L-苏糖酸锰的制备及标准生成焓

The pink powder of manganese L-threonate was obtained by extracting with alcohol the concentrated solution derived from the reaction between L-threonic acid solution prepared by double decomposition reaction of calcium L-threonate with oxalic acid and superfluous manganese oxide at 80℃ for certain time. The composition of the new compound was determined by chemical and elemental analyses and its formula fits Mn(C₄H₇O₅)₂·H₂O, the IR spectra indicated that Mn²⁺ in the compound coordinates to oxygen atom of the carboxyl group, while the proton of the carboxyl group is dissociated, it was assumed that the coordination number of Mn²⁺ was 4. The results of TG-DTG showed that the compound have fairish stability, the intermediate and final product of the thermal de-composition of the compound are Mn(C₄H₇O₅)₂ and MnO₂, respectively. The constant volume combustion energy of the compound, Δ_cE, were determined by a precise rotating-bomb calorimeter at 298.15K, it was (-3384.30±1.21)kJ·mol^-1, its standard enthalpy of Combustion,Δ_cH_m^?,and standard enthalpy of formation,Δ_fH_m^? , were calculated. They are (-3383.07±1.21)kJ·mol^-1 and (-2 571.68±1.63)kJ·mol^-1, respectively.     

Cu(Ⅱ)-牛磺酸缩水杨醛席夫碱-邻菲咯林三元配合物的合成、晶体结构及性质

The title complex was synthesized by reaction of taurine salicylic schiff base(TSSB), O-phenanthroline(phen) and cupric acetate in water-ethanol solution. The crystal structure was determined by X-ray diffraction method and the chemical formula weight of the complex is 498.00. The crystal structure of the title complex belongs to orthorhombic system with space group Pbcn and cell parameters: a=3.107 2(4) nm, b=1.289 09(18) nm, c= 1.034 78(14) nm; and V=4.144 7(10) nm³, Z=8, D_c=1.596 g·cm^-3, μ=1.197 mm^-1, F(000)=2 048. The compound is an one-dimensional chain complex of infinite length which are connected with hydrogen bonds. The Cu(Ⅱ) was coordinated by two oxygen atoms and three nitrogen while the o atoms of Ac- groups did not participate in the coordination. The Cu(Ⅱ) formed a distorted tetragonal pyramid and the capacities of coordination to Cu(Ⅱ) of atoms was discussed. Besides, the TG-IR of the complex was analyzed. The kinetics of the thermal decomposition reaction of the complex was studied under a non isothermal condition by TG-IR. TG and DTG curves indicate that the complex decomposed in three stages: (?) The kinetic parameters were obtained from the analysis of TG,DTG cures by OZAWA-Flynn-Wall method, and the activation energy and the value of A of the three stages are 74.98 kJ·mol^-1, 286.65 kJ·mol^-1, 87.55 kJ·mol^-1; 9.66×10⁸ s^-1,1.82×10²⁸ s^-1, 3.09×10³s^-1, respectively.     

D201×4树脂对金(III)的吸附

Sorption behavior and mechanism of D201×4 resin for Au(III) were investigated. D201×4 resin has a good adsorptivity for Au(III) in HAc-NaAc medium at pH value of 2.63. The statically saturated Au(III) sorption capacity was 689.11 mg·g^-1 resin. The Au(III) adsorbed on D201×4 resin could be eluted by 10%NH₂CSNH₂-1 mol·L^-1 HCl(1∶1) and the elution rate was 92.2%.The adsorption of Au(III) on D201×4 follows the Freundlich isotherm. The ΔH of the adsorption was 11.03 kJ·mol^-1. The sorption rate constant was 5.42×10^-5 s^-1. The activation energy was 13.26 kJ·mol^-1. The molar coordination ratio of the functional group of D201×4 to Au(III) was about 1:1. The adsorption mechanism of resin for Au(III) was suggested according to chemical analysis and IR spectraoscopy results.     

