Thermal properties of thio-and selenocyanatocopper(II) complexes with bipyridine and phenanthroline

Abstract

The paper deals with the thermal properties of complex compounds of the general formula CuL2(NCX)2 (where L = bipy or phen, X = S or Se). The phenanthroline complexes exhibit a higher thermal stability than those with bipyridine. For the latter complexes thermal decomposition begins with the release of bipyridine molecules, while for the phenanthroline complexes redox ,reactions of pseudohalogenide ligands with Cu(II) take place. The redox reactions start at a lower temperature for the selenocyanate complexes than for the thiocyanate complexes.In earlier papers, the thermal properties of thiocyanatocopper(II) complexes with pyridine and all the isomeric forms of picolines and lutidines were studied [1][2][3]. It was found that the properties of the heterocyclic ligand affect the thermal stability and the stoichiometry of thermal decomposition of these complexes. Thermal decomposition begins with the release of molecules of the heterocyclic base. The release of components stabilizing the oxidation state of Cu(II), together with increased temperature, create conditions for the commencement of redox reactions between the central atom and the thiocyanate ligand. The presence of methyl substituents on the pyridine ligand decreases the thermal stability of he thiocyanate ligands, the redox reactions are shifted to lower temperatures and they are accompanied by the release of heterocyclic ligands.Likewise, it was also found that a higher number of coordinated monodentate molecules of the heterocyclic base lowers the thermal stability of the thiocyanatocopper(II) complexes [4,5].

Thermal properties of cyanatocopper(II) complexes with pyridine, bipyridine and phenanthroline

“…An analogous course of thermal decomposition was also observed for [Cu(bipy)2(NCX)](NCX) (X=S or Se) [3]. It was found that the thermal stabilities of the complexes were found to increase in the order py<<bipy<phen ligands.…”

“…An analogous course of thermal decomposition was also observed for [Cu(bipy)2(NCX)](NCX) (X=S or Se) [3]. The decomposition temperature of thiocyanate ligands depends on the properties of the ligands L present in the coordination sphere.…”

Diiron Aminocarbyne Complexes with NCE− Ligands (E = O, S, Se)

“…Notwithstanding, the metal coordination of the {NCSe} − group might be unstable, resulting in decomposition into the cyanide ion and selenium atom; this reaction was previously reported with copper(II) acetate [ 24 , 25 ] and was exploited for catalytic purposes in cyanation reactions. Selenocyanate to cyanide degradation was also observed in human blood, and the ferric ion is typically involved in this process [ 26 ].…”