A 3-D Organically Templated Mixed Valence (Fe²⁺/Fe³⁺) Iron Phosphate with Oxide-Centered Fe₄O(PO₄)₄ Cubes:  Hydrothermal Synthesis, Crystal Structure, Magnetic Susceptibility, and Mössbauer Spectroscopy of [H₃NCH₂CH₂NH₃]₂[Fe₄O(PO₄)₄]·H₂O

Abstract

A 3-D, open framework, mixed valence iron phosphate, [H3NCH2CH2NH3]2[Fe4O(PO4)4]·H2O, which contains organic ethylenediammonium dications in the framework voids, has been prepared via hydrothermal synthesis and has been characterized by single-crystal X-ray diffraction, magnetic susceptibility, and variable temperature Mössbauer spectroscopy. Crystal data: tetragonal, space group I4̄2m with a = 10.1383(8) Å, c = 9.628(1) Å, V = 989.6(1) Å3, Z = 2, and R(R w) = 7.7(6.5) for 276 reflections (I > 3σ(I)) and 32 variables. The fundamental building block of the structure is a novel cubane-like cluster with trigonal bipyramidal iron and tetrahedral phosphorus atoms lying at alternate vertexes of a cube with a tetrahedrally coordinated oxygen atom at the center of the cube. Each cluster is linked by eight Fe−O−P bonds that extend along what would be all 〈111〉 directions of the putative cube to eight similar clusters to form a framework that is only slightly distorted (by the presence of the organic cations) from cubic 4̄3m symmetry. Mössbauer and ac magnetic susceptibility measurements show that equal amounts of valence trapped Fe2+ and Fe3+ are present, which undergo long range magnetic ordering at ∼12 K.

Design of Novel Inorganic−Organic Hybrid Materials Based on Iron-Chloranilate Mononuclear Complexes: Characteristics of Hydrogen-Bond-Supported Layers toward the Intercalation of Guests

“…This is attributed to the space group symmetry or the random superposition of Fe 2+ and Fe 3+ in the crystal lattice. 38b, 40 The common feature of the Mössbauer spectra in 1, 2, and 3 is that the values of IS and QS of high-spin iron(III) are very similar. These compounds are constructed from the common layers, which consist of the same building blocks of [Fe 3+ (CA) 2 -(H 2 O) 2 ] -.…”

Solvothermal synthesis, structure and Mössbauer spectroscopy of a new mixed-valence iron aluminophosphate [FeII(H2O)2 Fe0.8IIIAl1.2(PO4)3]·H3O

“…57 Fe Mössbauer spectroscopy can help to determine whether iron atoms are Fe(II), Fe(III) [22][23][24][25] or mixedvalence [26][27][28][29][30][31][32][33][34][35]. The room-temperature Mössbauer powder spectrum of the sample (Fig.…”

Synthesis, characterization and magnetic property of a new 3D iron phosphite: |C4N3H14|[Fe3(HPO3)4F2(H2O)2] with intersecting channels

“…Especially, iron phosphates with one- [3] two- [4][5][6] and threedimensional (3D) frameworks [7][8][9][10] exhibit a rich structural and compositional diversity. Recently, using pyramidal phosphite groups to substitute tetrahedral phosphate units have resulted in a new class of metal phosphites with great success [11].…”

“…Such as the two iron phosphites reported by Rojo and coworkers, jC 4 [20] with a mixed-valence nature and the presence of both the phosphite and hydrogen-phosphate-phosphate oxoanions, |C 5 H 18 N 3 |[Fe 3 (HPO 3 ) 6 ] [21] with a pillared structure formed by the interpenetration of two subnets. Natarajan and coworkers reported the synthesis of the first one-dimensional (1D) iron phosphite-phosphate |C 10 [24].…”