Thermal Decomposition Kinetics and Mechanism of Tb(Ⅲ) m-Methylbenzoate Complex with 1,10-Phenanthroline in Static Air Atmosphere

The thermal behavior of [Tb_2( m -MBA)_6(phen)_2](H_2O)_2( m -MBA=C_8H_7O_2, methoxybenzoate; phen=C_ 12 H_8N_2, 1,10-phenanthroline) in static air atmosphere was investigated by means of TG-DTG and DTA methods. The thermal decomposition of the title compound takes place mainly in two steps. The intermediate and the residue for each decomposition were identified by the TG curve. By the kinetic method of processing thermal analysis data put forward by Malek et al ., it is defined that the kinetics model for the first-step thermal decomposition is SB( m,n ).

Thermal Decomposition Mechanism and Non Isothermal Kinetics of Complex of [La_2(P-MBA)_6(PHEN)_2]2H_2O

The complex of [La 2(P MBA) 6(PHEN) 2]2H 2O (P MBA: p methylbenzoate and PHEN: 1,10 phenanthroline) was prepared and characterized by elemental analysis and IR spectroscopy. The thermal behavior of [La 2(P MBA) 6(PHEN) 2]2H 2O in dynamic nitrogen atmosphere was investigated by TG DTG techniques. The results show that the thermal decomposition process of the [La 2(P MBA) 6(PHEN) 2]2H 2O occurs in five steps. The empirical kinetic model for the first step thermal decomposition obtained by Malek method is SB(m,n). The activation energy E and the pre exponential factor lnA for this step reaction are 76.4 kJ·mol -1 and 24.92, respectively.

Kinetics Study on the Thermal Decomposition of Europium p-methyl-benzoate Complex with 1,10-penanthroline under Non-isothermal Con-ditions

The thermal decomposition reaction of Eu-2(p-MBA)(6)(PHEN)(2) (p-MBA=CH3C6H4COO, methylbenzoate; PHEN=C12H8N2, 1,10-phenanthroline) was studied in a static atmosphere using TG-DTG method. The thermal decomposition process of the complex was determined and its kinetics was investigated. Kinetic parameters were obtained from the analysis of TG-DTG curves by means of the Achar method and the Madhusudanan-Krishnan-Ninan (MKN) method. The most probable mechanism functions of the thermal decomposition reaction for the first stage are: f(alpha) =(1-alpha)(2), g(alpha) = (1-alpha)(-1)-1. The activation energy for the first stage is 255.18 kJ/mol, the entropy of activation DeltaS is 227.32 J/mol and the Gibbs free energy of activation DeltaG is 128.04 W/mol.

Thermal decomposition kinetics and lifetime of the complex of Tb_2(BA)_6(PHEN)_2

The thermal behavior of Tb_2(BA)_6(PHEN)_2 (BA: benzoate, and PHEN:1,10-phenanthroline) in a static air atmosphere was investigated by TG-DTG, SEM and IR techniques.By the kinetic method of processing thermal analysis data put forward by Malek et al., it is definedthat the kinetic model for the first-step thermal decomposition is SB(m, n). The activation energyE for this step reaction is 99.07 kJ/mol, the entropy of activation ΔS~≠ is -84.72 J/mol, theenthalpy of activation ΔH~≠ is 94.26 kJ/mol, the free energy of activation ΔG~≠ is 144.77 kJ/moland the pre-exponential factor lnA is 20.93. The lifetime equation at mass-loss of 10% was deducedas lnτ = -29.0312 + 19760.83/T by isothermal thermogravimetric analysis.

