Titelbild: Cyanide-Bridged Iron(III)–Cobalt(II) Double Zigzag Ferromagnetic Chains: Two New Molecular Magnetic Nanowires (Angew. Chem. 13/2003)

Nuclearity controlled cyanide-bridged bimetallic CrIII-MnII compounds: synthesis, crystal structures, magnetic properties and theoretical calculations.

The preparation, X-ray crystallography and magnetic investigation of the compounds PPh4[Cr(bipy)(CN)4].2 CH3CN.H2O (1) (mononuclear), [[Cr(bipy)(CN)4]2Mn-(H2O)4].4H2O (2) (trinuclear), [[Cr(bipy)(CN)4]2Mn(H2O)2] (3) (chain) and [[Cr(bipy)(CN)4]2Mn(H2O)].H2O.CH3CN (4) (double chain) [bipy=2,2'-bipyridine; PPh4 (+)=tetraphenylphosphonium] are described herein. The [Cr(bipy)(CN)4]- unit act either as a monodentate (2) or bis-monodentate (3) ligand toward the manganese atom through one (2) or two (3) of its four cyanide groups. The manganese atom is six-coordinate with two (2) or four (3) cyanide nitrogens and four (2) or two (3) water molecules building a distorted octahedral environment. In 4…

Heteropolymetallic Supramolecular Solid-State Architectures Constructed from [Cr(AA)(C2O4)2]- Tectons, and Sustained by Coordinative, Hydrogen Bond and π−π Stacking Interactions (AA = 2,2‘-Bipyridine; 1,10-Phenanthroline)

The paper reports on four novel solid-state architectures constructed by using tectons having the general formula:  [Cr(AA)(C2O4)2]- [AA = 2,2‘-bipyridine (bipy) and 1,10-phenanthroline (phen)]. These building blocks are involved in various intermolecular interactions:  coordinative, hydrogen bonds, and π−π contacts. Two new crystallohydrates in the Ba[Cr(AA)(C2O4)2]2·nH2O family have been characterized:  [BaCr2(bipy)2(C2O4)4(H2O)2]·4H2O (1) and [BaCr2(phen)2(C2O4)4(H2O)2] (2). Because of the different numbers of water molecules, their crystal structures are completely different from those of two others previously reported, [BaCr2(bipy)2(C2O4)4(H2O)]·H2O and [BaCr2(phen)2(C2O4)4(H2O)2]·4H2O…

4,2-Ribbon like ferromagnetic cyano-bridged FeIII2NiII chains: a magneto-structural study

The low-spin iron(III) complex AsPh(4)[Fe(III)(bpy)(CN)(4)].CH(3)CN (1) [AsPh(4) = tetraphenylarsonium cation] and the heterobimetallic chains [{Fe(III)(L)(CN)(4)}(2)Ni(II)(H(2)O)(2)].4H(2)O with L = bpy (2) and phen (3) [bpy = 2,2'-bipyridine and phen = 1,10-phenanthroline] have been prepared and their structures determined by X-ray diffraction methods. The structure of 1 consists of mononuclear [Fe(bpy)(CN)(4)](-) anions, tetraphenylarsonium cations and acetonitrile molecules of crystallization. The iron(III) is hexacoordinated with two nitrogen atoms of the bidentate bpy and four carbon atoms of four terminal cyanide groups building a distorted octahedral surrounding around the metal ato…

Design of single chain magnets through cyanide-bearing six-coordinate complexes

Abstract The design and preparation of stable cyanide-bearing six-coordinate complexes of formula [MIII(L)(CN)x](x + l − m)− (M = trivalent transition metal ion and L = polydentate blocking ligand) are summarized here. Their use as ligands towards either fully hydrated metal ions or coordinatively unsaturated preformed species, to afford a wide variety of low-dimensional metal assemblies whose nuclearity, dimensionality and magnetic properties can be tuned, is also reviewed. Special emphasis is put on the appropriate choice of the end-cap ligand L whose denticity determines the number of coordinated cyanide groups in the mononuclear precursors. Among the different new spin topologies obtain…

[Mn2(bipym)(H2O)8]4+and [Fe(bipy)(CN)4]−as building blocks in designing novel bipym- and cyanide-bridged heterobimetallic complexes (bipym = 2,2′-bipyrimidine and bipy = 2,2′-bipyridine)

