Spectroscopic and magnetic properties of the metastable states in the coordination network [{Co(prm)2}2{Co(H2O)2}{W(CN)8}2]·4H2O (prm = pyrimidine)

The study of the metastable states, obtained by thermal quenching or by light irradiation in the [{Co(prm)(2)}(2){Co(H(2)O)(2)}{W(CN)(8)}(2)]·4H(2)O complex, is reported using powder X-ray diffraction, Raman spectroscopy, optical reflectivity, and magnetic measurements. This compound is characterized by a electron-transfer (ET) phase transition occurring between a high-temperature phase (HT phase) formed by paramagnetic Co(II)-W(V) units and a low-temperature phase (LT phase) formed by diamagnetic Co(III)-W(IV) units. Metastable phases can be induced at low temperature either by thermal quenching rapidly cooling phase named RC or by irradiation photo-induced phase named PI similar to the well-known Light-Induced Excited Spin State Trapping effect. The relaxation dynamics of the metastable phases have been studied and revealed some differences between the RC and PI phases. The sigmoidal shape of the relaxation curves in the RC phase is in agreement with the cooperative nature of the process. Thermodynamic parameters that govern the relaxation have been determined and used to reproduce the experimental Thermal-Induced Excited Spin State Trapping curve.     

The reactions of AgI electrophile with [Fe2(η-C5H5)2(CO)2(L){CN(Me)H}]+ and [Fe2(η-C5H5)2(CO)2{CN(Me)H}2]2+ salts (L = CO or CNMe)

The protonated species [Fe₂(η-C₅H₅)₂(CO)₂(η-CO){μ-CN(Me)H}]X, [Fe₂(η-C₅H₅)₂(CO)(CNMe)(μ-CO){μ-CN(Me)H}][X], and [Fe₂(η-C₅H₅)₂(CO)₂{η-CN(Me)H}₂][X]₂ react with one equivalent of AgY. The Ag⁺ and one H⁺ act together as a two-electron oxidant. Silver metal is precipitated quantitatively and the substrates cleaved to give mono-nuclear products of the type (a) [Fe(η-C₅H₅)(CO)(L)X] and [Fe(η-C₅H₅(CO)(L)Y] or (b) Fe(η-C₅H₅(CO)(L)(CNMe)][X] (L = CO, CNMe). If X⁻ and Y⁻ are both coordinating anions such as NO₃⁻, I⁻, or Br⁻ or the solvent is MeCN products of type (a) are usually obtained with X = Y = MeCN⁺ if acetonitrile is used as the solvent. However, if either X⁻ or Y⁻ is a non-coordinating anion such as BF₄⁻ or PF₆⁻ and methanol is the solvent, the products are usually those of type (b). When X⁻ = [p-MeC₆H₄SO₃]⁻, both types of products are obtained in significant amounts. If two equivalents of Ph₃P are added to the methanol solution of [Fe₂(η-C₅H₅)₂(CO)₂{-CN(Me)H}₂[BF₆]₂, no reaction takes place until the third equivalent of AgNO₃ has been added. The products have been isolated and characterized by analysis and infrared spectroscopy. The previously unreported [Fe₂(η-C₅H₅)₂(CO)(CNMe)(η-CO){η-CN(Me)H}] X salts are described for X⁻ = BF₄⁻, PF₆⁻, Br⁻ · 2H₂O, I⁻ · H₂O, NO₃⁻ · 0.5H₂O, and p-MeC₆H⁴SO₃⁻.     

[μ4-SiCo(CO)4]2Co4(CO)11, a cobalt carbonyl cluster incorporating five-coordinate silicon

Si₂H₆ reacts with Co₂(CO)₈ to form Si₂Co₆(CO)₁₉, shown by X-ray structure analysis to contain a pseudo-octahedral trans-Si₂Co₄ core with terminal Co(CO)₄ groups on the silicon atoms. This is the first silicon example of a compound with the E₂M₄ type with M = transition metal and E = main group element, and has the silicon in a distorted square-pyramidal configuraion, with a Si...Si distance of 2.817 Å.     

