Thermochemistry on Coordination Behavior of Neodymium Chloride Hydrate with Diethylammonium Diethyldithiocarbamate

The complex of neodymium chloride lower hydrate with diethylammonium diethyldithiocarbamate (D-DDC) was synthesized conveniently in absolute alcohol and dry N_2 atmosphere. The title complex was identified as Et_2NH_2[Nd(S_2CNEt_2)_4] by chemical and elemental analyses and the bonding characteristics of which was characterized by IR. The enthalpies of solution of neodymium chloride hydrate and D-DDC in absolute alcohol at 298.15 K and the enthalpies change of liquid-phase reaction of formation for Et_2NH_2[Nd (S_2CNEt_2)_4] at different temperatures were determined by microcalorimetry. On the basis of experimental and calculated results, three thermodynamic parameters (the activation enthalpy, the activation entropy and the activation free energy), the rate constant and three kinetic parameters (the apparent activation energy, the pre-exponential constant and the reaction order) of liquid-phase reaction of formation were obtained. The enthalpy change of the solid-phase title reaction at 298.15 K was calculated by a thermochemical cycle.

Thermochemistry of Ternary Complex Dy(Et_2dtc)_3(phen)

The ternary solid complex was synthesized with sodium diethyldithiocarbamate (NaEt_2dtc), 1,10-phenanthroline (phen) and low hydrated dysprosium chloride in absolute ethanol by improved method of reference. The title complex was identified as the general formula of Dy(Et_2dtc)_3(phen) by chemical and elemental analyses. IR spectrum of the complex shows that the Dy^(3+) coordinated with six sulfur atoms of three NaEt_2dtc and two nitrogen atoms of phen. It is assumed that the coordination number of Dy^(3+) is eight.The enthalpy change of liquid-phase reaction of formation, Δ_rH~θ_m(l), is determined as (-19.091±0.015) kJ·mol^(-1) at 298.15 K by a microcalorimeter, and the enthalpy change of the solid-phase reaction of formation, Δ_rH~θ_m(s), is calculated as (139.641±0.482) kJ·mol^(-1) on the basis of a thermochemical cycle. The thermodynamic of reaction of formation was studied by changing the temperature of liquid-phase reaction. The constant-volume combustion energy of the complex, Δ_cU, is determined as (-16730.21±9.25) kJ·mol^(-1) by a precise rotating-bomb calorimeter at 298.15 K. Its standard enthalpies of combustion, Δ_cH~θ_m, and standard enthalpies of formation, Δ_fH~θ_m, are calculated as (-16749.42±9.25) kJ·mol^(-1) and (-2019.68±10.19) kJ·mol^(-1), respectively.

Phase Chemistry of the Complexes of RE Amino Acids

Forty three phase diagrams of ternary system concerning rare earth salts, α amino acids and water, which were constructed by phase equilibrium methods, were expounded. The influences of the factors such as cations, anions, the structure of amino acids, temperature on the phase diagrams were discussed. Under the guidance of phase equilibrium results, over 150 new solid complexes were prepared. IR, reflecting, UV, FS, and Raman spectra for these complexes were investigated and the regularity of 'tripartite effect', 'tetrad effect', 'Nephelanxetic effect', 'Oddo Harkins' was observed. Thermal decomposition processes of the complexes were confirmed. Based on the comparison with the known crystal structures of rare earth amino acid complexes, an estimation method for predicting the crystal structure data of series complexes was founded. The constant volume combustion energies of the complexes were determined by RBC 1 type rotating bomb calorimeter. The standard enthalpies of combustion and standard enthalpies of formation were calculated for these complexes.

Synthesis,Crystal Structure and Thermal Analysis of N-(2,3-Dimethyl-phenyl)-N'-(methoxyl formyl)thiourea