Lu(Et2dtc)3(phen)的生成反应焓变、摩尔热容和恒容燃烧能测定

A ternary solid complex Lu(Et₂dtc)₃(phen) has been obtained from the reaction of hydrated lutetium chloride with sodium diethyldithiocarbamate (NaEt₂dtc), and 1,10-phenanthroline (o-phen·H₂O) in absolute ethanol. IR spectrum of the complex indicates that Lu³⁺ binds with sulfur atom in the Na(Et₂dtc)₃ and nitrogen atom in the o-phen. The enthalpy change of liquid-phase reaction of formation of the complex, Δ_rH_m^Ө (l), was determined to be (-32.821 ± 0.147 ) kJ·mol^-1 at 298.15 K by an RD-496 Ⅲ type heat conduction microcalormeter. The enthalpy change of the solid-phase reaction of formation of the complex, Δ_rH_m^Ө (s), was calculated to be (104.160 ± 0.168) kJ · mol^-1 on the basis of an appropriate thermochemistry cycle. The thermodynamics of liquid-phase reaction of formation of the complex was investigated by changing the temperature of liquid-phase reaction. Fundamental parameters, such as the activation enthalpy (ΔH_≠^Ө), the activation entropy (ΔS_≠^Ө), the activation free energy (ΔG_≠^Ө), the apparent reaction rate constant (k), the apparent activation energy (E), the pre-exponential constant (A) and the reaction order (n), were obtained by combination the reaction thermodynamic and kinetic equations with the data of thermokinetic experiments. The molar heat capacity of the complex, c_m, was determined to be (82.23 ± 1.47) J·mol^-1·K^-1 by the same microcalormeter. The constant-volume combustion energy of the complex, Δ_cU, was determined as (-17 898.228 ± 8.59) kJ·mol^-1 by an RBC-Ⅱtype rotating-bomb calorimeter at 298.15 K. Its standard enthalpy of combustion, Δ_cH_m^Ө, and standard enthalpy of formation, Δ_fH_m^Ө, were calculated to be (-17 917.43 ± 8.11) kJ·mol^-1 and (-859.95 ±10.12) kJ·mol^-1, respectively.     

配合物[Mn(bipy)3](ClO4)2的晶体结构和热分析研究

The complex [Mn(bipy)₃]·(ClO₄)₂ was synthesied and characterized by X-ray diffraction. X-ray diffraction result for the single crystal showed that the crystal belongs to triclinic, space group P1, a=0.8123(2),b=1.1024(2), c=1.8646(4)nm,α=102.30(3)°,β=91.00(3)°,γ=99.69(3)°,V=1.6056(6)nm³,Z=2,D_c=1.494g·cm^-3. The thermal decomposition of [Mn(bipy)₃](ClO₄)₂ occurred in a three steps pattern. The reaction mechanism of the first step decomposition was deduced as n(1-α)[-ln(1-α)](n-1)/n with the activation energy of 130kJ·mol^-1.     

CH2(COO)2Cu·2H2O热分解的非等温动力学研究

The thermal dehydration and decomposition kinetics of CH₂(COO)₂Cu·2H₂O were investigated using the non-isothermal method by thermogravimetry (TG) technique in N₂. The iterative iso-conversional methods were applied to calculate the activation energy E_a of dehydration and decomposition， and the most probable mechanism function G(α) was determined by means of the master plots method. The pre-exponential factor A was obtained on the basis of E_a and G(α). Kinetic parameters (E_a and lnA) of dehydration were given as: E_a=139.79 kJ·mol^-1， ln(A/s^-1)=47.38. The mechanism function of the dehydration was G(α)=[-ln(1-α)]^2/3， and the decomposition of CH₂(COO)₂Cu proceeds to completion by two distinct reactions. These two reactions overlap in the transition process (0.45<α<0.65). Kinetic parameters (E_a and lnA )of the first reaction of decomposition were: E_a=201.15 kJ·mol^-1， ln(A/s^-1)=52.29， and the mechanism function was G(α)=[1-α]^-0.37. And in the second reaction G(α)=α+(1-α)ln(1-α)， E_a=156.74 kJ·mol^-1， ln(A/s^-1)=39.58.     

