Synthesis, structure and magnetic properties of a new one-dimensional iron phosphite, [Fe^III(1,10-phenanthroline)(HPO₃)(H₂PO₃)]

Abstract

A new iron phosphite, [Fe^III(1,10-phen)(HPO₃) (H₂PO₃)], I, has been synthesized hydrothermally from a mixture containing iron powder, phosphorous acid, 1,10-phenanthroline and water at 125°C for 7 days. The structure consists of an edge-shared four-membered rings formed by the connectivity between FeO₄N₂ octahedra and pseudo pyramidal HPO₃ units, connected through their edges forming a one-dimensional structure. The 1,10-phenanthroline molecules and H₂PO₃ pseudo-tetrahedral units bound with the Fe centre project into the inter-chain spaces. Magnetic investigations reveal that the iron is present in +3 oxidation state, and at lowtemperature the sample orders antiferromagnetically with T_N = ~ 16 K. Crystal data: I, monoclinic, space group = P2(1)/m (no. 11), a = 10.180(3), b = 6.424(1), c = 11.6668(5) Å, β₃ = 115.59(1)°, V = 668.2(4) ų, Z = 4, ρ_calc = 1.880 g/cm³, μm(Mo Kα) = 3.456 mm^-1, R₁ = 0.0313 and wR₂ = 0.0725 data [I > 2σ(I)].