N-（2,3-Dimethyl-phenyl）-N＇-（methoxyl formyl）thiourea was synthesized by the reacting of 2,3-dimethylaniline,potassium thiocyanate（KSCN） and methyl chloroformate（ClCOOCH 3）.Single crystal was obtained by slowly evaporation solvent at room temperature.The structure was characterized by elemental analysis,IR and X-ray crystalography.The compound crystallized：a triclinic system with space group Pī,a=0.83440（12） nm,b=0.89113（13） nm,c=0.93015（13） nm,α=76.548（2） o,β=63.906（2） o,γ=82.538（2） o,V=0.60379（15） nm 3,Z=2,D c =1.311 mg/m 3,F（000）=252,μ=0.256 mm-1,R 1 =0.0379,wR 2 =0.0919.The specific heat capacity of the title compound was determined by a Micro-DSC method,and the specific heat capacity was 1.25 J·g-1 ·K-1 at 298.15 K.Thermodynamic functions,relative to those at the standard temperature of 298.15 K,were calculated via thermodynamic relationship.The thermal behavior of the title compound under a non-isothermal condition was studied by differential scanning calorimetry/thermogravimetric（DSC/TG） method.There was an obvious endothermic peak in the DSC curve,the peak temperature was 479.43 K.The compound mass loss was 89.94% observed from the TG curve.

Measurements of Enthalpy Change of Reaction of Formation, Molar Heat Capacity and Constant-Volume Combustion Energy of Solid Complex Yb(Et_2dtc)_3(phen)

A ternary solid complex Yb（Et2dtc）3（phen） was obtained from the reaction of hydrous ytterbium chloride with sodium diethyldithiocarbamate （NaEt2dtc）, and 1, 10-phenanthroline （o-phen·H2O） in absolute ethanol. The bonding characteristics of the complex were characterized by IR. The result shows Yb3^＋ bands with two sulfur atoms in the Na（Et2dtc）3 and two nitrogen atoms in the o-phen. The enthalpy change of liquid-phase reaction of formation of the complex △rHm^θ（Ⅰ）, was determined as being （-24.838±0.114） 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 △rHm^θ（s）, was calculated as being （108.015±0.479） 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 during the liquid-phase reaction. Fundamental parameters, the activation enthalpy, △H≠^θ, the activation entropy, △S≠^θ, the activation free energy,△G≠^θ, the apparent reaction rate constant k, the apparent activation energy E, the pre-exponential constant A, and the reaction order n, were obtained by a combination of the reaction thermodynamic and kinetic equations with the data from the thermokinetic expenments. At the same time, the molar heat capacity of the complex cm. p, Was determined to be （86.34± 1.74） J·mol^-1·K^-1 by the same microcalormeter. The constant-volume combus- tion energy of the complex, △cU, was determined to be （ - 17954.08 ± 8.11） kJ·mol^-1 by an RBC-Ⅱ type rotating-bomb calo- rimeter at 298.15 K. Its standard enthalpy of combustion, △cHm^θ, and standard enthalpy of formation, △fHm^θ, were calculated to be （- 17973.29±8.11） kJ·mol^-1 and （-770.36±9.02） kJ·mol^-1, respectively.

Thermochemical Properties of the Complexes RE(HSal)_3·2H_2O (RE=La,Ce,Pr,Nd,Sm)

Five solid rare earth salicylate complexes were synthesized by low hydrated lathanide chloride and salicylic acid. The complexes in this experiment were identified as the general formula RE（HSal）3·2H2O（RE = La, Ce, Pr, Nd, Sm） by elemental analysis and EDTA volumetric analysis. IR spectra of the complexes show that carboxyl of salicylic acid coordinates to RE^3＋ ions. Electrochemical behaviors of the complexes on the glass-carbon electrode were researched with cyclic voltammetry （CV）. It is indicated that the electrochemical process of the complexes is a one-electron redox process and the electrochemical reversibility of complexes is less than that of the lanthanide chlorides. The constant-volume combustion energies of complexes,△c U, were determined with a precise rotating-bomb calorimeter at 298.15 K. Their standard molar enthalpies of combustion, △cH^θm, and standard molar enthalpies of formation, △fH^θm, were calculated.

ESTIMATION OF THE CRITICAL RATE OF TEMPERATURE INCREASE OF THERMAL EXPLOSION OF NITROCELLULOSE USING NON-ISOTHERMAL DSC

A method of estimating the critical rate of temperature increase of thermal explosion for the first orderautocatalytic decomposition reaction system using non-isothermal DSC is presented. Information is obtained on theincreasing rate of temperature in nitrocellulose containing 13.54% of nitrogen when the first order autocatalytic decomposition converts into thermal explosion.

