Synthesis and fluorescence of new 3-biphenylpyrrolo[1,2-c]pyrimidines

Abstract

New pyrrolo[1,2-c]pyrimidines derivates having a biphenyl moiety at position 3 have been synthesized by 1,3-dipolar cycloaddition of their corresponding N-ylides with activated alkynes. FTIR, 1H and 13C NMR spectroscopy and elemental analysis have been used to characterize the structures of the new nine pyrrolo[1,2-c]pyrimidine derivates. Absorption and fluorescence spectra have been recorded. The appropriate solvent for the photoluminescence properties of the studied compounds has been found to be chloroform:acetonitrile mixture (1:1). The main spectral features such as molar extinction coefficients (ε), Stokes shifts, quantum yields using quinine sulphate as standard, fluorescence quenching in the presence of benzoquinone and Stern-Volmer constants have been calculated. The substituent effects on intensity of absorption, maximum absorbance wavelengths and fluorescence parameters have been discussed. The highest quantum yield value was found for ethyl 3-(4-biphenylyl)-7-(3,4-dimethoxybenzoyl)pyrrolo[1,2-c]pyrimidine-5-carboxylate (0.55). The obtained results suggest that the studied compounds are promising candidates for future study in order to evaluate their use in practical applications in fluorescent chemical sensors.

Keywords

• Pyrrolo[1,2-c]pyrimidines
• 1,3-dipolar cycloaddition
• Stokes shift
• Fluorescence quenching
• Quantum yield