Hydrothermal synthesis of the first iron arsenate-oxalate [C4N2H12]2[Fe4(HAsO4)6(C2O4)2], possessing open architecture

The hydrothermal synthesis and structural characterization of the first iron arsenate-oxalate [C4N2H12](2)[Fe-4(HAsO4)(6)(C2O4)(2)], I, with open-framework structure has been described. Crystal data for I: triclinic, space group P(-1) (no. 2), n = 11.1066(2), b = 12.9842(1), c = 13.4294(1) Angstrom, alpha = 11 1.345(l), = 93.688(1), gamma = 93.879(1)degrees, V = 1706.33(4) Angstrom(3), Z = 2, rho(calc) = 2.755 g cm(-3), mu(Mo Kalpha) = 7.567 mm(-1), R-1 = 0.0441 and wR(2) = 0.113 for 3861 reflections with I > 2sigma(I). The framework structure of I consists of neutral inorganic sheets formed by the linkages between strictly alternating FeO6 octahedra and AsO4 tetrahedra cross-linked by the oxalate units forming an anionic three-dimensional network with channels. The charge compensating doubly protonated piperazine molecules occupy these channels and interact with the framework through strong hydrogen bonds. The compound shows strong anti-ferromagnetic interactions with T-N similar to 40 K. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.