Pressure-induced evolution of stoichiometries and electronic structures of host-guest Na-B compounds

Superionic and electride behaviors in materials,which induce a variety of exotic physical properties of ions and electrons,are of great importance both in fundamental research and for practical applications.However,their coexistence in hot alkali-metal borides has not been observed.In this work,we apply first-principles structure search calculations to identify eight Na-B compounds with host-guest structures,which exhibit a wide range of building blocks and interesting properties linked to the Na/B composition.Among the known borides,Na-rich Na9B stands out as the composition with the highest alkali-metal content,featuring vertex-and face-sharing BNa16 polyhedra.Notably,it exhibits electride characteristics and transforms into a superionic electride at 200 GPa and 2000 K,displaying unusual Na atomic diffusion behavior attributed to the modulation of the interstitial anion electrons.It demonstrates semiconductor behavior in the solid state,and metallic properties associated with Na 3p/3s states in the superionic and liquid regions.On the other hand,B-rich NaB7,consisting of a unique covalent B framework,is predicted to exhibit low-frequency phonon-mediated superconductivity with a T_(c) of 16.8 K at 55 GPa.Our work advances the understanding of the structures and properties of alkali-metal borides.

Insight into the ammonia torrefaction and pyrolysis system of cellulose:Unraveling the evolution of chemical structure and nitrogen migration mechanism

This study aimed to investigate the mechanism of nitrogen doping,migration,and conversion during ammonia torrefaction and also explore the evolution law of the chemical structure of cellulose.The results showed that the ammonia torrefaction pretreatment could significantly optimize the distribution of nitrogen and oxygen elements in cellulose.The carbon skeleton first captured the active nitrogenous radicals to form-NHn-N,and pyridine-N and pyrrole-N originated from the conversion of-NHn-N.The existence of C=O played a major role in the immobilization of nitrogen.The nitrogen in bio-oil exists mainly in the form of five-and six-membered heterocycles.The correlation analysis showed that the main precursors for the formation of nitrogenous heterocyclic compounds were five-membered Oheterocyclic compounds.Finally,the product distribution characteristics in the torrefaction-pyrolysis systems were summarized,and the nitrogen doping and conversion mechanisms were proposed.This study expanded the boundaries of cellulose pretreatment and the production of high-value chemicals.

Localized-domains staging structure and evolution in lithiated graphite

Intercalation provides to the host materials a means for controlled variation of many physical/chemical properties and dominates the reactions in metal‐ion batteries.Of particular interest is the graphite intercalation compounds with intriguing staging structures,which however are still unclear,especially in their nanostructure and dynamic transition mechanism.Herein,the nature of the staging structure and evolution of the lithium(Li)‐intercalated graphite was revealed by cryogenic‐transmission electron microscopy and other methods at the nanoscale.The intercalated Li‐ions distribute unevenly,generating local stress and dislocations in the graphitic structure.Each staging compound is found macroscopically ordered but microscopically inhomogeneous,exhibiting a localized‐domains structural model.Our findings uncover the correlation between the long‐range ordered structure and short‐range domains,refresh the insights on the staging structure and transition of Li‐intercalated/deintercalated graphite,and provide effective ways to enhance the reaction kinetic in rechargeable batteries by defect engineering.

Hydrothermal Synthesis,Crystal Structure and Fluorescence Spectrum Studies of a Supramolecular Compound {[2-(2-Pyridyl)benzimidazoleH_2]^(2+)·[SbCl_5]^(2-)}_2

A new supramolecular compound, { [2-（2-pyridyl）benzimidazoleH2]2＋.[SBC15]2-}2, was synthesized by the hydrothermal reaction of o-diaminobenzene, 2-pyridinecarboxylie acid and SbCl3 in 1：1 HC1 solution, and characterized by chemical analysis, elemental analysis, IR spectra, thermogravimetfic analysis and fluorescence spectra. The crystal structure was deter- mined by X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P211c, with a = 16.0397（13）, b = 14.3189（12）, c = 15.6370（13） A, β = 105.8980（10）°, V = 3454.0（5） A3, Z = 4, C24H22Cl10N6Sb2, Mr = 992.48, Dc = 1.909 g/cm3,/z = 2.366 mm-1, S = 1.010, F（000） = 1920, R = 0.0254 and wR = 0.0555. The coordination anion, [SbCl5]2- which is a distorted tetragonal pyramid, is composed by coordinating action with Sb3＋ ion and five adjacent chloride ions. Every four coordination anions of [SbCl5]2- form a biquaternion ring structure through the secondary bonding of Sb...Cl. Moreover, the compound adopts a three-dimensional network supramolecular structure because of the hydrogen bonds and π-π stacking between the rings and the 2-（2-pyridyl）benzimidazole divalent cations. The title compound also shows good fluorescent behaviors.

