1,5-Diaryl-3-Benzimidazolyl-2-Pyrazolines and Pyrazoles – Novel Fluorescent Dyes of Pyrazoline Family

Abstract

A series of novel aryl derivatives of 2-pyrazoline bearing 2-benzimidazolyl moiety was synthesized via condensation of corresponding chalcones with phenyl hydrazine. Pyrazoles on their background were obtained by the optimized oxidation procedure with manganese dioxide in benzene. Fluorescent characteristics of the title compounds were determined for their solutions in acetonitrile. Quantum-chemical modeling of molecular structure, UV/Vis spectra, electron density redistribution and structural relaxation at electronic excitation resulting in high fluorescence Stokes shifts were conducted as well.