bluuebunny/crossref_metadata_2025_split huggingface dataset:
Iodine‐Mediated sp3 C−H Amination Reactions Forming α‐Amino Ketones/Esters and Fused Imidazoles
Authors: Li Kailu , Li Qianmin , Shi Qinhao , He Yanmin , Yu Wenquan , Chang Junbiao 
Published: May 2022

AbstractAn iodine‐mediated direct sp3 C−H amination reaction has been established for the synthesis of nitrogen‐containing compounds from readily available substrates under transition‐metal‐free conditions. The I2‐promoted amination of ketones/esters with cyclic or acyclic secondary amines using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) as a base led to the formation of various α‐amino ketone or ester products including two medications, Amfepramone and Plavix. Sequential I2‐mediated sp3 C−H amination and condensation of ketones with 2‐aminopyridines in the presence of Na2CO3 produced a series of imidazo[1,2‐a]pyridines and related fused imidazoles in a one‐pot reaction. This synthetic method is operationally simple and can be conveniently conducted on a gram scale under mild reaction conditions.
Recent Developments in Quantum‐Circuit Refrigeration
Authors: Mörstedt Timm Fabian , Viitanen Arto , Vadimov Vasilii , Sevriuk Vasilii , Partanen Matti , Hyyppä Eric , Catelani Gianluigi , Silveri Matti , Tan Kuan Yen , Möttönen Mikko 
Published: May 2022

AbstractThe recent progress in direct active cooling of the quantum‐electric degrees of freedom in engineered circuits, or quantum‐circuit refrigeration is reviewed. In 2017, the discovery of a quantum‐circuit refrigerator (QCR) based on photon‐assisted tunneling of quasiparticles through normal‐metal–insulator–superconductor junctions inspired a series of experimental studies demonstrating the following main properties: i) the direct‐current (dc) bias voltage of the junction can change the QCR‐induced damping rate of a superconducting microwave resonator by orders of magnitude and give rise to nontrivial Lamb shifts, ii) the damping rate can be controlled in nanosecond time scales, and ii) the dc bias can be replaced by a microwave excitation, the amplitude of which controls the induced damping rate. Theoretically, it is predicted that state‐of‐the‐art superconducting resonators and qubits can be reset with an infidelity lower than 10−4 in tens of nanoseconds using experimentally feasible parameters. A QCR‐equipped resonator has also been demonstrated as an incoherent photon source with an output temperature above 1 K yet operating at millikelvin. This source has been used to calibrate cryogenic amplification chains. In the future, the QCR may be experimentally used to quickly reset superconducting qubits, and hence assist in the great challenge of building a practical quantum computer.
Solving Large‐Scale Linear Systems of Equations by a Quantum Hybrid Algorithm
Authors: Perelshtein M. R. , Pakhomchik A. I. , Melnikov A. A. , Novikov A. A. , Glatz A. , Paraoanu G. S. , Vinokur V. M. , Lesovik G. B. 
Published: May 2022

AbstractToday's intermediate‐scale quantum computers, although imperfect, already perform computational tasks that are manifestly beyond the capabilities of modern classical supercomputers. However, so far, quantum‐enabled large‐scale solutions have been realized only for limited set of problems. Here a hybrid algorithm based on phase estimation and classical optimization of the circuit width and depth is employed for solving a specific class of large linear systems of equations ubiquitous to many areas of science and engineering. A classification of linear systems based on the entanglement properties of the associated phase‐estimation unitary operation is introduced, enabling a highly efficient search for solutions that is facilitated by a straightforward matrix‐to‐circuit map. A 217‐dimensional problem is implemented on several IBM quantum computer superconducting quantum processors, a record‐breaking result for a linear system solved by a quantum computer. Demonstrated realisation sets a clear benchmark in the quest for the future quantum speedup in the linear systems of equations solution.
N‐Ligand‐Enabled Aromatic Nucleophilic Amination of 1,2‐Diaryl‐o‐Carboranes with (R2N)2Mg for Selective Synthesis of 4‐R2N‐o‐Carboranes and 2‐R2N‐m‐Carboranes
Authors: Zhang Jie , Xie Zuowei 
Published: May 2022

