Studies on energetic compounds

Summary Bis(propylenediamine)metal perchlorate (BPMP) complexes like [M(pn)₂](ClO₄)₂ (where M=Cr, Mn, Ni, Cu, Zn and pn=propylenediamine) have been prepared and characterized by gravimetric methods, infrared and elemental analysis. Thermal properties have been studied using simultaneous thermogravimetry-differential thermal analysis in atmospheres of nitrogen and air to examine the effect of atmospheric change on thermal decomposition of these complexes. Changing of the atmosphere does not cause any measurable changes in the decomposition of complexes. However, as indicated by thermoanalytical techniques, the thermal stability of present complexes decreases in the order: [Cr(pn)₂](ClO₄)₂>[Mn(pn)₂](ClO₄)₂>[Zn(pn)₂](ClO₄)₂>[Ni(pn)₂](ClO₄)₂>[Cu(pn)₂](ClO₄)₂. Isothermal thermogravimetry, over the temperature range of decomposition has been done for all the complexes. An analysis of the kinetics of thermal decomposition was made using a model fitting procedure as well as an isoconversional method, independent of any model. The results of both kinetic approaches have been discussed critically. The explosion delay (D_E) was measured to investigate the trend of rapid thermal analysis.     

Thermoanalytical investigations of 4-methylpiperazine-1-carbodithioic acid ligand and its iron(III), cobalt(II), copper(II) and zinc(II) complexes

The thermal decomposition studies on 4-methylpiperazine-1-carbodithioic acid ligand (4-MPipzcdtH) and its complexes, viz. [M(4-MPipzcdtH)_n](ClO4)_n (M=Fe(III) when n=3; M=Co(II), Cu(II) when n=2) and [Zn(4-MPipzcdtH)₂]Cl₂ have been carried out using non-isothermal techniques (TG and DTA). Initial decomposition temperatures (IDT), indicate that thermal stability is influenced by the change of central metal ion. Free acid ligand exhibits single stage decomposition with a sharp DTA endotherm. Complexes, [M(4-MPipzcdtH)_n](ClO₄)_n undergo single stage decomposition with detonation and give rise to very sharp exothermic DTA curves while the complex [Zn(4-MPipzcdtH)₂]Cl₂ shows three-stage decomposition patterns. The kinetic and thermodynamic parameters, viz. the energy of activation E, the frequency factor A, entropy of activation S and specific rate constant k, etc. have been evaluated from TG data using Coats and Redfern equation. Based upon the results of the differential thermal analysis study, the [M(4-MPipzcdtH)_n](ClO₄)_n complexes have been found to possess characteristic of high energy materials.     

Thermal decomposition of complexes of Co(II), Ni(II) and Zn(II) ions with thiosalicylic acid or ethylenediamine

The thermal decompositions of crystalline Co(II), Ni(II) and Zn(II) complexes with thiosalicylic acid or ethylenediamine were investigated via the respective thermal curves. On the basis of the decomposition temperatures, the following sequences of stabilities of the studied compounds have been proposed: 1. [Co(SR)][Ni(SR)]<[Zn(SR)]; 2. [Zn(en)₂](NO₃)₂·2H₂O<[Co(en)₂](NO₃)₂<[Ni(en)₃](NO₃)₂.     

Thermal Analysis Studies on Hydroxobridged Homo and Hetero Trinuclear Cobalt(III) Complexes

The synthesis and thermal analysis studies of several hydroxobridged homo and hetero trinuclear cobalt(III) complexes are reported. The complexes are of the type [M(H₂O)_x{(OH)₂Co(en)₂}₂](SO₄)₂ nH₂O and [M(H₂O)_x{(OH)₂Co(NH₃)₄}₂](SO₄)₂nH₂O where en denotes ethylenediamine and M =Co(II), Ni(II), Cu(II) and Zn(II) with x=0 for Cu(II), and 2 for other metal ions, and n =3, 4 or 5. The TG and DTA studies of these compounds show that one or more intermediate compounds are formed in each case before the metal oxides are produced.     

