A new colorimetric chemodosimeter for Hg 2+ based on charge-transfer compound of N-methylpyrrole with TCNQ

Abstract

Reaction of N-methylpyrrole and 7,7,8,8-tetracyanoquinodimethane (TCNQ) furnishes an intense blue unsymmetrical charge-transfer compound through regioselective attachment of tricyanoquinodimethane at the 2-position of N-methylpyrrole which was found to be selective chemodosimeter for Hg 2+ ions in CH 3CN:H 2O mixture (1:1 v/ v, pH = 7.0, 0.01 M HEPES, 0.15 M NaCl) as well as in the solid state when supported on silica, over a variety of metal ions. A plausible mechanism for the sensing process has been proposed and supported through the characterization of the resulting Hg 2+ complex and the density functional theory (DFT) studies.