bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tailoring the Structure of Hierarchically Porous Zeolite Beta through Modified Orientated Attachment Growth in a Dry Gel System
Authors: Chen Jiao , Hua Weiming , Xiao Yu , Huo Qisheng , Zhu Kake , Zhou Xinggui 
Published: September 2014

AbstractThe crystallization of zeolite beta in a dry gel system is found to follow the orientated attachment growth route, escorted with a temporal morphology change from bulky gel, through aggregation of the particulate to large zeolitic crystals. Modification of the precrystallized gel with organosilanes can be used to tune the morphology of the ultimate beta. When hexadecyltrimethoxysilane (HTS) is employed to modify precrystallized gel, a resumed secondary growth produces a hybrid mesocrystal of agglomerated nanozeolites. Combustive removal of organics leads to the formation of hierarchically porous zeolite beta of 100 to 160 nm, composed of nanocrystal building units ranging from 20 to 40 nm, with a noticeable micropore volume of 0.19 mL g−1 and a meso/macropore size between 5 and 80 nm. Conversely, when 1,8‐bis(triethoxysilyl)octane (BTO) is utilized to modify the same precrystallized gel, assemblages of discrete beta nanozeolite of around 35 nm are generated. These assemblages construct a hierarchical zeolite beta with a micropore volume of 0.20 mL g−1 and auxiliary pores ranging from 5 to 100 nm. Both organosilanes bring about well‐connected hierarchical pore networks. HTS has little effect on the Brønsted/Lewis acidity, whereas BTO causes a substantial reduction of strong Brønsted acid sites. The hierarchical beta zeolite‐supported Pt catalyst exhibits improved catalytic performance for the hydroisomerization of n‐heptane.
Static and Dynamic Properties of 1,1′‐Bi‐2‐naphthol and Its Conjugated Acids and Bases
Authors: Alkorta Ibon , Cancedda Céline , Cocinero Emilio José , Dávalos Juan Z. , Écija Patrica , Elguero José , González Javier , Lesarri Alberto , Ramos Rocio , Reviriego Felipe , Roussel Christian , Uriarte Iciar , Vanthuyne Nicolas 
Published: September 2014

AbstractSeveral convergent techniques were used to characterize 1,1′‐bi‐2‐naphthol (BINOL) and some of its properties. Its acidity in the gas‐phase, from neutral species to monoanion, was measured by mass spectrometry. The conformation and structure of BINOL in the gas phase was determined by microwave rotational spectroscopy. NMR experiments in fluorosulfonic acid established that BINOL was monoprotonated on one of the hydroxyl oxygen atoms. The enantiomerization barriers reported in the literature for BINOL under neutral, basic, and acid conditions were analyzed with regard to the species involved. Finally, DFT calculations allowed all of these results to be gathered in a coherent picture of the BINOL structure.
One‐Step Versus Multistep Equilibrium of Carbazole‐Bridged Dinuclear Zinc(II) Complex Formation: Metal‐Assisted π‐Association and ‐Dissociation Processes
Authors: Inukai Norie , Kawai Tsuyoshi , Yuasa Junpei 
Published: September 2014

AbstractThis work demonstrates a selection criteria that determines whether molecular assembly occurs through a one‐step or stepwise manner in ligand‐bridged dinuclear zinc(II) (Zn2+) complex formation, which is associated with the π stacking of building blocks. The building blocks of carbazole ligands (L1 and L4) that contain two imidazole moieties at the 3,6‐positions form 4:2 complexes (i.e., [L]4(Zn2+)2) at a molar ratio of 0.50 ([Zn2+]/[L]0=0.50), thereby providing π stacking between the carbazole ligands. At the molar ratio of 0.67 ([Zn2+]/[L]0=0.67), the 4:2 complexes change to 3:2 complexes (i.e., [L]3(Zn2+)2) with no π‐stacked carbazole unit. In contrast, when the imidazole groups in L1 are replaced with benzoimidazole groups (L3), L3 also yields the 4:2 complex [(L3)4(Zn2+)2] at a molar ratio of 0.50. However, there is no structural transition from (L3)4(Zn2+)2 to other complex species above a molar ratio of 0.50. Similarly, when two imidazole groups are introduced into the carbazole ring at 2,7‐positions (L5), L5 also gives the 4:2 complex [(L5)4(Zn2+)2] that shows no structural transition to other complex species at a higher molar ratio.
Probing the Role of π Interactions in the Reactivity of Oxygen Species: A Case of Ethylzinc Aryloxides with Different Dispositions of Aromatic Rings toward the Metal Center
Authors: Mąkolski Łukasz , Zelga Karolina , Petrus Rafał , Kubicki Dominik , Zarzycki Piotr , Sobota Piotr , Lewiński Janusz 
Published: September 2014

