bluuebunny/crossref_metadata_2025 huggingface dataset:
Micro‐/Nanofluidics for Liquid‐Mediated Patterning of Hybrid‐Scale Material Structures
Authors: Bae Juyeol , Lee Jongwan , Zhou Qitao , Kim Taesung
Published: January 2019

Various materials are fabricated to form specific structures/patterns at the micro‐/nanoscale, which exhibit additional functions and performance. Recent liquid‐mediated fabrication methods utilizing bottom‐up approaches benefit from micro‐/nanofluidic technologies that provide a high controllability for manipulating fluids containing various solutes, suspensions, and building blocks at the microscale and/or nanoscale. Here, the state‐of‐the‐art micro‐/nanofluidic approaches are discussed, which facilitate the liquid‐mediated patterning of various hybrid‐scale material structures, thereby showing many additional advantages in cost, labor, resolution, and throughput. Such systems are categorized here according to three representative forms defined by the degree of the free‐fluid–fluid interface: free, semiconfined, and fully confined forms. The micro‐/nanofluidic methods for each form are discussed, followed by recent examples of their applications. To close, the remaining issues and potential applications are summarized.
Directed and On‐Demand Alignment of Carbon Nanotube: A Review toward 3D Printing of Electronics
Authors: Goh Guo Liang , Agarwala Shweta , Yeong Wai Yee
Published: January 2019

Carbon nanotubes (CNTs) are 1D nanostructured materials with unique mechanical, optical, and electrical properties which can be potentially exploited for fabricating wide variety of devices. In addition, the biocompatibility of CNTs makes it attractive for wearable and implantable technology applications. Well‐aligned CNT structures show enhanced properties such as superior electron mobility, strain sensitivity, better mechanical property, and enhanced performance and reproducibility that are absent in their disordered counterparts, thus allowing more promising applications in various fields. With aligned CNTs, devices can be optimized to exhibit better performance with lesser materials and more miniature designs. This review summarizes the landscape of CNTs alignment, either during the growth or post‐growth processing. This paper delineates various CNTs alignment mechanism, process parameters, and challenges of each technique. A comparative discussion on the advantages, disadvantages, and degree of alignment of each technique is presented. A detailed discussion on the various applications that utilize properties of aligned CNTs devices is presented. The advent of 3D printing techniques for printing CNTs for novel and futuristic applications is also discussed.
A Reconfigurable Color Reflector by Selective Phase Change of GeTe in a Multilayer Structure
Authors: Jafari Mohsen , Guo L. Jay , Rais‐Zadeh Mina
Published: January 2019

It is shown that a phase change material (PCM), germanium telluride (GeTe), when integrated into a subwavelength layered optical cavity, can produce widely tunable reflective colors. It is shown that the crystallization temperature (Tx) of GeTe is dependent on the film thickness for thin films of less than ≈20 nm, which is exploited for color tuning. Four colors from the same physical structure are demonstrated by electrical heating, through novel optical and thermal engineering of a thin film stack that includes two GeTe layers with only a single integrated joule heater element. The selective sensitivity to incident light angle and low polarization dependence, as well as the low static power consumption of this device make it a good candidate for potential consumer electronics applications.
A Series of Imidazo[1,2‐f]phenanthridine‐Based Sky‐Blue TADF Emitters Realizing EQE of over 20%
Authors: Ohsawa Tatsuya , Sasabe Hisahiro , Watanabe Taiki , Nakao Kohei , Komatsu Ryutaro , Hayashi Yuya , Hayasaka Yuya , Kido Junji
Published: January 2019

Although imidazole derivatives are promising as blue fluorescent emitters in organic light‐emitting devices (OLEDs), the corresponding blue thermally activated delayed fluorescence (TADF) emitter is rarely explored. In this study, a series of imidazo[1,2‐f]phenanthridine‐based TADF materials in the blue to sky‐blue region is developed. The resultant benzimidazole (BIP)‐based TADF materials, with π‐expanded acceptor and electron‐donor phenoxazine (PXZ), namely PXZ‐BIP, shows a high maximum external quantum efficiency (ηext,max) of 21% with CIE coordinates of (0.21, 0.37). These results have clearly demonstrated that PXZ‐BIP exhibits the highest ηext,max among imidazole‐based fluorescent sky‐blue OLEDs. The corresponding imidazophenanthridine derivative, with a less π‐expanded acceptor, shows inferior OLED performances, with a ηext,max of 5.9% and CIE of (0.19, 0.30). This study provides a critical molecular design to realize high‐efficiency TADF materials based on imidazole derivatives.
Dimensionality Controlling of Cs3Sb2I9 for Efficient All‐Inorganic Planar Thin Film Solar Cells by HCl‐Assisted Solution Method
Authors: Umar Farooq , Zhang Jian , Jin Zhixin , Muhammad Ishaq , Yang Xiaokun , Deng Hui , Jahangeer Khan , Hu Qingsong , Song Haisheng , Tang Jiang
Published: January 2019

Since lead halide perovskite suffers from the obstructions of lead and stability, researchers recently pay more attention to the development of lead‐free and stable perovskite absorbers. A typical lead‐free antimony iodide perovskite (AIP) is synthesized through vapor reaction at high temperature for photoactive phase. Herein, hydrochloric acid is developed as an intermediate coordinated additive for Cs3Sb2I9 photoactive layered phase using HCl‐assisted solution method. The uniform and highly crystalline Cs3Sb2I9 layered film is obtained by antisolvent engineering. Isopropanol antisolvent is more suitable for present system comparing with traditional lead iodide perovskite‐based ones. Physical characterizations manifest the lower trap density, doubled carrier mobility, and improved junction quality from the new developed absorber film and its corresponding devices comparing with its dimer phase. Utilizing TiO2/AIP/Au all‐inorganic structure, the champion device demonstrates a power conversion efficiency (PCE) of 1.21%, which is the top value for all‐inorganic AIP solar cells. The nonencapsulated device exhibits negligible loss in the PCE under ambient environment with 50% humidity after 60 days storing. The obtained results portray important progress toward the understanding of reliable HCl‐assisted solution method and realization of highly stable AIP solar cells.
Palladium Catalyzed Regioselective C4‐Arylation and Olefination of Indoles and Azaindoles
Authors: Thrimurtulu Neetipalli , Dey Arnab , Singh Anurag , Pal Kuntal , Maiti Debabrata , Volla Chandra M. R.
Published: January 2019

