Energetic calcium(II) complexes of 3,6-bis(1H-1,2,3,4-tetrazol-5-yl-amino)1,2,4,5-tetrazine: synthesis,crystal structure,and thermal properties

We synthesized two calcium salts of 3,6-bis(1H-1,2,3,4-tetrazol-5-yl-amino)-1,2,4,5-tetrazine (BTATz): [Ca₂(BTATz)₂(H₂O)₈·6H₂O] (1) and Ca(BTATz)(phen)(H₂O)₅·4H₂O (2). Complexes 1 and 2 were characterized by elemental analysis, Fourier transform infrared spectrometry, and single-crystal X-ray diffraction. Structural analysis revealed that Ca(II) was present in different coordination structures in the two complexes. Complex 1 exhibited a symmetric octahedral coordination that included three nitrogens and five water molecules. Complex 2 formed an asymmetric seven-coordinate structure with calcium connected to nitrogen in BTATz and to oxygens. The thermal behaviors of 1 and 2 were characterized via differential scanning calorimetry and thermogravimetry–differential thermal gravimetry. The peak thermal decomposition temperatures of 1 and 2 was 557.39 and 573.86 K, respectively. The kinetic equations of the main exothermic decomposition reaction were also derived. Moreover, the thermal safety of the complexes was evaluated by calculating some important thermodynamic parameters, such as self-accelerated decomposition temperature, thermal ignition temperature, and critical temperature of thermal explosion. Results indicated that both complexes exhibit good potential as a propellant component.     

1，1'-二羟基-5，5'-联四唑的镧系金属配合物的合成、表征及热行为

以1,1′-二羟基-5,5′-联四唑(H_2BTO)为配体,镧系金属离子作为金属中心,采用溶剂热法制备了5种金属配合物:[La_2(BTO)_3(H_2O)_8]·2H_2O (1)、[Ce_2(BTO)_3(H_2O)_8]·2H_2O (2)、[Pr_2(BTO)_3(H_2O)_8]·2H_2O (3)、[Sm_2(BTO)_3(H_2O)_8]·2H_2O (4)和[Nd_2(BTO)_3(DMF)_4]·6H_2O (5)。通过单晶X射线衍射和元素分析对5种配合物的结构进行了表征。结果表明,5种配合物均属于单斜晶系,P2_1/n空间群。利用差示扫描量热法研究了配合物1～4的热稳定性,采用Kissinger法和Ozawa法分别计算了其热分解动力学参数。     

Analytical and thermal investigations of new solid Y(III) and La(III) complexes

New compounds with formulae Y(2,4′-bpy)_1.5Cl₃·8H₂O (I), Y(2,4′-bpy)_0.5Br₃·8H₂O (II), La(2,4′-bpy)Cl₃·5H₂O (III) and La(2,4′-bpy)_1.5Br₃·5H₂O (IV) were prepared and characterized by chemical and elemental analysis, IR spectroscopy and powder X-ray diffraction. The thermal properties of compounds in the solid state were studied using TG-DTA techniques under dry air atmosphere. The thermal behavior of investigated compounds was studied in the temperature range 298–1273 K. They are stable up to 323 K. The complexes decompose in several stages, accompanied by endo- and exothermic effects. In all cases, the first step of pyrolysis is partial or total dehydration. When the temperature rises, deamination takes place. The solid final products of decomposition are Y₂O₃ and La₂O₃, respectively. Additionally, for all complexes mass spectrometry was used to analyze principal volatile thermal decomposition and fragmentation products evolved during pyrolysis under dry air atmosphere.

     

Eco-friendly energetic complexes based on transition metal nitrates and 3,4-diamino-1,2,4-triazole (DATr)