AbstractThe nucleophilic aromatic BH substitution reaction of carboranes is uncommon, compared to the electrophilic one. This work reported a pyridine‐enabled transition‐metal‐free regioselective nucleophilic aromatic cage B(4)‐H amination of 1,2‐diaryl‐o‐carboranes with magnesium bisamides, giving a series of B(4)‐aminated o‐carboranes. DFT calculations showcased a stepwise B−N formation/B−H cleavage process, in which Mg−H formation/cage closure is the rate‐determining step. Unprecedentedly, in the presence of 4,4′‐di‐tert‐butyl‐2,2′‐dipyridyl (dtbpy), a tandem B(4)‐amination/cage isomerization reaction of o‐carboranes was discovered for the facile preparation of B(2)‐aminated m‐carboranes. Control experiments indicated that magnesium complex, bidentate ligand (dtbpy) and reaction temperature were crucial in the cage isomerization process. This direct nucleophilic aromatic cage B−H amination reaction offers an alternative strategy for selective amination of o‐ and m‐carboranes.
Asymmetric Total Synthesis of Natural Lindenane Sesquiterpenoid Oligomers via a Triene as a Potential Biosynthetic Intermediate
Authors: Huang Zhengsong , Huang Ganxing , Wang Xiao , Qin Song , Fu Shaomin , Liu Bo 
Published: May 2022

AbstractA previously proposed triene of the lindenane skeleton was synthesized, characterized, and identified as the common intermediate for the non‐enzymatic synthesis of natural lindenane oligomers through linear, [4+2]‐type and [6+6]‐type homo‐ and hetero‐ dimerization under simulated physiological conditions. As a result, the following six natural products were successfully synthesized through thermalhead‐to‐head,head‐to‐tail, andhead‐to‐backbinding modes: shizukaols A and J, cycloshizukaol A, chlorahupetone F, chlotrichene B, and trishizukaol A.
Photouncaging of Carboxylic Acids from Cyanine Dyes with Near‐Infrared Light**
Authors: Janeková Hana , Russo Marina , Ziegler Urs , Štacko Peter 
Published: May 2022

AbstractNear‐infrared light (NIR; 650–900 nm) offers unparalleled advantages as a biocompatible stimulus. The development of photocages that operate in this region represents a fundamental challenge due to the low energy of the excitation light. Herein, we repurpose cyanine dyes into photocages that are available on a multigram scale in three steps and efficiently release carboxylic acids in aqueous media upon irradiation with NIR light up to 820 nm. The photouncaging process is examined using several techniques, providing evidence that it proceeds via photooxidative pathway. We demonstrate the practical utility in live HeLa cells by delivery and release of the carboxylic acid cargo, that was otherwise not uptaken by cells in its free form. In combination with modularity of the cyanine scaffold, the realization of these accessible photocages will fully unleash the potential of the emerging field of NIR‐photoactivation and facilitate its widespread adoption outside the photochemistry community.
Oxygen‐Tolerant Photoredox Catalysis Triggers Nitric Oxide Release for Antibacterial Applications
Authors: Chen Zhenhua , Zheng Shaoqiu , Shen Zhiqiang , Cheng Jian , Xiao Shiyan , Zhang Guoying , Liu Shiyong , Hu Jinming 
Published: May 2022

AbstractPhotoredox catalysis has emerged as a robust tool for chemical synthesis. However, it remains challenging to implement photoredox catalysis under physiological conditions due to the complex microenvironment and the quenching of photocatalyst by biologically relevant molecules such as oxygen. Here, we report that UV‐absorbingN,N′‐dinitroso‐1,4‐phenylenediamine derivatives can be selectively activated byfac‐Ir(ppy)3photocatalyst within micellar nanoparticles under visible light irradiation (e.g., 500 nm) through photoredox catalysis in aerated aqueous solutions to form quinonediimine (QDI) residues with concomitant release of NO. Notably, the formation of QDI derivatives can actively scavenge the reactive oxygen species generated byfac‐Ir(ppy)3, thus avoiding oxygen quenching of the photocatalyst. Further, we exemplify that the oxygen‐tolerant photoredox catalysis‐mediated NO release can not only kill planktonic bacteria in vitro but also efficiently treat MRSA infections in vivo.
Role of Nanoscale Roughness and Polarity in Odd–Even Effect of Self‐Assembled Monolayers
Authors: Du Chuanshen , Wang Zhengjia , Chen Jiahao , Martin Andrew , Raturi Dhruv , Thuo Martin 
Published: May 2022