Thermal Stability,Thermal Decomposition and Mechanism Analysis of Cycloaliphatic Epoxy/4,4'-dihydroxydiphenylsulfone/Aluminum Complexes Latent Resin Systems

The thermal stability of latent resin systems, cycloaliphatic epoxy/4,4＇- dihydroxydiphenylsulfone/aluminum complexes, was investigated by dynamic differential scanning calorimetry （DSC） analysis. Experiments were conducted under non-isothermal condition in a nitrogen atmosphere at the heating rate of 10, 20, 30 and 40 ℃/min, respectively. TG curves showed that, in the temperature range of 25 to 600 ℃, the stability of the resin systems could be enhanced by increasing the length of the aliphatic chain in the initiator. Both the Kissinger method and the Ozawa-Flyrm-Wall method were employed to calculate activation energies of the decomposition reaction, and the values obtained from the two methods were compared. Moreover, the corresponding reaction mechanism was identified by the Achar differential method and the Coats- Redfem integral method. The experimental results showed that these four methods were reliable and effective to study the kinetics of the thermal decomposition reaction; and the most probable thermal decomposition mechanism of the resin systems we proposed was found to comply with Mampel power law （m=1）.

Synthesis, Crystal Structure and Kinetic Mechanism of Thermal Decomposition of a Zinc(II) Complex with N-Salicylidene-p-toluidine

The title complex, Zn（C24H13NO）2Cl21, has been synthesized by the reaction of zinc chloride with Schiff base ligand N-salicylidene-p-toluidine and its structure was determined by single-crystal X-ray diffraction. The crystal is of monoclinic, space group Cc with a = 14.896（3）, b = 12.506（2）, c = 15.352（3） A,β = 114.711 （4）°, V = 2598.0（8） A^3, C28H26ZnCl2N2O2, Mr = 558.80, Z = 4, Dc = 1 .429 g/cm^3,μ = 1.179 mm^-1, Flack parameter = 0.027（19）, F（000） = 1152, R = 0.0709 and wR = 0.1041 for 3117 observed reflections （Ⅰ 〉 2σ（Ⅰ））. In complex 1, the center Zn ion is four-coordinated by two O atoms from two Schiff base ligands and two Cl atoms in a distorted tetrahedral geometry. Additionally, the thermal decomposition of complex 1 as well as its kinetic mechanisms and equations is studied under the non-isothermal integral and differential methods in air by TG-DTG curves.

Synthesis and Thermal Decomposition Kinetics of La(Ⅲ) Complex with Unsymmetrical Schiff Base Zwitterion Ligand

A new unsymmetrical solid Schiff base (LLi) was synthesized using L-lysine, o-vanillin and 2-hydroxy-l-naphthaldehyde. Solid La(Ⅲ) complex of this ligand [LaL(NO3)](NO3)·2H2O was prepared and characterized by elemental analyses, IR, UV and molar conductance. The thermal decomposition kinetics of the complex for the second stage were studied under non-isothermal condition by TG and DTG methods. The kinetic equation may be expressed as: dα/dt=A·e-E/RT·(1-α)2. The kinetic parameters(E, A), activation entropy S≠ and activation free-energy G≠ were also gained.

Non-isothermal kinetics of the first-stage decomposition reaction of the complex of samarium p-methoxybenzoate with 1,10-phenanthroline

The complex of [Sm（p-MOBA）3phen]2 （p-MOBA, p-methoxybenzoate; phen,1 10-phenanthroline） was prepared and characterized by elemental analysis, IR, and UV spectroscopy. The thermal decomposition of the [Sm（p-MOBA）sphen]2 complex and its kinetics were studied under a static air atmosphere by TG-DTG methods. The intermediate and residue for each decomposition stage were identified from the TG curve. The kinetic parameters and mecha- nisms of the first decomposition stage were obtained from the analysis of the TG-DTG curves by a new method of processing the data of thermal analysis kinetics. The lifetime equation at a mass loss of 10% was deduced as lnr= - 30.6795 ＋ 21034.56/Tby isothermal thermogravimelric analysis.