Four eco-friendly energetic metal complexes of 3,4-diamino-1,2,4-triazole (DATr), including manganese (1), cobalt (2), nickel (3), and zinc (4), were synthesized by reacting DATr·HCl with the corresponding metal (Mn(II), Co(II), Ni(II), and Zn(II)) nitrate in aqueous solution and characterized by using Fourier transform-infrared spectroscopy and elemental analyses. The single crystals of 2, 3, and 4 were obtained and determined by X-ray single-crystal diffraction analysis. All three complexes crystallize in the monoclinic crystal system and belong to P2(1)/n space group. The thermal decomposition processes were investigated by differential scanning calorimeter (DSC) and thermogravimetry–derivative thermogravimetry analyses. The results show that the decomposition temperatures of 1–4 are above 260 °C, depending upon their onset DSC peaks. It can be predicted that these complexes based on 3,4-diamino-1,2,4-triazole have good thermal stability. The nonisothermal kinetic parameters of decomposition were calculated by using Kissinger and Ozawa–Doyle’s methods. Furthermore, the sensitivities of these complexes to impact, friction, and flame were determined. Sensitivity tests revealed that 2 was more sensitive to external stimuli compared to the other three complexes.     

Thermal behaviour of new Cu(II) complexes with Schiff bases functionalised with 1,3,5-triazine moieties as potential antibacterial agents

New complexes of type [Cu(L¹)₂(OH₂)]·4H₂O (1), [Cu(L²)(OH₂)]·0.5H₂O (2) and [Cu₃(L³)₂(OH₂)₃]·0.5H₂O (3) were synthesized by [1 + 1], [1 + 2] and [1 + 3], respectively, template condensation of 2,4,6-triamino-1,3,5-triazine and salicylic aldehyde in the presence of copper(II). The features of complexes have been established from microanalytical, IR and UV–Vis data. The thermal analyses have evidenced the thermal intervals of stability and also the accompanying thermodynamic effects. Processes as water elimination and oxidative degradation of the organic ligands were observed. After water elimination, complexes revealed a similar thermal behaviour. The final product of decomposition was copper(II) oxide as powder X-ray diffraction indicated.     

Synthesis,spectral, thermal and crystallographic investigations on oxovanadium(IV) and manganese(III) complexes derived from heterocyclic β-diketone and 2-amino ethanol

Novel mononuclear oxovanadium(IV) and manganese(III) complexes [VO(L¹)₂·H₂O] (1); [VO(L²)₂·H₂O] (2); [VO(L³)₂·H₂O] (3); [Mn(L¹)₂]ClO₄·H₂O (4); [Mn(L²)₂] ClO₄·H₂O (5); [Mn(L³)₂]ClO₄·H₂O (6) were prepared by condensation of 1 mol of VOSO₄·5H₂O or Mn(OAc)₃· 2H₂O with 2 mol of ligand HL¹, HL² or HL³ (where HL¹ = 4-[(2-hydroxy-ethylamino)-methylene]-5-methyl-2- phenyl-2,4-dihydro-pyrazol-3-one; HL²=4-[(2-hydroxy-ethylamino)-methylene]-5-methyl-2-p-tolyl-2,4-dihydro-pyrazol-3-one; HL³=4-{4-[(2-hydroxy-ethyl-amino)-methyl]-3-methyl-5-oxo-4,5-dihydropyrazol-1-yl} benzene sulfonic acid). The resulting complexes were characterized by elemental analyses, molar conductance, magnetic and decomposition temperature measurements, electron spin resonance, FAB mass, IR and electronic spectral studies. From TGA, DTA and DSC, the thermal behaviour and degradation kinetic were studied. Electronic spectra and magnetic susceptibility measurements indicate distorted octahedral stereochemistry of oxovanadium(IV) complexes and regular octahedral stereochemistry of manganese(III) complexes. Hamiltonian and bonding parameters found from ESR spectra indicate the metal ligand bonding is partial covalent. The X-ray single crystal determination of one of the representative ligand was carried out which suggests existence of amine-one tautomeric form in the solid state. The ¹H-NMR spectra support the existence of imine-ol form in solution state. The LC-MS studies sustain the¹H-NMR result. The electronic structure of the same representative ligand was optimized using 6-311G basis set at HF level ab initio studies to predict the coordinating atoms of the ligand.     

Tb(III) complexes with 1-phenyl-3-methyl-4-stearoyl-pyrazol-5-one as a material for luminescence Langmuir–Blodgett films

Abstract

Synthesis and properties of new luminescent amphiphilic Tb(III) complexes [TbL₃·2H₂O]·3H₂O, TbL₃·bipy, [H₃O][TbL₄]·6H₂O and [H₃O][TbL′₃L]·H₂O, where HL is 1-phenyl-3-methyl-4-stearoylpyrazolone-5 and HL′ is 1-phenyl-3-methyl-4-formylpyrazolone-5, are reported. The complexes have been characterized by elemental and thermal analysis, FTIR and luminescence spectroscopy methods. Formation and properties of Langmuir–Blodgett films of the complexes are described.     

