Fluorescent zinc–terpyridine complex containing coordinated peroxo counter ion in aqueous medium

We describe a mixed ligand–zinc (d10) complex containing coordinated peroxo ion and 2,2´2´´-terpyridine and exhibiting fluorescence in the visible region (473 nm) on excitation at 390 nm in aqueous medium at room temperature. We also discuss the unusual phenomenon of enhancement of this fluorescence intensity on addition of some transition metal ions (3d5, 3d10, 4d0 and 3d9 electronic configurations).