Guest-dependent negative thermal expansion in nanoporous prussian blue analogues M(II)Pt(IV)(CN)6.x{H2O} (0 < or = x < or = 2; M = Zn, Cd)

The guest-dependent thermal expansion behavior of the nanoporous Prussian Blue analogues MIIPtIV(CN)6.x{H2O} (0 相似文献   

Hydrogen storage in the dehydrated prussian blue analogues M3[Co(CN)6]2 (M = Mn, Fe, Co, Ni, Cu, Zn)

The porosity and hydrogen storage properties for the dehydrated Prussian blue analogues M3[Co(CN)6]2 (M = Mn, Fe, Co, Ni, Cu, Zn) are reported. Argon sorption isotherms measured at 87 K afford BET surface areas ranging from 560 m2/g for Ni3[Co(CN)6]2 to 870 m2/g for Mn3[Co(CN)6]2; the latter value is comparable to the highest surface area reported for any known zeolite. All six compounds show significant hydrogen sorption at 77 K and 890 Torr, varying from 1.4 wt % and 0.018 kg H2/L for Zn3[Co(CN)6]2 to 1.8 wt % and 0.025 kg H2/L for Cu3[Co(CN)6]2. Fits to the sorption data employing the Langmuir-Freundlich equation give maximum uptake quantities, resulting in a predicted storage capacity of 2.1 wt % and 0.029 kg H2/L for Cu3[Co(CN)6]2 at saturation. Enthalpies of adsorption for the frameworks were calculated from hydrogen isotherms measured at 77 and 87 K and found to increase with M varying in the order Mn < Zn < Fe < Co < Cu < Ni. In all cases, the binding enthalpies, which lie in the range of 5.3-7.4 kJ/mol, are higher than the 4.7-5.2 kJ/mol measured for Zn4O(1,4-benzenedicarboxylate)3.     

Complexation in Binary Cd2[Fe(CN)6]–M(II) Systems (M = Mn,Co, Ni,Cu, Zn) in Gelatin-Immobilized Cadmium(II) Hexacyanoferrates(II)

Complexation processes that occur between cadmium(II) hexacyanoferrate(II) (Cd₂[Fe(CN)₆]) and 3d-metal ions M(II) (M = Mn, Co, Ni, Cu, Zn) in thin gelatin layers with the immobilized cadmium(II) hexacyanoferrates when brought in contact with aqueous solutions of d-metal chlorides are studied. Cd²⁺ ions were found to be replaced to some extent by M²⁺ ions of the indicated d metals (except for Mn(II)) and form binuclear (dd)-metal hexacyanoferrates(II). A complete replacement of Cd(II) and formation of M₂[Fe(CN)₆] was observed in none of the cases.     

[MPy4(NCO)2]-2Py clathrates (M = M(II) = Mn,Fe, Co,Ni, Cu,Zn, Cd; Py = pyridine)

The title compounds form an iso structural series and are isomorphic with other [MPy₄X₂]-2Py clathrates (XRD, KM4 diffractometer, cell parameters and space group Ccca from 17–80 reflections). In the clathrate [NiPy₄(NCO)₂]-2Py studied in detail (XRD, CAD-4 diffractom eter, λCuK_α, Ω/2θ scan mode, θ_max = 78‡, 990 strong reflections, 104 parameters, R = 0.053), the host molecule has 222 symmetry, and the twofold axes run along the coordination bonds. The transoctahedral environment of nickel consists of six nitrogen atoms of four pyridine and two isocyanate ligands. The coordination polyhedron is slightly distorted due to changes in the bond lengths. The molecule has a propeller conformation. The guest molecules lie in the cavities of the crystal structure in conformity with the van der Waals type of packing. The host complex [NiPy₄(NCO)₂] (XRD, CAD-4 diffractometer, 4615 strong reflections, 560 parameters, R-0.037) crystallizes in the triclinic crystal system (space group P1) with two independent asymmetric molecules in the unit cell. The molecular structure is analogous to that in the ciathrate phase, but the coordination angles are severely distorted; one of the molecules acquires a distorted propeller conformation, and the other, a centrosvmmetric conformation, which is less favorable. While being structurally identical, the [MPy₄(NCO)₂]-2Py clathrates differ heavily in the properties. The first four complexes dissociate to host complexes, and their thermal stability changes in the sequence Mn< Fe< Co< Ni; the Cu and Zn clathrates decompose in one step to dipyridine complexes with decomposition of host complexes. Decomposition of the Cd ciathrate follows one of these patterns depending on conditions. The results are compared with those for other known systems. Synthetic procedures are given. Translated fromZhurnal Strukturnoi Khimii, Vol. 40, No. 5, pp. 935–953, September–October, 1999.     