The study of thermal decomposition kinetics of zinc oxide formation from zinc oxalate dihydrate

This study is devoted to the thermal decomposition of ZnC₂O₄·2H₂O, which was synthesized by solid-state reaction using C₂H₂O₄·2H₂O and Zn(CH₃COO)₂·2H₂O as raw materials. The initial samples and the final solid thermal decomposition products were characterized by Fourier transform infrared and X-ray diffraction. The particle size of the products was observed by transmission electron microscopy. The thermal decomposition behavior was investigated by thermogravimetry, derivative thermogravimetric and differential thermal analysis. Experimental results show that the thermal decomposition reaction includes two stages: dehydration and decomposition, with nanostructured ZnO as the final solid product. The Ozawa integral method along with Coats–Redfern integral method was used to determine the kinetic model and kinetic parameters of the second thermal decomposition stage of ZnC₂O₄·2H₂O. After calculation and comparison, the decomposition conforms to the nucleation and growth model and the physical interpretation is summarized. The activation energy and the kinetic mechanism function are determined to be 119.7 kJ mol^?1 and G(α) = ?ln(1 – α)^1/2, respectively.     

Thermal properties of solid complexes with biologically important heterocyclic ligands

The thermal decomposition of the complexes Mg(SCN)₂(2-OHpy)₄·H₂O(I), Mg(SCN)₂(quin)₄·2H₂O(II) and Mg(SCN)(quinox)₄·5H₂O(III) (2-OHpy–2-hydroxypyridine, quin–quinoline, quinox–quinoxaline) has been investigated in static air atmosphere at 20–1000 °C by means of thermogravimetry (TG), differential thermal analysis (DTA), and infrared (IR) spectroscopy. The composition of the complexes had been identified by means of elemental analysis and complexometric titration. The possible scheme of destruction of the complexes is suggested. The final product of the thermal decomposition was MgS. IR data suggest that heterocyclic ligands were coordinated to Mg(II) through the nitrogen atom of their heterocyclic ring. Thiocyanate group is also coordinated through the nitrogen atom.     

Thermal decomposition reaction kinetics of complexes of [Sm(o-MOBA)3bipy]2·H2O and [Sm(m-MOBA)3bipy]2·H2O

The complexes of [Sm(o-MOBA)₃bipy]₂·H₂O and [Sm(m-MOBA)₃bipy]₂·H₂O (o(m)-MOBA = o(m)-methoxybenzoic acid, bipy-2,2′-bipyridine) have been synthesized and characterized by elemental analysis, IR, UV, XRD and molar conductance, respectively. The thermal decomposition processes of the two complexes were studied by means of TG–DTG and IR techniques. The thermal decomposition kinetics of them were investigated from analysis of the TG and DTG curves by jointly using advanced double equal-double steps method and Starink method. The kinetic parameters (activation energy E and pre-exponential factor A) and thermodynamic parameters (ΔH ^≠ , ΔG ^≠ and ΔS ^≠) of the second-step decomposition process for the two complexes were obtained, respectively.     

Synthesis and thermal decomposition kinetics of the complexes [Sm(o‐NBA)3bipy]2·2H2O and [Sm(o‐BrBA)3bipy]2· 2H2O

Two new complexes [Sm(o‐NBA)₃bipy]₂·2H₂O ( 1 ) and [Sm(o‐BrBA)₃bipy]₂·2H₂O ( 2 ) (where o‐NBA is o‐nitrobenzoic acid, o‐BrBA is o‐bromobenzoic acid, and bipy is 2,2′‐bipyridine) were prepared and characterized by elemental analysis, IR, UV, and molar conductance, respectively. The thermal decomposition behaviors of the two complexes were investigated by means of TG–DTG and IR techniques. The thermal decomposition kinetics was studied by using advanced double equal‐double steps method, nonlinear integral isoconversional method, and nonlinear differential isoconversional method. The kinetic parameters of the second‐step process for the two complexes were obtained, respectively. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 607–616, 2008     

