Synthesis and fluorescent properties of poly(arylpyrazoline)’s for organic-electronics

Abstract The present work focuses on the synthesis and characterization of poly(arylchalcone)’s (PCH I-IV) by reacting acetone with various dialdehydes for the first time at below ambient temperature followed by cyclization with phenylhydrazinehydrochloride to yield luminescent poly(arylpyrazoline)’s (PPY I-IV). The synthesized polymers were characterized by standard techniques such as, GPC, SEM, TGA, FT-IR, 1 H NMR, UV–Vis absorption and fluorescence spectroscopy, and electrochemical studies by cyclic voltammetry analyses. The Pyrazoline group hooked with different aryl donors such as benzene, thiophene, carbazole, triphenylamine, thus results a series of blue and green emitting materials. The obtained optical bandgap energy of the polymers (PPY I-IV) were 2.53, 3.41, 3.07, 3.10 eV respectively, suggest that all the polymers belongs to semiconducting category. The solvent effect of polymers was thoroughly studied and explained by Lippert-Mataga equation. The polymers I & IV display large degree of intra-molecular charge transfer in excited state evidenced from solvatochromic shift on the emission spectra. The obtained results demonstrate that they are promising materials for organic electronics applications.