Thermochemical Study of Coordination of Holmium Chloride Hydrate with Diethylammonium Diethyldithiocarbamate

The complex of holmium chloride hydrate with diethylammonium diethyldithiocarbamate(D-DDC) was synthesized via mixing their solutions in absolute alcohol under a dry N 2 atmosphere. The elemental and chemical analyses show that the complex has the general formula Et 2NH 2[Ho(S 2CNEt 2) 4]. It was also characterized by IR spectroscopy. The enthalpies of the dissolution of holmium chloride hydrate and D-DDC in absolute alcohol at 298.15 K, and the enthalpy changes of liquid-phase reactions of the formation of Et 2NH 2[Ho(S 2CNEt 2) 4] at different temperatures were determined by microcalorimetry. On the basis of experimental and calculated results, three thermodynamic parameters(the activation enthalpy, the activation entropy and the activation free energy), the rate constant and three kinetic parameters(the apparent activation energy, the pre-exponential constant and the reaction order) of the liquid-phase reaction of the complex formation were obtained. The enthalpy change of the solid-phase complex formation reaction at 298.15 K was calculated by means of a thermochemical cycle.

Synthesis and Crystal Structure of a Copper(Ⅱ) Compound Constructed by N-(4,6-Dimethoxylpyrimidin)-N'-(ethoxycarbonyl)thiourea

A copper（Ⅱ） complex Cu（L）2（NO3）2 constructed by the L （L = N-（4,6-dimethoxylpyrimidin）-N＇-（ethoxycarbonyl）thiourea） ligand crystallizes in monoclinic, space group C2/c with a = 16.2416（16）, b = 9.1385（7）, c = 22.0008（18） A, β = 108.077（2）°, V = 3104.3（5） A^3, Dc = 1.627 g/cm^3, Z = 4, C20H28CuN10O14S2, Mr = 760.18,μ（MoKa） = 0.920 mm^-1, F（000） = 1564, R = 0.0471 and wR = 0.1284 for 2239 observed reflections （I 〉 2σ（I））. X-ray diffraction shows the existence of weak complementary intramolecular N-H...O （DA） hydrogen bonds which further strengthen the coordination from the two L ligands with the Cu（Ⅱ） ion, intermolecular C-H...O hydrogen bonds and weak π...π stacking interactions, leading to the formation of a multi-dimensional supramolecular network.

Analysis of Intra-and Intermolecular Hydrogen Bonds and Quantum Chemical Calculations on 1-(3-Fluorobenzoyl)-3-(4-trifluoromethylphenyl)thiourea

1-（3-Fluorobenzoyl）-3-（4-trifluoromethylphenyl）thiourea, C15H10F4N2OS, has been synthesized firstly and determined by single-crystal X-ray diffraction analysis. The title compound crystallizes in monoclinic system, space group C2/c with a = 31.87（3）, b = 7.705（9）, c = 12.591（14） A°, b = 106.06（2）°, V = 2971（6） A°^3, Z = 8, Dc=1.530 g·cm^-1, F（000） = 1392, m = 0.266 mm^–1, S = 1.06, the final R = 0.070 and w R（I 〉 2s（I）） = 0.249. The crystal structure revealed that the carbonyl thiourea unit in the determined compound was mostly planar due in part to the formation of intramolecular N–H···O=C and C–H···S=C hydrogen bonds that form two S（6） rings. The intermolecular contacts of the crystal structure have been preformed based on the Hirshfeld surface and their associated 2D fingerprint plots. In the packing diagram of the synthesized compound, the C=S group formed two types of intermolecular hydrogen bonds by the H–N（C=O） group and the H–C of the phenyl ring, respectively, and they formed R2^2（8） and R2^2（14） ring motifs, respectively. The crystal packing form was also stabilized by the intermolecular hydrogen bonds C–H···O（1–x, y, 0.5–z） with the R2^2（10） ring motifs. In addition, supramolecular layers sustained by π-π stacking interactions（between the C（2）～C（7） rings with the C（10）～C（15） rings） are formed in the crystal structure of the title compound. The electronic and reactivity were assessed by the natural bond orbital（NBO） analysis in this study.

Synthesis and Crystal Structure of Picrates of 3,5-Diamino-1,2,4-triazole

The title compound C2N5H6＋C6N3O7H2-was synthesized by the reaction of 3,5-diamino-1,2,4-triazole and picric acid in the mixture of ethanol and water solution.Single crystals suitable for X-ray measurement were obtained at room temperature.The structure was characterized by elemental analysis and IR and determined by X-ray diffraction analysis.Crystallographic data：C8N8H8O7,Mr = 328.22,monoclinic,space group C2/c with a = 22.815（2）,b = 4.8086（5）,c = 22.564（2）,β = 93.976（2）°,V = 2469.6（4）3,Dc = 1.766 g/cm3,Z = 8,μ = 0.156 mm-1,F（000） = 1344,the final R= 0.0309,wR= 0.0864.

