Novel mixed-valence tetranuclear iron-oxygen clusters in the organically templated iron phosphate [H3N(CH2)2NH3]2Fe4O(PO4)4•H2O

A novel iron phosphate templated with ethylenediammonium cation, [H3N(CH2)(2)NH3](2)Fe-4 O(PO4)(4). H2O, has been synthesized hydrothermally and characterized by single-crystal X-ray diffraction, thermo-gravimetric analysis, magnetic susceptibility and Mossbauer spectroscopy. The compound crystallizes in the mono-clinic space group C2 with a = 30.3801(5), b = 10.1204(5), c = 10.0977(5) Angstrom, beta = 107.712(1)degrees, V = 2957.5(4) Angstrom(3) and Z = 6. The structure contains 5 and 6-coordinated Fe atoms bridged by mu(4)-oxygen and PO4 groups to form two types of mixed-valence Fe4P4 cubane-like clusters, which are connected via Fe-O-P bonds to give rise to intersecting channels that house the ethylenediammonium cations and water molecules. Room-temperature Mossbauer data confirm the presence of Fe-II and Fe-III.