Fe(bipy)(CN)(4)](-) as a versatile building block for the design of heterometallic systems: synthesis, crystal structure, and magnetic properties of PPh(4)[Fe(III)(bipy)(CN)(4)] x H(2)O, [[Fe(III)(bipy)(CN)(4)](2)M(II)(H(2)O)(4)] x 4H(2)O, and [[Fe(III)(bipy)(CN)(4)](2)Zn(II)] x 2H(2)O [bipy = 2,2'-Bipyridine; M = Mn and Zn

The new cyano complexes of formulas PPh(4)[Fe(III)(bipy)(CN)(4)] x H(2)O (1), [[Fe(III)(bipy)(CN)(4)](2)M(II)(H(2)O)(4)] x 4H(2)O with M = Mn (2) and Zn (3), and [[Fe(III)(bipy)(CN)(4)](2)Zn(II)] x 2H(2)O (4) [bipy = 2,2'-bipyridine and PPh(4) = 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 [[Fe(III)(bipy)(CN)(4)](2)M(II)(H(2)O)(4)] heterotrinuclear units and crystallization water molecules. The [Fe(bipy)(CN)(4)](-) entity of 1 is present in 2 and 3 acting as a monodentate ligand toward M(H(2)O)(4) units [M = Mn(II) (2) and Zn(II) (3)] through one cyanide group, the other three cyanides remaining terminal. Four water molecules and two cyanide nitrogen atoms from two [Fe(bipy)(CN)(4)](-) units in trans positions build a distorted octahedron surrounding Mn(II) (2) and Zn(II) (3). The structure of the [Fe(phen)(CN)(4)](-) complex ligand in 2 and 3 is close to that of the one in 1. The intramolecular Fe-M distances are 5.126(1) and 5.018(1) A in 2 and 3, respectively. 4 exhibits a neutral one-dimensional polymeric structure containing two types of [Fe(bipy)(CN)(4)](-) units acting as bismonodentate (Fe(1)) and trismonodentate (Fe(2)) ligands versus the divalent zinc cations through two cis-cyanide (Fe(1)) and three fac-cyanide (Fe(2)) groups. The environment of the iron atoms in 4 is distorted octahedral as in 1-3, whereas the zinc atom is pentacoordinated with five cyanide nitrogen atoms, describing a very distorted square pyramid. The iron-zinc separations across the single bridging cyanides are 5.013(1) and 5.142(1) A at Fe(1) and 5.028(1), 5.076(1), and 5.176(1) A at Fe(2). The magnetic properties of 1-3 have been investigated in the temperature range 2.0-300 K. 1 is a low-spin iron(III) complex with an important orbital contribution. The magnetic properties of 3 correspond to the sum of two magnetically isolated spin triplets, the antiferromagnetic coupling between the low-spin iron(III) centers through the -CN-Zn-NC- bridging skeleton (iron-iron separation larger than 10 A) being very weak. More interestingly, 2 exhibits a significant intramolecular antiferromagnetic interaction between the central spin sextet and peripheral spin doublets, leading to a low-lying spin quartet.     

TCNE dimer dianion coordination complexes, [Mn(TPA)(TCNE)]2[micro2-(TCNE)2] and [Mn(TPA)(micro4-C4(CN)8)0.5].ClO4, TPA=tris(2-pyridylmethyl)amine: synthesis, structure and magnetic properties

