Ferrocene-based sulfonyl dihydropyrazole derivatives: Synthesis, structure, electrochemistry and effect on thermal decomposition of NH4ClO4

Three ferrocene-based sulfonyl-substituted dihydropyrazoles 3a–c have been synthesized, from the corresponding α,β-unsaturated diketones, and fully characterized. The crystal structures of 3a–c have been confirmed by X-ray crystallography, and electrochemistry behaviors of 3a–c have been examined by cyclic voltammetry (CV). Representatively, the mechanism of the electron transfer in redox process of 3a has been verified by density functional theory (DFT) calculation. It has been found that the activity of catalytic decomposition of ammonium perchlorate (AP) is significantly lowered (by 62.9–104.7 °C) with an addition of 3a–c. We expect that the ferrocene-based sulfonyl dihydropyrazole derivatives would have a great value in burning rate catalyst as composite solid propellants.