价电子能级连接性指数及其应用

价电子能级连接性指数( ^fE)被定义为： ^fE=Σ(m_i·m_j…)^-0.5,m为价电子能级值。其中0、1阶指数公式分别为： ⁰E=Σ(m_i)^-0.5、 ¹E=Σ(m_i·m_j)^-0.5。 ⁰E、 ¹E与化合物的总键能(ΔE)、晶格能(U)、标准生成焓(Δ_fH^?_m)以及非金属氢化物的pKa呈现高度相关性。它们的线性回归方程为：ΔE=-48.0095+1402.9463¹E,r=0.9474, U=-328.0770+1541.9351 ¹E, r=0.9801,-Δ_fH^?_m=-266.9299+1324.6461 ¹E, r=0.9509, pKa=-20.9723+28.1756 ¹E, r=0.98884, pKa=-14.6102-7.835 ⁰E+40.6461 ¹E, R=0.9933。m、^fE具有物理意义明确、计算方法简单等优点,而且预测结果令人满意。     

WxC-MCM-48催化剂的合成、表征及加氢脱硫催化性能

以正硅酸乙酯(TEOS)为硅源，十六烷基三甲基溴化铵(CTAB)为表面活性剂，仲钨酸铵为钨源，采用水热晶化法一步合成了不同钨含量(以Si、W物质的量比n_Si/n_W表示)的WO₃-MCM-48，然后经甲烷/氢气(V/V=1/4)混和气体程序升温还原碳化(TPC)，制备出了W_xC-MCM-48(x=1、2)催化剂，采用XRD、N₂吸附-脱附和NH₃-TPD对样品的结构进行了表征，用噻吩作为模型化合物，对W_xC-MCM-48催化剂的加氢脱硫催化活性进行了评价。结果表明，在一定钨含量的条件下，WO₃-MCM-48和W_xC-MCM-48样品仍然保持MCM-48的三维立方有序介孔结构，n_Si/n_W=30～15时，碳化钨的物相为W₂C；n_Si/n_W=7.5时，碳化钨为W₂C和WC物相，W_xC-MCM-48催化剂表现出了良好的加氢脱硫催化性能。     

铜(Ⅱ)与2，2′-联吡啶胺(dpa)和3-苯丙酸(HPPr)混配配合物的合成、晶体结构及表征

The new titled complex ［Cu(dpa)(PPr)₂］·2H₂O was prepared and characterized by elementary analyses, IR, molar conductance and differential thermal analyses. The crystal structure was determined by X-ray diffraction. The crystal belongs to triclinic, space group P1, with the crystal cell parameters: a=10.451(2) nm, b=11.126(1) nm, c=11.795(1) nm, α=90.57(1)°, β=90.34(1)°, γ=87.89(1)°, V=1370.6(4) nm³, Z=2, D_c=1.369 g/cm³, R=0.037, R_W=0.038. Four carboxyl oxygen atoms from two PPr^- and two nitrogen atoms from dpa coordinate with Cu(Ⅱ) respectively to form an elongated octahedron.     

[Na(DB18C6)(CH3CN)]2W6O19·(CH3CN)2的合成、晶体结构及谱学表征

A super-molecular complex, [Na(DB18C6)(CH₃CN)]₂W₆O₁₉·(CH₃CN)₂, was obtained by solvothermal reaction and characterized by IR , ¹H NMR, gumbc spectrum single crystal and X-ray diffraction. The compou- nd crystallizes in monoclinic space group P2₁/c with a=1.185 22(4) nm, b=2.091 51(8) nm, c=1.487 19(5) nm, β=117.467(2)° and Z=2. The complex contains four basic units: Na⁺, CH₃CN, DB18C6 and W₆O₁₉^2-. Sodium ions located in the cavity of dibenzo-18-crown-6 with 6 Na-O bonds and the crown ether-sodium ion complex is supported on the terminal oxygen atoms of the typical Lindqvist isopolyanion W₆O₁₉^2- via the coordinative interactions. W₆O₁₉^2- located between two DB18C6 and led to the formation of the “hamburger” structure. Two isolated CH₃CN are included in the complex. The whole title crystal is stabilized by van der waals force. CCDC: 292369.     