Synthesis, Crystal Structure and Quantum Chemical Study of the Ladder Organotin Compound {[(C_6H_5CH_2)2Sn]_2(O)(Cl_2)}_2

The title compound {[（C6H5CH2）2Sn]2（O）（Cl2）}2 has been synthesized by the reaction of bisbenzyltin dichloride with NaOH dilute solution, and its structure was determined by X-ray diffraction. The crystal belongs to monoclinic, space group C2/c, with a = 2.5081（17）, b = 1.0089（7）, c = 2.0909（14） nm, β = 94.267（8）°, V= 5.276（6） nm^3, Z = 4, De= 1.734 g/cm^3,μ（MoKa） = 21.55 cm^-1, F（000） = 2704, R = 0.0398 and Rw = 0.1024. According to structural analysis, the tin atom adopts a distorted five-coordinate trigonal bipyramidal geometry, and the ladder-like structure is shaped by one planar four-membered Sn2O2 ring together with two planar four-membered Sn2OCl rings.

Extended x-ray absorption fine structure study of MnFeP_(0.56)Si_(0.44) compound

The Mn Fe P0.56Si0.44 compound is investigated by x-ray diffraction, magnetic measurements, and x-ray absorption fine structure spectroscopy. It crystallizes in Fe2P-type structure with the lattice parameters a = b = 5.9823(0) and c = 3.4551(1) and undergoes a first-order phase transition at the Curie temperature of 255 K. The Fe K edge and Mn K edge x-ray absorption fine structure spectra show that Mn atoms mainly reside at 3g sites, while 3f sites are occupied by Fe atoms. The distances between the absorbing Fe atom and the first and second nearest neighbor Fe atoms in a 3f-layer shift from 2.65 and 4.01 in the ferromagnetic state to 2.61 and 3.96 in the paramagnetic phase. On the other hand, the distance between the 3g-layer and 3f-layer changes a little as 2.66 –2.73 below the Curie temperature and2.68 –2.75 above it.

Ionothermal Synthesis, Crystal Structure and Antibacterial Activities of a New 3d-4f Hetero-metallic Compound Containing Two Kinds of Ligands

A new 3d-4f（CuⅡ-CeⅢ） hetero-metallic compound containing two kinds of ligands, namely [CuⅡ（H2pdc）（phen）（H2O）]（HⅢ3O）2[CeⅢ（pdc）3][CuⅡ（phen）Ce（pdc）3]（1, H2 pdc = pyridine-2,6-dicarboxylic acid, phen = 1,10-phenanthroline）, has been synthesized by an ionothermal method using the ionic liquid 3-butyl-1-methylimidazolium bromide（[Bmim]Br） as solvent, and characterized by elemental analysis, energy-dispersive X-ray spectroscopy（EDS）, IR, XPS and single-crystal X-ray diffraction. The structure reveals that 1 belongs to the triclinic system, space group P1 with a = 12.044（7）, b = 14.841（8）, c = 22.305（13） A, α = 85.802（12）, β = 85.471（12）, γ = 89.174（11）°, Z = 2, V = 3964（4） A3, Dc = 1.804 g·cm-3, F（000） = 2140, μ = 1.757 mm-1, the final R = 0.0734, wR = 0.1094 and S = 1.013. The compound can be viewed as a two-dimensional layered structure composed by 3d-4f hetero-nuclear anions [Cu（phen）Ce（pdc）3]-, coordination cations [Cu（H2pdc）（phen）（H2O）]2＋, coordination anions [Ce（pdc）3]3- and protonated water molecules via hydrogen bonding interactions and π-π stacking. Moreover, the antimicrobial activities of 1 have been also investigated. The results indicated that its inhibitory activity is slightly higher than that of penicillin against Candida albicans.

