Synthesis, electrochemistry and fluorescence behavior of thiophene derivatives decorated with coumarin, pyrene and naphthalene moieties

A novel series of functionalized thiophenes incorporating coumarin, pyrene and naphthalene pendants were synthesized by Steglich esterification in the presence of DCC/DMAP (dicyclohexylcarbodiimide/N,N-dimethylaminopyridine) and the synthesized monomers were electrochemically deposited onto glassy carbon and carbon fiber micro electrodes as active electrode materials. The synthesized thiophene derivatives were characterized by 1H NMR, 13C NMR, FTIR, cyclic voltammetry, electrochemical impedance spectroscopy and electronic absorption as well as fluorescence spectroscopy. An electrochemical impedance study was performed on the surface modified electrodes. Variation of capacitance values was explained according to the different fluorophore groups attached to the thiophene as well as the different substrates. The fluorescence properties of the three compounds in dimethylsulfoxide were measured, with varying effects of the thiophene moiety on the fluorescence emission. The morphology of the monomers was monitored using SEM.