Über Hexafluorotitanate (IV): M11TiF6 mit M = Zn,Cd, Mn,Co, Ni

Hitherto unknown anhydrous GUINER patterns show that all these hexagonal compounds – except CdTiF₆ (LiSbF₆-structure type) – are isostructural with VF₃.     

Magneto-structural studies on heterobimetallic malonate-bridged M(II)Re(IV) complexes (M = Mn, Co, Ni and Cu)

The mononuclear Re(IV) compound of formula (PPh(4))(2)[ReBr(4)(mal)] (1) was used as a ligand to obtain the heterobimetallic species [ReBr(4)(μ-mal)Co(dmphen)(2)]· MeCN (2), [ReBr(4)(μ-mal)Ni(dmphen)(2)] (3), [ReBr(4)(μ-mal)Mn(dmphen)(2)] (4a), [ReBr(4)(μ-mal)Mn(dmphen)(H(2)O)(2)]·dmphen·MeCN·H(2)O (4b), [ReBr(4)(μ-mal)Cu(phen)(2)]·1/4H(2)O (5) and [ReBr(4)(μ-mal)Cu(bipy)(2)] (6) (mal = malonate dianion, dmphen = 2,9-dimethyl-1,10-phenanthroline, phen = 1,10-phenanthroline and bipy = 2,2'-bipyridine). The structures of 2 and 5 (single-crystal X-ray diffraction) are made up of neutral [ReBr(4)(μ-mal)M(AA)] dinuclear units [AA = dmphen with M = Co (2) and AA = phen with M = Cu (5)] where the metal ions are connected through a malonate ligand which exhibits simultaneously the bidentate [at the Re(IV)] and monodentate [at the M(II)] coordination modes. The carboxylate-malonate group in them adopts the anti-syn conformation with intramolecular ReM separation of 5.098(8) (2) and 4.947(2) ? (5). The magnetic properties of 1-6 were investigated in the temperature range 1.9-295 K. The magnetic behaviour of 1 is the expected for a magnetically isolated Re(IV) complex with a large value of the zero-field splitting (2D ca. -70 cm(-1)) whereas weak antiferromagnetic interactions between Re(IV) and M(II) are observed in the heterobimetallic compounds 2 (J = -0.63 cm(-1)), 3 (J = -1.37 cm(-1)), 4a (J = -1.29 cm(-1)), 5 (J = -1.83 cm(-1)) and 6 (J = -0.26 cm(-1)). Remarkably, 4b behaves as a ferrimagnetic chain with regular alternating Re(IV) and Mn(II) cations (J = -2.64 cm(-1)).     

MII-N-diisopropoxythiophosphorylthiobenzamide complexing processes in M2[Fe(CN)6]-gelatin-immobilized matrices (M = Co,Ni, Cu)

Complexing processes in M^II-N-diisopropoxythiophosphorylthiobenzamide binary systems (M = Co, Ni, Cu) in metal(II) hexacyanoferrate(II) gelatin-immobilized matrices upon contact with aqueous–alkaline (pH = 12.0 ± 0.1) solutions of organic compounds have been studied. It has been shown that, in Co^II and Cu^II, the initial act of complexing involves destruction of the Co^II and Cu^II hexacyanoferrates(II) by OH^– ions, leading to formation of the corresponding hydroxides which react with the ligand indicated. In the both systems, successive addition of two ligand molecules per M(OH)₂ fragment occurs and [MB(OH)(OH₂)] and [MB₂] coordination compounds are formed (B^–-a singly deprotonated ligand form). In the Ni^II-N-diisopropoxythiophosphorylthiobenzamide system, the formation of three complexes, (Ni₂BOH)₂[Fe(CN)₆], [NiB(OH)(OH₂)] and [NiB₂] occurs.     