Thermal Decomposition Kinetics of Ni(Ⅱ)Complex with Norfloxacin

The thermal decomposition of the 2H2O (NFA=C16H18FN3O3, norfloxacin) and its kinetics were studied under the nonisothermal condition in nitrogen by TGDTG and DTA methods. The intermediate and residue for each decomposition were identified from TG curve. The Achar method and the MadhusudananKrishnanNinan (MKN) method were used to analyze the nonisothermal kinetic data. The possible reaction mechanisms were investigated by comparing the kinetic parameters. The kinetic equation for the third stage and the mathematical expressions for the kinetic compensation effects of the third stage were obtained.

Kinetics of Thermal Decomposition for Complex [Zn(C_(16)H_(18)FN_3O_3)_2(NO_3)_2]·2H_2O

The thermal decomposition reaction of the [Zn(NFA)_2(NO_3)_2]·2H_2O(NFA=C_ 16H_ 18FN_3O_3,norfloxacin) was studied in a static atmosphere using TG-DTG and DTA methods. The thermal decomposition processes of the complex were determined and its kinetics was investigated. The kinetic parameters were obtained from analysis of the TG-DTG curves by differential and integral methods. The most pro- bable mechanism for the second stage was suggested by comparision of the kinetic parameters.

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.

Preparation,Characterization and Thermal Decomposition Kinetics of the Complexes [Dy(p-NBA)_3Phen]_2·3H_2O and [Dy(m-NBA)_3Phen]_2·4H_2O

The title complexes [Dy（p-NBA）3Phen]2-3H2O（Ⅰ） and [Dy（m-NBA）3Phen]2·4H2O（Ⅱ） were synthesized, in the two molecular formulas of which NBA is nitrobenzoate and Phen is 1,10-phenanthroline. The characterizations of the complexes were carried out by means of elemental analysis, UV, IR, XRD and molar conductivity. The thermal decomposition of the two complexes were studied under the non-isothermal condition by DSC, TG-DTG and IR methods in detail. The kinetic parameters of the dehydration process were also obtained by the analysis of DSC curves of the two complexes with Popescu and Vyazovkin methods, respectively.

Preparation and spectroscopic, and thermal decomposition kinetic studies of europium(Ⅲ) complex [Eu(HNBD)_3] (HNBD: 1-(6-hydroxy-1-naphthyl)-1,3-butanedione)

The complex of Eu（IH） with 1-（6-hydroxy- 1-naphthyl）- 1,3-butanedione （HNBD） was prepared for the first time and characterized by elemental analysis, IR, UV, fluorescence spectrum, and DTA-TG-DTG techniques. The IR and UV-visible spectra showed that Eu（Ⅲ） ion was coordinated to the HNBD ligand. The fluorescence spectrum showed the presence of Eu^3＋ characteristic emission. The TG-DTA-DTG curves showed that the thermal decomposition of the anhydrous complex was a two-stage process and the final residue was Eu2O3. The thermal decomposition kinetic parameters of the complex were evaluated from TG-DTG data by using three kinds of integral methods （Coat-Redfem equation, Horowitz and Metzger equation, Madhusudanan-Krishnan-Ninan equation）. The kinetic parameters of the first stage are E^＊ = 164.02 kJ.moll, A = 1.31 × 10^15 s^-l, AS^＊= 42.27 J·K^-l·mol^-l, △H^＊ = 159.51 kJ·mol^-l, △G^＊= 136.54 kJ·mol^-l, and n = 3.1, those of the second stage are E^＊= 128.52 kJ·mol^-l, A = 1.44× 106 s^-1, △S^＊= - 136.89 J·K^-l·mol^-l, △H^＊ = 120.41 kJ·mol^-l, △G^＊= 283.85 kJ·mol^-l, and n = 1.1.

