bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two‐Dimensional Metal‐Organic Framework Nanosheet Supported Noble Metal Nanocrystals for High‐Efficiency Water Oxidation
Authors: Jiang Qinyuan , Xu Jie , Li Ziqi , Zhou Chenhui , Chen Xiao , Meng Haibing , Han Ying , Shi Xiaofei , Zhan Chenhao , Zhang Yaqi , Zhang Qianfan , Jia Xilai , Zhang Rufan 
Published: January 2021

AbstractIt still remains a challenge to simultaneously optimize the nanostructure and electronic structure of electrocatalysts of noble‐metal‐based electrocatalysts to improve their performance and reduce their noble metal loadings, in which the dispersion and activity of the noble metal components play an important role. A series of hybrids of noble metal nanocrystals (NMNCs) and two‐dimensional metal‐organic framework (2D MOF) nanosheets are designed and synthesized by a facile, fast, and general approach, in which NMNC dispersion is quickly mixed with MOF precursors at room temperature. The NMNCs/2D MOF hybrids, denoted as M‐Ni‐NS (M = Ir, Ru or Pt, etc.), are assembled by taking advantage of abundant O‐atom arrays on the surface the of 2D MOF nanosheets and they enable excellent dispersity and stability. Experimental and computational results show that the M‐O‐Ni bridging bonds realize successful tuning of the electronic structure of active sites and modify their activity. Taken together with the merits of the nanostructure of the 2D MOF support, this multiscale optimization strategy produces Ir‐Ni‐NS electrocatalysts with excellent performance for the oxygen evolution reaction, achieving a low overpotential of 270 mV at 10 mA cm−2 in alkaline media and long time stability.
Graphene‐Integrated Reconfigurable Metasurface for Independent Manipulation of Reflection Magnitude and Phase
Authors: Huang Cheng , Liao Jianming , Ji Chen , Peng Jinqiang , Yuan Liming , Luo Xiangang 
Published: January 2021

AbstractReconfigurable metasurfaces are highly desirable for applications including dynamical camouflaging, intelligent electromagnetic (EM) skin and systems due to their tunable EM features or functions. So far most of the existing reconfigurable metasurfaces are developed by modulating their amplitude or phase. It is still very challenging to simultaneously achieve dynamical control of amplitude and phase in one design. This study reports a reconfigurable metasurface that can realize independent control of reflection magnitude and phase with the external bias voltages. In this metasurface, the graphene capacitor structure is used as an amplitude‐tuning layer for controlling the reflection magnitude by changing the effective sheet resistance of graphene, while the reflection phase is tuned by switching PIN diodes loaded in a periodic metallic structure. Such metasurface can control the scattering wave directions through phase coding, and the variation of graphene resistance can further modulate the intensity of the scattering beams. In addition, the metasurface can also function as a radar absorber where the absorbing magnitude and frequency can be dynamically tuned. Good agreements between simulations and experiments demonstrate its powerful ability to manipulate the EM waves by simultaneously tuning the reflection magnitude and phase, indicating a wide range of potential applications in EM fields.
Cross‐Coupling Reactions of Aryl Halides with Primary and Secondary Aliphatic Alcohols Catalyzed by an O,N,N‐Coordinated Nickel Complex
Authors: Hashimoto Toru , Shiota Keisuke , Funatsu Kei , Yamaguchi Yoshitaka 
Published: January 2021

AbstractA synthesis of alkyl aryl ethers was achieved via the cross‐coupling of aryl halides with primary and secondary aliphatic alcohols catalyzed by a bench‐stable nickel complex supported by a monoanionic O,N,N‐tridentate ligand. This nickel‐catalyzed reaction proceeds smoothly in the absence of a phosphine ligand, affording alkyl aryl ethers in moderate to good yields.magnified image
A Cascade Rh(III)‐catalyzed C−H Activation/Chemodivergent Annulation of N‐carbamoylindoles with Sulfoxonium Ylides for the Synthesis of Dihydropyrimidoindolone and Tricyclic [1,3]Oxazino[3,4‐a]indol‐1‐ones Derivatives
Authors: Xie Hui , Zhong Mei , Kang Hua‐Jie , Shu Bing , Zhang Shang‐Shi 
Published: January 2021

