Self-assembly of water cluster in iron(III) oxalate-bridged complexes

The synthesis and crystal structural characterization of the compound of formula {[FeII(phen)3]2[Fe2IIIox5]}•11H2O (1) has been reported. The most interesting feature of the solid state structure of 1 consists in the occurrence of hexameric water clusters with a quasi-planar conformation self-assembled by means of hydrogen bonding interactions. The discrete hexameric water clusters are connected to the host lattices via an extensive net of strong hydrogen bonds that finally lead to an extended 3D supramolecular organization, wherein hexameric water clusters are interconnected with dodecameric hybrid water-Ooxalate clusters. The comparison of this supramolecular architecture with that found in the already known compound of formula [Fe(bpm)3]2[Fe2(ox)5]•8H2O (2) allows some preliminary observations on the design and control of cyclic water hexamer conformation.