Thermal decomposition of cobalt(III), nickel(II), copper(II), palladium(II) and platinum(II) complexes of N-allyl-N'-(4'-methylthiazol)-2ylthiourea

Abstract

Thermal decomposition of Co(III), Cu(II), Ni(II), Pd(II), and Pt(II) complexes of N-allyl-N'-(4'-methylthiazol)-2ylthiourea (AllMeTzTu), HL, have been studied by TG, DTG, and DTA curves. The complexes have the molecular formulae as CoL₃.H₂O, [Cu(HL)Cl₂]0.5H₂O and [CuL₂(H₂O)₂]  a square for ML₂ (M = Ni^II, Pd^II and Pt^II), and [Pd(HL)Cl₂]. The TG curves show that the four-coordinate complexes decompose in two stages to yield a free metal  ,with exception  [Pd(HL)Cl₂] which gives PdS, as a residue, while the two six-coordinate complexes CoL₃.H₂O, and [CuL₂(H₂O)₂]  decompose in three stages to yield Co and Cu residues. The initial mass losses correspond to elimination of allylamine radical for all complexes in the same temperature range; and with MeTz when the temperature range extended beyond that range of the first stage  for Pd(II) and Pt(II) complexes. Kinetic parameters (E^#, n, ΔH^#, ΔS^#, ΔG^#) of the decomposition stages are determined and correlated with bonding and structural properties of the complexes.