AbstractA highly efficient cascade Rh(III)‐catalyzed C−H activation/intramolecular chemodivergent cyclization reaction of N‐carbamoylindoles and sulfoxonium ylides has been successfully achieved for the first time. This synergistic process provides rapid access to functionalized dihydropyrimidoindolone and tricyclic [1,3]oxazino[3,4‐a]indol‐1‐ones skeletons under redox neutral conditions with broad substrate scope and remarkable functional‐group compatibility. Further late‐stage modification of structurally complex drug molecules and mechanistic studies were also accomplished.magnified image
Intermediate‐dose anticoagulation, aspirin, and in‐hospital mortality in COVID‐19: A propensity score‐matched analysis
Authors: Meizlish Matthew L. , Goshua George , Liu Yiwen , Fine Rebecca , Amin Kejal , Chang Eric , DeFilippo Nicholas , Keating Craig , Liu Yuxin , Mankbadi Michael , McManus Dayna , Wang Stephen Y. , Price Christina , Bona Robert D. , Ochoa Chaar Cassius Iyad , Chun Hyung J. , Pine Alexander B. , Rinder Henry M. , Siner Jonathan M. , Neuberg Donna S. , Owusu Kent A. , Lee Alfred Ian 
Published: January 2021

AbstractThrombotic complications occur at high rates in hospitalized patients with COVID‐19, yet the impact of intensive antithrombotic therapy on mortality is uncertain. We examined in‐hospital mortality with intermediate‐ compared to prophylactic‐dose anticoagulation, and separately with in‐hospital aspirin compared to no antiplatelet therapy, in a large, retrospective study of 2785 hospitalized adult COVID‐19 patients. In this analysis, we established two separate, nested cohorts of patients (a) who received intermediate‐ or prophylactic‐dose anticoagulation (“anticoagulation cohort”, N = 1624), or (b) who were not on home antiplatelet therapy and received either in‐hospital aspirin or no antiplatelet therapy (“aspirin cohort”, N = 1956). To minimize bias and adjust for confounding factors, we incorporated propensity score matching and multivariable regression utilizing various markers of illness severity and other patient‐specific covariates, yielding treatment groups with well‐balanced covariates in each cohort. The primary outcome was cumulative incidence of in‐hospital death. Among propensity score‐matched patients in the anticoagulation cohort (N = 382), in a multivariable regression model, intermediate‐ compared to prophylactic‐dose anticoagulation was associated with a significantly lower cumulative incidence of in‐hospital death (hazard ratio 0.518 [0.308–0.872]). Among propensity‐score matched patients in the aspirin cohort (N = 638), in a multivariable regression model, in‐hospital aspirin compared to no antiplatelet therapy was associated with a significantly lower cumulative incidence of in‐hospital death (hazard ratio 0.522 [0.336–0.812]). In this propensity score‐matched, observational study of COVID‐19, intermediate‐dose anticoagulation and aspirin were each associated with a lower cumulative incidence of in‐hospital death.
Sleep phenotype of individuals with autism spectrum disorder bearing mutations in the PER2 circadian rhythm gene
Authors: Hoang Ny , Yuen Ryan K.C. , Howe Jennifer , Drmic Irene , Ambrozewicz Patricia , Russell Carolyn , Vorstman Jacob , Weiss Shelly K. , Anagnostou Evdokia , Malow Beth A. , Scherer Stephen W. 
Published: January 2021

AbstractThe Per family of genes functions as a primary circadian rhythm maintenance in the brain. Mutations in PER2 are associated with familial advanced sleep‐phase syndrome 1 (FASPS1), and recently suggested in delayed sleep phase syndrome and idiopathic hypersomnia. The detection of PER2 variants in individuals with autism spectrum disorder (ASD) and without reported sleep disorders, has suggested a role of circadian‐relevant genes in the pathophysiology of ASD. It remains unclear whether these individuals may have, in addition to ASD, an undiagnosed circadian rhythm sleep disorder. The MSSNG database was used to screen whole genome sequencing data of 5,102 individuals with ASD for putative mutations in PER2. Families identified were invited to complete sleep phenotyping consisting of a structured interview and two standardized sleep questionnaires: the Pittsburgh Sleep Quality Index and the Morningness‐Eveningness Questionnaire. From 5,102 individuals with ASD, two nonsense, one frameshift, and one de novo missense PER2 variants were identified (0.08%). Of these four, none had a diagnosed sleep disorder. Three reported either a history of, or ongoing sleep disturbances, and one had symptoms highly suggestive of FASPS1 (as did a mutation carrier father without ASD). The individual with the missense variant did not report sleep concerns. The ASD and cognitive profiles of these individuals varied in severity and symptoms. The results support a possible role of PER2‐related circadian rhythm disturbances in the dysregulation of sleep overall and sometimes FASPS1. The relationship between dysregulated sleep and the pathophysiology of ASD require further exploration.
Regiodivergent Synthesis of Spirocyclic Compounds through Pd‐Catalyzed Regio‐ and Enantioselective [3+2] Spiroannulation
Authors: Trost Barry M. , Zuo Zhijun 
Published: January 2021