Synthesis,Crystal Structure and Antitumor Activity of Mixed Ligand Coordination Compound of Copper with Norfloxacin and 1,10-Phen,[Cu(NFLX)(phen)(H2O)]NO3·3H2O

The mixed ligand coordination compound of copper with norfloxacin (NFLX) and 1, 10-phen has been synthesized and characterized by means of X-ray single crystal diffraction. The structure features of the coordination compound are described. Antibacterial activities of the coordination compound have been tested against different microorganisms. The antitumor activities of the coordination compound on leukemia HL-60 cell line and liver cancer BEL-7402 cell line have been measured, respectively. The results indicated that the coordination compound has strong inhibitory effect on HL-60 and BEL-7402 cell lines.

Reaction degree of composition B explosive with multi-layered compound structure protection subjected to detonation loading

The explosive reaction degree and protection from explosions are concerns in the military field.In this work,the reaction degree of the composition B explosive was investigated experimentally.Multi-layered compound structures were used as barriers to weaken the blast loads.A comprehensive experiment using a high-speed camera and image processing techniques,side witness plates,and bottom witness plates was presented.Using the experimental fragment velocities,fragment piercing patterns,and damage characteristics,the reaction degree of the explosive impeded by different multi-layered compound structures could be precisely differentiated.Reaction parameters of the explosive obstructed by compound structures were obtained by theoretical analysis and numerical simulations.Unlike the common method in which the explosive reaction degree is only distinguished based on the initial pressure amplitude transmitted into the explosive,a following shock wave reflected from the side steel casing was also considered.Different detonation growth paths in the explosive formed.Therefore,all these shock wave propagation characteristics must be considered to analyze the explosive response impeded by compound structures.

Syntheses and Crystal Structures of Two Novel Spiro Compounds Containing 1,5-Dioxaspiro[5.5]undecane-2,4-dione

Two novel spiro compounds,3-benzylidene-1,5-dioxaspiro[5.5]undecane-2,4-dione 1 and 3-（2-fluorobenzylidene）-1,5-dioxaspiro[5.5]undecane-2,4-dione 2,have been synthesized and characterized by X-ray single-crystal diffraction,IR and elemental analysis.Compound 1 belongs to the monoclinic system,space group P21/n with a=12.326（3）,b=5.6420（11）,c=20.089（4）,β= 101.79（3）o,C16H16O4,Mr= 272.29,V=1367.7（5）3,Z=4,Dc=1.322g/cm3,F（000）=576,μ（MoKa）=0.095 mm-1,the final R=0.0420 and wR=0.1159.Compound 2 is of monoclinic system,space group P21/n with a=12.283（3）,b=5.6367（11）,c=20.055（4）,β=102.00（3）o,C16H15FO4,Mr=290.28,V=1358.2（5）3,Z=4,Dc=1.420 g/cm3,F（000）=608,μ（MoKa）=0.110 mm-1,the final R=0.0353 and wR=0.0860.

ONE-CELL-STATE METHOD FOR DETERMINATION OF ELECTRONIC STRUCTURE OF INTERMETALLIC COMPOUNDS

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Syntheses,Crystal Structures and Antibacterial Activities of 5-Chloro-3-methyl-1-phenyl-1H-pyrazole-4-carboxylic Acid and Its Copper(Ⅱ) Compound

The title compounds 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carboxylic acid（C11H9Cl N2O2, HL）（1） and [Cu（L）2（H2O）]（2） were prepared and structurally characterized by elemental analysis, IR and single-crystal X-ray diffraction. Compound 1（C11H9Cl N2O2） crystallizes in the monoclinic system, space group P21/n with a = 7.249（3）, b = 20.515（10）, c = 7.249（3）,β= 96.30°, V = 1071.6（9） ？3, Z = 4, Mr = 236.65, Dc = 1.467 g/cm3, F（000） = 488, GOOF = 1.029, μ= 0.341 mm-1, the final R = 0.0736 and w R = 0.1966 for 1500 observed reflections with I 〉 2σ（I）. Compound 2（C22H18Cl2Cu N4O5） crystallizes in the monoclinic system, space group P21/c with a = 7.2931（6）, b = 24.548（2）, c = 13.2726（11）, β= 99.4040（10）°, V = 2344.2（3） ？3, Z = 4, Mr = 552.84, Dc = 1.566 g/cm3, F（000） = 1124, GOOF = 1.050, μ= 1.201 mm-1, the final R = 0.0376 and w R = 0.1000 for 3626 observed reflections with I 〉 2σ（I）. 1 and 2 are connected through hydrogen bonding interactions to generate 2D and 3D supramolecular structures, respectively. Moreover, the preliminary antibacterial activities of 1 and 2 against the gram positive bacteria（S. aureus, C. albicans and B. subtilis） and gram negative bacteria（E. coli and P. aeruginosa） have been tested by using the microdilution method, and the results indicate that 2 is more active than 1 against the tested bacteria.