Copper(II) complexes with 1,2,4-triazolo[1,5-a] pyrimidine and its 5,7-dimethyl derivative

Several Cu(II) complexes with 1,2,4-triazolo[1,5-a]pyrimidine (tp) and its 5,7-dimethyl derivative (dmtp) have been isolated and structurally characterized. Five of them are mononuclear and contain 1,10-phenanthroline (phen) or ethylenediamine (en) as auxiliary ligands, their formula being [Cu(H₂O)(phen)(tp)₂](ClO₄)₂ · H₂O, [Cu(H₂O)(phen)(dmtp)₂](ClO₄)₂, [Cu(NO₃)(H₂O)(phen)(tp)](NO₃), [Cu(H₂O)₂(en)(tp)₂](ClO₄)₂ and [Cu(H₂O)₂(en)(dmtp)₂](ClO₄)₂. In all these compounds the tp or dmtp ligand is monodentately coordinated via the nitrogen atom in position 3. The auxiliary ligand influences the coordination number, which is five when this ligand is phen and six when it is en whereas the number of triazolopyrimidine ligands linked to the metal seems to be influenced by the nature of the counteranion. A dinuclear compound with tp has also been isolated, its formula being [Cu₂(OH)(H₂O)_2.5(tp)₅](ClO₄)₃·(H₂O)_1.5, with both metal atoms linked by an hydroxydo group and by a tp bridging ligand, coordinated to one of the copper atoms via N3 and to the other via N4. This compound has several unusual features among the metal complexes with triazolopyrimidine derivatives: the presence of two different kinds of bridging moieties, the coexistence of bridging and terminal ligands and the formation of a N3–N4 bridge for a Cu(II) dinuclear compound for a derivative without exocyclic oxygen atoms.     

Single-crystal electronic spectra of some quadrate chromium(III) complexes

Polarised electronic spectra of trans-[Cr(tmd)₂F₂](ClO₄), trans-[Cr(en)₂(dma)₂](ClO₄)₃, trans-[Cr(en)₂(dmf)Cl](ClO₄)₂ and trans-[Cr(en)₂(dmf)Br](ClO₄)₂ have been measured at 77 K (tmd = trimethylenediamine; dma = N,N-dimethylacetamide; dmf = N,N-dimethylformamide; en = ethylenediamine, pn = propylenediamine). The observed quartet bands have been given definitive quadrate assignments based on polarisation characteristics. The four-component quadrate quartet bands have been uncovered and assigned also in the unpolarised crystal spectrum of trans-[Cr(en)₂(dmf)₂](ClO₄)₃ at 77 K and the solution spectrum of trans-[Cr(en)(pn)F₂]⁺. The band maxima derived by gaussian analysis in these spectra have been fitted with the theoretical energy equations of d³ configuration in quadrate ligand fields including full configuration interaction. The ligand field parameters Dq, Dt, and Ds and the election correlation parameter, B, extracted by such a fitting, have been compared with those obtained for other similar systems earlier. The significance of the ligand field symmetry parameters and the translated angular overlap model parameters is discussed.     

Mehrkernige Kobaltkomplexe. V. Präparative Herstellung von Tetrakis (äthylendiamin)-μ-peroxo-μ-amido- und μ-peroxo-μ-thiocyanatodikobalt (III)-Komplexen ausgehend von Tetrakis (äthylendiamin)bis-(ammin)-μ-peroxo-dikobalt (III)-tetraperchlorat

Polynuclear Cobalt Complexes. V. Preparation of tetrakis (ethylenediamine)-μ-peroxo-μ-amido and μ-peroxo-μ-thiocyanato-dicobalt (III) complexes starting from tetrakis (ethylenediamine)bis-(ammine)-μ-peroxo-dicobalt (III)-tetraperchlorate Racemic tetrakis (ethylenediamine)-μ-peroxo-μ-amido-dicobalt (III) thiocyanate and its corresponding hydroperoxo- and superoxo-complexes have been isolated from [(en)₂(NH₃)Co(O₂)(NH₃)(en)₂](ClO₄)₄. A new binuclear peroxo complex containing thiocyanate as bridging ligand was prepared by the same method. The stretching frequencies of the CN- and CS-group as well as the NCS-bending frequence in the IR. spectrum of [(en)₂Co(O₂, SCN)Co(en)₂](NO₃)₃ suggest that the μ-thiocyanato group is N-bonded (2050, 750, 475 cm^?1). A comparison of IR. spectra of known singly and doubly bridged μ-peroxo complexes is made. Characteristic absorption bands, assignable to ν(O? O) and ν(Co? O) are given.     