AbstractThe dependency of substrate roughness on wetting properties of self‐assembled monolayers (SAMs) has been studied extensively, but most previous studies used limited selection of probing liquid and range of surface roughness. These studies disregarded the limit to observation of sub‐nanometer odd–even parity effect, hence are inconclusive. In this work we report the role of solvent polarity on the roughness‐dependency of wetting behavior of SAMs by studying static con‐tact angle of a variety of probing liquids, with different polarities, on SAMs formed on Ag‐based substrate with different surface morphology. By overlapping the roughness ranges with previous studies on Au, the limitation of surface roughness (RMS=1 nm) to observation of the odd–even effect using water as probing liquid was confirmed, but other probing liquid yielded different roughness‐dependent behaviors, with more polar solvent showing more roughness‐dependent behavior. Based on these observations, we concluded that there exists a phase‐transition like behavior in SAMs due to substrate roughness and molecule chain length, but whose determination is dependent on the probing liquid.
Enantioselective (8+3) Cycloadditions by Activation of Donor–Acceptor Cyclopropanes Employing Chiral Brønsted Base Catalysis
Authors: McLeod David A. , Thøgersen Mathias Kirk , Barløse Casper Larsen , Skipper Mette Louise , Obregón Erlaitz Basabe , Jørgensen Karl Anker 
Published: May 2022

AbstractA novel enantioselective (8+3) cycloaddition between donor–acceptor cyclopropanes and heptafulvenoids catalysed by a chiral bifunctional Brønsted base is described. Importantly, the reaction, which leverages an anionic activation strategy, is divergent from prototypical Lewis‐acid activation protocols. A series of cyclopropylketones react with tropones affording the desired (8+3) cycloadducts in high yield and enantiomeric excess. For barbiturate substituted heptafulvenes, the (8+3) cycloaddition with cyclopropylketones proceeds in good yield, excellent diastereoselectivity and high enantiomeric excess. The experimental work is supported by DFT calculations, which indicate that the bifunctional organocatalyst activates both the donor–acceptor cyclopropane and tropone; the reaction proceeds in a step‐wise manner with the ring‐closure being the stereodetermining step.
Selenylation Chemistry Suitable for On‐Plate Parallel and On‐DNA Library Synthesis Enabling High‐Throughput Medicinal Chemistry
Authors: Xu Hongtao , Wang Yan , Dong Hewei , Zhang Yiyuan , Gu Yuang , Zhang Shuning , Meng Yu , Li Jie , Shi Xiao Jie , Ji Qun , Liu Lili , Ma Peixiang , Ma Fei , Yang Guang , Hou Wei 
Published: May 2022

AbstractClick chemistry is a concept wherein modular synthesis is used for rapid functional discovery. To this end, continuous discovery of clickable chemical transformations is the pillar to support the development of this field. This report details the development of a clickable C3‐H selenylation of indole that is suitable for on‐plate parallel and DNA‐encoded library (SeDEL) synthesis via bioinspired LUMO activation strategy. This reaction is modular, robust and highly site‐selective, and it features a simple and mild reaction system (catalyzed by nonmetallic B(C6F5)3at room temperature), high yields and excellent functional group compatibility. Using this method, a library of 1350 indole‐selenides was parallel synthesized in an efficient and practical manner, enabling the rapid identification of3 aias a promising compound with nanomolar antiproliferative activity in cancer cells via in situ phenotypic screening. These results indicate the great potential of this new clickable selenylation reaction in high‐throughput medicinal chemistry and chemical biology.
Spatiotemporal Mapping of Efficient Chiral Induction by Helicene‐Type Additives in Copolymer Thin Films
Authors: Morgenroth Marius , Scholz Mirko , Guy Laure , Oum Kawon , Lenzer Thomas 
Published: May 2022

AbstractWe observed efficient induction of chirality in polyfluorene copolymer thin films by mixing with helicene‐type chiral additives based on the dibenzo[c,h]acridine motif. Images obtained from circular dichroism (CD) and circularly polarized luminescence (CPL) microscopy provide information about the chiral arrangements in the thin films with diffraction‐limited resolution. The CD signal shows a characteristic dependence on the film thickness, which supports a supramolecular origin of the strong chiral response of the copolymer. In particular, we demonstrate the discrimination between films of opposite chirality based on their ultrafast transient chiral response through the use of femtosecond broadband CD spectroscopy and a newly developed setup for transient CPL spectroscopy with 28 ps time resolution. A systematic variation of the enantiomeric excess of the chiral additive shows that the “Sergeants and Soldiers” concept and “Majority Rules” are not obeyed.
Carbon Dioxide Capture at Nucleophilic Hydroxide Sites in Oxidation‐Resistant Cyclodextrin‐Based Metal–Organic Frameworks**
Authors: Zick Mary E. , Pugh Suzi M. , Lee Jung‐Hoon , Forse Alexander C. , Milner Phillip J. 
Published: May 2022