The structures and magnetic properties of two products that result from the reactions of [Mn(TPA)(CH3CN)2](ClO4)2, TPA=tris(2-pyridylmethyl)amine and potassium tetracyanoethylenide, KTCNE, are reported. [Mn(TPA)(TCNE)]2[mu2-(TCNE)2] (1) and [Mn(TPA)(micro4-C4(CN)8)0.5].ClO4 (2) are obtained by using two different ratios of the initial reactants. Each was intended to possess two or more cis-TCNE radical anions (TCNE*/-) as ligands. 1 is a dinuclear species that crystallizes in the triclinic system in the space group P, with a=10.4432(17), b=12.2726(16), and c=13.708(2) A; alpha=88.505(12), beta=75.560(14), and gamma=87.077(12) degrees; V=1698.9(4) A3; and Z=1 and features two metal centers each with three nearly orthogonal TCNE*/- ligands. However, the three TCNE*/- ligands are all dimerized via the formation of four-center, two-electron bonds: two bridge the two Mn(II) centers, and a third TCNE*/- ligand forms an intermolecular bond to another equivalent TCNE*/-. 2 crystallizes in the tetragonal system in the space group P42212, with a=17.170(3), b=17.170(3), and c=17.1837(6) A; V=5065.9(13) A3; and Z=8. It consists of a ribbon-like coordination polymer containing the previously observed but still relatively rare octacyanobutyl dianion. The [C4(CN)8]2- anion is derived from the dimerization of two TCNE radical anions via the formation of a new sigma bond, and each anion bridges four Mn(II) centers. Both 1 and 2 display magnetic behavior consistent with only weak antiferromagnetic coupling between the high-spin d5 Mn(II) in which the TCNE*/- are rendered diamagnetic through dimerization.     

Synthesis and magnetic properties of 3-D [Ru(II/III)(2)(O(2)CMe)(4)](3)[M(III)(CN)(6)] (M = Cr,Fe, Co)

Three-dimensional network structures of [Ru(II/III)(2)(O(2)CMe)(4)](3)[M(III)(CN)(6)] (M = Cr, Fe, Co) composition have been formed and their magnetic properties characterized. [Ru(II/III)(2)(O(2)CMe)(4)](3)[M(III)(CN)(6)] (M = Cr, Fe, Co) have nu(CN) IR absorptions at 2138, 2116, and 2125 cm(-1) and have body-centered unit cells (a = 13.34, 13.30, and 13.10 A, respectively) with -M-Ctbd1;N-Ru=Ru-Ntbd1;C-M- linkages along all three Cartesian axes. [Ru(II/III)(2)(O(2)CMe)(4)](3)[Cr(III)(CN)(6)] magnetically orders as a ferrimagnet (T(c) = 33 K) and has an unusual constricted hysteresis loop.     

Assignment of the electronic spectra of [Mo(CN)(8)](4)(-) and [W(CN)(8)](4)(-) by Ab initio calculations

CASPT2 calculations are performed on the dodecahedral and square antiprismatic isomers of the [Mo(CN)(8)](4)(-) and [W(CN)(8)](4)(-) complexes. The high-energy experimental bands above 40000 cm(-)(1) are assigned to MLCT transitions. The experimental observed trend of the extinction coefficients for the molybdenum and tungsten complex is reproduced by our CASSCF oscillator strengths. All bands below 40000 cm(-)(1) can be ascribed to ligand-field transitions, although small contributions from forbidden MLCT transitions cannot be excluded. In order to account for all experimental bands in the electronic spectrum of these octacyanocomplexes, a dynamic equilibrium in solution between the two isomeric forms must be hypothesized. Spin-orbit coupling effects are found to be more important for the square antiprismatic isomers; in particular, large singlet-triplet mixings are calculated for this isomer of [W(CN)(8)](4)(-). Ligand-field and Racah parameters as well as spin-orbit coupling constants are determined on the basis of the calculated transition energies. The obtained values for these parameters support the recently proposed model for exchange interactions in magnetic clusters and networks containing pentavalent octocyanometalates of molybdenum and tungsten.     

Corner sharing tetrahedral network in Co(3)(HAT)[N(CN)(2)](6)(OH(2))(2) (HAT = 1,4,5,8,9,12-hexaazatriphenylene)

We report a trinuclear Co(II) complex containing bridging dicyanamides and a tris-chelated HAT, which possesses approximately 37% void space. The magnetic exchange pathways appear in the structure as a corner sharing tetrahedral network. The compound crystallizes in the monoclinic space group P2(1)/c [a = 13.655(3) A, b = 15.189(3) A, c = 22.367(4) A, beta = 114.100(2) degrees, V = 4234.5(14) A(3), Z = 4, R(F(o)) = 0.0823]. The magnetic data were fit to an S = 3/2 model for systems dominated by zero-field splitting effects with g = 2.01 and D = 38.9 cm(-1).     

