A dioxotetraamine fluorenyl ligand and its nickel(II) complex - crystal structure and fluorescent sensing properties in aqueous solution

A new ligand consisting of fluorenyl and dioxotetraaza units, namely, 2 10-diamino-6-(9H-fluoren-9-yl)-4,8-diazaundecane-5,7-dione (L), and its nickel(II) complex were synthesized. The crystal structure of [Ni(H-2L)] showed that Ni(II) is in a square planar coordination environment. Studies of solution chemistry of the ligand and its nickel(II) complex indicate that the ligand can form a stable complex with Ni2+ ions and fluorescence quenching of the ligand is accompanied by the coordination of the metal ion to the dioxotetraaza unit and electron transfer from the Ni(II) center to fluorenyl in aqueous solution. (C) 2001 Elsevier Science Ltd. All rights reserved.