MC_2O_4(M=Mn、Fe、Co、Ni、Cu、Zn)的热力学及其热分析动力学

用DSC、TGA技术分别在N2气氛和O2气氛下对MC2O4(M=Mn、Fe、Co、Ni、Cu、Zn)的脱水和分解过程作了热力学和动力学的研究.在N2气氛下,MC2O4·2H2O(M=Mn、Fe、Co、Ni、Zn)脱水温度Tde和脱水焓!deHm随原子序数Zre递增呈现明显的“二分组效应”;!deHm在(96.46±7.00)kJ·mol-1范围内波动;MC2O4·2H2O(M=Mn、Fe、Ni)的分解温度Td随原子序数递增呈现良好的线性关系;且各草酸盐分解得到氧化物(CuC2O4生成Cu、CuO混合物)时,MC2O4(M=Co、Ni、Cu)分解焓随原子序数增大也存在良好的线性关系.各草酸盐除NiC2O4·2H2O脱水过程和FeC2O4分解过程外,其余各过程机理函数均为随机成核和随后成长型.     

MC2O4(M=Mn、Fe、Co、Ni、Cu、Zn)的热力学及其热分析动力学

用DSC、TGA技术分别在N₂气氛和O₂气氛下对MC₂O₄(M=Mn、Fe、Co、Ni、Cu、Zn)的脱水和分解过程作了热力学和动力学的研究. 在N₂气氛下, MC₂O₄•2H₂O(M=Mn、Fe、Co、Ni、Zn)脱水温度Tde和脱水焓ΔdeHm随原子序数Zre递增呈现明显的“二分组效应”；ΔdeHm在(96.46±7.00) kJ•mol^-1范围内波动；MC₂O₄•2H₂O (M=Mn、Fe、Ni)的分解温度Td随原子序数递增呈现良好的线性关系；且各草酸盐分解得到氧化物(CuC₂O₄生成Cu、CuO混合物)时, MC₂O₄(M=Co、Ni、Cu) 分解焓随原子序数增大也存在良好的线性关系. 各草酸盐除NiC₂O₄•2H₂O脱水过程和FeC₂O₄分解过程外, 其余各过程机理函数均为随机成核和随后成长型.     

Structure of (5656)macrotetracyclic chelates in the ternary systems M(II)-ethanedithioamide-acetone (M = Mn, Fe, Co, Ni, Cu, Zn) according to DFT calculations

The thermodynamic and geometric parameters of M(II) macrotetracyclic chelates (M = Mn, Fe, Co, Ni, Cu, and Zn) with the (NNNN) coordination of the donor ligand sites, formed by the complexation reactions of corresponding M(II) compounds, ethanedithioamide H₂N-C(=S)-C(=S)-NH₂, and acetone H₃C-C(=O)-CH₃ in gelatin-immobilized matrix implants have been calculated by the OPBE/TZVP density functional theory method with the use of the Gaussian 09 program package. The bond lengths and bond and torsion angles in these complexes have been reported. It has been shown that despite the fact that the MN₄ chelate core in them is almost planar, the five- and six-membered chelate rings are pronouncedly non-coplanar. In the Mn(II), Fe(II), Co(II), and Ni(II) complexes, these chelate rings are pairwise identical, whereas in the Cu(II) and Zn(II) complexes, they are noticeably different.     

Coordination-position isomeric M(II)Cu(II) and Cu(II)M(II) (M = Co, Ni, Zn) complexes derived from macrocyclic compartmental ligands

