CRYSTAL STRUCTURE OF A TRINUCLEAR COBALT COMPLEX Co_3(bdt)_3(PBu_3~n)_3 · ~2CH_2C1 (bdt = S_2C_6H_4~2- ) WITH MIXED o-BEN-ZENEDITHIOLATE AND TRIBUTYLPHOSPHINE LIGANDS

<正> Co3(S2C6H4)3{P(C4H9)3}3 ·2CH2Cl2, Mr = 1373. 45, mono-clinic, space group P21/c, a = 16. 110(5), b=36.313(10), c=13. 502(5) A , β= 105. 69(4)% V=7604. 4 A3, Z = 4, Dc = 1. 20 g. cm-3, μ=10. 03 cm-1, and F (000) = 2990. R(Rw) is 0. 086(0. 091) for 4559 observed unique reflections. The three cobalt atoms in the complex form an isosceles triangle with an average Co -Co bond distance of 2. 504(5) A. The average values of Co - S and Co - P bond distances are 2. 271(7) A , and 2. 198(8) A , respectively.     

Synthesis,crystal structure,spectroscopy, and magnetism of a mixed valence Co(III)–Co(II)–Co(III) complex stabilized by N-(2-hydroxybenzyl)salicylaldimine

Reaction of Co(OAc)₂ · 4H₂O with N-(2-hydroxybenzyl)salicylaldimine (H₂L_a) in dimethylformamide (DMF)–H₂O yields a linear trinuclear mixed valence complex [Co^III(μ-L_a)(μ-L_b)(μ-OAc)]₂Co^II · 2DMF (1). Here, HL_b is salicylaldimine, which is afforded by an in situ transformation of H₂L_a via cleavage of the C–N bond. Complex 1 has been characterized by X-ray crystallography as well as elemental analysis, UV-Vis, and IR spectroscopy. The cathodic and anodic responses of 1 in DMF appeared at ?1.46 V (Co^III → Co^II, quasi-irreversible) and +0.99 V (Co^II → Co^III, irreversible) versus saturated calomel electrode, respectively. The magnetic behavior of 1 has been analyzed by the one-ion approximation with spin–orbit coupling in O_h symmetry giving λ = ?121 cm^?1.     

A structure and magnetic properties of one-dimensional manganese/cobalt coordination polymers with 5-nitro-1,3-benzenedicarboxylic acid and imidazole

One-dimensional manganese(II) complex, [Mn₂(5-nbdc)₂(imH)₆] · 2H₂O (1) (5-nbdcH₂ = 5-nitro-1,3-benzenedicarboxylic acid and imH = imidazole), has been hydrothermally synthesized and structurally characterized by X-ray crystallography with the following data: orthorhombic, space group Pna2(1), M _r = 972.63 for Mn₂C₃₄H₃₄N₁₄O₁₄, a = 13.3391(12) Å, b = 16.4657(15) Å, c = 18.2177(16) Å; V = 4001.3(6) ų, Z = 4, D _calcd 1.615 g cm^?3, µ = 0.718 mm^?1, the final R = 0.0490 and wR = 0.1277 for 7278 observed reflections (I > 2σ(I)). Complex 1 exhibits very weak intra-chain ferromagnetic coupling (J k^?1 = 0.001 K) with g = 1.930. The magnetism of a one-dimensional cobalt(II) complex [Co(5-nbdc)₂(imH)₂] _n (2) indicates weak intra-chain anti-ferromagnetic coupling (J k^?1 = ?0.067 K) with g = 2.0791.     

