New fluorenyl-substituted ditopic dioxotetraamine ligands and their copper(ii) complexes—synthesis, crystal structure, magnetic properties and solution behavior

Abstract

A new fluorenyl-substituted dioxotetraamine salicylaldehyde Schiff-base ligand (L¹) has been synthesized by the non-template 1 + 2 condensation of ligand 6-(9-fluorenyl)-1,4,8,11-tetraazaundecane-5,7-dione (L) with salicylaldehyde. From reduction of L¹ with an excess of NaBH₄, a ditopic dioxotetraamine ligand (L²) has been obtained. The copper(II) complex of L¹ has been synthesized and its properties were examined by ES-MS and variable-temperature magnetic susceptibility as well as its crystal structure being determined. Detailed studies have been made on solution chemistry of Cu(II) complex of L² by pH-potentiometric and fluorometric titration.