Thermal decomposition of linear tetranuclear copper(II) complexes including μ-azido bridges

Abstract

In the first instance, mononuclear Cu(II) complexes are prepared with bis-N,N′(salicylidene)-1.3-propanediamine and derivatives. After that, these mononuclear complexes are combined with μ-bridges, by the help of azide ions, to obtain the tetranuclear complexes. Prepared complexes are characterised using IR spectroscopy, elemental analysis, and X-Ray techniques. In addition, the complexes are further analysed via TG and DSC. Molecular models of two of the nine prepared complexes are determined using X-Ray diffraction methods. The two terminal copper ions are observed to be in square pyramide coordination sphere between two oxygens of the organic ligand, two iminic nitrogens and an oxygen of the solvent while the other two cupper ions are observed to be in square pyramide coordination sphere between the fenolic oxygens of the organic ligand and the nitrogen donors of the three azide ions. It is found that the fenolic oxygens form μ-bridge and two azide ions are monodentate coordinated. In the TG analyses, the complexes are observed to decompose in a highly exothermic manner at about 200 °C. This thermal reaction is partially similar to that of explosive molecules and the data from DSC proved that the liberated heat is at explosive material levels.