含大环[Ni([15]aneN5]2+氰基桥联四核簇合物的合成、结构和磁性质

用1,4,7,10,13-五氮十五烷(cpad)作为端基配体,合成了2个同构化合物[{Ni(cpad)}₃M(CN)₆]₂[M(CN)₆](ClO₄)₃·6H₂O (M=Cr³⁺,1;Fe³⁺,2),其中[M(CN)₆]^3-通过氰基桥联配位,4个[Ni(cpad)]²⁺阳离子形成四核簇[{Ni(cpad)}₃M(CN)₆]³⁺,游离的[M(CN)₆]^3-和ClO₄^-为平衡阴离子。晶体参数如下：1,三方晶系,P3c1空间群,a=1.5144 1(18) nm,c=3.080 7(6) nm,V=6.118 9(15) nm³,Z=2;2,三方晶系,P3c1空间群,a=1.4976 2(17) nm,c=3.087 8(5) nm,V=5.997 6(14) nm³,Z=2。变温磁化率显示在四核簇内氰基桥联的金属离子之间存在铁磁相互作用。     

含dmpzm配体的锌和镉配合物的合成、结构及性质研究

通过M(NO₃)₂(M=Zn，Cd)和二(3，5-二甲基吡唑)甲烷(dmpzm)的反应，合成了2个锌和镉配合物[M(dmpzm)₂(NO₃)][NO₃](1：M=Zn；2：M=Cd)。配合物1和2经元素分析,红外光谱表征，并经X射线单晶衍射法证实。配合物1属于正交晶系，空间群为Pca2₁，晶体学参数：a=1.625 9(3) nm，b=0.832 10(17) nm，c=2.031 1(4) nm，V=2.747 9(10) nm³，Z=4。配合物2属于正交晶系，空间群为Pca2₁，晶体学参数：a=1.674 36(15) nm，b=0.821 29(7) nm，c=2.048 01(19) nm，V=2.816 3(4) nm³，Z=4。在这2个配合物的阳离子中，金属原子分别与2个dmpzm中的4个N原子及1个NO₃^-中的2个O原子配位，形成略为畸变的八面体构型。配合物1和2的晶体中，NO₃^-的O原子与配体dmpzm中的甲基及亚甲基间存在的C-H…O氢键作用，从而形成了有趣的三维网状结构。此外，还研究了配合物1和2的荧光性质。     

一种确定固相反应机理函数的新方法——固态草酸镍(Ⅱ)二水合物脱水过程的非等温动力学

The dehydration of nickel(Ⅱ) oxalate dihydrate in solid state was investigated by TG-DTA techniques. On the basis of Coats-Redfern′s and Ozawa′s integral equations, the double extrapolate method was suggested, i.e.heating rate Φ and proportion weight loss of a sample α were extrapolated to zero, respectively. Using comparision E_Φ→0 with E_α→0 the kinetic mechanism was concluded to be nuclear producing and growing process (n=1.5). The intergral function of the mechanism is ［-ln(1-α)］^1/1.5 and the corresponding kinetic parameters were determined.     

金刚乙胺水杨醛Schiff碱锌(Ⅱ)配合物的合成、表征、晶体结构和热分解动力学研究

A Zinc(Ⅱ) complex [ZnCl₂(HL)₂] with Schiff base HL derived from rimantadine and salicylaldehyde was synthesized and characterized by elemental analysis, infrared spectra, ¹H NMR spectra,molar conductance, ultraviolet and visible spectra, thermal analysis. Its structure was determined by single crystal X-ray diffraction method. The complex, C₃₈H₅₀Cl₂N₂O₂Zn, crystallizes in the orthorhombic system, space group Aba2 with a=1.381 7(3), b=2.275 0(5), c=1.145 0(2) nm, V=3.599(1) nm³, Z=4, M_r=653.79, F(000)=1 496, D_c=1.301 kg·m^-3, μ(Mo Kα)=0.866 mm^-1. The kinetic parameters were obtained from the analysis of TG curve by integral methods. The functions of thermal decomposition reaction mechanism are: F(α)=[1-(1-α)^1/3]², and kinetic compensation effect equation lnA=0.019 1E-0.142 7. CCDC: 253297.     