Cluster cyanide-bridged heterometallic coordination polymers: synthesis and crystal structures of compounds [{Cu2(dien)2(CN)}2{Mo4Te4(CN)12}]·14.5H2O and (H3O)3K[{Mn(H2O)2}2{Mn(H2O)2(NO3)}4{W4Te4(CN)12}2]·8H2O

The reactions of anionic molybdenum and tungsten cyanide cuboidal clusters with Cu^II and Mn^II salts afforded two new cyanide-bridged heterometallic coordination polymers with the composition [{Cu₂(dien)₂(CN)}₂{Mo₄Te₄(CN)₁₂}]?14.5H₂O (1) and (H₃O)₃K[{Mn(H₂O)₂}₂{Mn(H₂O)₂(NO₃)}₄{W₄Te₄(CN)₁₂}₂]·8H₂O (2). The structures of these compounds were established by X-ray diffraction analysis. Compound 1 has a layered structure, in which the cuboidal cluster fragments {Mo₄Te₄(CN)₁₂}^6? are linked to the copper atoms of the dinuclear fragments {(H₂O)(dien)Cu(μ-CN)Cu(dien)(H₂O)} through the bridging CN groups. Coordination polymer 2 has a framework structure, in which the cluster fragments {W₄Te₄(CN)₁₂}^6? are linked to the manganese(II) aqua complexes of two types, viz., the dinuclear fragment {Mn(μ₂-H₂O)₂Mn} and the tetranuclear cyclic fragment {(H₂O)₂Mn(μ₂-NO₃)}₄, through the bridging CN groups.     

配位聚合物{[Co(H2O)6][Co(H2O)4(pmts)]·4H2O}n的合成及晶体结构

以均苯四甲酸(pmts)和CoCl2·6H2O为原料,在碱件水溶液中通过水热法合成了配位聚合物{[Co(H2O)6][Co(H2O)4(pmts)]·4H2O}n,并对其进行了红外、紫外-可见吸收光谱和单品X-射线衍射结构测定.结果表明,Co2+分别与桥配体pmts的1,4位羧基氧及端配体水分子中的氧以轻度畸变的八血体...     

Crystal structure of a tantal cluster with tetraphenylborate-anion: [Ta6Br12(H2O)6](BPh4)2·4H2O

The crystal structure of the [Ta₆Br₁₂(H₂O)₆](BPh₄)₂·4H₂O salt (1), obtained from Ta₆Br₁₄·7H₂O and NaBPh₄, is determined by X-ray crystallographic analysis. The structure contains a network of hydrogen bonds, which organizes the cluster cations into layers.     

A STUDY OF THE REDOX CHARACTERISTICS OF THE TERNARY CLATHRATE COMPOUND {MolS2CN(C2H5)2]4} {FeCl4}-{C6H5CH2SSCH2C6H5}

The redox characteristics of the ternary clathrate compound{C6H5CH2SSCH2C6H5}was studied by electrochemical measurement and quantum-chemical calculations.The cyclic voltammogram of this ternary clathrate compound in 0.1M KC1O4-DMF with a platinum electride had 2.pairs of redox peak.Both the electrochemical parameters derived from the voltammogram and the results of EHMO calculations indicate that the pair of redox peak at relatively positive potentials corresponds to the redox reaction of "Fe(Ⅲ)/Fe(Ⅱ) which is irreversible in nature,while the pair of redox peak at more negative potentials corresponds to the redox reaction of Mo(Ⅴ)/ Mo(Ⅱ) which is semi-reversible.The calculations from experiment measurements are fairly agreement with the theoretical calculations.     

A fixation mode of gold(III) in the [Zn2{S2CN(iso-C3H7)2}4]-[AuCl4]−/2 M HCl chemisorption system: Supramolecular structure and thermal behavior of the heteropolynuclear complex ([H3O][Au3{S2CN(iso-C3H7)2}6][ZnCl4]2 · H2O) n

