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 λmax 387 and 446 nm, 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.