Structure and magnetic ordering of a 2-D Mn(II)(TCNE)I(OH2) (TCNE = tetracyanoethylene) organic-based magnet (T(c) = 171 K)

Mn(II)(TCNE)I(OH(2)) was isolated from the reaction of tetracyanoethylene (TCNE) and MnI(2)(THF)(3), and has a 2-D structure possessing an unusual, asymmetric bonded μ(4)-[TCNE]˙(-). Direct antiferromagnetic coupling between the S = 5/2 Mn(II) and S = 1/2 [TCNE]˙(-) leads to magnetic ordering as a canted antiferrimagnet at a T(c) of 171 K.     

Conversion of a Re(IV) tetrahedral cluster to a Re(III) octahedral cluster: synthesis of [(CH3)C(NH2)(2)](4)[Re(6)Se(8)(CN)(6)] by a solvothermal route

The compound [(CH(3))C(NH(2))(2)](4)[Re(6)Se(8)(CN)(6)] has been synthesized by the reaction at 200 degrees C for 3 days of Re(4)Te(4)(TeCl(2))(4)Cl(8), KSeCN, and NH(4)Cl in superheated acetonitrile. This compound crystallizes in the space group C2/c of the monoclinic system with four formula units in a cell of dimensions a = 20.3113(14) A, b = 10.1332(7) A, c = 19.9981(14) A, beta = 106.754(1) degrees, V = 3941.3(5) A(3) (T = 153 K). The [Re(6)Se(8)(CN)(6)](4-) anion comprises an Re(6) octahedron face capped by mu(3)-Se atoms, with each Re atom liganded by a CN group. The anions and cations are connected by an extensive network of hydrogen bonds. The conversion of a Re(IV) tetrahedral cluster to a Re(III) octahedral cluster appears to be unprecedented.     

Co(3)[Co(CN)(5)](2): a microporous magnet with an ordering temperature of 38 K

The reaction between [Co(H2O)6]2+ and [Co(CN)5]3- in deoxygenated water yields a dark blue solid of composition Co3[Co(CN)5]2.8H2O (1). X-ray powder diffraction data indicate a cubic Prussian blue-type framework, wherein the hexacyanometalate positions have only a two-thirds occupancy of square-pyramidal [Co(CN)5]3- units. Upon dehydration, the compound retains crystallinity and exhibits a Type I dinitrogen sorption isotherm, characteristic of a microporous solid. Magnetic measurements show 1 to behave as a ferrimagnet with an ordering temperature of 48 K, which is reduced to 38 K in the dehydrated solid. At 5 K, both 1 and dehydrated 1 exhibit magnetic hysteresis with a coercive field of 1160 G (the highest value yet reported for a cubic Prussian blue analogue) and remnant magnetizations of 1540 and 745 cm3G/mol, respectively. Thus, dehydrated 1 represents the first compound for which microporosity and long-range magnetic ordering have been demonstrated to coexist.     

Theoretical studies of magnetic interactions in Mn(II)(hfac)(2)[di(4-pyridyl)phenylcarbene] and Cu(II)(hfac)(2)[di(4-pyridyl)phenylcarbene].

