Structural and optical studies of 7-methoxy-8-(3-metrhylbut-2-enyl)-2-chromenone (osthol), a plant based coumarin

Osthol, [7-Methoxy-8-(3-metrhylbut-2-enyl)-2-chromenone], a simple Coumarin (Mol. Formula = C15H16O3), was isolated from petroleum ether extract of the root parts of the plant Prangos pabularia. The compound was characterized by MS, 1H NMR, 13C NMR, IR, X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis spectroscopy and photoluminescence (PL) measurements. Structural analysis confirmed the monoclinic structure for the system. The exploration of SEM predicted the compound to be comprising of micro crystals with irregular morphology. From UV–vis spectroscopy, high transmission was displayed by these crystals in the entire visible range. The optical band gap (Eg) was found to be around 3.39 eV and the compound exhibited indirect allowed transitions. PL data showed good emission at certain wavelengths in visible region. The present properties of the compound can be explored for optoelectronics.