The dinucleating macrocyclic ligands (L(2;2))(2-) and (L(2;3))(2-), comprised of two 2-[(N-methylamino)methyl]-6-(iminomethyl)-4-bromophenolate entities combined by the -(CH(2))(2)- chain between the two aminic nitrogen atoms and by the -(CH(2))(2)- or -(CH(2))(3)- chain between the two iminic nitrogen atoms, have afforded the following M(II)Cu(II) complexes: [CoCu(L(2;2))](ClO(4))(2).MeCN (1A), [NiCu(L(2;2))](ClO(4))(2) (2A), [ZnCu(L(2;2))](ClO(4))(2).0.5MeCN.EtOH (3A), [CoCu(L(2;3))(MeCN)(2-PrOH)](ClO(4))(2) (4A), [NiCu(L(2;3))](ClO(4))(2) (5A), and [ZnCu(L(2;3))](ClO(4))(2).1.5DMF (6A). [CoCu(L(2;2))(MeCN)(3)](ClO(4))(2) (1A') crystallizes in the monoclinic space group P2(1)/n, a = 11.691(2) A, b = 18.572(3) A, c = 17.058(3) A, beta= 91.18(2) degrees, V = 3703(1) A(3), and Z = 4. [NiCu(L(2;2))(DMF)(2)](ClO(4))(2) (2A') crystallizes in the triclinic space group P(-)1, a = 11.260(2) A, b = 16.359(6) A, c = 10.853(4) A, alpha= 96.98(3) degrees, beta= 91.18(2) degrees, gamma= 75.20(2) degrees, V = 1917(1) A(3), and Z = 2. 4A crystallizes in the monoclinic space group P2(1)/c, a = 15.064(8) A, b = 11.434(5) A, c = 21.352(5) A, beta= 95.83(2)degrees, V = 3659(2) A(3), and Z = 4. The X-ray crystallographic results demonstrate the M(II) to reside in the N(amine)(2)O(2) site and the Cu(II) in the N(imine)(2)O(2) site. The complexes 1-6 are regarded to be isomeric with [CuCo(L(2;2)))](ClO(4))(2).DMF (1B), [CuNi(L(2;2)))](ClO(4))(2).DMF.MeOH (2B), [CuZn(L(2;2)))](ClO(4))(2).H(2)O (3B)), [CuCo(L(2;3)))](ClO(4))(2).2H(2)O (4B), [CuNi(L(2;3)))](ClO(4))(2) (5B), and [CuZn(L(2;3)))](ClO(4))(2).H(2)O (6B) reported previously, when we ignore exogenous donating and solvating molecules. The isomeric M(II)Cu(II) and Cu(II)M(II) complexes are differentiated by X-ray structural, magnetic, visible spectroscopic, and electrochemical studies. The two isomeric forms are significantly stabilized by the "macrocyclic effect" of the ligands, but 1A is converted into 1B on an electrode, and 2A is converted into 2B at elevated temperature.     

Stability of isomerous chelates in M(II)-thiocarbamoylmethanamide-ethandial systems according to the DFT B3LYP method (M = Mn, Fe, Co, Ni, Cu, Zn)

Calculations of the optimal geometry and standard thermodynamic parameters of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn(II) isomerous macrotricyclic complexes with MN₂O₂, MN₂S₂, and MN₄ chelate bonds, which can in principle appear as a result of template processes between gelatine-immobilized hexacyanoferrates (II) of corresponding M(II) metal ions, thiocarbamoylmethaneamide (thiooxamide) H₂N-C(=S)-C(=O)-NH₂, and ethanedial HC(=O)-CH(=O), were performed according to the B3LYP hybrid density functional method using a 6-31G(d) basis set with the Gaussian 98 program. It was found that of all of the considered M(II), the most stable are complexes with MN₄ chelate bonds, where the values of a standard enthalpy Δ_f H ₂₉₈^o and a standard Gibbs energy, Δ_f G ^o for all complexes studied are positive.     

Magnetische Eigenschaften der Verbindungen BaMF4 und Pb2 MF6 (M=Mn,Fe, Co,Ni, Cu,Zn)

Zusammenfassung In den beiden untersuchten Doppelfluorid-Serien, BaMF₄ und Pb₂ MF₆ (M=Mn, Fe, Co, Ni, Cu, Zn), zeigen die Verbindungen des Cu und des Zn ein anderes Verhalten als die übrigen. Die Zn-Verbindungen sind diamagnetisch, die Cu-Verbindungen paramagnetisch. Pb₂CuF₆ befolgt dasCuriesche Gesetz, während BaCuF₄ eineCurie-Weiss-Abweichung unterhalb 212 K aufweist.Im untersuchten Temperaturbereich zeigt sich für alle anderen Verbindungen, mit Ausnahme von Pb₂FeF₆, Antiferromagnetismus.

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Magnetic properties of the compounds BaMF₄ and Pb₂ MF₆ (M=Mn, Fe, Co, Ni, Cu, Zn)

Two series of double fluorides, BaMF₄ and Pb₂ MF₆ (M=Mn, Fe, Co, Ni, Cu, Zn) have been studied, the compounds of Cu and Zn differing in behaviour from the others. The Zn componds are diamagnetic, the Cu compounds paramagnetic. Pb₂CuF₆ conforms toCurie's law while BaCuF₄ exhibits aCurie-Weiss deviation below 212° K.With the exception of Pb₂FeF₆, all the other compounds show antiferromagnetism in the studied temperature range.

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Mit 5 Abbildungen

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Herrn Prof. Dr.Hans Nowotny ergebenst gewidmet.     