AbstractEthylzinc derivatives of ortho‐hydroxybiphenyl and 2,6‐diphenylphenol that bear different nuclearity and dispositions of aromatic rings toward the metal center were synthesized and structurally characterized in the solid state and solution. This family of well‐defined compounds was examined as a model system for the activation of dioxygen mediated by using complexes that feature lack of a redox‐active metal center. Experimental and theoretical studies indicate an essential role in the oxygenation process of intramolecular interactions that involve aromatic subunits. Additionally, novel results for the oxygenation chemistry of alkylzinc compounds, including the isolation and structural characterization of the unique octanuclear aryloxide (hydroxide) compound Zn8(OAr)8(OH)6(O2) with an encapsulated peroxide species, are presented.
Rhodium‐Catalyzed Arylative Cyclization for the Enantioselective Synthesis of (Trifluoromethyl)cyclobutanols
Authors: Johnson Thomas , Choo Ken‐Loon , Lautens Mark 
Published: September 2014

AbstractA rhodium‐catalyzed cyclization of 1‐(trifluoromethyl)‐4‐alkyn‐1‐ones with arylboronic acids is described to yield a novel class of small rings: (trifluoromethyl)cyclobutanols bearing an exocyclic double bond. The use of a rhodium/chiral diene complex allowed the reaction to proceed under mild conditions, often with high enantioselectivity. An X‐ray crystal structure was obtained confirming the formation of the four‐membered ring products.
Culprit Vessel Only vs Immediate Complete Revascularization in Patients With Acute ST‐Segment Elevation Myocardial Infarction: Systematic Review and Meta‐Analysis
Authors: Sekercioglu Nigar , Spencer Frederick A. , Cruz Lopes Luciane , Guyatt Gordon H. 
Published: September 2014

AbstractAlthough multivessel coronary artery disease has been associated with poor health outcomes in patients with acute ST‐segment elevation myocardial infarction (STEMI), the optimal approach to revascularization remains uncertain. The objective of this review was to determine the benefits and harms of culprit vessel only vs immediate complete percutaneous coronary intervention (PCI) in patients with acute STEMI. We searched MEDLINE, EMBASE, the Cochrane Register of Controlled Trials, and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) for randomized controlled trials (RCTs). Teams of 2 reviewers, independently and in duplicate, screened titles and abstracts, completed full‐text reviews, and abstracted data. We calculated pooled risk ratios (RRs) and associated 95% confidence intervals (CIs) using random‐effect models for nonfatal myocardial infarction (MI), revascularization, cardiovascular mortality, all‐cause mortality, and adverse events, and used the GRADE approach to rate confidence in estimates of effect. Of 341 patients randomized to complete revascularization and followed to study conclusion, 31 experienced revascularization, as did 80 of 324 randomized to culprit vessel only revascularization (RR: 0.35, 95% CI: 0.24‐0.53). Ten patients in the complete revascularization group and 28 patients in the culprit vessel only revascularization group experienced nonfatal MI (RR: 0.35, 95% CI: 0.17‐0.72). All‐cause mortality and cardiac deaths did not differ between groups (RR: 0.69, 95% CI: 0.40‐1.21 for all‐cause mortality; RR: 0.48, 95% CI: 0.22‐1.04 for cardiac deaths). Pooled data from 3 RCTs suggest that immediate complete revascularization probably reduces revascularization in patients with acute STEMI; although results suggest possible benefits on MI and death, confidence in estimates is low.
The effect of food and formulation on the pharmacokinetics, safety, and tolerability of GSK1322322 in healthy volunteers
Authors: Naderer Odin , Jones Lori S. , Zhu John , Coffin Mark D. , Kurtinecz Milena , Dumont Etienne 
Published: September 2014