Two new cyano complexes, K[Fe(bipy)(CN)4]·H2O (1) and (μ-bipym)[Mn(H2O)3{Fe(bipy)(CN)4}]2[Fe(bipy)(CN)4]2·12H2O (2), have been synthesised and their structures determined by single-crystal X-ray diffraction. Complex 1 is made up of mononuclear [Fe(bipy)(CN)4]− anions, potassium cations and water molecules of crystallization. The iron(III) is six-coordinated, being surrounded by two nitrogen atoms of a chelating bipy and four carbon atoms of four cyanide groups [Fe–N and Fe–C 1.991(3)–1.990(3) and 1.958(5)–1.914(5) A, respectively]. Complex 2 consists of centrosymmetric tetranuclear (μ-bipym)[Fe(H2O)3{Fe(bipy)(CN)4}]22+ cations, [Fe(bipy)(CN)4]− anions and water molecules of crystallization.…

Ferromagnetic Coupling between Low- and High-Spin Iron(III) Ions in the Tetranuclear Complex fac-{[FeIII{HB(pz)3}(CN)2(μ-CN)]3FeIII(H2O)3}· 6H2O ([HB(pz)3]- = Hydrotris(1-pyrazolyl)borate)

The novel mononuclear PPh4-fac-[FeIII{HB(pz)3}(CN)3]·H2O (1) [PPh4+= tetraphenylphosphonium cation; (HB(pz)3)- = hydrotris(1-pyrazolyl)borate] and tetranuclear fac-{[FeIII{HB(pz)3}(CN)2(μ-CN)]3FeIII(H2O)3}·6H2O (2) have been prepared and characterized by X-ray diffraction analysis. Crystal data for compound 1:  monoclinic, space group P21/c, a = 9.575(3) A, b = 21.984(4) A, c = 16.863(3) A, β = 100.34(2)°, U = 3486(1) A3, Z = 4. Crystal data for compound 2:  orthorhombic, space group Pnam, a = 14.084(3) A, b = 14.799(4) A, c = 25.725(5) A, U = 5362(2) A3, Z = 4. Compound 1 is a low-spin iron(III) compound with three cyanide ligands in fac arrangement and a tridentate pyrazolylborate ligand …

Exchange Coupling in Cyano-Bridged Homodinuclear Cu(II) and Ni(II) Complexes:  Synthesis, Structure, Magnetism, and Density Functional Theoretical Study

The synthesis and structural characterization of several new cyano-bridged copper(II) and nickel(II) homodinuclear complexes is presented. The measure of magnetic properties for these complexes is complemented with a computational study of the exchange coupling for several model structures representing this family of compounds. The influence of several factors on the coupling constant has been examined, coordination position occupied by the bridging ligand, distortions of the coordination environment, and relative disposition of the cyanide ion with respect to the M-M vector. Comparison of experimental and calculated coupling constants allows for the rationalization of the most relevant fea…

Cyanide-bridged iron(III)-cobalt(II) double zigzag ferromagnetic chains: two new molecular magnetic nanowires.

and opened the perspective of a potential useof 1D magnetic molecular nanowires for information storage.Even though 1D magnetism is a very active area of research,such dynamic behavior was never detected before since it isnot clear how to fulfill experimentally the requirements of aperfect 1D Ising-type chain. This finding prompted us to lookcarefully at 1D systems containing anisotropic elements,suchas cobalt(ii) and low-spin iron(iii) centers that we synthesizedrecently,

Synthesis, crystal structure and magnetic properties of a new cyanide-bridged iron(III)–nickel(II) ferromagnetic chain

Abstract The reaction of the iron(III) unit fac-[Fe{HB(pz)3}(CN)3]− [ HB ( pz ) 3 - = hydrotris ( 1 - pyrazolyl ) borate ] as the lithium salt (1) with the nickel(II) complex mer-[Ni(dpt)(H2O)3](ClO4)2 [dpt = dipropylenetriamine] in water affords the heterometallic compound of formula {[FeIII{HB(pz)3}(CN)3]2[NiII(dpt)]}n · 3nH2O (2). The structure of 2 has been determined by X-ray diffraction on single crystals and their magnetic properties have been investigated in the temperature range 1.9–300 K. Compound 2 is a zigzag chain compound with regular alternating bis-monodentate [Fe(1){HB(pz)3}(CN)3]− units and [Ni(dpt)]2+ cations, the six coordination around the nickel atom being achieved by …

Cover Picture: Cyanide-Bridged Iron(III)–Cobalt(II) Double Zigzag Ferromagnetic Chains: Two New Molecular Magnetic Nanowires (Angew. Chem. Int. Ed. 13/2003)

