Study on Band Structure of YbB_6 and Analysis of Its Optical Conductivity Spectrum

The electronic structure of YbB6 crystal was studied by means of density functional （GGA ＋ U） method. The calculations were performed by FLAPW method. The high accurate band structure was achieved. The correlation between the feature of the band structure and the Yb-B6 bonding in YbB6 was analyzed. On this basis, some optical constants of YbB6 such as reflectivity, dielectric function, optical conductivity, and energy-loss function were calculated. The results are in good agreement with the experiments. The real part of the optical conductivity spectrum and the energy-loss function spectrum were analyzed in detail. The assignments of the spectra were carried out to correlate the spectral peaks with the interband electronic transitions, which justify the reasonable part of previous empirical assignments and renew the missed or incorrect ones.

Hydrogen-transfer conversion of furfural into levulinate esters as potential biofuel feedstock

Furfural is directly converted to levulinate esters（isopropyl levulinate and furan-2-ylmethyl-levulinate） as potential biofuel feedstocks, through a combined catalytic strategy. Nb;O;-ZrO;mixed oxide microspheres are used as bifunctional catalysts for hydrogen-transfer hydrogenation and acid-catalyzed alcoholysis in isopropanol. Bifunctional catalysts improve sustainability of furfural conversion through process intensification. Hydrogen transfer hydrogenation from isopropanol avoids dangerous hydrogen gas, and abates process and environmental costs. Isopropyl levulinate and furan-2-ylmethyl-levulinate are the main products that can be applied as blending components in biodiesel or hydrocarbon fuels.

Combination of diketone and PAO to achieve macroscale oil-based superlubricity at relative high contact pressures

1-(4-ethylphenyl)-nonane-1,3-dione(0206)is an oil-soluble liquid molecule with rod-like structure.In this study,the chelate(0206-Fe)with octahedral structure was prepared by the reaction of ferric chloride and 1,3-diketone.The experimental results show that when using 0206 and a mixed solution containing 60%0206-Fe and 40%0206(0206-Fe(60%))as lubricants of the steel friction pairs,superlubricity can be achieved(0.007,0.006).But their wear scar diameters(WSD)were very large(532µm,370µm),which resulted in the pressure of only 44.3 and 61.8 MPa in the contact areas of the friction pairs.When 0206-Fe(60%)was mixed with PAO6,it was found that the friction coefficient(COF)decreased with increase of 0206-Fe(60%)in the solution.When the ratio of 0206-Fe(60%)to PAO6 was 8:2(PAO6(20%)),it exhibited better comprehensive tribological properties(232.3 MPa).Subsequent studies have shown that reducing the viscosity of the base oil in the mixed solution helped to reduce COF and increased WSD.Considering the COF,contact pressure,and running-in time,it was found that the mixed lubricant(Oil3(20%))prepared by the base oil with a viscosity of 19.7 mPa·s(Oil3)and 0206-Fe(60%)exhibited the best tribological properties(0.007,161.4 MPa,3,100 s).

Marangoni-flow-assisted assembly of single-walled carbon nanotube films for human motion sensing

Single-walled carbon nanotubes(SWCNTs)present excellent electronic and mechanical properties desired in wearable and flexible devices.The preparation of SWCNT films is the first step for fabricating various devices.This work developed a scalable and feasible method to assemble SWCNT thin films on water surfaces based on Marangoni flow induced by surface tension gradient.The films possess a large area of 40 cm×30 cm(extensible),a tunable thickness of 15∼150 nm,a high transparency of up to 96%,and a decent conductivity.They are ready to be directly transferred to various substrates,including flexible ones.Flexible strain sensors were fabricated with the films on flexible substrates.These sensors worked with high sensitivity and repeatability.By realizing multi-functional human motion sensing,including responding to voices,monitoring artery pulses,and detecting knuckle and muscle actions,the assembled SWCNT films demonstrated the potential for application in smart devices.

Visible Light-Promoted Ring-Opening Alkenylation of Cyclic Hemiacetals through β-Scission of Alkoxy Radicals

The chemistry of alkoxy radicals was extensively explored during the period of 1960s to 1990s,but it has remained dormant for the past few decades.Recently,alkoxy radicals attract the attentions again,because new methods for generating alkoxy radical species have emerged.These newly developed methods are mainly based on the photolysis by visible light under mild conditions,thus allowing for new transformations of the carbon-centered radical species that are generated from theβ-scission or hydrogen abstraction of the alkoxy radicals.

