Synthesis, structure and electrochemical behaviour of 2,2-diferrocenylpropane-substituted dihydropyrazole derivatives

The reaction of α,β-unsaturated ketones of 2,2-diferrocenylpropane with hydrazine led to the formation of 2,2-diferrocenylpropane-substituted dihydropyrazole. The further reaction of dihydropyrazole with p-pyridinecarboxylic acid chloride or benzoyl chloride resulted in the isolation of two novel 2,2-diferrocenylpropane-substituted acyl dihydropyrazole derivatives. All of these compounds were analyzed by MS, IR and 1H NMR spectra. The crystal structure of representative compound, 1-p-pyridine acyl-3-ferrocenyl-5-(2,2-diferrocenylpropane)-4,5-dihydropyrazole (5a) has been elucidated by X-ray diffraction. The electrochemical behaviours of all the compounds have been examined.