MULTIDENTATE LIGAND EXCHANGE KINETICS:REACTIONS OF AMINOCARBOXYLATO-FERRATE(Ⅲ) COMPLEXES WITH 4-(2-PYRIDYLAZO) RESORCINOL

The kinetics and mechanism of ligand substitution reactions of nitnlotriacetatoiron(Ⅲ),(Fe(NTA)],and N-(2-hydroxycthyl)-ethylencdiaminetriacetatoiron(Ⅲ),[Fe(HEDTA)],complexes with 4-(2-pyridylazo) resorcinol (Par) has been investigated at pH=9.0±0.02,I=0.1mol·l^-1 (NaClO₄,and temp.=25±0.1℃ and 30±0.1℃ respectively. The reaction has been studied spectrophotometrically at 496 nm. (λmax of Fe(Par)₂. In both reactions the final product was [Fe(Par)₂]^-. The values of second order rate constants for NTA and HEDTA exchange reactions are (10.0±0.8)×10¹¹·mol^-1·s^-1 and (2.7±0.1)×10^-1·mol^-1·s_-1 respectively. The reactions of NTA and HEDTA exchange were studied in the pH range 6-9.5 and 7-10.85 respectively. The rate of reacton of [Fe(NTA)] with HPar^- first increases with pH and then levels off. However,in the case of [Fe(HEDTA)] reaction,the rate increases monotonically with increase of pH in the specified range.     

二水草酸亚铁热分解行为及脱水反应动力学研究

The thermal behavior of ferrous oxalate dihydrate (FeC₂O₄·2H₂O) was studied by thermogravimetry and differential thermal analysis (TGA and DTA). Three steps could be deduced for the decomposition from the TG,DTG and DTA curves obtained. One of the steps was the dehydration, the mass loss was 20.1%(the found value was in good agreement with the calculated value). Mathematical analysis with the integral and differential methods showed that the kinetics of dehydration of FeC₂O₄·2H₂O could be explained by F1 mechanism in nitrogen atmosphere. The kinetic equation of dehydration of FeC₂O₄·2H₂O could be expressed as: dα/dt=6.25×10¹⁹[exp(-170.27×10³/RT)](1-α)     

锆-氘反应热力学特性研究

The p-c-T curves and the relation between equilibrium pressure and temperature of deuterium absorption and desorption from zirconium were measured in the temperature range of 400～675 ℃. Equilibrium pressure of the absorption and desorption at different temperatures were given and then the thermodynamic parameters and the deuterium absorption capacity were determined according to Vant Hoff equation. There are different changes of enthalpy and entropy when zirconium changes to different phases. The change of enthalpy in the phase of α plus δ is -98.9 kJ·mol^-1 in the temperature range of 400～475 ℃. The changes of enthalpy in the first and second plateau are -75.1 kJ·mol^-1 and -161.7 kJ·mol^-1, respectively in the temperature range of 525～675 ℃. The corresponding changes of entropy are -66.5 J·K^-1·mol^-1, -32.4 J·K^-1·mol^-1 and -146.5 J·K^-1·mol^-1, respectively. There are obvious lagging effects when zirconium desorbs deuterium.     

CsCl-TmCl3-HCl-H2O(25 ℃)的相平衡及其固相化合物

The equilibrium solubilities of the quaternary system CsCl-TmCl₃-HCl-H₂O was determined at 25 ℃ and the corresponding equilibrium diagram was constructed. The diagram is a complicated system with limited solid solutions and formation of a new compound 3CsCl·2TmCl₃·14H₂O. The new compound has been characterized by XRD, TC-DTG and fluorescence spectrometry. Results show that upconversion spectrum exhibits at 335 nm when exciting at 860 nm, and fluorescence spectrum exhibits at 295 nm and 385 nm when exciting at 240 nm. The compound loses its crystal water by four steps at 50 to 250 ℃. Using a heat conduction calorimeter, the standard molar enthalpy of dissolution of 3CsCl·2TmCl₃·14H₂O was determined to be (-11.601 ± 0.050) kJ·mol^-1 at 298.15 K.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.