A novel chromogenic and fluorogenic chemosensor for detection of trace water in methanol

Abstract

A novel receptor (E)-1-(phthalazine-4-yl)-2-(1-(pyridine-2-yl)ethylidene) hydrazine (3) was developed for the detection of trace water content present in methanol. Upon interaction of water molecule with receptor 3, there appears a significant color change from colorless to yellow green and the absorption band at 355 nm was shifted to 435 nm (i.e. bathochromic or red shift) due to selective encapsulation of water molecule at 1-(pthalazine-4-yl) hydrazine-NH and imine groups leading to tautomeric transformation in the ground state which is caused by an intramolecular proton transfer. Also, there was remarkable enhancement in fluorescence intensity of 3 in methanol upon addition of water. Thus the chemosensor 3 has been developed for chromogenic and fluorogenic investigation of water and the detection limit is 5 ppm in methanol.