Palladium-Catalyzed Oxidative Alkynylation of Allenyl Ketones: Access to 3-Alkynyl Poly-substituted Furans

Furans bearing alkynyl substituents are highly useful in organic synthesis.However,the methodologies to access these important furan derivatives are rather limited.We herein report an efficient synthesis of alkynylated furan derivatives based on Pd-catalyzed oxidative cross-coupling reaction between allenyl ketones and terminal alkynes.This novel synthesis of alkynylated furans with wide substrate scope is operationally simple and tolerates various functional groups.Mechanistically,the formation of the palladium carbene through cycloisomerization and the subsequent alkynyl migratory insertion are proposed as the key steps in the transformation.The reaction reported in this paper further demonstrates the generality of the carbene-based cross coupling.

Approaching the uniaxiality of magnetic anisotropy in singlemolecule magnets

Single-molecule magnets(SMMs),which can exhibit slow magnetization relaxation and bulk-magnet-like hysteresis of purely molecular origin,are promising candidates for high-density information storage,molecular spintronics,and quantum computing.To realize their applications,it is crucial to improve the blocking temperature(TB)and the effective relaxation barrier(Ueff).Three decades of multidisciplinary research have yielded distinct SMMs with a state-of-the-art Ueff of up to 2,000 K and a TB of up to the liquid nitrogen region.Several strategies have been investigated and summarized,which revealed that enhancing the uniaxiality of magnetic anisotropy is critical for constructing high-performance SMMs.Therefore,magnetic anisotropy,a key property that connects the molecular structure symmetry and performance of SMMs,plays a fundamental role in dictating magneto-structural correlations.Understanding and employing magnetic anisotropy would be significantly beneficial for rationally designing high-performance SMMs.This review focuses on the magnetic anisotropy of SMMs.We illustrate the origin and manifestation of magnetic anisotropy in mononuclear 3d-and 4f-block metal complexes.We then introduce developed approaches to investigate magnetic anisotropy both theoretically and experimentally.Typical SMMs by optimizing uniaxial magnetic anisotropy through lanthanide metallocene,symmetry controlling,and low-coordination approaches are represented.Furthermore,the remaining challenges and opportunities in this field will be discussed.

Recent Progress of Circularly Polarized Luminescence Materials from Chinese Perspectives

The research on circularly polarized luminescence(CPL)has garnered significant attention in recent years due to its many potential applications.One aspect of this research involves the pursuit of chiral materials that posess both high luminescence efficiency and dissymmetry factors.The investigation of CPL behavior is of paramount importance because the structural information of chiral luminescent systems in the excited state can be uncovered.The objective of this review is to offer a comprehensive overview of the latest advancements in the CPL research field,with a particular focus on the development of chiral emissive materials,including organic,inorganic,and hybrid substances.Furthermore,this review outlines the recent applications of these materials in areas such as displays,photoelectric devices,anticounterfeiting measures,and sensors.Finally,we highlight the primary challenges and potential prospects of CPL materials.Our aspiration is that this endeavor will contribute new perspectives and insights that further advancements in related research fields.

Preparation of nano‐pico droplets using an open fibrous system

Manipulation and dispensing of ultra‐tiny droplets have attracted extensive research attention for their applications.Current approaches for dispensing liquids normally involve the use of micronozzles and microtips,which,however,suffer from limitations of clogging,high cost,and fragility.Here,we developed a facile open fibrous system for preparing nano‐pico droplets in a facile way,where the macroscopic droplet on a micro‐/nano‐textured copper fiber could be dispersed to a number of tiny droplets by applying and removing a suitable electric potential.The on‐site tunable interfacial energy,imparted by the electrical alterable density and orientation of the water molecules on the interface,leads to fine control of the spreading and retraction of the liquid on a large scale.Meanwhile,the fibrous microporous structure promotes the splitting of the liquid film based on the domain‐limiting effect during the retracting process.As a synergistic consequence,a big droplet firstly spreads completely on the poised fiber into a thin liquid film,which was then split and retracted toward the numerous anchoring points on the textured surface by removing the potential.Consequently,a big droplet can be dispersed into numerous nano‐pico droplets in a controllable way.The strategy is applicable for versatile low‐surface‐energy liquids,offering an innovative open system for continuous preparation of nano‐pico droplets.

