Synthesis, Characterisation and Photoluminescent Properties of Quinoline Derivatives Containing both a Biphenyl Group and an α, β-Diarylacrylonitrile Unit

Abstract

The synthesis of ( E)-2-(4-bromostyryl)quinoline involves an acid catalysed condensation of 2-methylquinoline and 4-bromobenzaldehyde. ( E)-4′-[(2-(Quinolin-2-yl)vinyl)]-(1,1′-biphenyl)-4-carbaldehyde has been synthesised from ( E)-2-(4-bromostyryl)quinoline and 4-formylphenylboronic acid via a Suzuki coupling reaction. A series of novel quinoline derivatives containing both a biphenyl group and an α, β-diarylacrylonitrile unit have been prepared by the base-catalysed condensation between ( E)-4′-[(2-(quinolin-2-yl)vinyl)]-(1,1′-biphenyl)-4-carbaldehyde and various arylacetonitriles. By contrast, the acid-catalysed condensation of the latter aldehyde with several aniline derivatives has been used to synthesise quinolines containing an imine group. These compounds, which have implications for the manufacture of organic light-emitting diodes, emit blue to green fluorescence with maximum emission peaks of 419–531 nm in solution and in the solid state under UV irradiation. Thermogravimetric analysis reveals their good thermal stability with a decomposition temperature range from 313 to 387°C.