A hybrid open-framework structure: synthesis and structure of an iron phosphate oxalate,[C₁₀N₄H₂₈][Fe₂(HPO₄)₃(C₂O₄)]₂

Abstract

A new inorganic-organic hybrid structure has been synthesized hydrothermally in the iron phosphate oxalate family using 1,4-bis(3-aminopropyl)piperazine as the structure-directing agent. Crystal data for I, [C₁₀N₄H₂₈][Fe₂(HPO₄) ₃(C₂O₄)]₂: M=589.8, monoclinic, space group=P2₁/n (no. 14), a=10.829(1), b=12.747(1), c=12.397(1) Å, β=95.1(1)°, V =1704.4(3) ų, Z=4, R=0.036 and R_w=0.083 [1860 observed reflections with I>2σ(I)]. The structure comprises a network of FeO₆ octahedra and PO₄ tetrahedra forming inorganic layers which are bridged by the oxalate units forming 8-membered channels in which the amine molecule resides. Magnetic susceptibility studies indicate an antiferromagnetic behavior with T_N=≈40 K, the highest known in an open-framework material.