Cu（I）-Catalyzed Three-Component Coupling of Trifluoromethyl Ketone N-Tosylhydrazones, Alkynes and Azides： Synthesis of Difluoromethylene Substituted 1,2,3-Triazoles

A Cul-catalyzed three-component coupling of trifluoromethyl ketone N-tosylhydrazones, alkynes and azides has been developed. The reaction represents a straightforward method to access difluoromethylene substituted 1,2,3-triazoles. Mechanistically, it has been proposed that the reaction follows a pathway involving the formation of Cu（1） triazolide intermediate, Cu（I） carbene formation, migratory insertion, and β-fluoride elimination. The trans- formation is featured by mild conditions, wide substrate scope and high efficiency.

Fast and accurate measurement of diffusion coefficient by Taylor’s dispersion analysis

This investigation aimed at improving the performance of Taylor’s dispersion analysis for the fast and accurate measurement of diffusion coefficient of a minute solute in various solvents. The investigation was carried out on a capillary electrophoresis instrument by monitoring the UV absorption peak of a solute pulse and calculating the diffusion coefficient by peak efficiency. With L-phenylalanine as a main testing solute, some key factors were afterward disclosed including especially the capillary size, carrier flow velocity, injection volume and capillary conditioning. Peak tailing, large volume of sample injection and slow migration were found to underestimate the diffusion coefficient while very fast migration and high sample concentration caused overestimation. At a moderate flow velocity of 0.1―1 cm/s with a capillary of 72.44 μm I.D.×60 cm (50 cm effective) maintained at 25℃, the diffusion coefficient of aqueous L-phenylalanine was determined, giving a value of 7.02×10-6 cm2/s with error <2% and relative standard deviation <0.2% (n=3). The method was shown to be applicable to the measurement of various samples such as aqueous phenylalanine, acetone, phenol, toluene and benzene, and nonaqueous benzene (in ethanol or 1-butanol).

Molecular-based conducting magnet

Molecular-based conducting magnet or magnetic conductor, is an overlap of organic conductor and molecular magnet. Due to the existence of ferromagnetism, antiferromagnetism and quantum magnetism in insulated charge-transfer salt, it becomes a common sense that magnetism is not good for conductivity. After the discovery of first molecular-based metallic ferromagnet, molecular-based conducting magnet with -unit from organic conductor and magnetism from coordination counterion became a hot area. The metallic ferromagnet, semiconductor room-temperature ferrimagnet, metallic weak ferromagnet and supercon-ducting antiferromagnet have been discovered. The new molecular-based conducting magnet with higher conductivity and higher magnetic ordering temperature is expected.

Green synthesis of gold nanoclusters using papayajuice for detection of L-lysine

Gold nanoclusters were rapid synthesized within 3 min at 120 ℃ by using papaya juice as a capping and reducing agent(P-AuNCs). The properties of the fluorescent probe were characterized by fluorescent spectroscopy, UV-vis spectroscopy, dynamic light scattering and transmission electron microscope.Based on the surface electron density increase-induced fluorescence enhancing principle, a high selective method for detection of L-lysine was developed with the as-prepared P-AuNCs coupling the fluorescence emission at 440 nm. The fluorescent probe showed high stability and good biocompatibility. Its fluorescence intensity was found to be linearly dependent on the L-lysine concentration in the range of 10.0μmol/L to 1000.0 μmol/L(R^2=0.969) with a limit of detection of 6.0μmol/L. Furthermore, the PAuNCs based approach was applied for monitoring the urine L-lysine contents, demonstrating great potential of fluorescent probes in real samples analysis.

Luminescent single-molecule magnet of metallofullerene DyErScN@Ih-C80

Magneto-luminescent molecules have significant applications in data storage and quantum computing.However,design of these bi-functional molecules coupled with magnetic behavior and photoluminescence is still challenging.In this work,we report a metallofullerene DyErScN @In-C80 exhibiting single-molecule magnet (SMM) behavior and near-infrared emission.For DyErScN @Ih-C80,two functional lanthanide metal ions of Dy^3+(SMM function) and Er^3+(luminescent function) are integrated inside a fullerene cage using a trimetallic nitride template,and its structure has been unambiguously characterized by single-crystal X-ray diffraction.Magnetic measurements revealed that DyErScN @Ih-C80 behaves as a SMM with a blocking temperature up to 9 K resulting from the intramolecular magnetic interaction between Dy^3+ and Er^3+ ions.Moreover,DyErScN @In-C80 exhibits temperature-dependent near-infrared emission around 1.5 pm with multiple splitting peaks from Er^3+,which arises from the influence of Dy^3+ ion.This study provides a new strategy to synthesize new magneto-luminescent molecule materials.