Heat capacity and thermodynamical properties of the crystal of [RE2(Glu)2(H2O)8](ClO4)4·H2O (RE = Nd, Eu, Dy)

Thermodynamical data of rare earth complexes with amino acid are important for engineering chemistry and fundamental chemistry. However, they have rarely been reported. In this work, a series of crystalline complexes of rare earth perchlorate coordinated with glutamic acid have been synthesized in water medium, and their thermodynamical data, including the heat capacity in low temperature range and the standard enthalpy of formation, were determined. These complexes were identified to be [RE₂(Glu)₂(H₂O)₈](ClO₄)₄·H₂O (RE = Nd, Eu, Dy) by using thermogravimetric analysis (TG), differential thermal analysis (DTA), and chemical and elementary analyses. Their purity has been determined. No melting points were observed for all the three complexes. The heat capacity of the complexes was measured by an adiabatic calorimeter from 79 to 370 K. Abnormal heat capacity values were detected for two of the complexes and the decomposition range of one complex was found. The temperature, enthalpy change and entropy change of the decomposition processes of the three complexes were calculated. The polynomial equations of heat capacity in the experimental temperature range have been obtained by least squares fitting. The standard enthalpy of formation was determined by an isoperibol reaction calorimeter at 298.15 K. Supported by the Research Fund of Beijing Institute of Petro-Chemical Technology (N06-06)     

Preparation,X-ray crystallography and thermolysis of transition metal nitrates of 2,2′-bipyridine (Part 63)

Recent work has described the preparation and characterization of the two complexes [Fe₂(C₁₀H₈N₂)₄O(OH₂)₂](NO₃)₄ and [Co(C₁₀H₈N₂)₃]₂[Co(OH₂)₆]·7(OH₂) (NO₃)₈ in which both the nitrogen atoms of 2,2′-bipyridine are directly bonded with the metals. Their structures were determined by single-crystal X-ray diffraction at 296 K. Thermolysis of these complexes has been detailed by the use of TG–DTA and ignition delay measurements. Kinetics of thermal decomposition has also been established. Model free isoconversional and model fitting kinetic approaches have been applied to isothermal TG data for the decomposition of these complexes.     

Lanthanoid metal nitrates with hydrogen bonded hexamethylenetetramine

Cerium, praseodymium, and neodymium nitrate complexes with hydrogen bonded hexamethylenetetramine (HMTA) of the formula [Ce(NO₃)₂(H₂O)₅](HMTA)₂(NO₃)(H₂O)₃, [Pr(NO₃)₂(H₂O)₆]₂[Pr(H₂O)₉](HMTA)₆(NO₃)₆(H₂O)₄ and [Nd(NO₃)₂(H₂O)₅](HMTA)₂(NO₃)(H₂O)₃ have been prepared and characterized by X-ray crystallography. All the complexes belong to monoclinic crystal system. Ce and Nd complexes have P21/n space group, whereas Pr complex has C2/c. Thermal analyses of these complexes were carried out using TG, DSC, which showed their multi-step decomposition. Kinetics of thermolysis has been done by applying model fitting as well as model free isoconversional method. In order to see the response of rapid heating, ignition delay measurements were carried out. The thermal decomposition pathways have also been demonstrated. On the basis of thermal studies the thermal stability of the complexes was found in the order; Pr > Ce > Nd. In order to identify the end products of thermolyses, X-ray diffraction patterns of end product were carried out which showed the formation of corresponding metal oxides.     