The interaction of freshly precipitated binuclear zinc dithiocarbamate [Zn₂{S₂CN(iso-C₃H₇)₂}₄] with solutions of AuCl₃ in 2 M HCl is studied. The heterogeneous reaction includes the chemisorption of gold(III) and the partial ion exchange to form a polynuclear ionic gold(III)-zinc complex. The molecular and supramolecular structures of the individual fixation mode of gold(III), coordination compound (H₃O[Au₃{S₂CN(iso-C₃H₇)₂}₆][ZnCl₄]₂ · H₂O) _n (I), are determined by X-ray diffraction analysis. Compound I includes three complex cations [Au{S₂CN(iso-C₃H₇)₂}₂]⁺, two of which (noncentrosymmetric, A) are structurally nonequivalent with respect to the third cation (centrosymmetric, B). The structural self-organization of compound I includes the formation of linear trinuclear fragments [Au₃{S₂CN(iso-C₃H₇)₂}₆]³⁺ by three cations (2A and B) due to nonsymmetric secondary Au…S bonds. The interaction between the [Au₃{S₂CN(iso-C₃H₇)₂}₆]³⁺ fragments results in the formation of zigzag polymer chains ([Au₃{S₂CN(iso-C₃H₇)₂}₆]³⁺) _n . The outer-sphere water molecule and the hydronium ion are involved in the pairwise linkage of the [ZnCl₄]₂-anions due to hydrogen bonds Cl…O. The chemisorption capacity of the zinc dithiocarbamate complex calculated from the reaction of gold(III) fixation is 471.2 mg of gold per 1 g of the sorbent. The conditions for the isolation of chemisorbed gold are determined by the simultaneous thermal analysis of the thermal behavior of compound I. The multistage thermal destruction includes two steps of dehydration of the complex, the thermolysis of the dithiocarbamate moiety and [ZnCl₄]^2? (with the release of metallic gold and zinc chloride and the partial formation of ZnS), and the evaporation of ZnCl₂. The final products of the thermal transformations are metallic gold and ZnS.     

Further studies on the taumerization of the hydrido (alkynyl) cluster Ru3Pt(μ-H) {μ4-ν2-C ≡ C1Bu} (CO)9(L2) to the vinylidene cluster Ru3Pt{μ4-ν2-C ≡ C(H)tBu} (CO)9(L2): X-ray structures of Ru3Pt(μ-H){μ4-ν2-C = C(H)tBu} (CO)9(L2); L2 = dppet,dppp, andS,S-dppb

The first order rate constants for the tautomerization of the hydrio(alkynyl) clusters Ru₃Pt(μ-H){μ₄-ν²-C ≡ C¹Bu}(CO)₉(L₂);1a: L₂ = dppe,1b; L₂ = dppet,1c; L₂ = dppp and1d; L₂ =S,S-dppb to the corresponding vinylidene clusters Ru₃Pt{μ₄-ν²-C = C(H)^tBu}(CO)₉(L₂)2 have been measured, and they follow the orser1d <1a <1b ～1c. The reactions involving1a and1d exhibit an inverse kinetic deuterium isotope effect. The structures of1b, 2b, 2c, and2d were determined by X-ray crystallography, and are compared with those of1a and2a which have been previously reported. Crystal data for1b, space groupPbca,a = 13.338(4) Å,b = 17.771(6) Å,c = 36.092(8) Å,Z = 8,R(R _w) = 0.059(0.058) for 2342 absorption corrected, observed data; for2b, space group P2₁/n,a = 10.566(2) Å,b = 20.234(5) Å,c = 20.270(3) Å,β = 96.11(1)°,Z = 4,R(R _w) = 0.043(0.053) for 5865 absorption corrected, observed data; for2c, space group P2₁/n,a = 14.211(5) Å,b = 19.534(2) Å,c = 15.870(2) Å,β = 100.81(2)°,Z = 4,R(R _w) = 0.055(0.031) for 6566 absorption corrected, observed data: for2d, space group P2₁2₁2₁,a = 12.309(4) Å,b = 19.047(6) Å,c = 19.206(4) Å,Z = 4,R(R _w) = 0.055(0.053) fpr 2151 absorption corrected, observed data. The fluxional behavior of1d and1e (which consists of two interconverting isomers) has been examined by variable temperature¹³C NMR spectroscopy and by³¹P EXSY.     