Bis(hexafluoroacetylacetonato(hfac))manganese(II) coordinated with di(4-pyridyl)phenylcarbene, Mn(II)(hfac)(2)[di(4-pyridyl)phenylcarbene] (1a) and its copper analogue Cu(II)(hfac)(2)[di(4-pyridyl)phenylcarbene] (2a) have attracted great interest from the viewpoint of photoinduced magnetism. The complexes 1a and 2a are regarded as the new d-pi-p conjugated systems containing transition metal ion and carbene as spin sources. The magnetic measurements demonstrated antiferromagnetic and ferromagnetic effective exchange interactions for 1a and 2a, respectively. Here, we have performed UHF and UHF plus DFT hybrid calculations (UB3LYP) to elucidate the nature of the through-bond effective exchange interaction between Mn(II) (or Cu(II)) ion and triplet carbene sites in 1a (or 2a) and their model complexes. The natural orbital analysis of the UHF and UB3LYP solutions and CASCI calculations for the simplest models of 1a and 2a are performed to elucidate relative contributions of spin polarization (SP) and spin delocalization (SD) (or superexchange (SE)) interactions for determination of the sign of J(ab) values. Mn(II) carbene complex 1a shows an antiferromagnetic interaction because of the pi-type antiferromagnetic SE effect and the pi-type SP effect, while the positive J(ab) value for Cu(II) carbene complex 2a can be explained by the fact that ferromagnetic SE and SP interactions due to orbital orthogonality are more effective than the sigma-type antiferromagnetic SE interaction. The ligand coordination effects of both 4-pyridylcarbene and hfac play crucial roles for determination of the J(ab) values, but the ligand coordination effect of hfac is more important for the active control of charge or spin density distributions than that of 4-pyridylcarbene. The spin alignment mechanisms of 1a and 2a are indeed consistent with SE plus SP rule, which is confirmed with the shape and symmetry of natural orbitals, together with charge and spin density distributions.     

Acetonitrile-facilitated reductive dimerization of TCNE to octacyanobutanediide, [C4(CN)8]2-, by Iron(II) chloride

The redox properties of MCl2 (M=Mn, Fe, Co) acetonitrile solvates were electrochemically and spectroscopically characterized. The three voltammogram waves at 0.86, 0.48, and 0.21 V versus SCE for FeCl(2) dissolved in MeCN are assigned as one-electron reduction potentials for [Fe(II)Cl(x)(NCMe)4-x]2-x (1相似文献   

Synthesis, structure and physical properties of the manganese(ii) selenide/selenolate cluster complexes [Mn(32)Se(14)(SePh)(36)(PnPr(3))(4)] and [Na(benzene-15-crown-5)(C(4)H(8)O)(2)](2)[Mn(8)Se(SePh)(16)

The synthesis, molecular structures, and magnetic and optical properties of [Mn(32)Se(14)(SePh)(36)(PnPr(3))(4)] and [Na(benzene-15-crown-5)(C(4)H(8)O)(2)](2)[Mn(8)Se(SePh)(16)] have been investigated which are the first examples of manganese chalcogenide cluster complexes, despite known manganese oxo compounds, which comprise more than four manganese atoms.     

Solid-state ligand dynamics in interpenetrating Mn[N(CN)(2)](2)(pyrazine): a neutron spectroscopy study

We have used quasielastic neutron scattering to probe the solid-state ligand dynamics in the coordination polymer Mn[N(CN)(2)](2)(pyz) [pyz = pyrazine] which has double-interpenetrating 3D lattices. A reversible structural phase transition occurs at 410 K as shown by neutron spectroscopy and differential scanning calorimetry. The origin of this transition is linked to rotational dynamics associated with the bridging pyz ligands. At 425 K, the pyrazine ring motion can be solely regarded as a 180 degrees reorientational jump about the axis defined by the Mn-N coordinative bonds, occurring with a correlation time of approximately 70 ps. This model can be extended to the 200-410 K temperature region using high-resolution backscattering spectroscopy to measure an identical motion on the time scale of nanoseconds with an activation energy of 24 +/- 2 kJ mol(-1). In contrast, no quasielastic scattering is seen for the 2D layered variant beta-Cu[N(CN)(2)](2)(pyz), owing to its more compact layer packing motif. Importantly, this work represents the very first study of solid-state rotational dynamics in an interpenetrating lattice structure.     

