bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractAlthough 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

AbstractSince 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

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

AbstractDue 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.magnified image
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

AbstractThis 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

AbstractLi–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

AbstractWater 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.
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

AbstractA 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

AbstractA 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

AbstractCondensation 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

AbstractPeptide‐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

AbstractLignin 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

AbstractA 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

AbstractChemical 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

AbstractMolybdenum 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

AbstractLipidomics 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

AbstractChiral 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

AbstractKnowledge 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

AbstractTo 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

AbstractSimultaneously 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

AbstractWe 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.