Thermodynamic Model for BiPO4(cr) and Bi(OH)3(am) Solubility in the Aqueous Na+–H+–\mathrm{H}_{2}\mathrm{PO}_{4}^{-}–\mathrm{HPO}_{4}^{2-}–\mathrm{PO}_{4}^{3-}–OH−–Cl−–H2O System

Prior to this study no data for the solubility product of BiPO₄(cr) or the complexation constants of Bi with phosphate were available. The solubility of BiPO₄(cr) was studied at 23±2?°C from both the over- and under-saturation directions as functions of a wide range in time (6–309 days), pH values (0–15), and phosphate concentrations (reaching as high as 1.0 mol?kg^?1). HCl or NaOH were used to obtain a range in pH values. Steady state concentrations and equilibrium were reached in <6 days. The data were interpreted using the SIT model. These extensive data provided a solubility product value for BiPO₄(cr) and an upper limit value for the formation of BiPO₄(aq). Because the aqueous system in this study involved relatively high concentrations of chloride, reliable values for the complexation constants of Bi with chloride were required to accurately interpret the solubility data. Therefore as a part of this investigation, existing Bi–Cl data were critically reviewed and used to obtain values of equilibrium constants for various Bi–Cl complexes at zero ionic strength along with the values for various SIT ion interaction parameters. Predictions based on these thermodynamic quantities agreed closely with our experimental data, the chloride concentrations of which ranged as high as 0.7 mol?kg^?1. The study showed that BiPO₄(cr) is stable at pH values <9.0. At pH values >9.0, Bi(OH)₃(am) is the solubility controlling phase. Reliable values for the Bi(OH)₃(am) solubility reactions involving Bi(OH)₃(aq) and $\mathrm{Bi}(\mathrm{OH})_{4}^{-}$ and the formation constants of these aqueous species are also reported.     

Iron salts with the tetracyanidoborate anion: [Fe(III)(H2O)6][B(CN)4]3, coordination polymer [Fe(II)(H2O)2{κ2N[B(CN)4]}2], and [Fe(II)(DMF)6][B(CN)4]2

The reaction of Fe(OH)(3) with tetracyanidoboronic acid, H[B(CN)(4)]·xH(2)O, in water leads to the first examples of tetracyanidoborates with a triply charged metal cation, [Fe(III)(H(2)O)(6)][B(CN)(4)](3) (1). Using elemental iron powder as starting material, [Fe(II)(H(2)O)(2){κ(2)ΝB(CN)(4)]}(2)] (2) is obtained. Anhydrous iron(II) tetracyanidoborate, which is synthesized by heating of 2, is soluble in dry dimethylformamide. After evaporation of the DMF solvent, single crystals of the third title compound, [Fe(II)(DMF)(6)][B(CN)(4)](2) (3), are obtained. Compound 3 is the first metal tetracyanidoborate soluble in nonpolar solvents. The title compounds have been characterized by single-crystal X-ray diffraction (1 rhombohedral, R3c (no. 167), a = 14.9017(7) ?, c = 20.486(1) ?, Z = 6; 2 tetragonal, I42d (no. 122), a = 12.3662(3) ?, c = 9.2066(4) ?, Z = 4; 3 triclinic, P1 (no. 2), a = 8.6255(3) ?, b = 11.0544(4) ?, c = 12.2377(5) ?, Z = 1). The metal ions in all three compounds are octahedrally coordinated. Whereas 1 and 3 are built up from isolated complex ions, 2 comprises a coordination polymer, in which the Fe(II) ion is coordinated by two oxygen atoms of two water molecules in a trans orientation and four nitrogen donor atoms of the [B(CN)(4)](-) groups, which bridge between neighboring iron ions. The iron(III) ion in 3 is in a perfect octahedral environment, which is formed by the O atoms of 6 molecules of water. The single-crystal X-ray structures, vibrational spectra, thermal properties, solubilities, and electrochemical characteristics are reported and compared with those of other known tetracyanidoborates.     

[(C2H5)4N]2{Fe4S4[S2CN(C2H5)2]4}的晶体和分子结构

[(C2H5)4N]2{Fe4S4[S2CN(C2H5)2]4}单晶样品在Nicolet-R3四圆衍射仪上收集X射线衍射数据. 分析结果给出其晶胞参数: a=22.125(6), b=11.313(3),c=25.053A; β=118.05(2)°; V=5534.19A^3, Z=4, 空间群Cc. 衍射数据经过Lρ因子和经验吸收效应校正. 分子中铁原子的位置从三维Patterson图上得到. 接着经过若干轮Fourier和差Fourier电子云密度合成, 发现全部其余非氢原子的坐标.氢原子位置根据理论模型计算. 结构修正最后收敛至R=0.073, Rw=0.069. 标题化合物是由[(C2H5)4N]^+和{FeS4[S2CN(C2H5)2]}^2^-组成的离子型化合物. 结构的主要特点表现在阴离子上, 而在阴离子中含有类立方烷型簇核Fe4S4. 该簇核中每个铁原子与五个硫原子配位, 其配位多面体构型均为畸变的四方锥.     