Thermal decomposition reactions of metal carboxylato complexes in the solid state. I.: Thermographic and differential thermal studies of metal oxalato,malonato and succinato complexes

Thermal investigation of metal carboxylato complexes of the first transition metals, Mn(II), Fe(II), Fe(III), Co(II), Ni(II) and Cu(II) and non-transition metals like Zn(II) and Cd(II) in the solid state has been carried out under non-isothermal conditions in nitrogen atmosphere by simultaneous TG and DTA. TG and DTA curves inferred that the thermal stability of the complex decreased approximately with the increase of the standard potential of the central metal ion. The thermal parameters like activation energy, E_a, enthalpy change, ΔH, and entropy change, ΔS, corresponding to the dehydration and decomposition of the complexes are determined from TG and DTA curves by standard methods. A linear correlation is found between ΔH and ΔS and E_a and ΔS in dehydration and decomposition processes. DTA curves show an irreversible phase transition for Na₂Mn(mal)₂], Na₂[Cu(mal)₂] and Na₂,[Co(suc)₂] complexes. The residual products in these decomposition processes being a mixture of two oxides, of oxide and carbonate or a mixture of two carbonates.     

Optical properties of single crystals of quasi-one-dimensional halogen-bridged mixed-valence platinum and palladium compounds

The absorption spectra of [Pt(en)₂][Pt(en)₂Cl₂](ClO₄)₄, [Pt(en)₂][Pt(en)₂I₂](ClO₄)₄, [Pd(en)₂][Pd(en)₂Br₂](ClO₄)₄ and Wolffram's red salt, and the reflectance spectra of [Pt(en)₂][Pt(en)₂Cl₂](ClO₄)₄ and [Pt(en)₂][Pt(en)₂I₂](ClO₄)₄, have been measured for polarized light both at room temperature and at 2 K. The charge-transfer absorption edges and their temperature dependence have been clearly determined, and the structures observed in the spectra are discussed within the one-dimensional band scheme. Interesting structures located below the absorption edges are found for light polarized parallel to the axis.     

Synthesis,Structure and Solvatochromism Studies on Copper(II) Complexes Containing Ethylenediamine,Pyridine and Imidazol Ligands

Two copper(II) complexes type [Cu(en)X₂](ClO₄)₂, where en = ethylenediamine and X = pyridine, 1 or imidazol, 2 have been synthesized and prepared on the bases of elemental analysis, spectroscopic and molar conductance measurements. The X‐ray crystal analysis of these complexes demonstrated that the copper(II) ions are in square planar environments through coordination by two nitrogen atoms of the ethylenediamine and two nitrogen atoms of two pyridine or imidazol molecules and the ClO₄^‐ ions are bound weakly above and below of the molecular plane. The complexes show three ions behavior in all solvents. The complexes are soluble in various solvents and are solvatochromic. The solvatochromism of the complexes were investigated by UV‐Vis spectroscopy with different solvent parameters such as DN, AN, α and β using multiple linear regression (MLR) method. The results suggested that the DN parameter of the solvent has the most contribution to the shift of the d‐d absorption band of the complex 1 but in complex 2 the DN and β have almost similar importance in the observed variation in the shift of the ν_max values with solvent nature.     

Thermal decomposition reactions of metal carboxylato complexes in the solid state: II. Thermographic and differential thermal studies of metal oxalato,malonato and succinato complexes

The thermal investigations of metal carboxylato complexes of the first transition metals, Mn(II), Fe(II), Fe(III), Co(II), Ni(II) and Cu(II) and non transition metals like Zn(II) and Cd(II) in solid state were carried out under non-isothermal condition in nitrogen atmopshere by thermogravimetric (TG) and differential thermal analyses (DTA) methods. The results of DTA curves inferred that the thermal stability of the complex decreased approximately with the increase of standard potential of the central metal ion. The thermal parameters like activation energy (E_a¹), enthalpy change (ΔH) and entropy change (ΔS) corresponding to deaquation, deammoniation and decomposition processes occurred simultaneously or separately were determined from TG and DTA curves by the standard methods. A linear correlation has been found in the plots of ΔH vs. ΔS and E_a¹ vs. ΔS in deaquation, deammoniation and decomposition processes. An irreversible phase transition was noticed for H₂[Mn(suc)₂] and H₂[Co(suc)₂] complexes in DTA curves. The residual pyrolysed products were metal carbonates.     