Synthesis, Characterization, Thermal Decomposition Mechanism and Non-Isothermal Kinetics of Salicylaldehyde Salicylhydrazone and Its Complex of Erbium(Ⅲ)

The salicylaldehyde salicylhydrazone and its complex of Er(Ⅲ) were synthesized. The formulae K·4H_2O(HL=[C_(14)H_(10)N_2O_3]^(2-), the bivalent form of the salicylaldehyde salicylhydrazone) were determined by elemental analysis and EDTA volumetric analysis. Molar conductance, IR, UV and X-ray power diffraction were carried out for the characterizations of the complex and the ligand. There are two stable five-numbered and six-numbered circles in the complex. The thermal decompositions of the ligand and the complex with the kinetic study are carried out by non-isothermal thermogravimetry. The stages of the decompositions were identified by TG-DTG curve. The non-isothermal kinetic data were analyzed by means of integral and differential methods. The possible reaction mechanism and the kinetic equation were investigated by the corresponding kinetic parameters.The activation energy value of the main step decomposition are also calculated by Kissinger′s method and Ozawa′s method.

Standard energies of combustion and standard enthalpies of formation for the complexes RE (Et_2dtc)_3(phen) (RE = Ho,Er,Tm,Yb,Lu)

The treatment of RECl3.xH2O （RE = Ho, Er, Tm, Yb, Lu; x = 3-4） with sodium diethyldithiocarbamate （NaEtEdtc-3H2O） and 1,10-phenanthroline hydrate （o-phen.H2O） in absolute ethanol yielded five ternary solid complexes RE（EtEdtC）a（phen）. IR spectra of the complexes showed that RE^3＋ coordinated to two sulfur atoms in NaEt2dtc and two nitrogen atoms in o-phen. The constant-volume energies of combustion of the complexes have been determined by a precise rotating-bomb calorimeter at 298.15 K. The standard enthalpies of combustion and standard enthalpies of formation were calculated.

Formation of infinite 2D water layers in a crystal host

一自我装配，(H 2 O ) 单音原子的铜(II ) 稳定的 38 簇建筑群 1 也就是 {；[Cu (phen )2(CO3)]·7H2 O } 被 X 光检查衍射研究描绘。邻近(H 2 O )38 簇一起连接导致无限的 2D 水层结构。水形态学在房间温度是稳定的，但是在热分解之上，水损失是不可逆的。

Standard Molar Enthalpy of Formation of RE(C_5H_8NS_2)_3(C_(12)H_8N_2)

Four solid ternary complexes of RE (C_5H_8NS_2)_3(C_(12)H_8N_2) (RE=Eu, Gd, Tb, Dy) were synthesized in absolute ethanol by rare earth chloride low hydrate with the mixed ligands of ammonium pyrrolidinedi-thiocarbamate (APDC) and 1, 10-phenanthroline·H_2O (o-phen·H_2O) in the ordinary laboratory atmosphere without any cautions against moisture or air sensitivity. IR spectra of the complexes show that the RE^(3+) coordinated with six sulfur atoms of three PDC^- and two nitrogen atoms of o-phen·H_2O. It was assumed that the coordination number of RE^(3+) is eight. The constant-volume combustion energies of the complexes, Δ_cU, were determined as (-16937 88±9 79 ), (-17588 79±8 62 ), ((-17747 14±)8 25 ) and (-17840 37±8 87 ) kJ·mol^(-1), by a precise rotating-bomb calorimeter at 298.15 K. Its standard molar enthalpies of combustion, Δ_cH~θ_m, and standard molar enthalpies of formation, Δ_fH~θ_m, were calculated as (-16953 37±9 79), (-17604 28±8 62), (-17762 63±8 25), (-17855 86±8 87) kJ·mol^(-1) and (-857.04±10.52), (-282.43±9.58), (-130.08±9.13), (-55.75±9.83) kJ·mol^(-1).