由2-甲基咪唑-4, 5-二羧酸构筑的双核平行六面体三维钙配位聚合物

合成了一个双核钙配合物{[Ca₂(μ₃-HMIA^2-)(μ₅-HMIA^2-)(H₂O)]·H₂O}_n(1, H₃MIA=2-甲基咪唑-4, 5-二羧酸), 并用元素分析、红外光谱和X-射线单晶衍射等对其进行了表征。结构分析表明, 1属单斜晶系, P2₁/c空间群, 晶胞参数为a=0.860 67(11) nm, b=1.656 5(2) nm, c=1.269 24(16) nm, β=108.005 0(10)°, V=1.720 9(4) nm³, C₁₂H₁₀Ca₂N₄N₁₀, M_r=450.40, Z=4, D_c=1.728 g·cm^-3, F(000)=920, μ=0.727 mm^-1, S=1.041, λ(Mo Kα)=0.071 073 nm, R=0.026 0 and wR=0.063 8。在1晶体结构中, 每个钙(Ⅱ)离子都是7配位的, 但展现2个不同的配位环境。4个μ₃-HMIA^2-配体, 2个μ₅-HMIA^2-配体和8个钙(Ⅱ)离子一个平行六面体结构[Ca₈( μ₃-HMIA)₄ (μ₅-HMIA)₂]⁴⁺。μ₅-HMIA^2-配体采用独特的配位模式并连接周围的平行六面结构形成一维链结构, 配体μ₃-HMIA^2-连接相邻的一维链形成一种新的蜂窝型的二维层状结构, 相邻的二维层通过μ₃-HMIA^2-配体的2个氧原子进一步形一个三维结构。还研究了配合物1的热重分析和抑菌活性。     

过氧铌钨酸钾的制备和晶体结构

合成的标题化合物K₈H₄Nb₄W₈O₃₆(O₂)₄·18H₂O晶体属立方晶系,Pm3-m空间群,晶胞参数a=1.064(1) nm, Z=1,阴离子骨架呈一种高对称的全新十二聚构型。钾离子无序分布在靠近对称中心的4个相关位置。     

Bonding and singlet–triplet gap of silicon trimer: Effects of protonation and attachment of alkali metal cations

We revisit the singlet–triplet energy gap (ΔE_ST) of silicon trimer and evaluate the gaps of its derivatives by attachment of a cation (H⁺, Li⁺, Na⁺, and K⁺) using the wavefunction‐based methods including the composite G4, coupled‐cluster theory CCSD(T)/CBS, CCSDT and CCSDTQ, and CASSCF/CASPT2 (for Si₃) computations. Both ¹A₁ and ³ states of Si₃ are determined to be degenerate. An intersystem crossing between both states appears to be possible at a point having an apex bond angle of around α = 68 ± 2° which is 16 ± 4 kJ/mol above the ground state. The proton, Li⁺ and Na⁺ cations tend to favor the low‐spin state, whereas the K⁺ cation favors the high‐spin state. However, they do not modify significantly the ΔE_ST. The proton affinity of silicon trimer is determined as PA(Si₃) = 830 ± 4 kJ/mol at 298 K. The metal cation affinities are also predicted to be LiCA(Si₃) = 108 ± 8 kJ/mol, NaCA(Si₃) = 79 ± 8 kJ/mol and KCA(Si₃) = 44 ± 8 kJ/mol. The chemical bonding is probed using the electron localization function, and ring current analyses show that the singlet three‐membered ring Si₃ is, at most, nonaromatic. Attachment of the proton and Li⁺ cation renders it anti‐aromatic. © 2015 Wiley Periodicals, Inc.     