A convergent strategy for the synthesis of biologically relevant C4‐substituted indole scaffolds was demonstrated using Pd(II)‐catalyzed remote C−H functionalization of indoles and azaindoles. The reaction displays high regioselectivity for the C4‐position of indole‐3‐carbaldehydes using glycine as an inexpensive transient directing group. Notable features of this transformation include the selective formation of six‐membered palladacyle and excellent functional group tolerance.

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Iodine(III) Enabled Dehydrogenative Aryl C−S Coupling by in situ Generated Sulfenium Ion
Authors: Choudhuri Khokan , Maiti Saikat , Mal Prasenjit
Published: January 2019

Due to the normal polarity preferences, arenes form stable complexes with thiols through S−H⋅⋅⋅π interaction and direct dehydrogenative aryl C−S coupling is usually restricted. We report here an umpolung based one pot and direct C−S coupling approach under metal free and mild condition. Electrophile sulfenium ions were generated in situ from thiols using iodine(III) reagent PhI(OAc)2 (PIDA) and subsequently used for aromatic electrophilic substitution (EArS) to synthesize diaryl sulfides. Also by using of appropriate amount of PIDA, cascaded synthesis of C−S and S=O bonds led to aryl sulfinyl arenes in one pot. Covalent self‐sorting or competitive experiments further confirmed the involvement of sulfenium ion in the EArS.

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Physicochemical processing of polyphenylsulfone: Optimization of processing parameters for microsphere production via spray drying using a response surface model
Authors: Mys Nicolas , Geiregat Maarten , Deruyck Frank , Verberckmoes An , Cardon Ludwig
Published: January 2019

This article describes the processing of polyphenylsulfone (PPSU) into microspheres via the physicochemical method called spray drying (SD). Polymeric microspheres have a potential in various fields of research like diagnostics, separations, thermal insulations, pigments, and additive manufacturing like selective laser sintering (SLS). These microspheres have the potential to be used as building material for SLS provided they have spherical morphology and have a submicrometer particle size. The effects of the different processing parameters on these two response factors have been investigated in SD of PPSU by design of experiment. A plot is predicted in which size and morphology are optimized and combined in order to find the ideal parameter set for production. The effect of polymer concentration, solution feed rate, atomization flow rate, inlet temperature, and polymer grade was optimized using a five‐factor three‐level factorial design. Through the statistical model, particles with a mean particle size of 13.27 μm can be obtained of which 19% are of adequate sphericity and roundness according to Powers’ scale for the low viscous grade (R5600, Radel® R5600 Solvay polymer, low viscous grade (or very high melt flow grade) of PPSU). In the case of the high viscous grade (R5000, Radel® R5000 Solvay polymer, high viscous grade of PPSU), a best particle size of 12.48 μm with 12.5% spherical particles can be achieved.
Exploiting Synergistic Effect by Integrating Ruthenium–Copper Nanoparticles Highly Co‐Dispersed on Graphene as Efficient Air Cathodes for Li–CO2 Batteries
Authors: Zhang Zhang , Yang Chao , Wu Shuangshuang , Wang Aonan , Zhao Linlin , Zhai Dandan , Ren Bo , Cao Kangzhe , Zhou Zhen
Published: January 2019

Li–CO2 batteries are attractive electrical energy storage devices; however, they still suffer from unsatisfactory electrochemical performance, and the kinetics of CO2 reduction and evolution reactions must be improved significantly. Herein, a composite of ruthenium–copper nanoparticles highly co‐dispersed on graphene (Ru–Cu–G) as efficient air cathodes for Li–CO2 batteries is designed. The Li–CO2 batteries with Ru–Cu–G cathodes exhibit ultra‐low overpotential and can be operated for 100 cycles with a fixed capacity of 1000 mAh g−1 at 200 and 400 mA g−1. The synergistic effect between Ru and Cu not only regulates the growth of discharge products, but also promotes CO2 reduction and evolution reactions by changing the electron cloud density of the surface between Ru and Cu. This work may provide new directions and strategies for developing highly efficient air cathodes for Li–CO2 batteries, or even practical Li–air batteries.
Rational Structure Optimized Hybrid Nanogenerator for Highly Efficient Water Wave Energy Harvesting
Authors: Wang Jiyu , Pan Lun , Guo Hengyu , Zhang Binbin , Zhang Rongrong , Wu Zhiyi , Wu Changsheng , Yang Lijun , Liao Ruijin , Wang Zhong Lin
Published: January 2019

Water wave energy is a promising renewable energy source that may alleviate the rising concerns over current resource depletion, but it is rarely exploited due to the lack of efficient energy harvesting technologies. In this work, a hybrid system with a triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG) based on an optimized inner topological structure is reported to effectively harvest water wave energy. The TENG with etched polytetrafluoroethylene films and Cu electrodes utilizing the contact‐freestanding mode is designed into a cubic structure, in which the EMG is well hybridized. An integration of TENG and EMG achieves mutual compensation of their own merits, enabling the hybrid system to deliver satisfactory output over a broad range of operation frequency. The output performance of TENG with varied inner topological structures is experimentally and theoretically compared, and a concept is proposed to further clarify the energy conversion efficiency, which should be considered in designing energy harvesting devices. The influences of oscillation frequency, amplitude, and dielectric materials on the output performance of the hybrid system are comprehensively studied on different platforms. Furthermore, the optimum operation frequency ranges for TENG and EMG are concluded. The proposed hybrid nanogenerator renders an effective approach toward large‐scale blue energy harvesting over a broad frequency range.
Balance between model detail and experimental information in steam methane reforming over a Ni/MgO‐SiO2 catalyst
Authors: Devocht Brigitte R. , Thybaut Joris W. , Kageyama Naoki , Toch Kenneth , Oyama Shigeo Ted , Marin Guy B.
Published: January 2019

