Aggregation of dinuclear {Fe2hpdta} units to form polynuclear oxy/hydroxy-bridged Fe(III) coordination complexes.

Abstract

An approach for the preparation of oxy/hydroxy briged FeIII clusters that takes advantage of hydrolytic condensations of well defined {Fe2hpdta(H2O)4} building units is presented. Co-ligands such as tripodal H3tea or bidentate organic bases such as ethylenediamine (enH2) can be used to complete the coordination spheres of the FeIII centres and stabilise unsymmetrical iron-oxo clusters with non-zero magnetic ground spin-states. This strategy led to the isolation of a pentanuclear complex [Fe5(?3-O)(hpdta)(H2tea)(Htea)2)(tea)]?{N(C2H4OH)3}?2EtOH?7H2O (1) and a nonanuclear coordination complex [Fe9(?3-O)5(?-OH)5(en)6(hpdta)2](NO3)2?7H2O (2).