Synthesis, characterization, electrochemistry and optical properties of new 1,3,5-trisubstituted ferrocenyl pyrazolines and pyrazoles containing sulfonamide moiety

This article describes the synthesis and characterization of a series of new 3-ferrocenyl-1-(4-sulphamylphenyl)-5-aryl-4,5-dihydro-1H-pyrazolines and the corresponding pyrazole derivatives derived from ferrocenyl chalcones and 4-hydrazino benzenesulfonamide hydrochloride. The compounds were characterized by spectroscopic means and the structure of the new ferrocenyl pyrazoline (3a) was determined by means of X-ray crystallography. The optical properties of these compounds were studied by means of UV/visible absorption spectroscopy and fluorescence spectroscopy (both steady state and time-resolved) in dichloromethane solvent. Electrochemical study revealed that all the compounds exhibited reversible oxidation behavior at 521–543 mV corresponding to ferrocene pyrazolines (3a–l) and 621–645 mV corresponding to ferrocene pyrazoles (4a–j) respectively, as confirmed by the ipc/ipa = 0.92–1.00.