AbstractA novel Pd0‐catalyzed highly regio‐ and enantioselective [3+2] spiroannulation reaction has been developed for rapid assembly of a new class of [5,5] spirocyclic carbo‐ and heterocycles. Notably, the regioselectivity could be dominated by fine‐tuning of the Pd‐π‐allyl intermediate. An array of coupling partners could be well‐tolerated with excellent regio‐, and enantioselectivities. Moreover, the potential application of this reaction was exemplified by several further transformations.
Chiral Self‐sorting of Giant Cubic [8+12] Salicylimine Cage Compounds
Authors: Wagner Philippe , Rominger Frank , Zhang Wen‐Shan , Gross Jürgen H. , Elbert Sven M. , Schröder Rasmus R. , Mastalerz Michael 
Published: January 2021

AbstractChiral self‐sorting is intricately connected to the complicated chiral processes observed in nature and no artificial systems of comparably complexity have been generated by chemists. However, only a few examples of purely organic molecules have been reported so far, where the self‐sorting process could be controlled. Herein, we describe the chiral self‐sorting of large cubic [8+12] salicylimine cage compounds based on a chiral TBTQ precursor. Out of 23 possible cage isomers only the enantiopure and amesocage were observed to be formed, which have been unambiguously characterized by single crystal X‐ray diffraction. Furthermore, by careful choice of solvent the formation ofmesocage could be controlled. With internal diameters ofdin=3.3–3.5 nm these cages are among the largest organic cage compounds characterized and show very high specific surface areas up to approx. 1500 m2 g−1after desolvation.
Colloidal Metal Nanocrystals with Metastable Crystal Structures
Authors: Janssen Annemieke , Nguyen Quynh N. , Xia Younan 
Published: January 2021

AbstractIn addition to the conventional knobs such as composition, size, shape, and defect structure, the crystal structure (or phase) of metal nanocrystals offers a new avenue for engineering their properties. Various strategies have recently been developed for the fabrication of colloidal metal nanocrystals in metastable phases different from their bulk counterparts. With a focus on noble metals, we begin with a brief introduction to their atomic packing, followed by a discussion about five major synthetic approaches to their colloidal nanocrystals in unconventional phases. We then highlight the success of synthesis in terms of mechanistic insights and experimental controls, as well as the enhanced catalytic properties. We end this Minireview with perspectives on the remaining issues and future opportunities.
Photochemically Activated Dimagnesium(I) Compounds: Reagents for the Reduction and Selective C−H Bond Activation of Inert Arenes
Authors: Jones Dafydd D. L. , Douair Iskander , Maron Laurent , Jones Cameron 
Published: January 2021

AbstractThe photochemical activation of dimagnesium(I) compounds, and subsequent high yielding, regioselective reactions with inert arenes are reported. Irradiating benzene solutions of [{(ArNacnac)Mg}2] (ArNacnac=[HC(MeCNAr)2]−; Ar=2,6‐diisopropylphenyl (Dip) or 2,4,6‐tricyclohexylphenyl (TCHP)) with blue or UV light, leads to double reduction of benzene and formation of the “Birch‐like” cyclohexadienediyl bridged compounds, [{(ArNacnac)Mg}2(μ‐C6H6)]. Irradiation of [{(DipNacnac)Mg}2] in toluene, and each of the three isomers of xylene, promoted completely regio‐ and chemo‐selective C−H bond activations, and formation of [(DipNacnac)Mg(Ar′)] (Ar′=meta‐tolyl; 2,3‐, 3,5‐ or 2,5‐dimethylphenyl), and [{(DipNacnac)Mg(μ‐H)}2]. Fluorobenzene was cleanly defluorinated by photoactivated [{(DipNacnac)Mg}2], leading to biphenyl and [{(DipNacnac)Mg(μ‐F)}2]. Computational studies suggest all reactions proceed via photochemically generated magnesium(I) radicals, which reduce the arene substrate, before C−H or C−F bond activation processes occur.
Frequency‐Upconverted Stimulated Emission by Up to Six‐Photon Excitation from Highly Extended Spiro‐Fused Ladder‐Type Oligo(p‐phenylene)s
Authors: Jiang Yi , Li King Fai , Gao Kun , Lin He , Tam Hoi Lam , Liu Yuan‐Yuan , Shu Yu , Wong Ka‐Leung , Lai Wen‐Yong , Cheah Kok Wai , Huang Wei 
Published: January 2021