The optimization and full understanding of chemical reactions is aided by the construction of an adequate kinetic model. The development of such a kinetic model remains a challenging task. To tackle this challenge in the most efficient way, an iterative, systematic methodology, originally demonstrated for n‐hexane hydroisomerization, is now extended aiming at finding the balance between the envisaged model detail and available information, often originating from time‐consuming and expensive experiments. Steam methane reforming on the Ni/MgO‐SiO2 case study is used for this purpose, that is, the construction of a kinetic model that embeds a maximum amount of information contained in the dataset. The kinetic model is expanded stepwise from a power law model over a model with reactant adsorption toward a Langmuir–Hinshelwood–Hougen–Watson model. The performance of the initially underparameterized model improved significantly by adding reactant adsorption, yet including product adsorption led to overparameterization rather than enhanced model performance. © 2019 American Institute of Chemical Engineers AIChE J, 65: 1222–1233, 2019
Pd/PTABS: Catalyst for Efficient C−H (Hetero)Arylation of 1,3,4‐Oxadiazoles Using Bromo(Hetero)Arenes
Authors: Bhujabal Yuvraj B. , Vadagaonkar Kamlesh S. , Kapdi Anant R.
Published: January 2019

A highly efficient catalytic protocol for the C−H (hetero)arylation of 1,3,4‐oxadiazoles using low catalyst loading of Pd/PTABS system with bromo(hetero)arenes has been disclosed. The developed reaction conditions enable the synthesis of a library of differently (hetero)arylated oxadiazoles along with a commercially available fluorescent organic scintillation material, butyl‐PBD as well as anti‐tubercular agent PHOXPY. The combination of C−H arylation of oxadiazoles with Sonogashira reaction (steroidal substructures bearing alkynes), Heck alkenylation or Suzuki‐Miyaura coupling in a one‐pot tandem procedure was also made possible with an intent for new drug discovery possibilities.
An Isolated Zinc–Cobalt Atomic Pair for Highly Active and Durable Oxygen Reduction
Authors: Lu Ziyang , Wang Bo , Hu Yongfeng , Liu Wei , Zhao Yufeng , Yang Ruoou , Li Zhiping , Luo Jun , Chi Bin , Jiang Zheng , Li Minsi , Mu Shichun , Liao Shijun , Zhang Jiujun , Sun Xueliang
Published: January 2019

A competitive complexation strategy has been developed to construct a novel electrocatalyst with Zn‐Co atomic pairs coordinated on N doped carbon support (Zn/CoN‐C). Such architecture offers enhanced binding ability of O2, significantly elongates the O−O length (from 1.23 Å to 1.42 Å), and thus facilitates the cleavage of O−O bond, showing a theoretical overpotential of 0.335 V during ORR process. As a result, the Zn/CoN‐C catalyst exhibits outstanding ORR performance in both alkaline and acid conditions with a half‐wave potential of 0.861 and 0.796 V respectively. The in situ XANES analysis suggests Co as the active center during the ORR. The assembled zinc–air battery with Zn/CoN‐C as cathode catalyst presents a maximum power density of 230 mW cm−2 along with excellent operation durability. The excellent catalytic activity in acid is also verified by H2/O2 fuel cell tests (peak power density of 705 mW cm−2).
Boron(III) Carbazosubphthalocyanines: Core‐Expanded Antiaromatic Boron(III) Subphthalocyanine Analogues
Authors: Chan Joseph Y. M. , Kawata Takahiro , Kobayashi Nagao , Ng Dennis K. P.
Published: January 2019

Condensation of 1,8‐diamino‐3,6‐dichlorocarbazole with a series of disubstituted 1,3‐diiminoisoindolines, followed by treatment with BF3⋅OEt2 led to the formation of the corresponding core‐expanded boron(III) subphthalocyanine analogues. These air‐stable π‐conjugated boron(III) carbazosubphthalocyanines possess two boron‐containing seven‐membered‐ring units and a 16 π‐electron skeleton, and represent the first examples of antiaromatic boron(III) subphthalocyanine analogues as supported by spectroscopic and theoretical studies. The molecular structure of one of these compounds was unambiguously determined by single‐crystal X‐ray diffraction analysis. In contrast to typical boron(III) subphthalocyanines, which adopt a cone‐shaped structure, the π skeleton of this compound is almost planar.
A Hybrid Platform Based on a Bispecific Peptide–Antibody Complex for Targeted Cancer Therapy
Authors: Yu Byeongjun , Hwang Dobeen , Jeon Hyungsu , Kim Hyungjun , Lee Yonghyun , Keum Hyeongseop , Kim Jinjoo , Lee Dong Yun , Kim Yujin , Chung Junho , Jon Sangyong
Published: January 2019

Peptide‐based therapeutics have suffered from a short plasma half‐life. On the other hand, antibodies suffer from poor penetration into solid tumors owing to their large size. Herein, we present a new molecular form, namely a hybrid complex between a hapten‐labeled bispecific peptide and an anti‐hapten antibody (“HyPEP‐body”), that may be able to overcome the aforementioned limitation. The bispecific peptide containing a cotinine tag was synthesized by linking a peptide specific to fibronectin extra domain B (EDB) and a peptide able to bind and inhibit vascular endothelial growth factor (VEGF), yielding cot‐biPEPEDB‐VEGF. Simple mixing of cot‐biPEPEDB‐VEGF and anti‐cotinine antibody (Abcot) yielded the hybrid complex, HyPEPEDB‐VEGF. HyPEPEDB‐VEGF retained the characteristics of the included peptides, and showed improved pharmacokinetic behavior. Moreover, HyPEPEDB‐VEGF showed tumor growth inhibition with excellent tumor accumulation and penetration. These findings suggest that the hybrid platform described here offers a solution for most peptide therapeutics that suffer from a short circulation half‐life in blood.
Highly Selective Oxidation and Depolymerization of α,γ‐Diol‐Protected Lignin
Authors: Lan Wu , de Bueren Jean Behaghel , Luterbacher Jeremy S.
Published: January 2019

