Synthesis, photophysical and DFT studies of naphthyl chalcone and nicotinonitrile derivatives

Abstract

Chalcone and cyanopyridine derivatives have emerged as attractive light sensitive materials, with potential use in cell probing and optoelectronic applications. They are highly fluorescent both in solution and solid state and thus well-suited for OLED applications. Herein, we report the synthesis of a chalcone derivative (CP1) using the Claisen Schmidt condensation of 2-acetyl thiophene and 2-methoxy naphthaldehyde followed by the heterocyclization to yield the novel cyanopyridine derivative (NP1). Synthesized molecules were characterized using elemental analysis, FTIR and NMR spectra. Density functional theory (DFT) calculations were performed on the molecules, in order to understand their absorption and emission properties. The orbital picture of all the excitations involved in these transitions were identified as π- > π*. The, experimentally obtained FTIR spectra were in excellent agreement with DFT calculated infrared spectrum. The steady state fluorescence spectra of CP1 showed dual emission in the blue and green regions while a single band, orange emission was observed for the other molecule NC1. NC1 showed the solid-state emission in orange region inferring its suitability for the OLED application.