Bis and tris(oxalato)ferrate(III) complexes as precursors of polynuclear compounds

The preparation and crystal structure of two oxalato-bridged NaI–FeIII compounds, [Na3Fe(ox)3(H2O)4]·H2O (1) and [FeII(phen)3][NaFe(ox)3(H2O)3]·4H2O (5), two mononuclear FeIII complexes AsPh4[Fe(bipy)(ox)2]·H2O (3) and AsPh4[Fe(phen)(ox)2]·H2O (4) and an oxalato-bridged FeIII compound [AsPh4]4[Fe2(ox)5]·5H2O (2) (ox = oxalate dianion, bipy = 2,2′-bipyridine, phen = 1,10-phenantroline and AsPh4+ = tetraphenylarsonium cation) are reported here. The structure of 1 consists of infinite anionic [NaFe(ox)3]2− layers linked trough centrosymmetric [Na4(H2O)8]4+ tetranuclear units yielding a three-dimensional motif. Crystallization water molecules ensure the cohesion of the crystal lattice in 1. The iron environment is distorted octahedral being surrounded by six oxygen atoms of three oxalate groups, with an average iron to oxalate-oxygen bond distance of 2.012(3) A. There are four crystallographically independent sodium atoms, all of which have a highly distorted octahedral environment. Six oxalate-oxygen atoms are bound to Na(1) and Na(2), whereas the other two sodium atoms are surrounded by four water oxygen and two oxalate oxygen atoms [Na(3)] and three water oxygen and three oxalate oxygen atoms [Na(4)]. The structure of compound 2 consists of centrosymmetric dinuclear [Fe2(ox)5]4− anions, AsPh4+ cations and crystallization water molecules. The anionic unit contains two Fe(III) atoms, four bidentate and one bridging oxalato ligands. Each iron atom has a distorted octahedral environment. The structures of 3 and 4 consist of discrete [Fe(AA)(ox)2]− [AA = bipy (3) and phen (4)] anions, tetraphenylarsonium cations and uncoordinated water molecules which are linked by hydrogen bonds. Each iron atom is six-coordinated with two nitrogen atoms from the bidentate AA ligand and four oxalate-oxygen atoms building a distorted octahedral environment. The structure of compound 5 consists of anionic [Fe(ox)3Na(H2O)3]2− chains, tris-chelated low-spin iron(II) [Fe(phen)3]2+ units and lattice water molecules linked to the chains through hydrogen bonds in which the water molecules and oxygen atoms of the oxalate groups are involved. The chains contain Fe3+ and Na+ cations alternatively bridged by oxalate groups, the tris-chelated [Fe(ox)3]3− unit acting as a bidentate ligand through one oxalato group toward a central sodium atom. Magnetic susceptibilty measurements in the temperature range 2.0–290 K for 2 that reveal the occurrence of antiferromagnetic coupling (J = −6.5 cm−1, the Hamiltonian being defined as H = −JS1S2) between the high-spin iron(III) ions across the oxalato bridge.

[1]  Wen-xia Tang,et al.  Synthesis, crystal structure and properties of [Fe2O(bipy)4C12](ClO4)2 · 0.25CH3CN · 0.25CH30H · 0.25H2O, a μ-Oxo diiron(III) complex , 1998 .

[2]  E. Coronado,et al.  Oxalato-bridged dinuclear complexes of Cr(III) and Fe(III): synthesis, structure, and magnetism of [(C2H5)4N]4[MM'(ox)(NCS)8] with MM' = CrCr, FeFe, and CrFe. , 2000, Inorganic chemistry.

[3]  S. Decurtins,et al.  A Concept for the Synthesis of 3-Dimensional Homo- and Bimetallic Oxalate-Bridged Networks [M2(ox)3]n. Structural, Moessbauer, and Magnetic Studies in the Field of Molecular-Based Magnets , 1994 .

[4]  F. Lloret,et al.  Syntheses, crystal structures, and magnetic properties of the oxalato-bridged mixed-valence complexes (FeII(bpm)3]2[FeIII2(ox)5].8H2O and FeII(bpm)3Na(H2O)2Fe(ox)(3).4H2O (bpm = 2,2'-bipyrimidine). , 2001, Inorganic chemistry.

[5]  E. Kemnitz,et al.  A BINUCLEAR CHLOROFERRATE ANION WITH OCTAHEDRAL METAL COORDINATION : OCTACHLORO(MU -OXALATO)DIFFERATE(III), (FECL4)2(MU -C2O4)4- , 1996 .

[6]  C. Mathonière,et al.  Ferrimagnetic Mixed-Valency and Mixed-Metal Tris(oxalato)iron(III) Compounds: Synthesis, Structure, and Magnetism. , 1996, Inorganic chemistry.

[7]  M. Fontecave,et al.  Structure of a (μ-Oxo)(dihydroxo)diiron(III) Complex and Its Reactivity toward Phosphodiesters , 1997 .

[8]  J. Ladrière,et al.  Crystal-structure and Mossbauer Study of Tetralithium Iron(iii) Trioxalate Chloride Nonahydrate , 1993 .