Lignin oxidation offers a potential sustainable pathway to oxygenated aromatic molecules. However, current methods that use real lignin tend to have low selectivity and a yield that is limited by lignin degradation during its extraction. We developed stoichiometric and catalytic oxidation methods using 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) as oxidant/catalyst to selectively deprotect the acetal and oxidize the α‐OH into a ketone. The oxidized lignin was then depolymerized using a formic acid/sodium formate system to produce aromatic monomers with a 36 mol % (in the case of stoichiometric oxidation) and 31 mol % (in the case of catalytic oxidation) yield (based on the original Klason lignin). The selectivity to a single product reached 80 % (syringyl propane dione, and 10–13 % to guaiacyl propane dione). These high yields of monomers and unprecedented selectivity are attributed to the preservation of the lignin structure by the acetal.
Insight into 6π Electrocyclic Reactions of 1,8‐Dioxatetraene
Authors: Si Xiaodong , Jia Yuanyuan , Luan Xinqi , Yang Luo , Pei Yong , Zhou Wang
Published: January 2019

A variety of benzofuranone‐based spiroisochromenes were originally designed and synthesized to gain insight into the oxa‐6π electrocyclic reaction of cis,cis‐1,8‐dioxatetraene for the first time. The stability of the 1,8‐dioxatetraene intermediate is governed by its steric congestion and can be fine‐tuned through modification of the backbone structure, leading to the reactivity differences in the 6π electrocyclic reaction and the emergence of photochromic properties.
Aromatic Azide Transformation on the Ag(111) Surface Studied by Scanning Probe Microscopy
Authors: Hellerstedt Jack , Cahlík Aleš , Stetsovych Oleksander , Švec Martin , Shimizu Tomoko K. , Mutombo Pingo , Klívar Jiří , Stará Irena G. , Jelínek Pavel , Starý Ivo
Published: January 2019

Chemical transformation of 9‐azidophenanthrene on the Ag(111) surface was studied by nc‐AFM in UHV. High‐resolution imaging supported by first‐principle calculations revealed the structure of the final products that originated from a common and elusive 9‐phenanthryl nitrenoid intermediate chemisorbed on the Ag(111) surface. A formal nitrene insertion into the C−H bond along with its dimerisation and hydrogenation were identified as main reaction channels. Thus, the ability of aryl azides to form covalent σ‐ and π‐bonds between their transformation products on a solid surface was demonstrated at a single‐molecule level.
Activation of MoS2 Basal Planes for Hydrogen Evolution by Zinc
Authors: Wu Wenzhuo , Niu Chunyao , Wei Cong , Jia Yu , Li Chong , Xu Qun
Published: January 2019

Molybdenum disulfide (MoS2) has been widely studied as a potential earth‐abundant electrocatalyst for the hydrogen‐evolution reaction (HER). Defect engineering and heteroelemental doping are effective methods to enhance the catalytic activity in the HER, so exploring an efficient route to simultaneously achieve in‐plane vacancy engineering and elemental doping of MoS2 is necessary. In this study, Zinc, a low‐cost and moderately active metal, has been used to realize this strategy by generation of sulfur vacancies and zinc doping on MoS2 in one step. Density functional theory calculations reveal that the zinc atoms not only lower the formation energy of S vacancies, but also help to decrease ΔGH of S‐vacancy sites near the Zn atoms. At an optimal zinc‐reduced MoS2 (Zn@MoS2) example, the activated basal planes contribute to the HER activity with an overpotential of −194 mV at 10 mA cm−2 and a low Tafel slope of 78 mV/dec.
Reshaping Lipid Biochemistry by Pushing Barriers in Structural Lipidomics
Authors: Porta Siegel Tiffany , Ekroos Kim , Ellis Shane R.
Published: January 2019

Lipidomics is a rapidly growing field with numerous examples showing the importance of lipid molecules throughout biology. It has also shed light onto the vast and complex functions performed by many lipids that possess an immense diversity in molecular structures. Mass spectrometry (MS) is the tool of choice for analyzing lipids and has been the key catalyst driving the field forward. However, MS does not yet permit true molecular lipidomics wherein the identification and quantification of lipids having defined molecular structures can be routinely achieved. Here we describe recent advances in MS‐based lipidomics that allow access to higher levels of molecular information in lipidomics experiments. These advances will form a key piece of the puzzle as the field moves towards systems characterization of lipids at the molecular level.
Enantioselective Aminohydroxylation of Styrenyl Olefins Catalyzed by an Engineered Hemoprotein
Authors: Cho Inha , Prier Christopher K. , Jia Zhi‐Jun , Zhang Ruijie K. , Görbe Tamás , Arnold Frances H.
Published: January 2019

Chiral 1,2‐amino alcohols are widely represented in biologically active compounds from neurotransmitters to antivirals. While many synthetic methods have been developed for accessing amino alcohols, the direct aminohydroxylation of alkenes to unprotected, enantioenriched amino alcohols remains a challenge. Using directed evolution, we have engineered a hemoprotein biocatalyst based on a thermostable cytochrome c that directly transforms alkenes to amino alcohols with high enantioselectivity (up to 2500 TTN and 90 % ee) under anaerobic conditions with O‐pivaloylhydroxylamine as an aminating reagent. The reaction is proposed to proceed via a reactive iron‐nitrogen species generated in the enzyme active site, enabling tuning of the catalyst's activity and selectivity by protein engineering.
Optical Spectroscopy of the Au4+ Cluster: The Resolved Vibronic Structure Indicates an Unexpected Isomer
Authors: Förstel Marko , Schewe Wolfgang , Dopfer Otto
Published: January 2019

