Structure and Mössbauer Study of the First Mixed‐Valence Iron Diphosphonate: $^{2}_{\infty}[\rm \{Fe^{II/III}(H_{2}O)_{2}\}\{Fe^{III/II}Cl\}_{2}(\mu_{4}-O_{3}P-C(OH)\{(CH_{2})_{4}NH_{3}\}-PO_{3})_{2}]\cdot4H_{2}O$

Abstract

The title compound bis(µ 4 -5-ammonio-1-hydroxypentylidene-1,1-bisphosphonato-κ 7 O, OЈ,OЉ,Oٞ,OЈ v aquairon)-di(chloroiron)(II/III)-tetrahydrate was prepared by hydrothermal synthesis and consists of nets of corner sharing {FeO 6 } or {FeClO 5 } octahedra linked by {CPO 3 } tetrahedra. Neighboring layers interdigitate with their ammoniopentylidene tails and connect to a three-dimensional network by N-H···O and O(hydrate)-H···O hydrogen bonds. The ligand [PO 3 -C(OH){(CH 2 ) 4ϩ NH 3 }-PO 3 ] 3Ϫ is a zwitter-ion of overall charge Ϫ3. Different from other 629 known iron diphosphonates, which contain only either Fe II or Fe III , the iron bisphosphonate here is found from Mössbauer-Spectroscopy to be a trapped mixed-valence system with Fe II and Fe III disordered over both crystallographic sites Fe1 and Fe2 in what could be described as a coherent superposition of different states. At 4.2 K the Fe III is completely magnetically ordered.

Low temperature heat capacity Study of Fe(PO3)3 and Fe2P2O7

“…Recently, iron phosphate compounds have attracted considerable research interest in the field of material science due to their outstanding chemical, thermal, electrical and magnetic properties [1][2][3][4][5]. Crystalline and amorphous iron phosphate materials have been developed and applied widely in various technologically important fields such as catalysis [6][7], electrochemistry [8][9][10][11], optical and magnetic materials [12][13][14][15][16], biosensor fabrication [17], bio-absorbable glass fibers [18], industrial coatings [19], and tissue engineering [20]. Moreover, the high chemical durability of iron phosphate glasses makes them suitable as alternative materials for safe immobilization and permanent disposal of a variety of high-level nuclear waste [3,[21][22][23][24][25][26][27].…”

Ultra-Microporous Fe-MOF with Exceptional NO Delivery Kinetics in Biological Media for Therapeutic Application

“…If a few water stable microporous metal(III or IV) bis, tris or tetra phosphonates MOFs have been reported [10][11][12] , to our knowledge there is not yet any iron(III) phosphonate MOF with accessible OMS to bind guest molecules such as NO. This was likely due either to the presence of Cl counter anions 13 and/or the dense framework using a short organic spacer 14 .…”

Charge-Assisted Hydrogen-Bonded Networks of NH4+ and [Co(NH3)6]3+ with the New Linker Anion of 4-Phosphono-Biphenyl-4′-Carboxylic Acid

“…The use of metal phosphonates in catalysis, luminescence [6], ion or proton exchange or conductivity [7,8] and in separation is discussed and investigated [9]. Further, cobalt and iron organophosphonates are investigated for their magnetic properties [10][11][12][13]. Metal phosphonates are also promising porous materials [14,15], and can be reversibly hydrated and dehydrated [16].…”