<strong>Periodic mesoporous organosilica: as a novel and efficient nanocatalyst for the one-pot synthesis of 3,3'-arylmethylene-bis-4-hydroxycoumarins in water</strong>

Abstract

Isocyanurate bridging periodic mesoporous organosilica (PMO-ICS) was shown to be a highly active and efficient recyclable catalyst for the synthesis of biscoumarin derivatives from 4-hydroxy coumarin, different aldehydes under mild reaction conditions in short reaction times and good to excellent yields in H2O. Moreover, the catalyst was also recovered and reused at least four times without significant decrease in its activity. The PMO-ICS catalyst was characterizred by Fourier transformer infrared (FTIR) spectroscopy, thermogravimetry analysis (TGA), powder X-ray diffraction (XRD) and nitrogen adsorptiondesorption isotherms (NADI) techniques as well as field emission scanning electron microscopy (FESEM). Compared to the classical methodologies, this method illustrated significant advantages including low loading of the catalyst, avoiding the use of toxic transition metals or reactive reagents for modification of the catalytic activity, short reaction times, high to excellent yields, easy separation and purification of the products, and reusability of the catalyst.