Thermochemistry of AII(VUO6)2 · nH2O Compounds (AII = Mn, Fe, Co, Ni, Cu, Zn, Cd)

Standard enthalpies of formation of uranovanadates of 3(4)d transition metals at 298.15 K were determined. The isobaric heat capacity of Co(VUO₆)₂ · 4H₂O was measured. The standard Gibbs functions of formation of the compounds were calculated on the basis of these data using approximate methods of absolute entropy calculation. The thermochemical characteristics of the synthesis and dehydration of uranovanadates were considered.     

Phase Transitions in Crystalline [M(H2O)6](ClO4)2 (M=Mg,Mn, Fe,Co, Ni,Cu, Zn,Cd and Hg)

The results of DSC measurements in the temperature range 140–370 K on nine crystalline compounds of the type [M(H₂O)₆](ClO₄)₂, where M=Mg, Mn, Fe, Co, Ni, Cu, Zn, Cd and Hg, are discussed. Anomalies detected in the DSC curves are related to the existence of solid-solid phase transitions and/or to the melting points of these compounds. In consequence of two different hypothetical structural modifications of [Fe(H₂O)₆](ClO₄)₂, two DSC curves are obtained. For the compounds with M=Fe, Cd and Hg, new phase transitions have been discovered. The transition temperatures of the other phase transitions are in good agreement with literature data obtained by adiabatic calorimetry. For the compounds with M=Mg, Ni and Cd, DTA measurements were also carried out and the melting points of theses compounds were established. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal decomposition of cyano complexes of the type M(NH3)3Ni(CN)4 (M=Cu,Zn, Cd)

Three complex compounds with the compositions Cu(NH₃)₃Ni(CN)₄ (CuA), Zn(NH₃)₃Ni(CN)₄ (ZnA), and Cd(NH₃)₃Ni(CN)₄ (CdA) were prepared and identified. Their structures were examined by the methods of infrared spectroscopy and X-ray powder diffraction and compared with one another. The thermal stabilities and stoichiometries of thermal decomposition were investigated with a derivatograph. It follows from the results that the thermal stability increases in the sequence CuA < ZnA < CdA.

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Zusammenfassung Drei Komplexverbindungen der Zusammensetzung Cu(NH₃)₃Ni(CN)₄ (CuA), Zn(NH₃)₃Ni(CN)₄ (ZnA) und Cd(NH₃)₃Ni(CN)₄ (CdA) wurden dargestellt und identifiziert. Die Strukturen der Verbindungen wurde infrarotspektroskopisch und röntgendiffraktometrisch untersucht und miteinander verglichen. Die thermische Stabilität und die Stöchiometrie der thermischen Zersetzung wurden mittels eines Derivatographen untersucht. Die thermische Stabilität nimmt in der Reihenfolge CuA < ZnA < CdA zu.

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Cu(NH₃)₃Ni(CN)₄ (CuA), Zn(NH₃)₃Ni(CN)₄ (ZnA) Cd(NH₃)₃Ni(CN)₄ (CdA). , . . , CuA     

Heterobimetallic oxalato-bridged M(II)Re(IV) complexes (M = Mn,Fe, Co,Ni): synthesis,crystal structure,and magnetic properties

Four rhenium(IV)-M(II) bimetallic complexes of formula [ReCl(4)(mu-ox)M(dmphen)(2)].CH(3)CN with M = Mn (1), Fe (2), Co (3), and Ni (4) (ox = oxalate anion, dmphen = 2,9-dimethyl-1,10-phenanthroline) have been synthesized and the crystal structures of 1 and 3 determined by single-crystal X-ray diffraction. 1 and 3 are isostructural and crystallize in the monoclinic system, space group P2(1)/c, with a = 16.008(4) A, b = 12.729(2) A, c = 18.909(5) A, beta = 112.70(2) degrees, and Z = 4 for 1 and a = 15.998(4) A, b = 12.665(2) A, c = 18.693(5) A, beta = 112.33(2) degrees, and Z = 4, for 3. The structure of 1 and 3 is made up of neutral [ReCl(4)(mu-ox)M(dmphen)(2)] bimetallic units (M = Mn (1), Co (3)) and acetonitrile molecules of crystallization. M(II) and Re(IV) metal ions exhibit distorted octahedral coordination geometries being bridged by a bis(bidentate) oxalato ligand. The magnetic behavior of 1-4 has been investigated over the temperature range 2.0-300 K. A very weak antiferromagnetic coupling between Re(IV) and Mn(II) occurs in 1 (J = -0.1 cm(-)(1)), whereas a significant ferromagnetic interaction between Re(IV) and M(II) is observed in 2-4 [J = +2.8 (2), +5.2 (3), and +5.9 cm(-)(1) (4)].     