AbstractGSK1322322 is the first in a new class of antibiotics that inhibit peptide deformylase, necessary for bacterial protein maturation. Previously, low absolute bioavailability was observed for the 1500‐mg oral tablet formulation, resulting in a less than dose‐proportional increase from the 1000‐mg dose. Furthermore, high variability of pharmacokinetic (PK) parameters within cohorts was suggested to be associated with differences in body weight. This open‐label, randomized, 4‐period, crossover, single‐dose phase I study in healthy individuals compared the PK, safety, and tolerability of free base oral tablets under fasted or fed conditions with intravenous and oral mesylate salt solution of GSK1322322 under fasted conditions. Absolute bioavailability of GSK1322322 1500‐mg free base tablets under fasted conditions, fed conditions, and oral mesylate salt solution was 57%, 77%, and 92%, respectively. Moderate‐fat/calorie food intake increased area under the concentration–time curve (AUC0−∞) by 36%, maintained maximum observed concentration (Cmax), and delayed time to Cmax. It appeared that AUC0−∞ decreased with body weight, whereas clearance increased. GSK1322322 administration resulted in only mild‐to‐moderate adverse events. These results support future clinical investigations of the free base oral tablet formulation of GSK1322322 1500 mg after intake of a moderate‐fat/calorie meal, including further investigation of a potential weight‐based dosage change.
Effect of canagliflozin on the pharmacokinetics of glyburide, metformin, and simvastatin in healthy participants
Authors: Devineni Damayanthi , Manitpisitkul Prasarn , Murphy Joseph , Skee Donna , Wajs Ewa , Mamidi Rao N. V. S. , Tian Hong , Vandebosch An , Wang Shean‐Sheng , Verhaeghe Tom , Stieltjes Hans , Usiskin Keith 
Published: September 2014

AbstractDrug–drug interactions between canagliflozin, a sodium glucose co‐transporter 2 inhibitor, and glyburide, metformin, and simvastatin were evaluated in three phase‐1 studies in healthy participants. In these open‐label, fixed sequence studies, participants received: Study 1‐glyburide 1.25 mg/day (Day 1), canagliflozin 200 mg/day (Days 4–8), canagliflozin with glyburide (Day 9); Study 2‐metformin 2,000 mg/day (Day 1), canagliflozin 300 mg/day (Days 4–7), metformin with canagliflozin (Day 8); Study 3‐simvastatin 40 mg/day (Day 1), canagliflozin 300 mg/day (Days 2–6), simvastatin with canagliflozin (Day 7). Pharmacokinetic parameters were assessed at prespecified intervals. Co‐administration of canagliflozin and glyburide did not affect the overall exposure (maximum plasma concentration [Cmax] and area under the plasma concentration–time curve [AUC]) of glyburide and its metabolites (4‐trans‐hydroxy‐glyburide and 3‐cis‐hydroxy‐glyburide). Canagliflozin did not affect the peak concentration of metformin; however, AUC increased by 20%. Though Cmax and AUC were slightly increased for simvastatin (9% and 12%) and simvastatin acid (26% and 18%) following coadministration with canagliflozin, compared with simvastatin administration alone; however, no effect on active 3‐hydroxy‐3‐methyl‐glutaryl‐CoA (HMG‐CoA) reductase inhibitory activity was observed. There were no serious adverse events or hypoglycemic episodes. No drug–drug interactions were observed between canagliflozin and glyburide, metformin, or simvastatin. All treatments were well‐tolerated in healthy participants.
Boron and other Triel Lewis Acid Centers: From Hypovalency to Hypervalency
Authors: Grabowski Sławomir J. 
Published: September 2014

