANG 
Published: October 2015

AbstractOn the basis of the results of the thermal conductivity of 127 rock samples in the tested coal measure strata and combining 59 reliable system temperature measurement data in mine field, we calculated out the heat flow values in Huainan‐Huaibei coalfield and drew the distribution map of terrestrial heat flow. The results show that the heat flow values in Huainan‐Huaibei coalfield range from 29.7 to 83.9 mW·m−2 and the average is 58.3 mW·m−2. There is a certain difference compared to other energy basins and the heat flow value in Huainan coalfield which is 63.7 mW·m−2 is much higher than that in Huaibei coalfield which is 55.2 mW·m−2. Through comprehensive analysis, we come to the conclusion that the difference between the terrestrial heat flow in study area and the one in other basins, and the phenomenon that the heat flow value in Huainan coalfield is higher than the one in Huaibei coalfield are controlled by tectonic evolution and regional geological background. And the reasons of heat flow maldistribution in study area is mainly influence of the geological structure on the geothermal field. Especially, the influence of nappe tectonic on the difference of current heat flow values on upper and lower side is very obvious.
A Stable and Efficient Attenuation Compensation Method based on Inversion
Authors: Ben‐Feng WANG , Xiao‐Hong CHEN , Jing‐Ye LI , Zeng‐Bao CHEN , Guo‐Chang LIU 
Published: October 2015

AbstractInverse Q filtering, which can compensate amplitude and correct phase, is an effective method to improve the resolution of seismic data. The conventional inverse Q method is usually based on wavefield continuation, which is unstable or under‐compensation. Based on the forward Q filtering equation in wavefield continuation, this work proposes a new attenuation compensation method, which is stable and accurate, taking advantages of the inverse theory and regularization strategy to obtain compensated seismic data eventually. It is also computationally efficient because only effective frequency components are calculated. Tests on synthetic and real data prove that the proposed method is effective.
Comprehensive Understanding of the Zipingpu Reservoir to the MS8.0 Wenchuan Earthquake
Authors: Hui‐Hong CHENG , Huai ZHANG , Yao‐Lin SHI 
Published: October 2015

AbstractSince the 12 May 2008 Wenchuan earthquake, whether this massive event was triggered by the impoundment of the nearby Zipingpu reservoir has attracted wide attention in international academic community. In addition to qualitative discussions, many scholars have made calculations on this issue. However, due to the different results, they draw very different conclusions. In this paper, we take the disputes from different teams in the quantitative calculation of Zipingpu reservoir as the starting point. Based on the basic principle of quantitative calculation of the stress changes after the impoundment of the reservoir, we analyze all kinds of influence factors to find out the key factors during the numerical simulation. The results show that the calculation methods, dimension of models, diffusion model, diffusion coefficient and focal mechanism are the main factors that resulted in the differences, especially the diffusion coefficient of the fractured rock mass. The Coulomb failure stress changes of the epicenter of the Wenchuan earthquake attained from the 2D model is about 3 times of that of the 3D model. And it is not reasonable that only considering the fault permeability or homogeneous isotropic rock mass permeability. The different focal mechanisms also could dramatically affect the Coulomb failure stress changes, of which the differences can research 2∼7 times. And the differences of Coulomb failure stress changes can reach several hundred times when selecting different diffusion coefficients. According to existing research that the magnitude of Coulomb failure stress change is about several kPa, we can not rule out the possibility that the Zipingpu reservoir may trigger the Wenchuan earthquake. However, for the background stress is not clear and Coulomb failure stress change is too small, we are not sure there must be a connection between the reservoir and earthquake. In the future work, we should target on the basis of field surveys and indoor experiments, improve the model and develop high‐performance simulation. Based on these calculation methods, we can compare more typical reservoir‐triggered earthquakes with different mechanisms both in China and elsewhere in the world to explore the mechanism of reservoir‐induced earthquakes.
Ambient Noise Tomography in Central‐South Mongolia
Authors: Jia‐Tie PAN , Qing‐Ju WU , Yong‐Hua LI , Da‐Xin YU , Meng‐Tan GAO , Ulziibat M. , Demberel S. 
Published: October 2015

