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

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)](NO3)(2)center dot H2O (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 Co2+ and Ni2+ ions but not for metal ions such as Mg2+, Pb2+, Cu2+, Fe2+, In3+, Zn2+, Cd2+ and Fe3+. Furthermore, EDTA (ethylene diamine tetraacetic acid) can selectively turn on the quenched fluorescence of complex 1 induced by Co2+ (on-off-on type sensor) but cannot turn on the one induced by Ni2+ (on-off type sensor). (C) 2012 Elsevier B.V. All rights reserved.