Solvent free and green synthesis of efficient solvochromism based coumarin moieties for quick visualization of LFPs and OLEDs applications

Abstract

We report a novel solvochromism based coumarin thiophene fluorescent tags (CTFTs) namely, 3-(thiophen-2-yl)-2H-chromen-2-one (3a) and 6, 8-dichloro-3-(thiophen-2-yl)-2H-chromen-2-one (3b) via solvent free, eco-friendly, low-cost and one-pot multicomponent reaction system under microwave irradiation protocol. The synthesized CTFTs derivatives were characterized by different analytical techniques namely, Fourier transform infrared spectroscopy (FTIR), Proton nuclear magnetic resonance spectroscopy (1H NMR), Mass spectrometer, Powder X-ray diffraction (PXRD), Scanning electron microscope (SEM), Energy dispersive X-ray analysis (EDAX), Ultraviolet-visible (UV−vis) and Photoluminescence spectrometer (PL). The CTFTs show strong excitation peaks at 407 nm (3a) and 431 nm (3b) due to π-π* and n-π* transitions in the aromatic core and CTFTs show strong emission peaks at 456 nm (3a) and 501 nm (3b) due to σ-π* and π-π* transitions. The CTFTs derivatives exhibit cyan blue (3a) and greenish blue (3b) luminescence in liquid and solid-state. The CTFTs are investigated as an innovative category for the visualization of latent fingerprints on various non-porous material surfaces. The obtained results prove that the CTFTs can be served as promising small organic fluorescent tags for flat-panel display and latent fingerprint applications.