AbstractMP2/aug‐cc‐pVTZ calculations were performed on triel trifluorides, ZF3(Z=B, Al, Ga, In, Tl), and their complexes with N2and HCN species, which are acting as Lewis bases. Interaction of the ZF3trigonal structure with a single HCN or N2ligand may lead to a tetrahedral structure with the tetravalent triel atom, whereas interaction of ZF3with two ligands results in a trigonal bipyramidal structure with a pentacoordinate Z atom. Consequently, the Z atom in ZF3compounds suffers from electron deficiency (hypovalency), it obeys the octet rule in ZF3–NCH and ZF3–N2moieties, and it may be considered as a hypervalent center in complexes of ZF3with two ligands. Much weaker interactions are observed for the boron complexes than for the other triel systems. This is because of the lower acidity of the B center relative to that of the other triel centers, and it may be the result of a stronger backbonding effect for BF3than for the other triel trifluorides. Interactions in aluminum complexes are characterized by meaningful electrostatic contributions, whereas for gallium complexes, the most important electron charge shift is observed as a result of complexation. Analysis of the geometry of the triel complexes and of the Z⋅⋅⋅N interactions (triel bonds) in these complexes is based on ab initio calculations as well as on the quantum theory of atoms in molecules and the natural bond orbitals method.
Almost Enclosed Buckyball Joints: Synthesis, Complex Formation, and Computational Simulations of Pentypticene‐Extended Tribenzotriquinacene
Authors: Henne Stefan , Bredenkötter Björn , Alaghemandi Mohammad , Bureekaew Sareeya , Schmid Rochus , Volkmer Dirk 
Published: September 2014

AbstractWe report the synthesis of a tribenzotriquinacene‐based (TBTQ) receptor (3) for C60 fullerene, which is extended by pentiptycene moieties to provide an almost enclosed concave ball bearing. The system serves as a model for a self‐assembling molecular rotor with a flexible and adapting stator. Unexpectedly, nuclear magnetic resonance spectroscopic investigations reveal a surprisingly low complex stability constant of K1=213±37 M−1 for [C60⊂3], seemingly inconsistent with the previously reported TBTQ systems. Molecular dynamics (MD) simulations have been conducted for three different [C60⊂TBTQ] complexes to resolve this. Because of the dominating dispersive interactions, the binding energies increase with the contact area between guest and host, however, only for rigid host structures. By means of free‐energy calculations with an explicit solvent model it can be shown that the novel flexible TBTQ receptor 3 binds weakly because of hampering entropic contributions.
Strong Coupling and Laser Action of Ladder‐Type Oligo(p‐phenylene)s in a Microcavity
Authors: Höfner Michael , Kobin Björn , Hecht Stefan , Henneberger Fritz 
Published: September 2014

AbstractWe investigate the coupling of ladder‐type quarterphenyl to the photon modes of a dielectric ZrOx/SiOx microcavity at ultraviolet wavelengths. For a relatively long cavity (≈10 μm) with high‐reflectivity mirrors (0.998), optically pumped laser action is demonstrated in the weak‐coupling regime. We observe single‐mode operation with a threshold of 0.4 mJ cm−2. Strong coupling is achieved by using a short λ/2 cavity. We find pronounced anti‐crossing features of the molecular (0,0) and (0,1) vibronic transitions and the cavity mode in angle‐dependent reflectivity measurements providing Rabi splittings of (90±10) meV. All these features occur spectrally resonant to the exciton transition of ZnO demonstrating the potential of ladder‐type oligo(p‐phenylene)s for the construction of inorganic/organic hybrid microcavities.
Assessment of Luminescent Downshifting Layers for the Improvement of Light‐Harvesting Efficiency in Dye‐Sensitized Solar Cells
Authors: Hosseini Zahra , Diau Eric Wei‐Guang , Mehrany Khashayar , Taghavinia Nima 
Published: September 2014

