Siderophore analogues: a new macrocyclic tetraamine tris(hydroxamate) ligand; synthesis and solution chemistry of the iron(III), aluminium(III) and copper(II) complexes†

Abstract

A new siderophore analogue TETMAHA (1,4,8,11-tetraazacyclotetradecane-N,N′,N″-tris(N-methylacetohydroxamic acid), a ligand with three hydroxamic acid groups bonded to the macrocycle CYCLAM, has been synthesized and characterized. Its acid–base and chelating properties towards iron(III), aluminium(III) and copper(II) have been studied by potentiometric and spectroscopic techniques. This ligand forms quite stable complexes with those metal ions and the formation constants have been determined. The mechanism of the electron transfer of the iron complexes, thought to be important in the biological activity shown by this ligand, has also been studied by cyclic voltammetry.