Thermochemical properties of Ternary Complex Yb[(C_5H_8NS_2)_3(C_(12)H_8N_2)]

A novel ternary solid complex, Yb （C5H8NS2）3 （C12H8N2）, was obtained from treating hydrous ytterbium chloride, ammonium pyrrolidin- edithiocarbamate （ APDC ） and 1, 10-phenanthroline （o-phen· H2O） in absolute ethanol, and characterized by elemental analysis. The enthalpies of solution of hydrous ytterbium chloride, APDC, o-phen·H2O, the mixture of APDC with o-phen· H2O in absolute ethanol at 298. 15 K, and the enthalpy changes of liquid- phase reaction of formation for Yb （ C5H8NS2 ）3 （ C12H8N2） at different temperatures were measured by using a RD496-Ⅲ microcalorimeter. Fundamental paconduction microcalorimeter, determining the specific heat a calculation model for capacity of solid subrameters, the activation enthalpy （ΔH≠^θ）, the activation entropy （ΔS≠^θ）, the activation free energy （ΔG≠^θ）, the apparent reaction rate constant （k）, the apparent activation energy （ E ）, the pre-exponential constant （A） and the reaction order （n）, were obtained by the combination of the thermochemical data of the reaction and kinetic equations with the data of thermokinetic experiments. The enthalpy change of complex formation from the reaction of the regents in solid phase, ΔrH≠^θ（s）, was calculated on the basis of an appropriate thermochemical cycle and other auxiliary thermodynamic data. Based on a RD496-Ⅲ heat stance was developed, and the title complex, c m, were accordingly determined.

Kinetics of the Exothermic Decomposition Reaction of s-Tripicryaminotrinitrobenzene

The kinetic parameters of the exothermic decomposition reaction of s-Tripicryaminotrinitrobenzene under linear temperature rise condition are studied by means of DSC. The results show that the empirical kinetic model function in differential form, apparent activation energy and pre-exponential constant of the reaction are 225.4 kJ·mol-1 and 1 019.53 s-1, respectively. The critical temperature of thermal explosion of the compound is 267.36 ℃.

Synthesis, Characterization and Thermal Decomposition of Ln(Me_2dtc)_3(phen)

Four solid complexes of Ln(Me2dtc)3(phen) (Ln=Eu, Gd, Tb, Dy) were synthesized in anhydrous ethanol by the reaction of lanthanide chloride low hydrate with the mixed ligands of sodium dimethyldithiocarbamate and 1, 10-phenanthroline·H2O (abbreviated as phen·H2O), and characterized by elemental analysis, IR spectroscopy, TG-DTG and X-ray diffraction techniques. Combining with the crystal structures, the complexes are identified as the general formula of Ln(Me2dtc)3(phen). TG-DTG with X-ray powder diffraction showed that these compounds could decompose to lanthanide sulfides under relatively lower temperature, which indicated that the title complexes could be ideal precursors to prepare lanthanide sulfides.

Kinetics of Thermal Decomposition of Nd[(C_5H_ (10)NS_2)_3(C_ (12)H_8N_2)] in Non-Isothermal Conditions

The non-isothermal decomposition reaction of Nd[(C_5H_ 10NS_2)_3(C_ 12H_8N_2)] were carried out by means of TG-DTG and the thermal decomposition mechanism, and the associated kinetics was investigated. The kinetic parameters are obtained from an analysis of the TG-DTG curves at different heating rate by integral and differential methods. The most probable kinetic model function of the decomposition reaction is Maple Power of n=3/2, f(α)=2/3α -1/2 and the apparent activation energy E is 116.67 kJ·mol -1 and the pre-exponential factor lg[A/s -1] is 7.6891.

Synthesis,Characterization and Thermal Decomposition of Ln(Me_2dtc)_3 (phen) (Ln=La,Pr,Nd,Sm)

Four solid complexes of Ln(Me2dtc)3(phen) (Ln=La, Pr, Nd, Sm) were synthesized in anhydrous ethanol by the reaction of lanthanide chloride low hydrate with the mixed ligand of sodium dimethyldithiocarbamate and 1, 10-phenanthroline·H2O (phen·H2O), and characterized by elemental analysis, IR spectroscopy, TG-DTG, and X-ray diffraction analysis. TG-DTG with X-ray powder diffraction showed that these compounds could decompose to lanthanide sulfides at relatively lower temperature, which indicated that the title complexes could be favorable precursors to prepare lanthanide sulfides.