Kinetics on Thermal Decomposition of Iron(III) Complexes of 1,2-Bis(Imino-4’-Antipyrinyl)Ethane with Varying Counter Anions

A comparative thermal decomposition kinetic investigation on Fe(III) complexes of a antipyrine Schiff base ligand, 1,2-Bis(imino-4’-antipyrinyl)ethane (GA)), with varying counter anions viz. CIO4-, NO3-, SCN-, Cl-, and Br-, has been done by thermogravimetric analysis by using Coats-Redfern equation. The kinetic parameters like activation energy (E), pre-exponential factor (A) and entropy of activation (ΔS) were quantified. On comparing the various kinetic parameters, lower activation energy was observed in second stage as compared to first thermal decomposition stage. The same trend has been observed for pre-exponential factor (A) and entropy of activation (ΔS). The present results show that the starting materials having higher activation energy (E), are more stable than the intermediate products, however;the intermediate products possess well-ordered chemical structure due to their highly negative entropy of activation (ΔS) values. The present investigation proves that the counter anions play an important role on the thermal decomposition kinetics of the complexes.

Microwave assisted synthesis, spectroscopic, thermal, and antifungal studies of some lanthanide(Ⅲ) complexes with a heterocyclic bishydrazone

A bishydrazone formed by the condensation of isatinmonohydrazone and salicylaldehyde reacted with lanthanide（Ⅲ） chloride to form complexes of the type [Ln（HISA）2Cl3], where, Ln=La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, or Gd（Ⅲ） and HISA= [（2-hydroxybenzaldehyde）-3-isatin]bishydrazone. Both reactions were carried out under microwave conditions. The ligand and the metal complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements, UV visible, infrared, far infrared, and proton NMR spectral data. The ligand acted as neutral tridentate, coordinating through the carbonyl oxygen, azomethine nitrogen, and phenolic oxygen without deprotonation. The ligand and lanthanum（Ⅲ） complex were subjected to X-ray diffraction studies. The X-ray diffraction pattern of ligand exhibited its crystalline nature and that of the lanthanum（Ⅲ） complex indicated its amorphous character. The thermal decomposition behaviour of the complex, [La（HISA）2Cl3], was examined in the temperature range of 40-800 ℃ using TG, DTG, and DTA. The ligand and the metal complexes were screened for their antifungal activities.

Thermal Behaviour of Some New Polyoxometalate Complexes of Ciprofloxacin with Keggin-type Heteropoly Acids

Four polyoxometalate complexes, (CPFX·HCl)_3H_4SiW_~12 O_~40 , (CPFX·HCl)_3H_3PW_~12 O_~40 , (CPFX·HCl)_3H_3PMo_~12 O_~40 and (CPFX·HCl)_4H_4SiMo_~12 O_~40 , were prepared from ciprofloxacin hydrochloride(CPFX·HCl) reacting with H_nXM_~12 O_~40 ·nH_2O(X=P,Si; M=W,Mo) in an aqueous solution, and characterized by elemental analysis, IR spectrometry and TG-DTA. The IR spectrum confirms the presence of Keggin-type anions of heteropoly acids and the characteristic functional groups of ciprofloxacin. The TG/DTA curves show that their thermal decomposition is a multi-step process including simultaneous collapse of the Keggin-type structure. At first, these compounds had a mass loss of water molecules, then several other mass losses occured due to the decomposition of ciprofloxacin hydrochloride and its fragments with the degradation of Keggin anions. The end product of decomposition is the mixture of WO_3(or MoO_3) and SiO_2(or P_2O_5), identified by X-ray diffraction and IR spectroscopy. The possible thermal decomposition mechanisms of these complexes are proposed. This study exemplified that the thermal stability of the complexes containing tungsten is much better than that of the complexes containing molybdenum.