Crystal Structure and Luminescent Properties of a 3D Cd(Ⅱ) Compound Constructed from Succinate and 3,6-Di(4-pyridyl)pyridazine

A three-dimensional（3D） coordination polymer,[Cd（SC）（DPPD）]_n（1,H_2SC = succinic acid and DPPD = 3,6-di（4-pyridyl）pyridazine）,has been synthesized by the solvothermal reaction of Cd（NO_3）_2·4H_2O with H_2 SC and DPPD at 120 ℃ in DMF solvent. Compound 1 crystallizes in the monoclinic system,space group P2_1/c,with a = 10.7993（4）,b = 11.7705（3）,c = 13.5336（6） A,V = 1678.89（11） A^3,Z = 4,C18H14N4O_4 Cd,M_r = 462.73,D_c = 1.831 g/cm^3,μ = 1.335 mm^（-1）,F（000） = 920.0,the final R = 0.0500 and wR = 0.1567 for 3714 observed reflections with I 〉 2s（I）. In compound 1,the Cd（Ⅱ） ions are linked by the SC^2– ligands to give a two-dimensional（2D） undulating sheet based on the centrosymmetric dinuclear Cd_2（COO）_2 units. The 2D sheets are further connected by the DPPD ligands to produce a 3D structure,which is a 6-connected（4^4·6·^10·8） topological network based on the dinuclear Cd_2（COO）_2 node. Compound 1 exhibits a photoluminescent emission with a maximum at 540 nm upon excitation at 460 nm.

Synthesis, Structure and Properties of Two Photochromic Compounds Containing A Pyrazolone-ring

Two photochromic compounds with the pyrazolonering as the photochromic functional structure, 2(1phenyl3methyl4benzoformylpyrazolone5)thiosemicarbazone(PMBPTSC) and 2(1phenyl3methyl4benzoformylpyrazolone5)smethylthiosemicarbazone(PMBPMTSC), were synthesized and characterized by elemental analysis, MS, IR spectra, NMR spectra. The crystal structure of the photocolored product of PMBPTSC was determined by single crystal XRD analysis. The results show that the photochromic phenomenon is due to the photoisomerization from enol form to keto form. Their photochromic properties were studied by powderUV reflectance spectra under the irradiation of 200—380 nm light. The firstorder rate constants of the photocoloring reaction were found to be 780×10 -3 s -1 for compound 1A and 103×10 -3 s -1 for compound 2A.

Synthesis, Crystal Structure, Luminescence Property and DFT Calculations of a New Coordination Compound Containing 8-Aminoquinoline Ligand

A new luminescent compound, Zn（8-aminoql）2（SCN）2 （1, 8-aminoql = 8-amino quinoline）, has been synthesized and its structure was characterized by IR, elemental analysis and X-ray single-crystal diffraction. Compound 1 belongs to the orthorhombic system, space group Pbca with a = 8.503（2）, b = 14.427（4）, c = 31.922（8）A, V= 3916.0（18） A3, Z = 8, C20H16N6S2Zn, Mr = 469.88, Dc = 1.594 Mg/m3, μ = 1.488 mm-1, F（000） = 1920, T = 296（2） K, the final R = 0.0293 and wR = 0.0645 for all 2763 observed reflections （1 〉 2a（/））. Compound 1 displays a 3D supramolecular architecture formed by N-H--S hydrogen bonds and π...π aromatic packing interactions. Photoluminescence studies reveal that it displays obvious fluorescent emission band （λex = 320 nm） at 533 nm in the solid state at room temperature. The emission bands possess a broad asymmetric feature, which can be assigned to ligand-to-ligand charge transfer transitions based on DFT calculations.