Synthesis and crystal structure of ionic multicomponent complex: ([Cr(I)(PhH)(2)].+))(2)[Co(II)TPP(C(60)(CN)(2))]-[C(60)(CN)(2)](.-).3(o-C(6)H(4)Cl(2)) containing C(60)(CN)(2).- radical anion and sigma-bonded diamagnetic Co(II)TPP(C(60)(CN)(2)) -anion

The ionic multicomponent complex complex: ([Cr(I)(PhH)(2)].+))(2)[Co(II)TPP(C(60)(CN)(2))]-[C(60)(CN)(2)](.-).3(o-C(6)H(4)Cl(2)) (Co(II)TPP: cobalt (II) tetraphenylporphyrin; Cr(PhH)(2): bis(benzene)chromium; o-C(6)H(4)Cl(2): o-dichlorobenzene) containing CoTPP(C(60)(CN)(2)- anion and C(60)(CN)(2).- radical anion was obtained. The complex has the cage structure with channels, which accommodate Cr(I)(PhH)(2)(.+) and o-C(6)H(4)Cl(2) molecules. For the first time the sigma-bonding of Co(II)TPP to the fullerene radical anion with the essentially shortened Co.C(C(60)(CN)(2)) contact of 2.282 A is observed. The sigma-bonding results in the diamagnetism of Co(II)TPP(C(60)(CN)(2))(-) anion. The nonbonded C(60)(CN)(2)(.-) radical anion retains both the C(2)(v)symmetry and the shape of the molecule. The length of the C(triple bond)N bonds is 1.141 and 1.152 A.     

Octadecanuclear cluster or 1D polymer with [[ML](2)Nb(CN)(8)](n) motifs as a function of [ML] (M = Ni(II), n = 6; M = Mn(II), n = infinity; L = macrocycle)

A nanosized octadecaheteronuclear aggregate, [[NiL(2)](12)[Nb(CN)(8)](6)(H(2)O)(6)], and a 1-D coordination polymer, [[MnL(1)](2)[Nb(CN)(8)](H(2)O)]( infinity ), have been obtained by self-assembly between the octacyanometalate [Nb(CN)(8)](4)(-) and [ML](2+) complexes. The dimensionality of the supramolecular architectures was found to be controlled by the [ML] module for which the equatorial coordination sites are blocked by a macrocyclic ligand. The crystal structures and magnetic properties for both the compounds are described.     

Magnetic ordering (Tc = 90 K) observed for layered [Fe(II)(TCNE*-)(NCMe)2]+[Fe(III)Cl4]- (TCNE = tetracyanoethylene)

[Fe(TCNE)(NCMe)2][FeCl4] is isolated from the reaction of TCNE and FeCl2(NCMe)2 and orders as a ferrimagnet below 90 K and is the initial member of a new class of magnets. It is the first metal-TCNE magnet with direct bonding between metal ion and [TCNE]*- whose structure has been determined, and it possesses a novel planar mu4-[TCNE]*- spin coupling unit bonded to four FeII's, with an axial pair of MeCNs. The [FeIIICl4]- anion occupies sites between the [FeII(TCNE*-)(NCMe)2]+ layers. [Fe(TCNE)(NCMe)2][FeCl4] has a coercive field of 1730 Oe and a remnant magnetization of 7500 emuK/mol at 50 K.     

EXAFS study of aqueous Zr(IV) and Th(IV) complexes in alkaline CaCl(2) solutions: Ca(3)[Zr(OH)(6)](4+) and Ca(4)[Th(OH)(8)](4+)