Thermochemical Properties and Decomposition Kinetics of Ammonium Magnesium Phosphate Monohydrate

Ammonium magnesium phosphate monohydrate NH4MgPO4·H2O was prepared via solid state reaction at room temperature and characterized by XRD, FT-IR and SEM. Thermochemical study was performed by an isoperibol solution calorimeter, non-isothermal measurement was used in a multivariate non-linear regression analysis to determine the kinetic reaction parameters. The results show that the molar enthalpy of reaction above is （28.795 ± 0.182） kJ/mol （298.15 K）, and the standard molar enthalpy of formation of the title complex is （-2185.43 ± 13.80） kJ/mol （298.15 K）. Kinetics analysis shows that the second decomposition of NH4MgPO4·H2O acts as a double-step reaction： an nth-order reaction （Fn） with n=4.28, E1=147.35 kJ/mol, A1=3.63×10^13 s^-1 is followed by a second-order reaction （F2） with E2=212.71 kJ/mol, A2= 1.82 × 10^18 s^-1.     

Viscosity and structural relaxation of 15Na<Subscript>2</Subscript>O·<Emphasis Type="Italic">x</Emphasis>MgO·(10−<Emphasis Type="Italic">x</Emphasis>)CaO·75SiO<Subscript>2</Subscript> glasses

Temperature dependence of viscosity of title glasses (x=0, 2, 4, 6, 8, 10, abbreviated as M0, M2, M4, M6, M8, and M10, respectively) was measured by rotational viscometry (high temperature region: 10²−10^6.5 dPas) and thermomechanical analysis (low temperature region: 10^8.5−10^11.5 dPas) and described by the Vogel-Fulcher-Tammann equation. The MgO/CaO equimolar substitution (i.e. the increasing x value) smoothly shifts the high temperature viscosity to higher values. In the low temperature region the mixed alkali effect is demonstrated, and the highest viscosities are observed for the glasses M0 and M10. In the low temperature range the activation energy of viscous flow linearly decreases with the increasing x value (E _act/kJ mol⁻¹=479−9.0x). No significant dependence of activation energy on x was found in the high temperature range (E _act/kJ mol⁻¹=238.1±4.2). The structural relaxation was measured by thermomechanical experiment and theoretically interpreted in the frame of Tool-Narayanaswamy-Mazurin’s model. The broadening of the relaxation time spectrum was observed for the calcium-magnesium glasses in comparison with the pure calcium or magnesium glasses.     

Theoretical investigation on identical anionic halide‐exchange SN2 reaction processes on N‐haloammonium cation NH3X+ (X = F,Cl, Br,and I)

CCSD(T) calculations have been used for identically nucleophilic substitution reactions on N‐haloammonium cation, X^? + NH₃X⁺ (X = F, Cl, Br, and I), with comparison of classic anionic S_N2 reactions, X^? + CH₃X. The described S_N2 reactions are characterized to a double curve potential, and separated charged reactants proceed to form transition state through a stronger complexation and a charge neutralization process. For title reactions X^? + NH₃X⁺, charge distributions, geometries, energy barriers, and their correlations have been investigated. Central barriers ΔE for X^? + NH₃X⁺ are found to be lower and lie within a relatively narrow range, decreasing in the following order: Cl (21.1 kJ/mol) > F (19.7 kJ/mol) > Br (10.9 kJ/mol) > I (9.1 kJ/mol). The overall barriers ΔE relative to the reactants are negative for all halogens: ?626.0 kJ/mol (F), ?494.1 kJ/mol (Cl), ?484.9 kJ/mol (Br), and ?458.5 kJ/mol (I). Stability energies of the ion–ion complexes ΔE_comp decrease in the order F (645.6 kJ/mol) > Cl (515.2 kJ/mol) > Br (495.8 kJ/mol) > I (467.6 kJ/mol), and are found to correlate well with halogen Mulliken electronegativities (R² = 0.972) and proton affinity of halogen anions X^? (R² = 0.996). Based on polarizable continuum model, solvent effects have investigated, which indicates solvents, especially polar and protic solvents lower the complexation energy dramatically, due to dually solvated reactant ions, and even character of double well potential in reactions X^? + CH₃X has disappeared. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011     

Single and Double Threading of Congo Red into γ-Cyclodextrin. Solution Structures and Thermodynamic Parameters of 1:1 and 2:2 Adducts,as Obtained from NMR Spectroscopy and Microcalorimetry

