One-pot synthesis and photophysical studies of dihydropyrimidinone-based dyes : novel violet-blue light emitting fluorophores

A one-pot, four-component methodology have been developed for the synthesis of coumarin-linked triazolyl-dihydropyrimidinones (DHPM). The Biginelli reaction was combined with the click reaction for the first time in a sequential multicomponent tandem reaction approach. A series of ten such compounds have been synthesised and examined for their fluorescent properties. These were found to emit violet-blue light in the visible region of the spectrum with very high Stoke's shift values. The compounds have demonstrated high quantum yields which makes them attractive targets for their utilization as new fluorescent probes. The electronic structure of these coumarin-based donor-pi-acceptor (D-pi-A)-type organic dyes have been studied by Density Functional Theory (DFT). Thermal analysis of few of the compounds show that they are stable up to temperature range of 0-290 degrees C. The synthesised compounds have been characterised by NMR and mass spectrometry