Mercury(ii)-mediated formation of imide-Hg-imide complexes

Abstract

Three different kinds of cyclic imides with imido protons are chosen to interact with Hg(II): succinimide, the simplest cyclic imide (five-membered ring); phthalimide (conjugated five-membered ring); and 1,8-naphthalimide (conjugated six-membered ring). Based on the results of MS, ¹H-NMR, XPS, IR spectroscopy and fluorescence response analyses, it is suggested that N-unsubstituted cyclic imides react specifically with Hg(II) and form imide-Hg-imide complexes through an imido proton–metal exchange process. The reaction is reversible and occurs rapidly at moderate to high pH. This discovery expands the comprehension of the specific interaction of Hg(II) with the nucleobase thymine, and may open up new possibilities in designing novel ligands for sensing and removing Hg(II) based on cyclic imides.