Knowledge of the geometric and electronic structure of gold clusters and nanoparticles is vital for understanding their catalytic and photochemical properties at the molecular level. In this study, we report the vibronic optical photodissociation spectrum of cold and mass‐selected Au4+ clusters measured at a resolution high enough to allow for comparison with Franck–Condon simulations of the excited state transitions based on time‐dependent density functional theory calculations. The three vibrational frequencies identified for the lowest‐lying optically accessible excited state at 2.17 eV stem from the Y‐shaped isomer (C2v) and not from the rhombic isomer (D2h) considered to be the ground state structure of Au4+. This study demonstrates that an analysis of low‐resolution electronic spectra by calculations of vertical transitions alone is not sufficient for a reliable isomer assignment of such metal clusters.
Palladium/Norbornene‐Catalyzed Indenone Synthesis from Simple Aryl Iodides: Concise Syntheses of Pauciflorol F and Acredinone A
Authors: Liu Feipeng , Dong Zhe , Wang Jianchun , Dong Guangbin
Published: January 2019

To show the synthetic utility of palladium/norbornene (Pd/NBE) cooperative catalysis, here we report concise syntheses of indenone‐based natural products, pauciflorol F and acredinone A, which are enabled by direct annulation between aryl iodides and unsaturated carboxylic acid anhydrides. Compared to the previous indenone‐preparation approaches, this method allows simple aryl iodides to be used as substrates with complete control of the regioselectivity. The total synthesis of acredinone A features two different Pd/NBE‐catalyzed ortho acylation reactions for constructing penta‐substituted arene cores, including the development of a new ortho acylation/ipso borylation.
Chemical and Topographical Single‐Cell Imaging by Near‐Field Desorption Mass Spectrometry
Authors: Yin Zhibin , Cheng Xiaoling , Liu Rong , Li Xiaoping , Hang Le , Hang Wei , Xu Jingyi , Yan Xiaomei , Li Jianfeng , Tian Zhongqun
Published: January 2019

Simultaneously acquiring chemical and topographical information within a single cell at nanoscale resolutions is vital to cellular biology, yet it remains a great challenge due to limited lateral resolutions and detection sensitivities. Herein, the development of near‐field desorption mass spectrometry for correlated chemical and topographical imaging is reported, thereby bridging the gap between laser‐based mass spectrometry (MS) methods and multimodal single‐cell imaging. Using this integrated platform, an imaging resolution of 250 nm and 3D topographically reconstructed chemical single‐cell imaging were achieved. This technique offers more in‐depth cellular information than micrometer‐range laser‐based MS imaging methods. Considering the simplicity and compact size of the near‐field device, this technique can be introduced to MALDI‐MS, expanding the multimodal abilities of MS at nanoscale resolutions.
Chemical Consequences of the Mechanical Bond: A Tandem Active Template‐Rearrangement Reaction
Authors: Modicom Florian , Jamieson Ellen M. G. , Rochette Elise , Goldup Stephen M.
Published: January 2019

We report the unexpected discovery of a tandem active template CuAAC‐rearrangement process, in which N2 is extruded on the way to the 1,2,3‐triazole product to give instead acrylamide rotaxanes. Mechanistic investigations suggest this process is dictated by the mechanical bond, which stabilizes the CuI‐triazolide intermediate of the CuAAC reaction and diverts it down the rearrangement pathway; when no mechanical bond is formed, the CuAAC product is isolated.
Terphen[n]arenes and Quaterphen[n]arenes (n=3–6): One‐Pot Synthesis, Self‐Assembly into Supramolecular Gels, and Iodine Capture
Authors: Li Bin , Wang Bin , Huang Xiayang , Dai Lu , Cui Lei , Li Jian , Jia Xueshun , Li Chunju
Published: January 2019

Herein, two new classes of macrocyclic compounds, terphen[n]arenes (TPns) (n=3–6) and quaterphen[n]arenes (QPns) (n=3–6), were designed and synthesized by a one‐step condensation reaction in relatively high yields. They comprise 2,2′′‐dimethoxy terphenyl and 2,2′′′‐dimethoxy quaterphenyl monomers, respectively, linked by methylene bridges. Given their long and rigid monomers, TPns and QPns have much larger cavities and better self‐assembly properties than classic macrocycles. More interestingly, the cyclic pentamers and hexamers TP5, TP6, QP5, and QP6 formed supramolecular organogels, which were composed of interwoven fibers, nanosheets, or entangled macropore networks formed by multiple face‐to‐face and edge‐to‐face π⋅⋅⋅π stacking interactions. The xerogel materials effectively captured volatile iodine, not only in aqueous media but also in the gaseous state, and could be recycled multiple times without obvious loss in performance.
C−F Bond Activation by a Saturated N‐Heterocyclic Carbene: Mesoionic Compound Formation and Adduct Formation with B(C6F5)3
Authors: Pait Moumita , Kundu Gargi , Tothadi Srinu , Karak Suvendu , Jain Shailja , Vanka Kumar , Sen Sakya S.
Published: January 2019

The reaction of SIPr, [1,3‐bis(2,6‐diisopropylphenyl)‐imidazolin‐2‐ylidene] (1), with C6F6 led to the formation of an unprecedented mesoionic compound (2). The formation of 2 is made accessible by deprotonation of the SIPr backbone with simultaneous elimination of HF. The C−F bond para to the imidazolium ring in 2 is only of 1.258(4) Å, which is the one of the shortest structurally authenticated C−F bonds known to date. The liberation of HF during the reaction is unequivocally proved by the addition of one more equivalent of SIPr, which leads to the imidazolium salt with the HF2− anion. To functionalize 2, the latter reacted with B(C6F5)3 to give an unusual donor–acceptor compound, where the fluoride atom from the C6F5 moiety coordinates to B(C6F5)3 and the carbanion moiety remains unaffected. Such coordination susceptibility of the fluoride atom of a nonmetallic system to a main‐group Lewis acid (Fnon‐metal→BR3) is quite unprecedented.
Sulfilimines as Versatile Nitrene Transfer Reagents: Facile Access to Diverse Aza‐Heterocycles
Authors: Tian Xianhai , Song Lina , Rudolph Matthias , Rominger Frank , Oeser Thomas , Hashmi A. Stephen K.
Published: January 2019