Detailed NMR studies of aqueous solutions (pH 7) of γ-cyclodextrin (γCD) and the azo dye Congo Red (CR) show distinct, concentration-independent ¹H NMR signals for different species. A very stable 1:1 pseudorotaxane (K ¹¹=38,000±1100?M^-1) is formed. In addition, a second complex corresponding to a 2:2 adduct (K ²²=13±3?M^?-1) is produced by dimerisation of the 1:1 species. The structure of the 1:1 pseudorotaxane involves fast motion of the γCD ring along the CR backbone, leaving the outer naphthalene rings free. This entity undergoes structural reorganisation and dimerises to form the 2:2 adducts. Variable-temperature spectra did not lead to coalescence and allowed for the calculation of K ¹¹ and K ²² at each temperature and also of the corresponding thermodynamic parameters. Therefore, formation of the 1:1 complex is favourable (ΔG=-26.1±0.1?kJ/mol) and exothermic (ΔH=-21.7±1.0?kJ/mol), whereas formation of the 2:2 entity is also favourable (ΔG=-6.36±0.58?kJ/mol) but endothermic (ΔH=+43.3±8.7?kJ/mol). The corresponding values for entropy change are both positive (ΔS ¹¹=+14.5±0.7?J/mol, ΔS ²²=+166±33?J/mol). Isothermal titration calorimetry studies confirm the NMR findings. For the 1:1 complexation, the dependence of K upon the concentration is indicative of the dimerisation to form the 2:2 complex. When CR is in excess, aggregation processes involving 2:2 complexes and CR molecules are observed by NMR and calorimetry.     

Hydrogen Storage in a Potassium‐Ion‐Bound Metal–Organic Framework Incorporating Crown Ether Struts as Specific Cation Binding Sites

To develop a metal–organic framework (MOF) for hydrogen storage, SNU‐200 incorporating a 18‐crown‐6 ether moiety as a specific binding site for selected cations has been synthesized. SNU‐200 binds K⁺, NH₄⁺, and methyl viologen(MV²⁺) through single‐crystal to single‐crystal transformations. It exhibits characteristic gas‐sorption properties depending on the bound cation. SNU‐200 activated with supercritical CO₂ shows a higher isosteric heat (Q_st) of H₂ adsorption (7.70 kJ mol^?1) than other zinc‐based MOFs. Among the cation inclusions, K⁺ is the best for enhancing the isosteric heat of the H₂ adsorption (9.92 kJ mol^?1) as a result of the accessible open metal sites on the K⁺ ion.     

环丙沙星-钨硅多金属氧酸盐的制备及热分解动力学

A new polyoxometalate （CPFX·HCl）3H4SiW12O40·10H2O was prepared from ciprofloxacin hydrochloride and H4SiW12O40·nH2O in aqueous solution, and characterized by elemental analysis, IR spectra and DTA-TG-DTG techniques. The IR spectrum confirmed the presence of Keggin structure and the characteristic functional group for ciprofloxacin in the compound. The TG-DTA-DTG curves showed that its thermal decomposition was a four-step process consisting of simultaneous collapse of Keggin type structure. The residue of decomposition was the mixture of WO3 and SiO2, confirmed by X-ray diffraction and IR spectroscopy. The decomposition mechanism and nonisothermal kinetic parameters of the polyoxometalate were obtained from an analysis to the TG-DTG curves by the single scanning methods （the Achar method and Coats-Redfern method） and the multiple scanning methods （the Kissinger method, Flynn-Wall-Ozawa method and Starink method）. The results indicate that the kinetic equationswith parameters describing the thermal decomposition reaction are dα/dt=6.65×10^6[3（1-α）^2/3]e^-10495.5/T with E=87.26 kJ/mol and A=6.65×10^6 s^-1 for the second step,dα/dt=7.01×10^9（1-α）e^-18770.7/T with E=156.06 kJ/mol and A=7.01×10^9 s^-1 for the third step,dα/dt=9.77×10^43[（1-α）^2]e^-88980.0/T with E=739.78 kJ/mol and A=9.77×10^43 s^-1 for the fourth step.     