Synthesis, crystal structure and magnetic properties of three polynuclear manganese compounds bearing ferrocenecarboxylato ligands

The reactions of sodium ferrocenecarboxylate (FcCO₂Na) and Mn(ClO₄)₂ · 6H₂O in methanol in the presence of ancillary ligands of 1,10-phenanthroline (phen) or 2,2′-bipyridine (2,2′-bpy) produce three discrete polynuclear complexes bearing ferrocenecarboxylato ligands: [Mn₂(FcCO₂)₃(phen)₂](ClO₄) · 2CH₂Cl₂ (1), [Mn₃(FcCO₂)₆(2,2′-bpy)₂] · 2H₂O (2) and [Mn₄O₂(FcCO₂)₇(2,2′-bpy)₂]ClO₄ · 2CH₂Cl₂ · 6H₂O (3). It is shown that their composition and skeletons are tuned by the ancillary ligands and the ratios of starting materials. In dimanganese complex 1, both Mn(II) ions are pentacoordinated in a distorted trigonal bipyramidal geometry and bridged by three ferrocenecarboxylato ligands in a distorted syn-syn bridging mode, which is rare in triply carboxylato-bridged dimanganese complexes. Compound 2 presents a linear trinuclear [Mn₃(μ₂-η¹:η¹-O₂CFc)₄(μ₂-η¹:η²-O₂CFc)₂] core, in which six ferrocencarboxylato ligands show two different bridging modes. The cationic Mn₄O₂ core of 3 has a butterfly structure, in which two Mn(III) ions at “body” sites are bridged by an additional ferrocenecarboxylato ligand and they are further connected to the Mn(III) ions at “wing-tip” sites by ferrocenecarboxylato ligands. Magnetic susceptibilities of 1 and 2 were measured. Both of them mediate a weak antiferromagnetic coupling between the Mn(II) ions bridged by ferrocenecarboxylato ligands.     

A 3-D cobalt(II)-coordination polymer with mixed-connected network topology constructed from 4-pyridin-3-yl-benzoic acid

A new coordination polymer, [Co₂(μ-H₂O)(4,3-pybz)₄] _n (1), has been hydrothermally synthesized from Co(NO₃)₂ · 6H₂O and an unsymmetrical 4-pyridin-3-yl-benzoic acid (4,3-Hpybz), which is characterized by IR, elemental analysis, thermogravimetric analysis, and single crystal X-ray diffraction. This compound crystallizes in monoclinic, space group C2/c with a = 11.876(3) Å, b = 15.462(3) Å, c = 21.545(4) Å, β = 94.873(5)°, V = 3942.0(15) ų, Z = 4, Dc = 1.565 g cm^?3, F(000) = 1904, GOF = 1.025, μ = 0.910 mm^?1, R ₁ = 0.0456, wR ₂ = 0.0983. Compound 1 shows a 3-D (3,6)-connected coordination framework with (3.4.5)(3².4⁴.5⁵.6².7²) topology, in which cobalt is a six-connected node, and the 4,3-Hpybz ligands serve as two-connected spacers and three-connected nodes. In addition, the magnetic and thermal properties of 1 have also been investigated.     

Cyanide-bridged FeIII–MnIII bimetallic chain derived from [Fe(bipy)(CN)4]−: synthesis,structure and magnetic characteristics

A chain-like compound of [Mn(salpn)][Fe(bipy)(CN)₄] (1) (salpn = N,N′-propylenebis(salicylideneiminato)dianion; bipy = 2,2′-bipyridine), assembled from building blocks of [Fe(bipy)(CN)₄]^? and [Mn(salpn)]⁺, has been characterized by elemental analyses, ICP, IR, thermoanalysis, single crystal X-ray structure analysis and magnetic measurements. In 1, each [Fe(bipy)(CN)₄]^? anion coordinates with two [Mn^III(salpn)]⁺ cations via two trans-CN^? groups, and each [Mn^III(salpn)]⁺ cation is axially coordinated by two [Fe(bipy)(CN)₄]^? ions, resulting in a straight 1-D chain. The chains stack via aromatic π–π-type interactions. Magnetic studies reveal the presence of weak antiferromagnetic interactions between adjacent Fe^III and Mn^III ions through cyanide-bridges.     