Spectral,thermal and magnetic investigations of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) 4-methylphthalates

Conditions for the preparation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) 4-methylphthalates were investigated and their composition, solubility in water at 295 K and magnetic moments were determined. IR spectra and powder diffraction patterns of the complexes prepared with molar ratio of metal to organic ligand of 1.0:1.0 and general formula: M [ CH₃C₆H₃(CO₂)₂]·nH₂o (n=1-3) were recorded and their decomposition in air were studied. During heating the hydrated complexes are dehydrated in one (Mn, Co, Ni, Zn, Cd) or two steps (Cu) and next the anhydrous complexes decompose to oxides directly (Cu, Zn), with intermediate formation of carbonates (Mn, Cd), oxocarbonates (Ni) or carbonate and free metal (Co). The carboxylate groups in the complexes studied are mono- and bidentate (Co, Ni), bidentate chelating and bridging (Zn) or bidentate chelating (Mn, Cu, Cd). The magnetic moments for paramagnetic complexes of Mn(II), Co(II), Ni(II) and Cu(II) attain values 5.92, 5.05, 3.36 and 1.96 M.B., respectively. This revised version was published online in July 2006 with corrections to the Cover Date.     

Syntheses, structures, and properties of trinuclear complexes [M(bpca)(2)(M'(hfac)(2))(2)], constructed with the complexed bridging ligand [M(bpca)(2)] [M, M' = Ni(II), Mn(II); Cu(II), Mn(II); Fe(II), Mn(II); Ni(II), Fe(II); and Fe(II), Fe(II); Hbpca = Bis(2-pyridylcarbonyl)amine, Hhfac = Hexafluoroacetylacetone

Five trinuclear complexes [M(bpca)(2)(M'(hfac)(2))(2)] (where MM'(2) = NiMn(2), CuMn(2), FeMn(2), NiFe(2), and FeFe(2); Hbpca = bis(2-pyridylcarbonyl)amine; and Hhfac = hexafluoroacetylacetone) were synthesized almost quantitatively by the reaction of [M(bpca)(2)] and [M'(hfac)(2)] in 1:2 molar ratio, and their structures and magnetic properties were investigated. Three complexes, with M' = Mn, crystallize in the same space group, Pna2(1), whereas two complexes, with M' = Fe, crystallize in P4(1), and complexes within each set are isostructural to one another. In all complexes, [M(bpca)(2)] acts as a bis-bidentate bridging ligand to form a linear trinuclear complex in which three metal ions are arranged in the manner M'-M-M'. The central metal ion is in a strong ligand field created by the N(6) donor set, and hence the Fe(II) in the [Fe(bpca)(2)] moiety is in a low-spin state. The terminal metal ions (M') are surrounded by O(6) donor sets with a moderate ligand field, which leads to the high-spin configuration of Fe(II). Three metal ions in all complexes are almost collinear, and metal-metal distances are ca. 5.5 A. The magnetic behavior of NiMn(2) and NiFe(2) shows a weak ferromagnetic interaction between the central Ni(II) ion and the terminal Mn(II) or Fe(II) ions. In these complexes, sigma-spin orbitals of the central Ni(II) ion and those of terminal metal ions have different symmetry about a 2-fold rotation axis through the Ni-N(amide)-M'(terminal) atoms, and this results in orthogonality between the neighboring sigma-spin orbitals and thus ferromagnetic interactions.     

Vibrational Spectroscopic Studies on the Hofmann-dabn-Type Benzene Clathrates: M(1,4-diaminobutane)Ni(CN)4° 1.5C6H6 (M = Mn, Fe, Co, Ni or Cd)

IR spectra of M(1,4-diaminobutane)Ni(CN)4° 1.5C6H6 (M = Mn, Fe, or Co), and IR and Raman spectra of M(1,4-diaminobutane)Ni(CN)4° 1.5C6H6 (M = Ni or Cd) clathrates are reported. The spectral features suggest that the compounds are similar in structure to the Hofmann-dabn-type clathrates.