Synthesis and characterization of cobalt(II), nickel(II) and copper(II) perchlorate complexes with bis [(diphenylphosphinyl)methyl] phenylphosphine oxide,bis [(disphenylphosphinyl)methyl]ethyl phosphinate,and bis [(diphenylphosphinyl)methyl] phosphinic acid

The synthesis and characterization of cobalt(II), nickel(II) and copper(II) perchlorate complexes containing bis [(diphenylphosphinyl)methyl] [phenylphosphine oxide (RPPH), bis [(diphenylphosphinyl)methyl] ethyl phosphinate (RPOEt), and bis [(diphenylphosphinyl)methyl] phosphinic acid (RPOH) have been studied. The substituent at the central phosphorus atom of the ligand is responsible for the types of complexes formed. The new complexes [M(RPPh)₂(ClO₄)₂.nH₂O, [M(RPPh)₃](ClO₄)₂.4H₂O, [M(RPOEt)₂](ClO₄)₂.2H₂O, and [M(RPOH)₃] (ClO₄)₂.nH₂O are characterized as high spin and most of them have an octahedral or distorted octahedral geometry [M = Co(II), Ni(II), or Cu(II); n = 2?5]. The coordination of two P = O groups from one ligand to the metal has been proposed for most of the complexes formed. The coordination of all three P = O groups has been assumed for complexes [M(RPPh)₂](ClO₄)₂.nH₂O and [M(RPOEt)₂](ClO₄)₂.2H₂O.     

Tetrahedral and octahedral coordination for cobalt(II) complexes of N-isopropyl-2-pyrrolidinone

Complexes of the formulas [Co(NIPP)₄](ClO₄)₂ and [Co(NIPP)₆](ClO₄)₂ have been synthesized and isolated (NIPP = N-isopropyl-2-pyrrolidinone). IR spectra and conductance data are presented as proof that perchlorate coordination in [Co(NIPP)₄](ClO₄)₂ does not occur. Vibrational spectra indicate that coordination occurs through the NIPP carbonyl oxygen for both complexes. Spectral parameters obtained from the electronic spectra and magnetic moments indicate tetrahedral and octahedral coordination for [Co(NIPP)₄](ClO₄)₂ and [Co(NIPP)₆](ClO₄)₂, respectively. The powder X-ray diffraction data appear to support the assignments of these two geometries. The crystal-field prediction that Δ(T_d)/Δ(O_h) = 0.44 is in reasonably good agreement with the experimental results.     

Thermal and structural behavior of Buriti oil/poly(methyl methacrylate) and Buriti oil/polystyrene materials

Melting processes and thermal decompositions of [Ca(H₂O)₄](ClO₄)₂ and [Ca(NH₃)₆](ClO₄)₂ were studied by thermogravimetry analysis (TG) and differential scanning calorimetry (DSC). The gaseous products of the decomposition were on-line identified by a quadruple mass spectrometry (QMS). In both compounds the processes of loss of the ligands start at ca. 340–350 K and continue up to ca. 600 K. Tetraaquacalcium perchlorate dissolves in own coordination water (melts) at T _m=350 K. The decomposition of the sample proceeds in three main stages. In stage I (351–602 K) dehydration of [Ca(H₂O)₄](ClO₄)₂ to anhydrous Ca(ClO₄)₂ undergoes in two steps, in which consecutively 2/4 and 2/4 of all H₂O molecules are liberated. In stage II (602–701 K) anhydrous Ca(ClO₄)₂ has one solid-solid phase transition at T _c=619 K and then melts at T _m=689 K. Stage III (above 700 K) is connected with decomposition of melted Ca(ClO₄)₂ to oxygen and solid CaCl₂. The decomposition of the [Ca(NH₃)₆](ClO₄)₂ proceeds also in three main stages. In stage I (341–601 K) deamination of [Ca(NH₃)₆](ClO₄)₂ to Ca(ClO₄)₂ undergoes in two steps, in which consecutively 3/6 and 3/6 of all NH₃ molecules are liberated. Stages II and III (601–868 K) are exactly the same as they were observed for [Ca(H₂O)₄](ClO₄)₂.     