Synthesis, Crystal Structure and Thermal Property of a Manganese(II) 4-Carboxyphenoxyacetate Complex

The manganese(II) complex, [Mn(phen)2(4-CPOA)(H2O)]?5H2O (4-CPOAH2 = 4- carboxyphenoxyacetic acid) has been synthesized and characterized by elemental analyses, IR, TG and single-crystal X-ray diffraction. The crystal is of monoclinic, space group C2/c, with a = 27.471(3), b = 18.490(4), c = 14.507(3) ?, β = 115.13(3)o, V = 6671(3) ?3, Z = 8, Mr = 717.58, Dc= 1.429 g/cm3, μ = 0.462 mm–1, F(000) = 2984, the final R = 0.0535 and wR = 0.1200 for 5413 observed reflections with I > 2σ(I). The Mn(II) atom is coordinated by one O atom of 4-carboxy- phenoxyacetate, four N atoms of two 1,10-phenanthroline and one water molecule, residing in a distorted octahedral environment. A supramolecular network structure is formed by hydrogen bonds and π-π stacking interactions.

Synthesis, Characterization and Thermodecomposition Kinetics of Dy-Complex with Furfural and DL-α-Alanine

A new schiff base complex derived from furfural-DL-α-alanine and Dy(NO_3)·6H_2O was synthesized. It was characterized by elemental analysis, infrared spectra, ultraviolet spectra, molar conductivity measurements and thermogravimetric analysis. The stoichiometry was deduced to be [Dy(C_8H_8NO_3)(H_2O)(NO_3)](H_2O)(NO_3). Its thermal decomposition reaction kinetics was studied by thermogravimetry.

Synthesis, Structure and Physical Properties of a Barium(II) Complex with 5-Sulfoisophthalic Acid Sodium

An alkaline earth metal-organic framework [Ba（Hsip）（H2O）4]n （1, NaH2sip = 5-sulfoisophthalic acid sodium） has been constructed, and characterized by single-crystal X-ray diffraction. In complex 1, each Ba（II） atom coordinates to one ligand Hsip3- and four water molecules with a distorted nine-coordinated monocapped tetragonal antiprism geometry. Each Hsip2- anion acts as a μ3-bridging ligand, in which two carboxylate groups adopt the same bidentate chelating coordinating model and the sulfonate group takes a monodentate coordinating model, resulting in a wave-like two-dimensional network with a （6, 3） topological structure. The two-dimensional networks are further linked by O–H···O to form a three-dimensional structure. Luminescent property and thermal stability of complex 1 are investigated. 1 belongs to the orthorhombic system, space group Pna21 with a = 7.3333（2）, b = 16.7044（3）, c = 10.4817（2）, Z = 4, V = 1283.99（5）3, Mr = 453.58, Dc = 2.346 g/cm3, F（000） = 880, μ = 3.314 mm–1, the final R = 0.0261 and wR = 0.0592 for 2425 observed reflections with I 2σ（I）.

Synthesis, Structure and Properties of a Strontium(Ⅱ) Complex with 2, 3-Pyrazinedicarboxylic Acid

Complex [Sr2（pdc）2（H2O）7]·H2O （1, H2pdc = 2,3-pyrazinedicarboxylic acid） has been synthesized and characterized by single-crystal X-ray diffraction studies and FT-IR. Structural determination reveals that there are two crystallographically independent strontium ions in 1. The coordination geometry of Sr（1） is a nine-coordinated distorted monocapped tetragonal antiprism, while Sr（2） is a nine-coordinated distorted monocapped tetragonal prism. The ligand pdc2- takes two different connecting modes and links St（If） centers to generate a 2D layer structure. The 2D layers are linked through O-H...O and O-H...N hydrogen bonds to form a 3D framework structure. Thermal stability and luminescent properties of complex 1 are investigated. 1 belongs to the monoclinic system, space group P21/n with a = 10.7182（10）, b = 7.0377（6）, c = 29.225（3） A, β = 95.7170（10）°, Z = 4, V = 2193.5（3） A3, Mr = 651.56, Dc = 1.973 g/cm3, F（000） = 1296,μ = 4.951 mm-1, the final R = 0.0318 and wR = 0.0726 for 3938 observed reflections with I 〉 2σ（/）.