Cu（I）-Catalyzed Asymmetric Cross-Coupling of N-Tosylhydrazones and Trialkyl- silylethynes： Enantioselective Construction of C（sp）--C（sp^3） Bonds

The first catalytic enantioselective C（sp）-C（sp^3） cross-coupling reaction between N-tosylhydrazones and trialkylsilylethynes in the presence of Cu（I） salts and chiral phosphoramidite ligands was developed. A series of svnthetically interesting, functionalized alkynes were obtained with moderate to good enanttiselectivities （up to 83% ee）. Cu（ll） carbene migratory insertion is proposed to be the enantio-determining step. KEYWORDS C（sp）--C（sp^3） cross-coupling, metal carbene, asymmetric catalysis, Cu（I） catalysts, N-tosylhydrazones

Direct synthesis of ordered mesoporous ZSM-5 zeolites from in situ crystallization of carbonaceous SBA-15

Two types of ordered mesoporous ZSM-5 zeolites with different mesopores were synthesized by a two-step method. First,carbonaceous SBA-15 was produced by in situ carbonization of SBA-15/P123 composite. Then the obtained SBA-15/C composite was transformed into crystallized mesoporous ZSM-5 by impregnation TPAOH followed by steam-assisted crystallization. The final calcined samples synthesized with typical SBA-15/P123 precursor showed a wormlike morphology with the mean mesopore size of 4.6 nm, while samples synthesized with the addition of trimethylbenzene as swelling agent in the precursor exhibited the morphology of microsphere with the mesopore size of about 9.5 nm. Both two types of mesoporous ZSM-5 zeolites exhibited large surface area and mesopore structure. The steam-assisted crystallization(SAC) was performed with lower consumption of solvents. This two-step method may also be suitable for synthesizing other ordered mesoporous zeolites used as catalysts in some catalytic processes.

Construction of Alkenyl-Functionalized Spirocarbocyclic Scaffolds from Alkyne-Containing Phenol-Based Biaryls via Sequential lodine-Induced Cyclization/Dearomatization and Pd-Catalyzed Coupling of N-Tosylhydrazones

of main obse rvation and conclusion An efficient strategy for the formation of alkenyl-functionalized spirocarbocyclic scaffolds from alkyne-containing phenol-based biaryls via sequential iodine-induced cyclization/dearomatization and Pd-catalyzed coupling of N-tosylhydrazones is developed.The approach provides various spirocarbocyclic compounds in moderate to excellent yields with good functional tolerance.The results also demonstrate the feasibility for the direct cross-couplings of N-tosyl hydrazones with sterically congested tetrasubstituted alkenyl halides.

Interaction of straight chain alcohol vapors with self-assembled MOF film by surface plasmon resonance sensing and imaging

Interaction of straight chain alcohol vapors with MOF-199-functionalized films was studied by SPR. The signals had linear relationships with the concentration of alcohols over a wide range from 0 to 70% （v/v） and were reversible in proportional to the chain length, with R2 all above 0.99.

Ovalbumin-stabilized gold nanoclusters with ascorbic acid as reducing agent for detection of serum copper

Ovalbumin-stabilized gold nanoclusters （OVA@AuNCs） were prepared with ascorbic acid as a reducing agent. This strategy could realize the synthesis of water-soluble OVA@AuNCs within 20 min. The asprepared fluorescent probe showed a red fluorescence emission at 630 nm. Moreover, the properties of the OVA@AuNCs were characterized by transmission electron microscope, dynamic light scattering, ultraviolet-visible spectroscopy, fluorescent spectroscopy. Based on the surface electron density decrease-induced fluorescence quenching mechanism, the OVA@AuNCs provided high sensitivity and selectivity for sensing copper ions. A good linear relationship was obtained between the fluorescence intensity of OVA@AuNCs and the concentration of copper ions in the range of 5.0-100.0pumol/L （R2z0.999） with a detection limit of 640 nmol/L. Furthermore, the rat serum copper contents were determined by using the OVA@AuNCs based assay, indicating great potential of fluorescent probes for application in biological and clinical analysis.

Diastereoselective addition of lithium enolate of γ-substituted α-diazoacetoacetate to N-sulfinyl imines

Highly diastereoselective addition of lithium enolate of γ-substituted α-diazoacetoacetate to chiral N-sulfinyl imines has been developed. The addition products were further subjected to photo-induced Wolff rearrangement or Rh(Ⅱ)-catalyzed intramolecular N-H insertion to afford chiral 4,5-disubstituted 2-oxo and 3-oxo pyrrolidines,respectively.