We herein report the unprecedented synthesis of diverse biologically important aza‐heterocycles by employing sulfilimines as nitrene transfer reagents. This class of sulfur‐based aza‐ylides had not been successfully used for gold nitrene transfer before. This work contains an efficient generation of α‐imino gold carbenes by N−S cleavage of sulfilimines. These gold carbenes undergo C−H insertion, cyclopropanation, and nucleophilic attack to form indoles (44 examples), 3‐azabicyclo[3.1.0]hexan‐2‐imines (24 examples), and imidazoles (3 examples). Our study represents a unique gold‐catalyzed reaction between alkynes and sulfur ylides, and also includes the first aza‐heterocycle synthesis that proceeds by intermolecular nitrene transfer followed by cyclopropanation of the α‐imino gold carbenes. Moreover, an unexpected synthesis of 4‐acylquinolines (3 examples) from 2‐acylphenyl sulfilimines and propargylic silyl ether derivatives by a 1,2‐hydride shift onto the α‐imino gold carbene and a subsequent Mukaiyama aldol cyclization was discovered.
Influence of Hydronium Ions in Zeolites on Sorption
Authors: Eckstein Sebastian , Hintermeier Peter H. , Zhao Ruixue , Baráth Eszter , Shi Hui , Liu Yue , Lercher Johannes A.
Published: January 2019

In the presence of sufficient concentrations of water, stable, hydrated hydronium ions are formed in the pores and at the surface of solid acids such as zeolites. For a medium‐pore zeolite, such as zeolite MFI, hydrated hydronium ions consist of eight water molecules and have an effective volume of 0.24 nm3. In their presence, larger organic molecules can only adsorb in the portions of the pore that are not occupied by hydronium ions. As a consequence, the available pore volume decreases proportionally to the concentration of the hydronium ions. The higher charge density (the increasing ionic strength) that accompanies an increasing concentration of hydronium ions leads to an increase in the activity coefficients of the adsorbed substrates, thus, weakening the interactions between the organic part of the molecules and the zeolite and favoring the interactions with polar groups. The quantitative understanding of these interactions makes it possible to link a collective property such as hydrophilicity and hydrophobicity of zeolites to specific interactions on molecular level.
Next‐Generation D2‐Symmetric Chiral Porphyrins for Cobalt(II)‐Based Metalloradical Catalysis: Catalyst Engineering by Distal Bridging
Authors: Hu Yang , Lang Kai , Tao Jingran , Marshall McKenzie K. , Cheng Qigan , Cui Xin , Wojtas Lukasz , Zhang X. Peter
Published: January 2019

Novel D2‐symmetric chiral amidoporphyrins with alkyl bridges across two chiral amide units on both sides of the porphyrin plane (designated “HuPhyrin”) have been effectively constructed in a modular fashion to permit variation of the bridge length. The CoII complexes of HuPhyrin, [Co(HuPhyrin)], represent new‐generation metalloradical catalysts where the metal‐centered d‐radical is situated inside a cavity‐like ligand with a more rigid chiral environment and enhanced hydrogen‐bonding capability. As demonstrated with cyclopropanation and aziridination as model reactions, the bridged [Co(HuPhyrin)] functions notably different from the open catalysts, exhibiting significant enhancement in both reactivity and stereoselectivity. Furthermore, the length of the distal alkyl bridge can have a remarkable influence on the catalytic properties.
Nanostars on Nanopipette Tips: A Raman Probe for Quantifying Oxygen Levels in Hypoxic Single Cells and Tumours
Authors: Nguyen Thanh Danh , Song Min Seok , Ly Nguyễn Hoàng , Lee So Yeong , Joo Sang‐Woo
Published: January 2019

Multiple sharp‐edged gold nanostars were efficiently assembled on nanopipette tips through electrostatic interactions for use as a potent intracellular hypoxia‐sensing Raman probe. Colloidal stability and surface immobilization were checked using scanning electron microscopy, light scattering, and zeta potential measurements. Site‐specific intracellular hypoxia levels can be estimated in vitro and in vivo using Raman lancets (RL). Distinct Raman spectral changes for the nitro‐(NO2) functional group of the redox marker 4‐nitrothiophenol (4NTP) can be quantified according to the intracellular oxygen (O2) content, ranging from 1 % to 10 %. Redox potential changes in mitochondrial respiration were also examined through serial injections of inhibitors. 3D‐cultured cells and in vivo tests were used to validate our method, and its application in the assessment of the aggressiveness of cancer cells by differentiating spectral changes between malignant and benign cells was demonstrated.
Direct Carbohydroxylation of Arylalkenes with Allylic Alcohols: Cooperative Catalysis of Copper, Silver, and a Brønsted Acid
Authors: Ahmed Waqar , Zhang Sheng , Yu Xiaoqiang , Feng Xiujuan , Yamamoto Yoshinori , Bao Ming
Published: January 2019

The cooperative catalysis of copper, silver, and Brønsted acid is presented as a new strategy for olefin functionalization. The catalytic direct carbohydroxylation of arylalkenes with allylic alcohols provided a straightforward and efficient approach for preparing 4,5‐unsaturated alcohols. Synthetically useful functional groups, such as Cl, Br, carbonyl, and chloromethyl, remained intact during the functionalization reaction.
Z‐Scheme 2D/2D Heterojunction of Black Phosphorus/Monolayer Bi2WO6 Nanosheets with Enhanced Photocatalytic Activities
Authors: Hu Jundie , Chen Dongyun , Mo Zhao , Li Najun , Xu Qingfeng , Li Hua , He Jinghui , Xu Hui , Lu Jianmei
Published: January 2019