Synthesis, crystal structures and magnetic properties of trinuclear oxo-centered homo- and mixed-valence manganese pivalate complexes with imidazole (Im) and 1-methylimidazole (1-MeIm): and

Two new μ₃-oxo-centered trinuclear manganese complexes, one of them a homo-valence (1) pivalate complex and the other a mixed-valence (2) pivalate complex (where Im = imidazole, 1-MeIm = 1-methylimidazole), have been synthesized and characterized by IR spectroscopy, thermogravimetric analysis, X-ray crystallography and magnetochemistry. Complexes 1 and 2 are μ₃-oxo-trinuclear compounds with the three manganese atoms bridged by six pivalate groups. At each axial position there is an Im (1) or 1-MeIm (2) molecule. In both compounds, the manganese coordination geometry is slightly distorted octahedral, consisting of the oxygen of the central triangle, four oxygen atoms from bridging pivalate ligands, and a terminal Im or 1-MeIm nitrogen atom. The crystal packing of 1 involves hydrogen bonding between complex cations [Mn₃O(Piv)₆(Im)₃]⁺ and outersphere pivalate ions, whereas in compound 2 interactions of the C–Hπ type, formed by both the aromatic and methyl C–H groups of 1-MeIm molecules, are present. Magnetic studies reveal that both compounds represent antiferromagnetically coupled, spin-frustrated triangular systems exhibiting weak to moderate exchange coupling constants.     

A novel manganese(II) complex with phen ligands: hydrothermal synthesis,structure and magnetic properties of [Mn(phen)(H2O)4] SO4·2H2O

A novel manganese(II) complex, [Mn(phen)(H₂O)₄]SO₄·2H₂O (1), has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. The manganese(II) complex contains only one phen ligand and four water ligands. By a catalytic test, complex 1 provided direct evidence that phen is a key ligand instead of an auxiliary one in manganese catalase mimics. Magnetic susceptibility measurements for complex 1 have been performed down to 2?K, suggesting paramagnetic behavior for this complex.     

Synthesis and crystal structure of d–f heteronuclear Gd(III)–Co(II) system

A carboxylate-bridged Co(II)–Gd(III) complex, [(bipy)CoL₃Gd(NO₃)L₃Co(bipy)] (HL =?α-methylacrylic acid, bipy =?2,2′-bipyridine), was prepared and characterized. Single crystal X-ray analysis reveals that the complex assumes a carboxylate-bridged CoGdCo unit. Magnetic measurements showed χ_m T decreases when the temperature is lowered.     

Struktur und magnetische Eigenschaften von Bis{3‐amino‐1,2,4‐triazolium(1+)}pentafluoromanganat(III): (3‐atriazH)2[MnF5]

Structure and Magnetic Properties of Bis{3‐amino‐1,2,4‐triazolium(1+)}pentafluoromanganate(III): (3‐atriazH)₂[MnF₅] The crystal structure of (3‐atriazH)₂[MnF₅], space group P1, Z = 4, a = 8.007(1) Å, b = 11.390(1) Å, c = 12.788(1) Å, α = 85.19(1)°, β = 71.81(1)°, γ = 73.87(1)°, R = 0.034, is built by octahedral trans‐chain anions [MnF₅]^2–_∞ separated by the mono‐protonated organic amine cations. The [MnF₆] octahedra are strongly elongated along the chain axis (<Mn–F_ax> 2.135 Å, <Mn–F_eq> 1.842 Å), mainly due to the Jahn‐Teller effect, the chains are kinked with an average bridge angle Mn–F–Mn = 139.3°. Below 66 K the compound shows 1D‐antiferromagnetism with an exchange energy of J/k = –10.8 K. 3D ordering is observed at T_N = 9.0 K. In spite of the large inter‐chain separation of 8.2 Å a remarkable inter‐chain interaction with |J′/J| = 1.3 · 10^–5 is observed, mediated probably by H‐bonds. That as well as the less favourable D/J ratio of 0.25 excludes the existence of a Haldene phase possible for Mn³⁺ (S = 2).