AbstractLuminescence downshifting (LDS) of light can be a practical photon management technique to compensate the narrow absorption band of high‐extinction‐coefficient dyes in dye‐sensitized solar cells (DSSCs). Herein, an optical analysis on the loss mechanisms in a reflective LDS (R‐LDS)/DSSC configuration is reported. For squaraine dye (550–700 nm absorption band) and CaAlSiN3:Eu2+ LDS material (550–700 nm emission band), the major loss channels are found to be non‐unity luminescence quantum efficiency (QE) and electrolyte absorption. By using an ideal LDS layer (QE=100 %), a less absorbing electrolyte (Co‐based), and antireflection coatings, approximately 20 % better light harvesting is obtained. If the absorption/emission band of dye/LDS is shifted to 800 nm, a maximal short‐circuit current density (Jsc) of 22.1 mA cm−2 can be achieved. By putting the LDS layer in front of the DSSC (transmissive mode), more significant loss channels are observed, and hence a lower overall efficiency than the R‐LDS configuration.
Understanding Aqueous Electrolyte Stability through Combined Computational and Magnetic Resonance Spectroscopy: A Case Study on Vanadium Redox Flow Battery Electrolytes
Authors: Vijayakumar Murugesan , Nie Zimin , Walter Eric , Hu Jianzhi , Liu Jun , Sprenkle Vincent , Wang Wei 
Published: September 2014

AbstractThe investigation of the vanadium electrolyte stability issue on the molecular‐level solvation structure and the dynamics has led to the successful designing of mixed acid‐based vanadium electrolytes. This new mixed‐acid based electrolyte system render approximately 70 % increase in energy density (≈40 Wh L−1) and approximately 80 % increase in stable temperature window (−10 to +50 °C) compared with conventional sulfuric acid‐based vanadium electrolyte. Through a comprehensive study by density functional theory and nuclear magnetic resonance spectroscopies, the improved stability is attributed to the hydrochloric acid as optimal cosolvent providing chloride anions for a ligand‐exchange process in the vanadium solvation structure. The role of the chloride counteranion in the solvation structure and dynamics of vanadium species was studied using combined magnetic resonance spectroscopy and DFT‐based theoretical methods. The solvation phenomenon of multiple vanadium species and their impact on vanadium redox flow battery electrolyte chemical stability are discussed.
Comparative Analysis of the Olfactory Properties of Silicon/Germanium/Tin Analogues of the Lily‐of‐the‐Valley Odorants Lilial and Bourgeonal
Authors: Dörrich Steffen , Gelis Lian , Wolf Steffen , Sunderkötter Astrid , Mahler Christoph , Guschina Elena , Tacke Reinhold , Hatt Hanns , Kraft Philip 
Published: September 2014

AbstractThe silicon/germanium/tin analogues of the lily‐of‐the‐valley odorants lilial (rac‐1 a), compounds rac‐1 b, rac‐1 c, and rac‐1 d, and bourgeonal (2 a), compounds 2 b, 2 c, and 2 d, were synthesized and characterized for their olfactory properties, including GC–olfactometry studies. Compounds rac‐1 a–c and 2 a–c possess a typical lily‐of‐the‐valley odor, whereas the stanna‐analogues rac‐1 d and 2 d, despite some floral aspects, clearly no longer belong to the lily‐of‐the‐valley family. In both series of the carbon/silicon/germanium/tin analogues studied, the lily‐of‐the‐valley odor decreases in the order of carbon<silicon<germanium<tin. A HEK293 cell line with stable tetracycline‐regulated expression of hOR17‐4 was generated to analyze recombinant hOR17‐4 activation by rac‐1 a–d and 2 a–d by using Ca2+ imaging. Bourgeonal (2 a) showed the highest activation potency, whereas lilial (rac‐1 a) and sila‐bourgeonal (2 b) exhibited lower activation potencies. Sila‐lilial (rac‐1 b), germa‐lilial (rac‐1 c), and stanna‐lilial (rac‐1 d), as well as germa‐bourgeonal (2 c) and stanna‐bourgeonal (2 d), did not activate heterologously expressed hOR17‐4 at the concentrations tested. The carbon/silicon/germanium/tin switch strategy thus showed that the stanna‐derivatives clearly exceeded the molecular dimensions of the odorant receptor(s) responsible for the recognition of lily‐of‐the‐valley odorants, although the receptor affinity was already affected with the sila‐ and germa‐analogues. These data could later be used in the qualitative and quantitative evaluation of computational receptor models.
Activated‐Carbon‐Supported Gold–Cesium(I) as Highly Effective Catalysts for Hydrochlorination of Acetylene to Vinyl Chloride
Authors: Zhao Jia , Xu Jiangtao , Xu Jinhui , Ni Jun , Zhang Tongtong , Xu Xiaoliang , Li Xiaonian 
Published: September 2014