AbstractRelying on cooperation projects in Mongolia, “Observation and modeling on the geomagnetic, gravitational field and deep structure in the Far East Areas”, we got dense seismic array data in the area for the first time. By using the vertical component of continuous data, recorded by 69 broadband seismic stations from Aug. 2011 to Jul. 2013 in south‐central Mongolia (103.5°E–111.5° E, 43°N–49°N), we calculated the inter‐station Empirical Green functions (EGFs) from cross‐correlation. In addition, a time‐frequency analysis based on a continuous wavelet transform was used to extract the Rayleigh wave phase velocity dispersion curves. Through quality control and manually screening, we finally obtained a total number of 1478 phase velocity dispersion curves at periods ranging from 6 s to 30 s. The Ditmar & Yanovskaya method was utilized to obtain phase velocity maps of the Rayleigh wave at periods of 6∼30 s in the study area. Checkerboard tests showed that the tomographic results had a high resolution of 0.5° ×0.5°. The results revealed that the phase velocity maps of Rayleigh waves have a small perturbation of about ±2%. A phase velocity map with a short period (e. g. 6 s) was imaged with high‐speed anomalies corresponding to the mountain ranges in the north and low‐speed anomalies coinciding with the sedimentary basin and Gobi Desert in the central‐south region. As the period (15 s, 20 s) increased, the imaging still showed a high‐velocity zone (HVZ) in the north and low‐velocity zone (LVZ) in the central‐south. However, the effect of the phase velocity distribution controlled by the surface geological structure was significantly weaker. The phase velocity maps with a long period (e.g. 30 s) showed an HVZ in the north that expanded further to the south than those with shorter periods (e.g., 15 s and 20 s), which is associated with the thinner crust in the south compared to that in the north. On those maps with long periods (e.g., 20 s, 30 s), there were significant differences between the northern and southern sides of Main Mongolian Lineament (MML), indicating that MML was not only a boundary for the topography and tectonics, but also for the crustal structure. The Middle Gobi area always showed an LVZ at periods from 6 s to 30 s, which could have been related to Cenozoic volcanism, while the Hangay‐Hentey basin was always imaged with an HVZ, which could have been associated with the old, stable layers in the north.
The Prognostic Significance of Right Bundle Branch Block: A Meta‐analysis of Prospective Cohort Studies
Authors: Xiong Yunyun , Wang Lian , Liu Wenyan , Hankey Graeme J. , Xu Biao , Wang Shang 
Published: October 2015

ABSTRACTBackgroundThe prognostic significance of right bundle branch block (RBBB) is inconsistent across studies. We aimed to assess the association between RBBB (in general population and patients with heart disease) and risk of all‐cause mortality, cardiac death, acute myocardial infarction (MI), and heart failure (HF).HypothesisRBBB may be associated with increased risk of death.MethodsPubMed, EMBASE, and the Cochrane Library up to February 2015 were searched for prospective cohort studies that reported RBBB at baseline and all‐cause mortality, cardiac death, MI, and HF at follow‐up. A meta‐analysis of published data was undertaken primarily by means of fixed‐effects models.ResultsNineteen cohort studies including 201 437 participants were included with a mean follow‐up period ranging from 1 to 246 months. For general population with RBBB, the pooled adjusted hazard ratio (HR) for all‐cause mortality was 1.17 (95% confidence interval [CI]: 1.03–1.33) compared with no BBB. General population with RBBB had an increased risk of cardiac death (HR: 1.43, 95% CI: 1.17–1.74). For patients with RBBB and acute MI, the pooled risk ratio was 2.31 (95% CI: 2.13–2.49) for in‐hospital mortality, 2.85 (95% CI: 2.46–3.30) for 30‐day mortality, and 1.96 (95% CI: 1.59–2.42) for longer‐term mortality. For acute HF patients, the pooled risk ratio of all‐cause mortality was 1.11 (95% CI: 1.06–1.16), and for chronic HF patients it was 1.75 (95% CI: 1.38–2.22).ConclusionsRight bundle branch block is associated with an increased risk of mortality in general population and patients with heart disease.
BMO‐Type Norms Related to the Perimeter of Sets
Authors: Ambrosio Luigi , Bourgain Jean , Brezis Haim , Figalli Alessio 
Published: October 2015

AbstractIn this paper we consider an isotropic variant of the BMO‐type norm recently introduced (Bourgain, Brezis, and Mironescu, 2015). We prove that, when considering characteristic functions of sets, this norm is related to the perimeter. A byproduct of our analysis is a new characterization of the perimeter of sets in terms of this norm, independent of the theory of distributions.© 2016 Wiley Periodicals, Inc.
Cancer Cell Imaging Using in Situ Generated Gold Nanoclusters
Authors: Chattoraj Shyamtanu , Amin Md. Asif , Mohapatra Saswat , Ghosh Surajit , Bhattacharyya Kankan 
Published: October 2015

AbstractIn situ generated fluorescent gold nanoclusters (Au‐NCs) are used for bio‐imaging of three human cancer cells, namely, lung (A549), breast (MCF7), and colon (HCT116), by confocal microscopy. The amount of Au‐NCs in non‐cancer cells (WI38 and MCF10A) is 20–40 times less than those in the corresponding cancer cells. The presence of a larger amount of glutathione (GSH) capped Au‐NCs in the cancer cell is ascribed to a higher glutathione level in cancer cells. The Au‐NCs exhibit fluorescence maxima at 490–530 nm inside the cancer cells. The fluorescence maxima and matrix‐assisted laser desorption ionization (MALDI) mass spectrometry suggest that the fluorescent Au‐NCs consist of GSH capped clusters with a core structure (Au8‐13). Time‐resolved confocal microscopy indicates a nanosecond (1–3 ns) lifetime of the Au‐NCs inside the cells. This rules out the formation of aggregated Au–thiolate complexes, which typically exhibit microsecond (≈1000 ns) lifetimes. Fluorescence correlation spectroscopy (FCS) in live cells indicates that the size of the Au‐NCs is ≈1–2 nm. For in situ generation, we used a conjugate consisting of a room‐temperature ionic liquid (RTIL, [pmim][Br]) and HAuCl4. Cytotoxicity studies indicate that the conjugate, [pmim][AuCl4], is non‐toxic for both cancer and non‐cancer cells.