Kinetic analysis of thermogravimetric data on some nickel(II) N-alkyldithiocarbamates

Abstract

Thermogravimetric and derivative thermogravimetric curves of some complexes [Ni(S2CNHR)2] (R = Me, Et, Pr i, Bu i, Bu t, Bz, p:MePh, p-MeOPh, p-C1Ph, p-NO2Ph) in a dynamic nitrogen atmosphere were studied to determine their modes of decomposition. All these complexes show similar TG profiles. The weight losses in the main decomposition stages indicate conversion of the nickel(II) dithiocarbamates to sulphide. Reaction orders were estimated via the shape characteristics of the corresponding derivative thermogravimetric curves and kinetic analysis of the thermogravimetric data was performed by using the Coats-Redfern and Horowitz-Metzger methods.Dithiocarbamates constitute a class of organo-sulphur compounds with strong binding properties, which are also known to have profound effects on biological systems [1]. Interest in the study of metal dithiocarbamato complexes has been stimulated by their use in industry as vulcanization accelerators and as highpressure lubricants, whereas their use as fungicides and pesticides has induced a vast number of biological and biochemical investigations [2]. In this respect, several d 8 metal complexes of aliphatic and aromatic dithiocarbamates have already been studied in our laboratory in an attempt to establish the chemical and electronic properties of the various coordination geometries obtainable within the dithio-acid system [3 6]. One logical extension of this work was to study the thermal decomposition of bis(N-monosubstituted-dithiocarbamato)metal(II) complexes, [M(S2CNHR)2] (M = Ni, Pd, Pt), as a literature survey revealed that little work has been carried out on thermal studies of metal(II) N-alkyldithiocarbamates [7]. To this end, thermoanalytical data (TG and DTG) on some typical square-planar Ni(II) dithiocarbamates with substituents displaying various electronic effects are reported in the present paper. Moreover, an interpretation and numerical analysis of these data is attempted, since thermogravimetric analysis is an important method John W~ile.l~ & Sons, Limited, Chichester Akad~miai Kiad6; Budapest

Synthesis, Characterization, and Biological Activity of N1‐Methyl‐2‐(1H‐1,2,3‐Benzotriazol‐1‐y1)‐3‐Oxobutan‐ ethioamide Complexes with Some Divalent Metal (II) Ions

“…The negative values of Δ S *, see Table 5 , indicate that the reaction rates are slower than normal [ 30 ] which is consistent with the results reported previously [ 31 ]. Furthermore, these data indicate that the activated complexes have more ordered structure than the reactants [ 29 – 31 ].…”

“…Furthermore, these data indicate that the activated complexes have more ordered structure than the reactants [29–31]. …”

Temperature effect on the solvent extraction of copper(II), cobalt(II) and nickel(II) with salicylideneaniline from sulphate media

“…This trend has been supported by Indira and Parameswaran's studies [17]. In addition, the complexes have a more ordered structure than the reactant [18]. The negative entropy finding values indicate an increase in order as the metal cation is surrounded by the bidentate SAN.…”

Binuclear Copper(II), Nickel(II) and Cobalt(II) Complexes with N2O2 Chromophores of Glycylglycine Schiff-Bases of Acetylacetone, Benzoylacetone and Thenoyltrifluoroacetone

“…The activation energy values for the Cu(II), Ni(II) and Co(II) complexes are expected to increase proportionally to the decrease in their radius [40]. [41,42].…”