CRYSTAL STRUCTURE AND X-RAY POWDER DIFFRACTION DATA FOR RE COMPOUND HoNiSb

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Crystal Structure and Magnetic Properties of a Dinuclear Terbium Compound Tb_2(μ_2-anthc)_4(anthc)_2(1,10-phen)_2

A dinuclear Tb（Ⅲ） compound, Tb_2（μ_2-anthc）_4（anthc）_2（1,10-phen）_2（1, Hanthc = 9-anthracenecarboxylic acid and 1,10-phen = 1,10-phenanthroline）, was synthesized under solvothermal condition and structurally characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic system, space group P1, with a = 12.5061（12）, b = 13.3168（10）, c = 15.0079（12） ？, α = 110.620（7）, β = 102.941（7）, γ = 107.036（7）o, V = 2081.8（3） ？~3, Z = 1, C_（114）H_（70）N_4O_（12）Tb_2, M_r = 2005.58, D_c = 1.600 g/cm^3, μ = 1.759 mm^（-1）, F（000） = 1008, the final R = 0.0294 and w R = 0.0608 for 8900 observed reflections with I 〉 2s（I）. In compound 1, two Tb（Ⅲ） ions are linked by four carboxylate groups of the bridging anthc– ligands to give a dinuclear Tb_2（μ_2-anthc）_4 unit wherein each Tb（III） ion is further capped by a terminal anthc– ligand and a 1,10-phen ligand in a chelating fashion. Detailed direct-current and alternating-current susceptibility measurements showed no slow magnetism relaxation phenomenon was observed for 1.

Two [Ni(dmit)_2]^- Compounds Showing Layered and Chain Alignments: Crystal Structures and Magnetic Properties

Two metal-dithiolene compounds with a formula of[4-ClBz-l-APy][Ni（dmit）2]（1）and[4-NO2Bz-l-APy][Ni（dmit）2]（2,4-ClBz-1-APy = 1-N-（4＇-chlorobenzyl）pyridinium,4-NO2Bz-1-APy = l-N-（4＇-nitrobenzyl）pyridinium,dmit^（2-）= 1,3-dithiole-2-thione-4,5-dithiolate） were synthesized and characterized.Two compounds crystallize in triclinic space group P1 and P1,respectively,but with different cell parameters and packing structures.The[Ni（dmit）2]^- anions and cations of 1 form mixed column stacks along the a axis and alternately layered alignments in the crystal of 2,which are parallel to the crystallographic（110） plane.Two compounds show a similar magnetic behavior,the magnetic exchange natures are mainly antiferromagnetic,and the magnetic susceptibility data can be fitted to the simple Curie-Weiss law.For 1 and 2,the fitted Curie constants are much less than the spin-only value expected for an S =1/2 system,and the fitted Weiss constants marking magnetic interaction are also very smaller.This fact implies that the weak CurrieWeiss-type paramagnetism is not the intrinsic characteristics of two compounds.

Synthesis and Structure of a Hydrogen-bonding Assembled Three-dimensional Supramolecular Indium(III) Compound Involving One-dimensional Helices

The title compound [In（H2ip）（pdc）（H2O）] （H3ip = 5-hydroxyisophthalic acid, H2Pdc = pyridine-2,6-dicarboxylic acid） has been synthesized and characterized by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/c with a = 13.830（8）, b = 6.488（4）, c = 17.632（10）A^°, β = 92.510（10）°, C15H10InNO10, Mr= 479.06, V = 1580.6（15）A^°3, Z = 4, De= 2.013 g/cm^3, F（000） = 944,μ = 1.557 mm^-1, the final R = 0.0413 and wR = 0.0793 for 2950 observed reflections with I 〉 2σ（I）. The In（Ⅲ） ion is seven-coordinated in a slightly distorted penta-bipyramidal geometry. The mixed ligands connect the In（Ⅲ） ions into 21 helical chains along the [010] direction, and the hydrogen bonds assemble the chains into a three-dimensional supramolecular network.

SYNTHESIS AND CRYSTAL STRUCTURE OF A NEW COMPOUND Sr_6Sn_2Nb_8O_30

A new compound Sr6Sn2Nb8O30 was found in the ternary system of SrO-SnO2-Nb2O5. The transparent colorless crystal with needle-like shape can be grown by flux method. The crystal structure of new compound was determined by X-ray diffraction, and its belongs to tungsten bronze structure. Sr6Sn2Nb8O30 crystallizes in orthorhombic system with unit cell parameters a= 17. 579 (DA,6= 17. 509(DA,c=7. 7880(5)A,Z = 4 and space group Cmm2.