AbstractCarbon capture and sequestration (CCS) from industrial point sources and direct air capture are necessary to combat global climate change. A particular challenge faced by amine‐based sorbents—the current leading technology—is poor stability towards O2. Here, we demonstrate that CO2 chemisorption in γ‐cylodextrin‐based metal–organic frameworks (CD‐MOFs) occurs via HCO3− formation at nucleophilic OH− sites within the framework pores, rather than via previously proposed pathways. The new framework KHCO3 CD‐MOF possesses rapid and high‐capacity CO2 uptake, good thermal, oxidative, and cycling stabilities, and selective CO2 capture under mixed gas conditions. Because of its low cost and performance under realistic conditions, KHCO3 CD‐MOF is a promising new platform for CCS. More broadly, our work demonstrates that the encapsulation of reactive OH− sites within a porous framework represents a potentially general strategy for the design of oxidation‐resistant adsorbents for CO2 capture.
Local divergence and obstacles to spur inclusive coastal development in Iloilo Province, the Philippines
Authors: Andriesse Edo 
Published: May 2022

AbstractThis purpose of this article is to demonstrate (1) how growing seaweed in the central Philippines is affected by multifaceted local dynamics and (2) how it is also dependent on the complementary livelihood strategies of in situ and ex situ diversification. This article explores the livelihood trajectories of 45 households that were all engaged in growing seaweed in 2015. Surveys and semi‐structured interviews were conducted with households and key informants in two municipalities. Results reveal a process of livelihood divergence. While in one municipality growing seaweed has become a relative success, virtually all households in the other municipality have had to stop growing seaweed, returned to fishing, and remained poor. The reasons for this divergence can be found in the spheres of environmental challenges, value chain governance dynamics, and local coastal governance. Three implications are put forward that could improve the inclusiveness of coastal development in the Philippines and beyond.
Purification and characterization of a chitinase from Aeromonas media CZW001 as a biocatalyst for producing chitinpentaose and chitinhexaose
Authors: Ding Zhiwen , Li Tian , Chen Meng , Fang Yaowei , Hou Xiaoyue , Yang Gaung , Lu Jing , Ye Qinwen , Zhu Rongjun , He Fuxiang , Xia Mengjie , Liu Shu 
Published: May 2022

AbstractDeveloping chitinase suitable for the bioconversion of chitin to chitin oligosaccharides has attracted significant attention due to its benefits in environmental protection. In this study, chitinase from Aeromonas media CZW001 (AmChi) was purified and characterized. The molecular weight of AmChi was approximately 40 kDa. AmChi exhibited maximum catalytic activity at pH 8.0 with an optimum temperature of 55°C and showed broad stability between 15 and 65°C and between pH 5.0 and 9.0. AmChi was activated by Mg2+, Na+, and K+ and inhibited by Hg+, Co2+, Fe2+, Ca2+, Ag+, Zn2+, and EDTA. The main products of AmChi on colloidal chitin were chitinhexaose and chitinpentaose. AmChi had better substrate specificity for powdered chitin than colloidal chitin and had a higher catalytic efficiency toward (GlcNAc)5 than colloidal chitin. AmChi inhibited fungal growth in a dose‐dependent manner. These results suggest that AmChi could be used for the enzymatic degradation of chitin to produce chitinhexaose and chitinpentaose, which have several industrial applications.
The financial and green effects of cultural values on mission drifts in European social enterprises
Authors: Esposito Paolo , Doronzo Emanuele , Dicorato Spiridione Lucio 
Published: May 2022

AbstractThe sustainable social enterprises (SEs) literature shows that SEs have to simultaneously pursue economic, social, and environmental aims. However, tensions between these objectives can make this a challenging task and lead towards mission drift. This work investigates if the cultural dimension can forecast the mission drift. We empirically analyze this relationship in three stages. In the first stage, we identify a homogeneous dataset of 287 sustainable SEs from seven EU countries from 2011 to 2020. Then, in the second stage, we apply the data envelopment analysis (DEA) methodology to calculate the efficiency of the SEs. An efficient SE has to simultaneously achieve social, environmental, and economic aims. We calculate a proxy of the mission drift and generate a dichotomous category variable that assigns value 1 to the SE not affected by mission drift, 0 otherwise. In the last stage, we implement the 2SLS logistic regression between the variable that identifies the SEs affected by mission drift and three cultural dimensions: avoidance of uncertainty, masculinity, and short‐term orientation.
Percutaneous approach to left ventricular assist device decommissioning
Authors: Moroni Francesco , Shah Keyur B. , Quader Mohammed A. , Klein Katherine , Smallfield Melissa C. , Parris Kendall E. , Gertz Zachary M. 
Published: May 2022