Thermal decomposition kinetics of lanthanum and neodymium bromide complexes with glycine or alanine

Four complexes of rare earth bromides with amino acids, REBr₃·3L·3H₂O (RE=La, Nd;L=glycine or alanine) were prepared and characterized by means of chemical analysis, elemental analysis, molar conductivity, thermogravimetry, IR spectra and X-ray diffraction. Their thermal decomposition kinetics from ambient temperature to 500°C were studied by means of TG-DTG techniques under non-isothermal conditions. The kinetic parameters (activation energyE and pre-exponential constantA) and the most probable mechanisms of thermal decomposition were obtained by using combined differential and integral methods. The thermal decomposition processes of these complexes are distinguished as being of two different types, depending mainly on the nature of the amino acid.     

Spectroscopic and thermal investigations of Cu(II), Zn(II), Cd(II), Pb(II) and Al(III) caproates

Five complexes: Cu(cap)₂·4H₂O, Zn(cap)₂, Cd(cap)₂·4H₂O, Pb(cap)₂ and Al(cap)₃·4H₂O (where cap is the caproate anion?=?CH₃(CH₂)₄COO^?) were synthesized and characterized by elemental analysis, IR-spectroscopy, thermogravimetric analysis (TG), differential thermal analysis (DTA), UV-Vis spectra, ¹H NMR and X-ray powder diffraction (XRD). Using the non-isothermal, Horowitz-Metzger (HM) and Coats-Redfern methods, the kinetic parameters for the non-isothermal degradation of the complexes were calculated using TG data. The infrared and ¹H NMR data are in agreement with coordination through carboxylate, with cap acting as a bridging bidentate ligand. Thermogravimetric analysis of the hydrated complexes shows that the first degradation step is release of water molecules followed by decomposition of the anhydrous complexes, with release of caproate molecules.     

Syntheses and crystal structures of two supramolecular isomers of manganese(II) with 3,5-bis(isonicotinamido)benzoate

Two new supramolecular isomeric complexes [Mn(BBA)₂(H₂O)₂] _n · 4nH₂O (1) and [Mn(BBA)₂(H₂O)₂] · 4H₂O (2) were obtained by hydrothermal reactions of MnCl₂ · 4H₂O with 3,5-bis(isonicotinamido)benzoic acid (HBBA) under different ratio of NaOH/HBBA. Complex 1 is a 1-D zigzag chain in which the Mn(II) is six-coordinate with distorted octahedral geometry. The 1-D chains are further connected by hydrogen bonds to give a 3-D supramolecular framework. Complex 2 is a monomeric molecular complex, assembled through intermolecular hydrogen bonds into a 3-D supramolecular network. Reaction conditions have remarkable influence on the structures of the complexes. The thermal and non-linear optical properties of the complexes were studied.     

Synthesis and some properties of light lanthanide complexes with 4,4′-bipyridine and dibromoacetates

In this study, new complexes with formulae: Ce(4-bpy)(CHBr₂COO)₃·H₂O, Ln(4-bpy)_0.5(CHBr₂COO)₃·2H₂O (where Ln(III) = Pr, Nd, Sm; 4-bpy = 4,4′-bipyridine) and Eu(4-bpy)(CHBr₂COO)₃·2H₂O were prepared, and characterized by chemical and elemental analyses, and IR spectroscopy. The way of metal–ligand coordination was discussed. They are small crystalline. The complexes of Pr(III), Nd(III), and Sm(III) are isostructural in group. Conductivity studies (in methanol, dimethylformamide, and dimethylsulfoxide) were also performed and described. The thermal properties of complexes in the solid state were studied using TG–DTG techniques under dynamic flow of air atmosphere. TG–MS system was used to analyze principal volatile thermal decomposition and fragmentation products evolved during pyrolyses of Ce(III) and Sm(III) complexes in dynamic flow of air atmosphere.     

Some transition metal nitrate complexes with hexamethylenetetramine

Three hexamethylenetetramine (HMTA) metal nitrate complexes such as [M(H₂O)₄(H₂O-HMTA)₂](NO₃)·4H₂O (where M=Co, Ni and Zn) have been prepared and characterized by X-ray crystallography. Their thermal decomposition have been studied by using dynamic, isothermal thermogravimery (TG) and differential thermal analysis (DTA). Kinetics of thermal decomposition was undertaken by applying model-fitting as well as isoconversional methods. The possible pathways of thermolysis have also been proposed. Ignition delay measurements have been carried out to investigate the response of these complexes under condition of rapid heating.     