Black phosphorus (BP), a star‐shaped two‐dimensional material, has attracted considerable attention owing to its unique chemical and physical properties. BP shows great potential in photocatalysis area because of its excellent optical properties; however, its applications in this field have been limited to date. Now, a Z‐scheme heterojunction of 2D/2D BP/monolayer Bi2WO6 (MBWO) is fabricated by a simple and effective method. The BP/MBWO heterojunction exhibits enhanced photocatalytic performance in photocatalytic water splitting to produce H2 and NO removal to purify air; the highest H2 evolution rate of BP/MBWO is 21042 μmol g−1, is 9.15 times that of pristine MBWO and the NO removal ratio was as high as 67 %. A Z‐scheme photocatalytic mechanism is proposed based on monitoring of .O2−, .OH, NO2, and NO3− species in the reaction. This work broadens applications of BP and highlights its promise in the treatment of environmental pollution and renewable energy issues.
Comparative Adsorption of Acetone on Water and Ice Surfaces
Authors: Cyran Jenée D. , Backus Ellen H. G. , van Zadel Marc‐Jan , Bonn Mischa
Published: January 2019

Small organic molecules on ice and water surfaces are ubiquitous in nature and play a crucial role in many environmentally relevant processes. Herein, we combine surface‐specific vibrational spectroscopy and a controllable flow cell apparatus to investigate the molecular adsorption of acetone onto the basal plane of single‐crystalline hexagonal ice with a large surface area. By comparing the adsorption of acetone on the ice/air and the water/air interface, we observed two different types of acetone adsorption, as apparent from the different responses of both the free O−H and the hydrogen‐bonded network vibrations for ice and liquid water. Adsorption on ice occurs preferentially through interactions with the free OH group, while the interaction of acetone with the surface of liquid water appears less specific.
Catalysis with Palladium Complexes Photoexcited by Visible Light
Authors: Chuentragool Padon , Kurandina Daria , Gevorgyan Vladimir
Published: January 2019

Palladium catalysis induced by visible light is an emerging field of catalysis. In contrast to classical reactions catalyzed by Pd complexes in the ground state, which mostly proceed through two‐electron redox processes, the mechanisms of these new methods based on photoexcited Pd complexes usually operate through transfer of a single electron. Such processes lead to putative hybrid Pd/radical species, which exhibit both radical and classical Pd‐type reactivity. This Minireview highlights the recent progress in this rapidly growing area.
An Enantioselective CpxRh(III)‐Catalyzed C−H Functionalization/Ring‐Opening Route to Chiral Cyclopentenylamines
Authors: Wang Shou‐Guo , Cramer Nicolai
Published: January 2019

A chiral CpxRhIII catalyst system in situ generated from a CpxRhI(cod) precatalyst and bis(o‐toluoyl) peroxide as activating oxidant was developed for a C−H activation/ring‐opening sequence between aryl ketoxime ethers and 2,3‐diazabicyclo[2.2.1]hept‐5‐enes. This transformation provides access to densely functionalized chiral cyclopentenylamines in excellent yields and enantioselectivities of up to 97:3 er. The reported method is also well suitable for asymmetric alkenyl C−H functionalizations of α,β‐unsaturated oxime ethers, furnishing skipped dienes with high levels of enantiocontrol.
Three‐in‐One Oxygen Vacancies: Whole Visible‐Spectrum Absorption, Efficient Charge Separation, and Surface Site Activation for Robust CO2 Photoreduction
Authors: Yu Hongjian , Li Jieyuan , Zhang Yihe , Yang Songqiu , Han Keli , Dong Fan , Ma Tianyi , Huang Hongwei
Published: January 2019

A facile and controllable in situ reduction strategy is used to create surface oxygen vacancies (OVs) on Aurivillius‐phase Sr2Bi2Nb2TiO12 nanosheets, which were prepared by a mineralizer‐assisted soft‐chemical method. Introduction of OVs on the surface of Sr2Bi2Nb2TiO12 extends photoresponse to cover the whole visible region and also tremendously promotes separation of photoinduced charge carriers. Adsorption and activation of CO2 molecules on the surface of the catalyst are greatly enhanced. In the gas‐solid reaction system without co‐catalysts or sacrificial agents, OVs‐abundant Sr2Bi2Nb2TiO12 nanosheets show outstanding CO2 photoreduction activity, producing CO with a rate of 17.11 μmol g−1 h−1, about 58 times higher than that of the bulk counterpart, surpassing most previously reported state‐of‐the‐art photocatalysts. Our study provides a three‐in‐one integrated solution to advance the performance of photocatalysts for solar‐energy conversion and generation of renewable energy.
Improved line weighting reduces seabird bycatch without affecting fish catch in the Brazilian pelagic longline fishery
Authors: Santos Rodrigo C. , Silva‐Costa Augusto , Sant'Ana Rodrigo , Gianuca Dimas , Yates Oliver , Marques Caio , Neves Tatiana
Published: January 2019

Increasing the sink rate of baited hooks by adding weights in close proximity to the hook is crucial to reduce seabird mortality in pelagic longline fisheries. However, weights placed next to the hook are a cause for concern for fishing crew because they can fly back in the event of a line break, injuring deck crew.

Lumo Leads, an alternative weight system designed to slide in the event of a line break, and therefore prevent accidents, were trialled in pelagic longline fisheries off southern Brazil. Four fishing trips were conducted and 26,377 hooks sampled to compare sink rates, seabird bycatch rates and catch rates of target species between three treatments: (1) 60 g Lumo Lead attached at 1.0 m from the hook; (2) 60 g Lumo Lead at 3.5 m; and (3) 60 g leaded swivels at 3.5 m from the hook.