A hitherto unknown type of aqueous complex, ternary Ca-MIV-OH complexes (M = Zr and Th), causes unexpectedly high solubilities of zirconium(IV) and thorium(IV) hydrous oxides in alkaline CaCl2 solutions (pHc = 10-12, [CaCl2] > 0.05 mol.L(-1), and pHc = 11-12, [CaCl2] > 0.5 mol.L(-1), respectively). The dominant aqueous species are identified as Ca3[Zr(OH)6]4+ and Ca4[Th(OH)8]4+ and characterized by extended X-ray absorption fine structure (EXAFS) spectroscopy. The number of OH- ligands in the first coordination sphere detected by EXAFS, NO = 6 (6.6 +/- 1.2) for Zr and NO = 8 (8.6 +/- 1.2) for Th, are consistent with the observed slopes of 2 and 4 in the solubility curves log [M]tot vs pHc. The presence of polynuclear hydrolysis species and the formation of chloride complexes can be excluded. EXAFS spectra clearly show a second coordination shell of calcium ions. The [Zr(OH)6]2- and [Th(OH)8]4- complexes with an unusually large number of OH- ligands are stabilized by the formation of associates or ion pairs with Ca2+ ions. The number of neighboring Ca2+ ions around the [Zr(OH)6]2- and [Th(OH)8]4- units is determined to be NCa = 3 (2.7 +/- 0.6) at a distance of RZr-Ca = 3.38 +/- 0.02 A and NCa = 4 (3.8 +/- 0.5) at a distance of RTh-Ca = 3.98 +/- 0.02 A. The Ca3[Zr(OH)6]4+ and Ca4[Th(OH)8]4+ complexes have first (M-O) and second (M-Ca) coordination spheres with the Ca2+ ions bound to coordination polyhedra edges.     

Doppelkettenstruktur von (pipzH2)[MnF2(HPO4)(H2O)](H2PO4)

By adding piperazine to a hydrofluoric and phosphoric acid solution of Manganese(III) fluoride, the fluoride phosphate (pipzH₂)[MnF₂(HPO₄)(H₂O)](H₂PO₄) can be crystallized. Its structure is built by piperazinium(2+) cations, (H₂PO₄)^? anions, and an anionic double‐chain of [HPO₄] tetrahedra and [MnO₃F₂(H₂O)] octahedra. The structure is triclinic, space group P , Z = 2, a = 622.97(4), b = 923.46(6), c = 1183.62(7) pm, α = 98.343(6)°, β = 100.747(7)°, γ = 107.642(5)°, R = 0.0289. It is worth noting that a ferrodistortive Jahn‐Teller order is observed with [MnO₃F₂(H₂O)] octahedra strongly elongated along the F–Mn–OH₂ axes perpendicular to the chain plane. The structure is stabilized by very strong hydrogen bonds.     

Structural comparisons of silver(I) complexes of third-generation ligands built from tridentate (o-C(6)H(4)[CH(2)OCH(2)C(pz)(3)](2)) versus bidentate poly(1-pyrazolyl)methane units (o-C(6)H(4)[CH(2)OCH(2)CH(pz)(2)](2)) (pz = pyrazolyl ring)

The new bitopic, bis(1-pyrazolyl)methane-based ligand o-C6H4[CH2OCH2CH(pz)2]2 (L2, pz = pyrazolyl ring) is prepared from the reaction of (pz)2CHCH2OH (obtained from the reduction of (pz)2CHCOOH with BH3.S(CH3)2) with NaH, followed by the addition of alpha,alpha'-dibromo-o-xylene. The reaction of L2 with AgPF6 or AgO3SCF3 yields {o-C6H4[CH2OCH2CH(pz)2]2(AgPF6)}n or {o-C6H4[CH2OCH2CH(pz)2]2(AgO3SCF3)}n, respectively. Both compounds in the solid state have tetrahedral silver(I) centers arranged in a 1D coordination polymer network. The analogous ligand based on tris(1-pyrazolyl)methane units, o-C6H4[CH2OCH2C(pz)3]2 (L3), reacts with AgO3SCF3 to form a similar coordination polymer, {o-C6H4[CH2OCH2C(pz)3]2(AgO3SCF3)}n. In this case, each tris(pyrazolyl)methane unit in L3 adopts the kappa2-kappa0 bonding mode. Crystallization of a 3:1 mixture of AgO3SCF3 and L3 yields {o-C6H4[CH2OCH2C(pz)3]2(AgO3SCF3)2}n, in which the tris(1-pyrazolyl)methane units adopt a kappa2-kappa1 coordination mode.