AbstractObjectiveTo assess the outcomes of a single‐center experience with percutaneous left ventricular assist device (LVAD) decommissioning.BackgroundPatients with LVADs may eventually require their removal, either due to recovery of left ventricular function or recurrent complications. Traditionally, withdrawal of LVAD support has been managed with surgical device explantation, which carries significant procedural risks. Transcatheter LVAD decommissioning, with outflow graft occlusion and driveline transection, has recently been described as an alternative to surgical removal.MethodsHere, we report on a retrospective cohort of five consecutive cases treated with transcatheter LVAD decommissioning.ResultsThe procedure was effective in all cases, and no patient experienced procedure‐related complications. At midterm follow‐up, the three patients who had myocardial function recovery were alive and had not experienced heart failure‐related symptoms or complications.ConclusionPercutaneous LVAD decommissioning appears to be a safe and effective approach to LVAD treatment discontinuation.
Dynamics of Reaction‐Induced Changes of Model‐Type Iron Oxide Phases in the CO2‐Fischer‐Tropsch‐Synthesis
Authors: Arinchtein Aleks , Ye Meng‐Yang , Yang Qingxin , Kreyenschulte Carsten , Wagner Andreas , Frisch Marvin , Brückner Angelika , Kondratenko Evgenii , Kraehnert Ralph 
Published: May 2022

AbstractIron‐based catalysts are employed in CO2‐FTS due to their ability to convert CO2 into CO in a first step and their selectivity towards higher hydrocarbons in a second CO hydrogenation step. According to the literature, iron carbides represent the active phase for hydrocarbon formation and are claimed to emerge in the presence of CO. We propose nanostructured FeOx films as model systems to assess information about the complex phase transformations during CO2‐FTS. Mesoporous hematite, ferrihydrite, maghemite, maghemite/magnetite films were exposed to CO2‐FTS atmospheres at 20 bar and 300 °C. Up to three distinct phases were observed depending on the time‐on‐stream (TOS): a sintered maghemite/magnetite phase, a carbidic core‐shell structure, and a low‐crystalline, needle‐type oxide phase. Our findings indicate that the formation of an intermediary maghemite/magnetite phase, predominant after short TOS (30 h), precedes the evolution of the carbide phase. Yet, even after prolonged TOS (185 h), no full conversion into a bulk carbide is observed.
Dibenzophenazine‐Based TADF Emitters as Dual Electrochromic and Electroluminescence Materials
Authors: Zimmermann Crocomo Paola , Okazaki Masato , Hosono Takumi , Minakata Satoshi , Takeda Youhei , Data Przemyslaw 
Published: May 2022

AbstractPrevious work has reported the synthesis of donor–acceptor–donor molecules based on dibenzophenazine acceptor group, presenting thermally activated delayed fluorescent (TADF) properties and their application in the assembly of highly efficient electroluminescent devices. Herein, we focus on the characterisation of charge carrier species through UV‐Vis‐NIR spectroelectrochemical and potentiostatic EPR techniques, in addition to the investigation of electropolymerisation properties of some compounds depicted in this study. The promising electrochromic features of both small molecules and conjugated polymers led to the assembly and investigation of electrochromic devices, evidencing the materials’ versatility, applied in such different approaches as electrochromic windows and electroluminescent devices. Furthermore, the assembled OLEDs provided high efficiencies, with small roll‐off, EQEs up to 20.5 % and luminance values up to 85 000 cd/m2.
Flow Synthesis of Single and Mixed Metal Oxides
Authors: Campbell Zachary S. , Baro Steven , Gao Yunfei , Li Fanxing , Abolhasani Milad 
Published: May 2022

AbstractA generalizable and versatile microfluidic approach for facile synthesis of a wide range of metal oxide microparticles using atypical metal‐organic precursors is reported. Microparticles of three single oxide materials, zinc(II) oxide, tin(IV) oxide, and cerium(IV) oxide, as well as a binary rare earth mixed oxide, lanthanum(III) praseodymium(III) oxide, are synthesized in flow. The tin(IV) oxide is shown to vary in composition from 14.2 % to 0 % orthorhombic phase at annealing temperatures ranging from 500 °C to 900 °C, while the lanthanum(III) praseodymium(III) oxide forms at a relatively low temperature of ∼700 °C.