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Cereal Research Communications
Authors: P. Szakál, R. Schmidt, M. Barkóczi, R. Kalocsai, D. Beke, and O. Csatai

Szakál, P. Schmidt, R. 1997 Copper fertilization of wheat with copper complex and changes in flour quality. 17. Arbeitstagung Die Bedeutung der Mengen-und Spurelemente. Jena. p. 53–64. Szentpéteri Zs., Jolánkai M

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Abstract  

Copper complexes of some 1-phenyl-3-methyl-4-acyl-5-pyrazolones have been prepared. The complexes were characterized by elemental analyses and thermal analyses. It was shown that the melting points decrease linearly in increasing the molecular weight of the complexes.

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Abstract  

The copper(II) complex of 6-benzylaminopurine (6-BAP) has been prepared with dihydrated cupric chloride and 6-benzylaminopurine. Infrared spectrum and thermal stabilities of the solid complex have been discussed. The constant-volume combustion energy, Δc U, has been determined as −12566.92±6.44 kJ mol−1 by a precise rotating-bomb calorimeter at 298.15 K. From the results and other auxiliary quantities, the standard molar enthalpy of combustion, Δc H m θ, and the standard molar of formation of the complex, Δf H m θ, were calculated as −12558.24±6.44 and −842.50±6.47 kJ mol−1, respectively.

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Various copper(II) complexes as guests were immobilised among the layers of montmorillonite or on silica gel as hosts. Anchoring took place through hydrogen bonds and ion exchange for montmorillonite, while the forces of interaction were either hydrogen bonding or covalent bonds for the copper complex-silica gel nanohybrids. The thermal stabilities of these substances were studied under oxidizing atmosphere and it was found that anchoring increased the durability of the host-guest complexes relative to the host-free ones.

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Abstract  

Vic-dioxime ligandsand their metal complexes are used in analytical, bio, pigment and medicinal chemistry. Complexes of nickel(II), copper(II), and cobalt(II) with benzylamino-p-chlorophenylglyoxime (BpCPG) are synthesised. Thermal behaviour of these complexes was studied in dynamic nitrogen atmosphere by DTA, DTG and TG techniques. GC-MS combined system was used to identify the products during pyrolytic decomposition. The pyrolytic end products were identified by X-ray powder diffraction. Thermoanalytical data of these complexes are presented in this communication. Interpretation and mathematical analysis of these data and evaluation of order of reaction, the energy and entropy of activation based on the integral method using the Coats-Redfern equation and the approximation method using the Horowitz-Metzger equation are also given. The metal complexes undergo decomposition in three stages and metal oxides remained as end products of the complexes.

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Abstract  

The oxidation of aliphatic thiols by air oxygen under mild conditions catalyzed by copper(II) complexes with amines (e.g. benzylamine) has been investigated. It was found that the reaction proceeds as a conjugated oxidation of both amines and thiols. The products of transformation of benzylamine have been identified. Copper(I) dodecanethiolate was synthesized for the first time, and its composition was determined. The thiolate is shown to be an intermediate of the process in the systems which demonstrate low activity. The intermediate in the most active systems is a mixed-ligand copper(II) complex containing both molecules of amine and thiolate anions in the coordination sphere.

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Thermal investigation of cobalt, nickel and copper complexes with 8-aminoquinoline

Correlation between thermal stability and crystal field splitting energy

Journal of Thermal Analysis and Calorimetry
Authors: A. M. Donia and H. A. El-Boraey

Complexes of Co(II), Ni(II) and Cu(II) with 8-aminoquinoline were prepared and characterized, and their thermal behaviour and decomposition pathways were studied. The thermal stabilities are discussed in terms of ionic radii, crystal field splitting energy and steric hindrance. The effective roles of the counter-ions (Cl and NO3 ) on the decomposition temperatures and the final products were also clarified. The energies of activation (E a) and the orders of some decomposition reactions were determined. Light is shed on the nature of the interaction of the water of crystallization and the polymorphic transformation phenomenon.

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Summary

Gel-permeation chromatographic (GPC) and visible spectrophotometric methods have been developed and validated for quantitative analysis of complexes of copper(II) with the polysaccharides pullulan and dextran, active pharmaceutical compounds in new antihypocupremical formulations. Linearity, precision, accuracy, specificity, and limits of detection (LOD) and quantification (LOQ) were determined in accordance with ICH Q2(R1) guidelines. GPC was performed isocratically with redistilled water as mobile phase at a flow rate of 1 mL min−1. Visible spectrophotometry was performed in water, using 640 nm for direct assay of the copper(II) complex with pullulan and dextran. The calculated F and t values at the 95% confidence level were less than the theoretical values, showing there were no significant differences between the performance of the methods.

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Abstract  

A new high-nitrogen complex [Cu(Hbta)2]·4H2O (H2bta = N,N-bis-(1(2)H-tetrazol-5-yl) amine) was synthesized and characterized by elemental analysis, single crystal X-ray diffraction and thermogravimetric analyses. X-ray structural analyses revealed that the crystal was monoclinic, space group P2(1)/c with lattice parameters a = 14.695(3) Å, b = 6.975(2) Å, c = 18.807(3) Å, β = 126.603(1)°, Z = 4, D c = 1.888 g cm−3, and F(000) = 892. The complex exhibits a 3D supermolecular structure which is built up from 1D zigzag chains. The enthalpy change of the reaction of formation for the complex was determined by an RD496–III microcalorimeter at 25 °C with the value of −47.905 ± 0.021 kJ mol−1. In addition, the thermodynamics of the reaction of formation of the complex was investigated and the fundamental parameters k, E, n,
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,
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, and
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were obtained. The effects of the complex on the thermal decomposition behaviors of the main component of solid propellant (HMX and RDX) indicated that the complex possessed good performance for HMX and RDX.
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