AbstractFrequency‐upconverted fluorescence and stimulated emission induced by multiphoton absorption (MPA) have attracted much interest. As compared with low‐order MPA processes, the construction of high‐order MPA processes is highly desirable and rather attractive, yet remains a formidable challenge due to its inherent low transition probability. We report the observation of the first experimental frequency‐upconverted fluorescence and stimulated emission by simultaneous six‐photon excitation in an organic molecular system. The well‐designed organic conjugated system based on cross‐shaped spiro‐fused ladder‐type oligo(p‐phenylene)s (SpL−z, z=1–3) manifests reasonably high MPA cross‐sections and brilliant luminescence emission simultaneously. The six‐photon absorption cross‐section of SpL‐3 with an extended π‐conjugation was evaluated as 8.67×10−169 cm12 s5 photon−5. Exceptionally efficient 2‐ to 6‐photon excited stimulated emission was achieved under near‐infrared laser excitation.
An Organic–Inorganic Hybrid Electrolyte as a Cathode Interlayer for Efficient Organic Solar Cells
Authors: Zhao Chaowei , Zhang Zhou , Han Faming , Xia Dongdong , Xiao Chengyi , Fang Jie , Zhang Yuefeng , Wu Binghui , You Shengyong , Wu Yonggang , Li Weiwei 
Published: January 2021

AbstractAn organic–inorganic hybrid electrolyte based on a cyclic Ti‐oxo cluster as the inorganic core and naphthalene‐based organic ammonium bromide salts as the electrolyte was developed with easy synthesis and low cost. The new hybrid electrolyte exhibits excellent solubility in methanol, aligned work function, good conductivity, and amorphous state in thin film, enabling its successful application as a cathode interlayer in organic solar cells with a high power conversion efficiency of 17.19 %. This work demonstrates that the hybrid electrolytes are a new kind of semiconductor, exhibiting promising applications in organic electronics.
Development of High‐Performance Pyrimidine Nucleoside and Oligonucleotide Diarylethene Photoswitches
Authors: Kolmar Theresa , Büllmann Simon M. , Sarter Christopher , Höfer Katharina , Jäschke Andres 
Published: January 2021

AbstractNucleosidic and oligonucleotidic diarylethenes (DAEs) are an emerging class of photochromes with high application potential. However, their further development is hampered by the poor understanding of how the chemical structure modulates the photochromic properties. Here we synthesized 26 systematically varied deoxyuridine‐ and deoxycytidine‐derived DAEs and analyzed reaction quantum yields, composition of the photostationary states, thermal and photochemical stability, and reversibility. This analysis identified two high‐performance photoswitches with near‐quantitative, fully reversible back‐and‐forth switching and no detectable thermal or photochemical deterioration. When incorporated into an oligonucleotide with the sequence of a promotor, the nucleotides maintained their photochromism and allowed the modulation of the transcription activity of T7 RNA polymerase with an up to 2.4‐fold turn‐off factor, demonstrating the potential for optochemical control of biological processes.
Fe‐Catalyzed Anaerobic Mukaiyama‐Type Hydration of Alkenes using Nitroarenes
Authors: Bhunia Anup , Bergander Klaus , Daniliuc Constantin Gabriel , Studer Armido 
Published: January 2021

AbstractHydration of alkenes using first row transition metals (Fe, Co, Mn) under oxygen atmosphere (Mukaiyama‐type hydration) is highly practical for alkene functionalization in complex synthesis. Different hydration protocols have been developed, however, control of the stereoselectivity remains a challenge. Herein, highly diastereoselective Fe‐catalyzed anaerobic Markovnikov‐selective hydration of alkenes using nitroarenes as oxygenation reagents is reported. The nitro moiety is not well explored in radical chemistry and nitroarenes are known to suppress free radical processes. Our findings show the potential of cheap nitroarenes as oxygen donors in radical transformations. Secondary and tertiary alcohols were prepared with excellent Markovnikov‐selectivity. The method features large functional group tolerance and is also applicable for late‐stage chemical functionalization. The anaerobic protocol outperforms existing hydration methodology in terms of reaction efficiency and selectivity.
Strain‐Modulated Reactivity: An Acidic Silane
Authors: Tretiakov Serhii , Witteman Léon , Lutz Martin , Moret Marc‐Etienne 
Published: January 2021