The stability of inclusion compounds under heating

The thermal decomposition of three inclusion compounds: [Zn₂(camph)₂dabco]·DMF·H₂O, [Zn₂(camph)₂bipy]·3DMF·H₂O and [Zn₂(camph)₂bpe]·5DMF·H₂O was studied in the inert atmosphere. TG and DTG curves confirm multi-step decomposition process, the dehydration being the first step. Thermogravimetric data (obtained at different rates of linear heating) were processed with computer program (with ‘Model-free’ approach). Kinetic parameters of decomposition were calculated for the DMF multi-step removal, the processes are described by Avrami–Erofeev equations. The connection between the kinetic parameters and structural features of the host frameworks (ligand linker lengths and porous-free volumes) are discussed.     

Ag(I), Cu(II), and Cd(II) sulfacetamide complexes: Synthesis,spectral, thermal study,and antimicrobial activity assessment

Sulfacetamide complexes of Ag(I), Cu(II), and Cd(II) were synthesized and characterized by the elemental analyses and IR and ¹H NMR spectra. Structural assessment revealed two modes of coordination in the sulfacetamide complexes, showing that sulfacetamide reacts as a bidentate ligand and coordinates to Ag(I) and Cd(II) through the amido and sulfonyl oxygens and to Cu(II) through the NH₂ nitrogen. Molar conductance measurements in DMSO showed that both the complexes are nonelectrolytes in nature, which allowed they to be assigned the formulas [Ag(SAM-Na)(NO₃)H₂O)]·3H₂O, [Cu(SAM-Na)₂(Cl)₂], and [Cd(SAM-Na)(Cl)₂]·10H₂O. The kinetic and thermodynamic parameters of the thermal decomposition reactions of the complexes were estimated from the TG/DTG curves by the Coats–Redfern and Horowitz–Metzeger methods. The surface morphology of sulfacetamide complexes was scanned using X-ray powder diffraction (XRD) and scanning electron microscope (SEM) analyses.     

Novel platinum(II) and (IV) complexes of naphthaldimine schiff bases

Naphthaldimines containing N₂O₂ donor centers react with platinum(II) and (IV) chlorides to give two types of complexes depending on the valence of the platinum ion. For [Pt(II)], the ligand is neutral, [(H₂L¹)PtCl₂]·3H₂O (1) and [(H₂L³)₂Pt₂Cl₄]·5H₂O (3), or monobasic [(HL²)₂Pt₂Cl₂]·2H₂O (2) and [(HL⁴)₂Pt]·2H₂O (4). These complexes are all diamagnetic having square-planar geometry. For [Pt(IV)], the ligand is dibasic, [(L¹)Pt₂Cl₄(OH)₂]·2H₂O (5), [(L²)Pt₃Cl₁₀]·3H₂O (6), [(L³)Pt₂Cl₄(OH)₂]·C₂H₅OH (7) and [(L⁴)Pt₂Cl₆]·H₂O (8). The Pt(IV) complexes are diamagnetic and exhibit octahedral configuration around the platinum ion. The complexes were characterized by elemental analysis, UV-Vis and IR spectra, electrical conductivity and thermal analyses (DTA and TGA). The molar conductances in DMF solutions indicate that the complexes are non-ionic. The complexes were tested for their catalytic activities towards cathodic reduction of oxygen.     

TG-DTA study on the lanthanoid trifluoromethanesulfonate complexes

The thermal decomposition of the lanthanoid trifluoromethanesulfonate (triflate) complexes {Ln(CF₃SO₃)₃·9H₂O; Ln=La-Lu{ was studied by TG and DTA methods. From the endothermic and exothermic data of Ln(CF₃ SO₃)3·9H₂O complexes, pyrolysis behavior of the complexes is classified into three groups: 1) La-Nd salts, 2) Sm-Ho salts, 3) Er-Lu salts. It has also shown that all the final decomposition products were found to result in the formation of LnF₃. This revised version was published online in July 2006 with corrections to the Cover Date.