Preparation, X-ray crystallography and thermal decomposition of transition metal perchlorate complexes with perchlorate and 2,2′-bipyridyl ligands

Three transition metal perchlorate complexes of 2,2′-bipyridyl such as [Mn(bipy)2(H2O)(ClO4)]ClO4, [Cu(bipy)(ClO4)2(H2O)2], [Zn(bipy)2(H2O)](ClO4)2 have been prepared, and characterized by X-ray crystallography. Their thermal decomposition has been studied using iso and non-isothermal thermogravimetry (TG); differential scanning calorimetry (DSC). Kinetics parameters were evaluated by model-fitting and isoconversional methods. Their thermolytic pathways have also been suggested which involves decomposition followed by explosion. The Mn and Cu complexes decompose in single step whereas Zn complex decomposes in two steps. The coordination number of Mn and Cu atoms is found to be six and that of Zn is five. In order to evaluate the response of rapid heating, explosion delay (DE) measurements were undertaken. The explosion delay and activation energy were found to decrease in the order: Zn > Cu > Mn.

Graphical abstractTransition metal perchlorate complexes of 2,2′-bipyridyl such as [Mn(bipy)2(H2O)(ClO4)]ClO4, [Cu(bipy)(ClO4)2(H2O)2] and [Zn(bipy)2(H2O)](ClO4)2 have been prepared and characterized by X-ray crystallography. Their thermal decomposition studies have been studied using TG–DSC (in nitrogen), isothermal TG (in static air) and explosion delay (DE) measurements. Kinetics of their thermal decomposition have been evaluated by applying mechanism based fourteen kinetics models and, model free isoconversional method. The possible pathways of thermolysis have also been proposed.Figure optionsDownload full-size imageDownload as PowerPoint slide