[Fe(bipy)(CN)4]- as a Versatile Building Block for the Design of Heterometallic Systems:  Synthesis, Crystal Structure, and Magnetic Properties of PPh4[FeIII(bipy)(CN)4]·H2O, [{FeIII(bipy)(CN)4}2MII(H2O)4]·4H2O, and [{FeIII(bipy)(CN)4}2ZnII]·2H2O [bipy = 2,2‘-Bipyridine; M = Mn and Zn]

The new cyano complexes of formulas PPh4[FeIII(bipy)(CN)4]·H2O (1), [{FeIII(bipy)(CN)4}2MII(H2O)4]·4H2O with M = Mn (2) and Zn (3), and [{FeIII(bipy)(CN)4}2ZnII]·2H2O (4) [bipy = 2,2‘-bipyridine and PPh4 = tetraphenylphosphonium cation] have been synthesized and structurally characterized. The structure of complex 1 is made up of mononuclear [Fe(bipy)(CN)4]- anions, tetraphenyphosphonium cations, and water molecules of crystallization. The iron(III) is hexacoordinated with two nitrogen atoms of a chelating bipy and four carbon atoms of four terminal cyanide groups, building a distorted octahedron around the metal atom. The structure of complexes 2 and 3 consists of neutral centrosymmetric […

[Criii(L)(CN)4]−: a new building block in designing cyanide-bridged 4,2-ribbon-like chains {[Criii(L)(CN)4]2Mn(H2O)2}·nH2O [L = 2-aminomethylpyridine (n = 6) and 1,10-phenanthroline (n = 4)]

The preparation, X-ray crystallography and magnetic study of compounds PPh4[Cr(ampy)(CN)4]·H2O (1), PPh4[Cr(phen)(CN)4]·H2O·CH3OH (2), {[Cr(ampy)(CN)4]2Mn(H2O)2}·6H2O (3) and {[Cr(phen)(CN)4]2Mn(H2O)2}·4H2O (4), with PPh4+ = tetraphenylphosphonium cation, ampy = 2-aminomethylpyridine and phen = 1,10-phenanthroline, are reported here. 1 and 2 are mononuclear complexes whereas 3 and 4 are 4,2-ribbon-like bimetallic chains. The magnetic properties of 1–4 were investigated in the temperature range 1.9–300 K. A quasi Curie law behaviour for a magnetically isolated spin quartet is observed for 1 and 2. Compounds 3 and 4 are ferrimagnetic CrIII2MnII chains, which exhibit a metamagnetic behaviour, …

[Cr(AA)(C2O4)2]− and [Cu(bpca)]+ as building blocks in designing new oxalato-bridged CrIIICuII compounds [AA=2,2′-bipyridine and 1,10-phenanthroline; bpca=bis(2-pyridylcarbonyl)amide anion]

Abstract The monouclear complex PPh4[Cr(bipy)(ox)2]·H2O (1) and the heterodinuclear compounds [Cu(bpca)(H2O)Cr(bipy)(ox)2]·2.5H2O (2) and [Cu(bpca)(H2O)Cr(phen)(ox)2]·2H2O (3) [PPh4+=tetraphenylphosphonium cation, bpca=bis(2-pyridylcarbonyl)amide anion, ox=oxalate dianion, bipy=2,2′-bipyridine and phen=1,10-phenanthroline] have been synthesized and characterized by single-crystal X-ray diffraction. Discrete [Cr(bipy)(ox)2]− mononuclear anions and tetraphenylphosphonium cations are present in 1 whereas the structures of 2 and 3 are made up neutral oxalato-bridged bimetallic CrIIICuII units. The chromium environment is distorted octahedral in the three complexes: two nitrogen atoms from a bi…

Cyanide-bridged Fe(III)–Co(II) bis double zigzag chains with a slow relaxation of the magnetisation

Reaction of [FeIII(bipy)(CN)4]¯ with fully solvated MII cations [M = Co (1) and Mn (2)] produces the isostructural bis double zigzag chains [[FeIII(bipy)(CN)4]2MII(H2O)]·MeCN·1/2H2O; 1 exhibits intrachain ferromagnetic and interchain antiferromagnetic couplings, slow magnetic relaxation and hysteresis effects. Luminita Marilena, Toma, Luminita.Toma@uv.es ; Lescouezec, Alain Francois Rodri, Alain.Lescouezec@uv.es ; Lloret Pastor, Francisco, Francisco.Lloret@uv.es ; Julve Olcina, Miguel, Miguel.Julve@uv.es