Zinc(II) complex with teirpyridine derivative ligand as “on–off” type fluorescent probe for cobalt(II) and nickel(II) ions

Abstract A new terpyridine derivative ligand 4′-4-(1,2,4-triazol-1-yl)-phenyl-2,2′:6′,2″-terpyridine (L) was prepared and its metal complex [Zn(L) 2 ](NO 3 ) 2 ·H 2 O ( 1 ) was obtained by reaction of L with zinc(II) nitrate hexahydrate. The structure of the complex was determined by X-ray crystallography. The fluorescent spectral measurements revealed that complex 1 is a selective fluorescent sensor for Co 2 + and Ni 2 + ions but not for metal ions such as Mg 2 + , Pb 2 + , Cu 2 + , Fe 2 + , In 3 + , Zn 2 + , Cd 2 + and Fe 3 + . Furthermore, EDTA (ethylene diamine tetraacetic acid) can selectively turn on the quenched fluorescence of complex 1 induced by Co 2 + (“ on–off–on ” type sensor) but cannot turn on the one induced by Ni 2 + (“ on–off ” type sensor).