铀(Ⅵ)与不对称希夫碱配合物的合成和热分解反应动力学

邻苯二胺与5－氯－2－羟基二苯酮、邻香草醛作用合成了一种不对称希夫碱配体C₂₇H₂₁N₂O₃Cl（H₂L）。在正丁醇和甲醇体系中硝酸铀酰与该配体反应合成了一种固体希夫碱配合物[UO₂(HL)(NO₃)(H₂O)]·H₂O。通过元素分析、IR、UV、¹H NMR、TG-DTG及摩尔电导率分析等手段对合成的配合物进行了表征,用非等温热重法研究了铀(Ⅵ)配合物的热分解反应动力学,推断出第三步热分解的动力学方程为：d α /d t = A · e^{- E/RT} ·3/2[(1- α )^-1/3-1]^-1,得到了动力学参数E和A。并计算出了活化熵△S^¹和活化吉布斯自由能△G^¹。     

First-principles study of O2 adsorption and dissociation on the CuCr2O4 (100) surface

The adsorption and dissociation of molecular oxygen on spinel CuCr₂O₄ (100) surface were carried out by first-principles calculations based on density functional theory (DFT). The calculated results indicate that the Cr site is most favorable for atomic oxygen adsorption, with an adsorption energy of 402.8 kJ/mol. For molecular oxygen adsorption, there are three types of favorable interaction modes: O₂ forms bonds with the Cu site or O₂ binds to two Cr sites or O₂ interacts with both Cu and Cr sites simultaneously. The lowest activation energy (E_a = 35.4 kJ/mol) was found through exploring possible reaction pathways for O₂ dissociation. The relationship between E_a and reaction enthalpy (ΔH) for O₂ dissociation adsorption reactions fits Brønsted-Evans-Polanyi (BEP) behavior.     

Quantitative studies on furfural and organic acid formation during hydrothermal,acidic and alkaline degradation ofD-xylose

Summary Chromatographic analysis of the degradation ofD-xylose either in plain water or aqueous sulfuric acid at temperatures ranging from 180 – 220°C gave up to 50 mol% of furfural. Activation energies did not differ significantly between reactions in plain water (E _a =119.4 kJ/mol), 0.001M H₂SO₄ (E _a =120.6 kJ/mol), 0.01M H₂SO₄ (E _a =130.8 kJ/mol), and 0.1M H₂SO₄ (E _a =120.7 kJ/mol). However, under alkaline conditions the activation energy was only 63.7 kJ/mol, indicating a different reaction mechanism. Isotachophoretic analyses revealed the formation of pyruvic, formic, glycolic, lactic, and acetic acid. While the relative yields of these acids ranged from 0.8 to 7% under hydrothermal and acidic conditions, 10 – 23% were obtained in alkaline degradation.

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Quantitative Studien zur Bildung von Furfural und organischen Säuren während des hydrothermalen, sauren und alkalischen Abbaues vonD-Xylose

Zusammenfassung Die chromatographische Analyse des Abbaues vonD-Xylose in reinem Wasser und Schwefelsäure bei Temperaturen von 180 – 220°C ergab die Bildung von bis zu 50 mol% Furfural. In bezug auf die Aktivierungsenergie zeigten sich keine signifikanten Unterschiede zwischen dem Abbau vonD-Xylose in reinem Wasser (E _a =119.4 kJ/mol), 0.001M H₂SO₄ (E _a =120.6 kJ/mol), 0.01M H₂SO₄ (E _a =130.8 kJ/mol), and 0.1M H₂SO₄ (E _a =120.7 kJ/mol). Unter alkalischen Bedingungen hingegen betrug die Aktivierungsenergie nur 63.7 kJ/mol. Dies weist auf einen unterschiedlichen Reaktionsmechanismus hin. Ferner konnte mittels Isotachophorese die Bildung von Brenztraubensäure, Ameisensäure, Glycolsäure, Milchsäure und Essigsäure nachgewiesen werden. Während sich die relativen Ausbeuten in Wasser und Schwefelsäure zwischen 0.8 und 7% bewegten, betrugen sie unter alkalischen Bedingungen 10 bis 23%.