[9]  N. Achiwa,et al.  Design of metal-complex magnets. Syntheses and magnetic properties of mixed-metal assemblies {NBu4[MCr(ox)3]}x (NBu4+ = tetra(n-butyl)ammonium ion; ox2- = oxalate ion; M = Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+) , 1992 .

[10]  A. Bousseksou,et al.  A New Type of Trinuclear Oxoiron(III) Cluster , 1995 .

[11]  C. Ruiz-Pérez,et al.  Weak Ferromagnetism in Chiral 3-Dimensional Oxalato-Bridged Cobalt(II) Compounds. Crystal Structure of [Co(bpy)(3)][Co(2)(ox)(3)]ClO(4). , 1998, Inorganic chemistry.

[12]  J. Šima,et al.  Photochemistry of iron (III) complexes , 1997 .

[13]  F. Lloret,et al.  [Cr(phen)(ox)2]−: a versatile bis-oxalato building block for the design of heteropolymetallic systems. Crystal structures and magnetic properties of AsPh4[Cr(phen)(ox)2]·H2O, [NaCr(phen)(ox)2(H2O)]·2H2O and {[Cr(phen)(ox)2]2[Mn2(bpy)2(H2O)2(ox)]}·6H2O , 2000 .

[14]  J. McCusker,et al.  Studies on bis(catecholato)iron(III) complexes. Structure and bonding in members of the Fe(bpy)(Cl4SQ)(Cl4Cat)/Fe(bpy)(Cl4Cat)2- redox couple , 1992 .

[15]  F. Lloret,et al.  Two-Dimensional Assembling of (2,2'-Bipyrimidine)bis(oxalato)chromate(III) Units through Alkaline Cations. , 1999, Inorganic chemistry.

[16]  E. Coronado,et al.  Molecule-based magnets formed by bimetallic three-dimensional oxalate networks and chiral tris(bipyridyl) complex cations. The series [ZII(bpy)3][ClO4][MIICrIII(ox)3] (ZII = Ru, Fe, Co, and Ni; MII = Mn, Fe, Co, Ni, Cu, and Zn; ox = oxalate dianion). , 2001, Inorganic chemistry.

[17]  D. Proserpio,et al.  The cation as a tool to get spin-canted three-dimensional ironIII networks. , 2004, Inorganic chemistry.

[18]  B. Malézieux,et al.  Rational Design of Three-Dimensional (3D) Optically Active Molecule-Based Magnets: Synthesis, Structure, Optical and Magnetic Properties of {[Ru(bpy)3]2+, ClO4-, [MnIICrIII(ox)3]-}n and {[Ru(bpy)2ppy]+, [MIICrIII(ox)3]-}n, with MII = MnII, NiII. X-ray Structure of {[ΔRu(bpy)3]2+, ClO4-, [ΔMnIIΔCrIII , 2001 .

[19]  A. Hauser,et al.  Chiral, Three-Dimensional Supramolecular Compounds: Homo- and Bimetallic Oxalate- and 1,2-Dithiooxalate-Bridged Networks. A Structural and Photophysical Study. , 1996, Inorganic chemistry.

[20]  Vincenzo Balzani,et al.  Photochemistry of coordination compounds , 1970 .

[21]  M. Hursthouse,et al.  Molecular Charge-Transfer Salt of BEDT−TTF [Bis(ethylenedithio)tetrathiafulvalene] with the Oxalate-Bridged Dimeric Anion [Fe2(C2O4)5]4- , 2000 .

[22]  F. Lloret,et al.  [Fe(Phen)(CN)4]-: a versatile building block for the design of heterometallic systems. Crystal structures and magnetic properties of PPh4[Fe(Phen)(CN)4]*2H2O and [[Fe(Phen)(CN)4]2M(H2O)2]*4H2O [Phen = 1,10-phenanthroline; M = Mn(II) and Zn(II)]. , 2001, Inorganic chemistry.

[23]  Joel S. Miller,et al.  Organic magnets: A history , 2002 .

[24]  Gang Li,et al.  Photolysis of diacylferrocenes and their photo-ligand exchange reactions with 1,10-phenanthroline , 1997 .

[25]  C. Pierpont,et al.  POTENTIAL FOR REDOX ISOMERISM BY QUINONE COMPLEXES OF IRON(III). STUDIES ON COMPLEXES OF THE FEIII(N-N)(DBSQ)(DBCAT) SERIES WITH 2,2'-BIPYRIDINE AND N ,N,N',N'-TETRAMETHYLETHYLENEDIAMINE COLIGANDS , 1995 .

[26]  S. Padhye,et al.  Communication: : The first well characterized Fe (phen) Cl3 complex : Structure of aquo mono(1,10-phenanthroline) iron (III) trichloride : [Fe (phen) Cl3 (H2O)] , 1998 .

[27]  M. Mellon,et al.  Properties and Analytical Applications of the Iron(II)-2,2´-Bipyrimidine Complex. , 1963 .

[28]  F. Lloret,et al.  [Cr(bpym)(C2O4)2]− in designing heterometallic complexes. Crystal structures and magnetic properties of PPh4[Cr(bpym)(C2O4)2]·H2O and [Ag(bpym)][Cr(C2O4)2](H2O)2]·2H2O (bpym=2,2′-bipyrimidine) , 2002 .