Preparation of Macrometallocycle and Selective Sensor for Copper Ion

Two bis-imidazolium salts 1,8-bis[2’-(N-R-imidazoliumyl)acetylamino]naphthalene chloride (L(1)H(4)·Cl(2): R = Et; L(2)H(4)·Cl(2): R = (n)Bu), as well as their four NHC metal complexes [L(1)H(2)Ag]Cl (1), [L(1)Ni] (2), [L(2)Ni] (3) and [L(1)H(2)Hg(HgCl(4))] (4) have been synthesized. In each of the cationic moieties of complexes 1 or 4, there is a groove-like 14-membered macrometallocycle, and each macrometallocycle is consisted of one biscarbene ligand L(1)H(2) and one metal ion (silver(I) ion for 1 and mercury(II) ion for 4). Three 6-membered cycles are contained in each molecule of complexes 2 or 3. Additionally, the selective recognition of macrometallocycle 1 for Cu(2+) was studied with the methods of fluorescence and ultraviolet spectroscopy, (1)H NMR titrations, MS and IR spectra. The experimental results display macrometallocycle 1 can discriminate Cu(2+) from other cations effectively.