Synthesis of a novel pyrylium salt with chemoselectivity to a cyanide anion

Abstract

The high-yield one-pot synthesis of a novel chemosensor based on a 4-methyl 2,6-diphenyl pyrylium trifluoromethanesulfonate (Pyr) salt that absorbs in the visible region is reported. The ability of pyr to sense various anions has been investigated using UV-visible spectroscopy and fluorescence spectroscopy. Pyr selectively detects CN- in competition with various other anions such as Cl-, Br-, I-, SCN-, ClO4-, NO3-, HSO4- and PF6-, due to its highly reactive nature towards nucleophiles. The selective detection of CN- with pyr gave rise to a significant hypochromic effect in CH3CN solution at lambda(max) 387 and 446nm, which are the absorption and fluorescence peaks, respectively. These studies indicated a high affinity of CN- for pyr, and forming a 1:1 ratio leads to cyano-enone derivative.