A Lumo Lead placed at 1.0 m from the hook resulted in a faster sink rate and caught fewer seabirds (0.11 birds per unit of effort [BPUE]) when compared with a Lumo Lead (0.33 BPUE) or weighted swivel (0.85 BPUE) placed at 3.5 m. The bycatch with Lumo Lead placed at 1.0 m from the hook was 90% lower than the bycatch of Lumo Lead or weighted swivel placed at 3.5 m combined. There was no difference in the catch rates of target species between the three treatments.

These findings support a growing body of evidence that placing weights close to the hook reduces seabird bycatch without affecting the catchability of the target species. The high seabird bycatch rates recorded despite night setting and recommended line weighting regimes reinforces the need of simultaneous deployment of a toriline with these other two mitigation measures to reduce seabird bycatch to negligible levels in the south‐west Atlantic.
Efficient synthesis of meso‐substituted porphyrins and molecular docking as potential new antioxidant and cytotoxicity agents
Authors: Abu‐Melha Sraa
Published: January 2019

An improved methodology is reported for the synthesis of new series of mesotetrakis[aryl]‐21H,23H‐porphyrin derivatives 2a–h and was considered as a model to study their antioxidant and cytotoxic activities. The structures of the novel compounds were determined in 1H and 13C NMR, UV‐Vis, and elemental analyses. Among the derivatives, compounds 2c, 2d, and 2h showed strongest radical‐scavenging activity. Moreover, according to our results, compounds 2c, 2d, 2g, and 2h have very strong activity against the HepG2 hepatoma cell line, with IC50 values from 9 to 25 μg/mL. Molecular docking was performed to investigate the binding between the most active porphyrin derivatives 2c, 2d, 2g, 2h and the two molecular targets Bcl‐2 and caspase‐3. Compounds 2c and 2d seem to have better affinities to both proteins than 2g and 2h.
Aminopyrazole‐substituted metallophthalocyanines: Preparation, aggregation behavior, and investigation of metabolic enzymes inhibition properties
Authors: Güzel Emre , Koçyiğit Ümit M. , Arslan Barış S. , Ataş Mehmet , Taslimi Parham , Gökalp Faik , Nebioğlu Mehmet , Şişman İlkay , Gulçin İlhami
Published: January 2019

The synthesis, characterization, aggregation behavior, theoretical studies, and investigation of antimicrobial, antidiabetic, and anticholinergic properties of 4‐(2‐(5‐amino‐4‐(4‐bromophenyl)‐3‐methyl‐1H‐pyrazol‐1‐yl)ethoxy)phthalonitrile (2) and its soluble aminopyrazole‐substituted peripheral metallo (Mn, Co, and Ni)‐phthalocyanine complexes (3–5) are reported for the first time. The synthesized compounds and phthalocyanine complexes were characterized spectroscopically. The new phthalonitrile derivative (2) and its peripheral metallophthalocyanine complexes (3–5) were found to be effective inhibitors of α‐glycosidase, acetylcholinesterase (AChE), human carbonic anhydrase I and II isoforms (hCA I and II), and butyrylcholinesterase (BChE) with Ki values in the range of 1.55 ± 0.47 to 10.85 ± 3.43 nM for α‐glycosidase, 8.44 ± 0.32 to 21.31 ± 7.91 nM for hCA I, 11.73 ± 2.82 to 31.03 ± 4.81 nM for hCA II, 101.62 ± 26.58 to 326.54 ± 89.67 nM for AChE, and 68.68 ± 11.15 to 109.53 ± 19.55 nM for BChE. This is the first study of peripherally substituted phthalocyanines containing an aminopyrazole group as potential carbonic anhydrase enzyme inhibitor. Also, the antimicrobial activities of the synthesized compounds were evaluated against six microorganisms (four bacteria and two Candida species) using the broth microdilution method. The gram‐positive bacteria were detected to be more sensitive than gram‐negative bacteria and yeasts in the synthesized compounds.
Synthesis, crystal structure, and biological evaluation of optically active 2‐amino‐4‐aryl‐7,7‐dimethyl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐3‐carbonitriles: Antiepileptic, antidiabetic, and anticholinergics potentials
Authors: Maharramov Abel , Kaya Ruya , Taslimi Parham , Kurbanova Malahat , Sadigova Arzu , Farzaliyev Vagif , Sujayev Afsun , Gulçin İlhami
Published: January 2019

In the presence of chiral organic catalysts, the optically active 4H‐chromine was synthesized from the multicomponent condensation of 5,5‐dimethylcyclohexane‐1,3‐dione with malononitrile and methylene‐active compound, and the specific angle of rotation of the compounds was determined in the AUTOPOL‐III polarimeter and their structures were confirmed by the X‐ray spectroscopic analysis method. These optically active 2‐amino‐4‐aryl‐7,7‐dimethyl‐5‐oxo‐5,6,7,8‐tetrahydro‐4H‐chromen‐3‐carbonitriles were effective inhibitors of α‐glycosidase, the cytosolic carbonic anhydrase I and II isoforms (hCA I and II), and acetylcholinesterase (AChE) enzymes with Ki values in the range of 21.33 ± 1.11 to 40.24 ± 10.78 μM for hCA I, 28.91 ± 6.51 to 59.97 ± 15.62 μM for hCA II, 18.16 ± 3.18 to 66.57 ± 1.36 μM for α‐glycosidase, and 8.68 ± 0.93 to 102.61 ± 24.96 μM for AChE.
A Heterobimetallic AuIII‐PtII Photocatalyst for Water Reduction to Hydrogen
Authors: Su Yi‐Bing , Yuan Yong‐Jun , Liu Xiao‐Le , Chen Guang‐Hui , Chen Xin , Yu Zhen‐Tao , Zou Zhi‐Gang
Published: January 2019

A supramolecular complex, [Au(C^N^C)(C≡CC6H4C≡C)Pt(terpy)]+, has been synthesized as a photocatalyst for water reduction. This compound consists of a cyclometalated alkyne‐gold(III) photosensitizer and a platinum(II) terpyridine complex bridged through a central phenylethynyl group.