AbstractCompounds of main‐group elements such as silicon are attractive candidates for green and inexpensive catalysts. For them to compete with state‐of‐the‐art transition‐metal complexes, new reactivity modes must be unlocked and controlled, which can be achieved through strain. Using a tris(2‐skatyl)methylphosphonium ([TSMPH3]+) scaffold, we prepared the strained cationic silane [TSMPSiH]+. In stark contrast with the generally hydridic Si−H bond character, it is acidic with an experimental pKaDMSO within 4.7–8.1, lower than in phenol, benzoic acid, and the few hydrosilanes with reported pKa values. We show that ring strain significantly contributes to this unusual acidity along with inductive and electrostatic effects. The conjugate base, TSMPSi, activates a THF molecule in the presence of CH‐acids to generate a highly fluxional alkoxysilane via trace amounts of [TSMPSiH]+ functioning as a strain‐release Lewis acid. This reaction involves a formal oxidation‐state change from SiII to SiIV, presenting intriguing similarities with transition‐metal‐mediated processes.
Efficient and Selective Interplay Revealed: CO2 Reduction to CO over ZrO2 by Light with Further Reduction to Methane over Ni0 by Heat Converted from Light
Authors: Zhang Hongwei , Itoi Takaomi , Konishi Takehisa , Izumi Yasuo 
Published: January 2021

AbstractThe reaction mechanism of CO2 photoreduction into methane was elucidated by time‐course monitoring of the mass chromatogram, in situ FTIR spectroscopy, and in situ extended X‐ray absorption fine structure (EXAFS). Under 13CO2, H2, and UV/Vis light, 13CH4 was formed at a rate of 0.98 mmol h−1 gcat−1 using Ni (10 wt %)‐ZrO2 that was effective at 96 kPa. Under UV/Vis light irradiation, the 13CO2 exchange reaction and FTIR identified physisorbed/chemisorbed bicarbonate and the reduction because of charge separation in/on ZrO2, followed by the transfer of formate and CO onto the Ni surface. EXAFS confirmed exclusive presence of Ni0 sites. Then, FTIR spectroscopy detected methyl species on Ni0, which was reversibly heated to 394 K owing to the heat converted from light. With D2O and H2, the H/D ratio in the formed methane agreed with reactant H/D ratio. This study paves the way for using first row transition metals for solar fuel generation using only UV/Vis light.
Interplay between a Foldamer Helix and a Macrocycle in a Foldarotaxane Architecture
Authors: Gauthier Maxime , Koehler Victor , Clavel Caroline , Kauffmann Brice , Huc Ivan , Ferrand Yann , Coutrot Frédéric 
Published: January 2021

AbstractThe design and synthesis of a novel rotaxane/foldaxane hybrid architecture is reported. The winding of an aromatic oligoamide helix host around a dumbbell‐shaped thread‐like guest, or axle, already surrounded by a macrocycle was evidenced by NMR spectroscopy and X‐ray crystallography. The process proved to depend on the position of the macrocycle along the axle and the associated steric hindrance. The macrocycle thus behaves as a switchable shield that modulates the affinity of the helix for the axle. Reciprocally, the foldamer helix acts as a supramolecular auxiliary that compartmentalizes the axle. In some cases, the macrocycle is forced to move along the axle to allow the foldamer to reach its best recognition site.
30th Anniversary of comprehensive two‐dimensional gas chromatography: Latest advances
Authors: Zanella Delphine , Focant Jean‐François , Franchina Flavio A. 
Published: January 2021

AbstractIn this review, we report on the latest (2020‐Early 2021) instrumental advances and applications of comprehensive two‐dimensional gas chromatography (GC×GC), including its hyphenation with novel upstream or downstream processes (sample preparation approaches or detection technologies). We also discuss software and analysis workflow developments necessary to elaborate the dense chemical information obtained. Thirty years after its inception, the use of GC×GC, as the main analytical tool or as a complementary platform, is undoubtedly shifting toward more applied challenges in a vast breadth of applications. Therefore, we consider the major fields (energy, fuel, foodstuff, plant, biological, and environmental) in which GC×GC has been successfully used, discussing some of the recent innovative research works.
A review of retention mechanism studies for packed column supercritical fluid chromatography
Authors: Si‐Hung Le , Bamba Takeshi 
Published: January 2021

AbstractThe packed column supercritical fluid chromatography has risen as a promising alternative separation technique to the conventional liquid chromatography and gas chromatography. Although the packed column supercritical fluid chromatography has many advantages compared to other chromatographic techniques, its separation mechanism is not fully understood due to the complex combination effects of many chromatographic parameters on separation quality and the lacking of global strategies for studying separation mechanisms. This review aims to provide recent information regarding the chromatographic behaviors and the effects of the parameters on the separation, discuss the results, and point out the remaining bottlenecks in the packed column supercritical fluid chromatography retention mechanism studies.