Rhodium(I) and rhodium(III) arene complexes with N-carbazolyltriphenylphosphinegold(I) and other polycyclic arene ligands

The new heteronuclear arene complexes [(COD)Rh(μ-cbz)AuPPh₃]ClO₄, [{(COD)Rh}₂(μ-cbz)AuPPh₃](ClO₄)₂, [(C₅Me₅)Rh(μ-cbz)AuPPh₃](ClO₄)₂ and [{C₅Me₅) Rh}₂(μ-cbz)AuPPh₃](ClO₄)₄ (COD = 1,5-cyclooctadiene, cbz = carbazolyl), and the mononuclear arene complexes [(COD)Rh(arene)]ClO₄ (arene = tetralin, biphenyl, fluorene, indene, 9,10-dihydroanthracene or carbazole) have been prepared by reaction of the acetone solvated complexes [(COD)Rh(Me₂CO)_x]ClO₄ or [(C₅Me₅)Rh(Me₂CO)₃](ClO₄)₂ with (cbz)AuPPh₃ or the appropriate polycyclic arene ligand.     

Synthesis and characterization of two new asymmetrical branched amines and related Mn(II) and Ni(II) Schiff base complexes containing pyridine moieties: Crystal structures of Mn(II) and Ni(II) complexes and their antibacterial properties

Two new branched pentadentate amines (N₅), 3,7-bis(2-pyridylmethyl)-5,5-dimethyl-3,7-diazaheptane-1-amine (1) and 4,8-bis(2-pyridylmethyl)-6,6-dimethyl-4,8-diaza octane-1-amine (2) have been prepared. These have been used to synthesis two new Schiff base complexes containing a pyridine and 2-pyridylmethyl pendant arm, by template [1+1] condensation of pyridine-2-carbaldehyde with the amines in the presence of Mn(II) in methanol. Elemental and spectral results are used to characterize the complexes and their structures are confirmed by single crystal X-ray diffraction studies. The structure of MnL¹(ClO₄)₂ indicates that in the solid state the Mn(II) ion adopts a slightly distorted octahedral geometry. The crystal structure of [Ni(1)(MeCN)](ClO₄)₂ is also reported and exhibits a slightly distorted octahedral geometry. Also the synthesized complexes were screened for their antibacterial activity against Escherichia coli (Lio), Serratia marcescens (PTCC 1330), Staphylococcous aureus (ATCC 6633), and Proteus vulgaris (Lio) and results showed that the all complexes have antibacterial effects and [NiL¹](ClO₄)₂, [MnL²](ClO₄) and [MnL¹](ClO₄)₂ have more effective ones against E. coli.     

Thermoanalytical investigations of tris(ethylenediamine)nickel(II) oxalate and sulphate complexes

Investigations on the thermal behaviour of [Ni(en)₃]C₂O₄·2H₂O and [Ni(en)₃]SO₄ have been carried out in air and helium atmosphere. Simultaneous TG/DTA coupled online with mass spectroscopy (MS) in helium atmosphere detected the presence of H₂, O, CO, N₂/CH₂=CH₂ and CO₂ fragments during the decomposition of tris(ethylenediamine)nickel(II) oxalate and H₂, O, NH, NH₂, NH₃ and N₂/CH₂=CH₂ fragments for tris(ethylenediamine)nickel(II) sulphate complex. The thermal events during the decomposition were monitored by temperature-resolved X-ray diffraction. In air, both the complexes give nickel oxide as the final product of the decomposition. In helium atmosphere, tris(ethylenediamine)nickel(II) oxalate gives nickel as the residue, whereas tris(ethylenediamine)nickel(II) sulphate gives a mixture of nickel and nickel sulphide phases as the final residue. Kinetic analyses of these complexes by isoconversional methods are discussed and compared.