A facile route to the new triazene dyes based on substituted pyrazolidin-3,5-dione derivatives

Several substituted triazenes dyes were synthesized by coupling functionalized pyrazolidin-3,5-dione derivatives, to various heteroarene azides in excellent yields (98%). Electron delocalization between the two coupled components of these triazene dyes was studied using UV–vis spectra and NMR spectroscopy. Their thermolysis was investigated and by using an isotopically labeled triazene, the mechanism decomposition reaction was also identified. The protolysis of these triazenes was evaluated and showed that they are highly stable and even in strongly acidic medium.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights►Pyrazolidin-3,5-dione triazenes were synthesized under mild condition in high yields. ► For studied molecules we analyze the electronic and thermal properties. ►The mechanism decomposition reaction is also identified. ►These molecules are highly stable and even in strongly acidic medium.