AbstractThe synthesis of vinyl chloride from acetylene by hydrochlorination has gained tremendous interest in coal‐based chemistry. Bimetallic gold–cesium(I)/activated carbon (AuCsI/AC) catalysts were found to have a higher catalytic activity and stability for acetylene hydrochlorination when compared with gold catalysts. Over 1 Au4 CsI/AC catalysts, the maximum conversion of acetylene was 94 % and there was only 5 % C2H2 conversion loss after 50 h of running time. Moreover, the 1 Au4 CsI/AC catalyst delivered a stable performance during a 500 h test with the conversion of acetylene and the selectivity of vinyl chloride reaching more than 99.8 and 99.9 %, respectively. Temperature‐programmed reduction of H2, temperature‐programmed desorption of C2H2, and X‐ray photoelectron spectroscopy techniques were further applied to detect structural information on the AuCsI/AC catalysts. Additives of CsCl indeed stabilized the catalytically active Au3+ species and inhibited the reduction of Au3+ to Au0, thereby improving the activity and long‐term stability of gold‐based catalysts.
In Situ Synthesis of Neutral Dinuclear Rhodium Diphosphine Complexes [{Rh(diphosphine)(μ2‐X)}2]: Systematic Investigations
Authors: Meißner Antje , Preetz Angelika , Drexler Hans‐Joachim , Baumann Wolfgang , Spannenberg Anke , König Anja , Heller Detlef 
Published: September 2014

AbstractAs the workhorses for many applications, neutral dimeric μ2‐X‐bridged diphosphine rhodium complexes of the type [{Rh(diphosphine)(μ2‐X)}2] (X=Cl, OH) are usually prepared in situ by the addition of diphosphine ligands to the rhodium complex [{Rh(diolefin)(μ2‐X)}2] (diolefin=cyclooctadiene (cod) or norbornadiene (nbd)) or [{Rh(monoolefin)2(μ2‐Cl)}2] (monoolefin=cyclooctene (coe) or ethylene (C2H4)). The in situ procedure has been investigated for the diphosphines 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (BINAP), 5,5′‐bis(diphenylphosphino)‐4,4′‐bi‐1,3‐benzodioxole (SEGPHOS), 5,5′‐bis[di(3,5‐xylyl)phosphino]‐4,4′‐bi‐1,3‐benzodioxole (DM‐SEGPHOS), 5,5′‐bis[di(3,5‐di‐tert‐butyl‐4‐methoxyphenyl)phosphino]‐4,4′‐bi‐1,3‐benzodioxole (DTBM‐SEGPHOS), 2,2′‐bis(diphenylphosphino)‐1,1′‐dicyclopentane (BICP), 1‐[2‐(diphenylphosphino)ferrocenyl]ethyldi‐tert‐butylphosphine (PPF‐PtBu2), 1,1′‐bis(diisopropylphosphino)ferrocene (DiPPF), 1,2‐bis(diphenylphosphino)ethane (DPPE), 1,2‐bis(o‐methoxyphenylphosphino)ethane (DIPAMP), 4,5‐bis(diphenylphosphinomethyl)‐2,2‐dimethyl‐1,3‐dioxalane (DIOP), 1,2‐bis(2,5‐dimethylphospholano)benzene (Me‐DuPHOS), 1,4‐bis(diphenylphosphino)butane (DPPB), and 1,3‐bis(diphenylphosphino)propane (DPPP); the resulting complexes have been characterized by 31P NMR spectroscopy and, in most cases, also by X‐ray analysis. Depending on the diphosphine ligand, the solvent, the temperature, and the rhodium precursor, species other than the desired one [{Rh(diphosphine)(μ2‐X)}2] are formed, for example, [(diolefin)Rh(μ2‐Cl)2Rh(diphosphine)], [Rh(diphosphine)(diolefin)]+, [Rh(diphosphine)2]+, and [Rh(diphosphine)(diolefin)(Cl)]. The results clearly show that the in situ method commonly applied for precatalyst preparation cannot be regarded as an optimal strategy for the formation of such neutral [{Rh(diphosphine)(μ2‐X)}2] complexes.