J.P. Smith

Bio: J.P. Smith is an academic researcher. The author has contributed to research in topic(s): Thermal decomposition & Copper. The author has an hindex of 1, co-authored 1 publication(s) receiving 18 citation(s).

The thermal decomposition of metal complexes—XII: Some copper(II) ammine complexes

Abstract: The thermal dissociation of [Cu(NH 3 ) 6 ]Br 2 , [Cu(NH 3 ) 6 ]Cl 2 , [Cu(NH 3 ) 5 ]SO 4 , and [Cu(NH 3 ) 4 ]I 2 , was studied by differential thermal analysis, thermomagnetic analysis, pyrolysis on the mass spectrometer, and by chemical analysis of the residues and reaction products. The complexes dissociated through the loss of ammonia, forming stable lower ammines, and upon further heating, the reduction of the copper(II) to copper(I) took place. The stoicheiometry of the thermal dissociation reaction was determined.

4-, 5- and 6-coordinate complexes of copper(II) with substituted imidazoles

Abstract: Several new complexes of copper(II) halides, isothiocyanate, perchlorate, sulphate and nitrate with a series of 1-substituted, 2-substituted and 1,2-disubstituted imidazoles were synthesised and characterised. The microanalytical data, conductivity, magnetic susceptibility, IR and electronic spectral measurements were employed to deduce the possible stereochemistry. 1-vinyl 2-methyl imidazole formed a bis compound with CuX 2 (X = Cl, 0.5 SO 4 ), a tris compound with X = NCS, but tetrakis compounds with all other anions studied. 1-Vinyl imidazole formed a tris compound with X = 0.5 SO 4 and tetrakis compounds in all other cases. 2-Ethyl imidazole formed a tris compound with X = Br and tetrakis compounds with other anions. 2-Isopropyl imidazole formed tris compounds with X = Cl, Br and tetrakis compounds with X = NO 3 , ClO 4 . All bis compounds are shown to be 4-coordinate and square planar the tris compounds to be 5-coordinate with perhaps a trigonal-bipyramidal geometry and the tetrakis compounds to be 6-coordinate with a tetragonally distorted octahedral structure. On the basis of IR evidence, it is shown that the NO 3 groups are unidentate, the SO 4 groups bidentate and the ClO 4 groups involved in unidentate “semi-coordination”. The TGA, DTG and DTA studies have been made and the complexes were found to dissociate endothermically through loss of imidazole ligands. The stoichiometry of the thermal dissociation reactions was determined.

Effect of metal ion and ligand on thermal stability of metal amine complexes

Abstract: A series of transition-metal (II) pyridine complexes, [M(py) 2 X 2 where M  Cu 2+ , N 2+ , Co 2+ , Mn 2+ , Zn 2+ , and X  Cl − , NO 3 − , NCS − ,] and two series of copper (II) chloride complexes with mono- and dimethyl substituted pyridines and with 4-substituted pyridines were studied by differential thermal analysis. The thermal stability was correlated with thermodynamic constants determined in solution and with bond energies determined by far infra-red spectroscopy. In the transition-metal series thermal stability increased with increasing stability in solution. In the copper series the opposite trend was found. As base strength of the ligand increased the thermal stability decreased. This can be best explained by an oxidation-reduction reaction occurring during decomposition.

Thermal decomposition kinetics: Part XVII. Kinetics and mechanism of thermal decomposition of bis(ethylenediamine)copper(II) halide monohydrate

Abstract: The thermal decomposition studies of bis(ethylenediamine)copper(II) chloride monohydrate and bis(ethylenediamine)copper(II) bromide monohydrate were carried out using thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA). The kinetics and mechanism of the dehydration and the deamination stages of both the complexes were evaluated. The different stages of decomposition were identified from TG, DTG and DTA. The intermediate and residue analysis done using optical microscopy and X-ray diffraction showed the formation of CuCl and CuBr at about 450°C and copper as fine linear wires at about 700°C. The kinetic parameters for the dehydration and the deamination reactions were evaluated from the TG and DTA curves using four integral methods. For both the complexes the dehydration and the deamination processes follow the mechanism of random nucleation with the formation of one nucleus on each particle (Mampel equation). The heat of reaction for each stage of decomposition was determined using DTA.

Thermal decomposition kinetics: Part XV. Kinetics and mechanism of thermal decomposition of tetrammine copper(II) sulphate monohydrate

Abstract: The kinetics and mechanism of the thermal decomposition of tetrammine copper(II) sulphate monohydrate have been studied using non-isothermal thermogravimetry. Kinetic parameters were calculated for each step in the decomposition reaction from the TG curve using four integral methods, three “exact” and one “approximate”. The rate-controlling process for all the four stages of decomposition is random nucleation with the formation of one nucleus on each particle (Mampel equation). The stages of decomposition have been identified from X-ray diffraction and independent pyrolysis.