配位聚合物{[Co(4,4''''-bpy)(H2O)4](Fum)·4H2O}n的合成和晶体结构

0引言近年来,利用晶体工程方法设计、裁剪和组装具有一维、二维和三维有序超分子结构的配位聚合物引起了人们极大的兴趣,并成为材料科学和化学学科中最活跃的研究领域之一[1~3]。在超分子结构设计方面,利用过渡金属借助配体配位作用引导的自组装已成为一个热点。其中多联吡啶类     

Unique seven-node rare-earth octacyanomolybdate(IV) three-dimensional molecular frameworks: {[Er(H2O)5(Er(H2O)4)3][Mo(CN)8]3·11H2O}n and {[Eu(H2O)5(Eu(H2O)4)3][Mo(CN)8]3·11H2O}n

The crystal structure analyses of {[Er(H₂O)₅(Er(H₂O)₄)₃][Mo(CN)₈]₃·11H₂O}_n (1) and {[Eu(H₂O)₅(Eu(H₂O)₄)₃][Mo(CN)₈]₃·11H₂O}_n (2), show that they are not only new neutral three-dimensional rare-earth octacyanomolybdate(IV) molecular frameworks, but that they also belong to an unknown structure type having seven different nodes. To the best of our knowledge this is different to any other known molybdenum(IV) octacyanide complexes published to date. Both compounds crystallize in the triclinic system, space group P-1, and are isostructural and isotypic. The coordination polyhedra of the molybdenum atoms in the three different [Mo(CN)₈]⁴⁻ anions are trigonal prisms, with two additional atoms. A new bridging mode for octacyanometallates is also observed with five of the eight cyanide groups involved in bridging either three or four rare-earth atoms, while the three remaining cyanide groups are terminal and are involved in hydrogen bonding. The four rare-earth atoms in 1 and 2 have different coordination polyhedra in the form of trigonal prisms with two additional atoms. The three-dimensional structures are made up of infinite two-dimensional slabs linked by one of the rare-earth metal atoms. In both compounds, apart from the 17 coordinated water molecules, there are 11 lattice water molecules of crystallization present in the cavities of the three-dimensional frameworks. The 28 water molecules and the terminal CN⁻ groups are involved in an extensive O–H⋯O and O–H⋯N hydrogen bonding network.     

{Mo[S_2CN(C_2H_5)_2]_4}~( 1)·{FeCl_4}~(-1)·{C_6H_5CH_2S_2CH_2C_6H_5}三元包合物的晶体结构

成分为MoFeS_(10)Cl_4N_4C_(34)H_(54)的单晶样品,用SYNTEX-R3型四圆衍射仪以θ/2θ扫描方式收集3499个独立的X射线衍射强度数据进行结构分析。晶体属空间群C_s~4—C_c,晶胞参数a=17.900(5),b=18.466(7),c=15.483(4),β=92.78(2)°,Z=4,经PL,K,B及吸收因子的校正得绝对强度,由Patterson函数先导出Mo参数,随后用Fourier法有层次地导出S,Fe,Cl,N,C等非氢原子的坐标参数,另由直接法亦导出大部分非氢原子的位置,所得结果是平行的。用块矩阵最小二乘法对坐标及各向同性与各向异性的热参数进行多轮的修正,最后加入全部氢原子,同时进行氢原子各向同性热参数的修正,得一致性因子R=0.054,结构分析证实:晶体中存在有三类物种,四个二乙胺基硫代甲酸根与Mo(Ⅴ)组成了{Mo[S_2CN(C_2H_5)_2]_4}~(=1)络离子,它与负络离子{FeCl_4}~(-1)交替排列构成了沿c轴方向伸展的空腔,而电中性的苄基二硫化物,则充填其间组成了结构新颖的三元体系包合物。     

Synthesis and structural characterisation of the mixed-metal cluster cation [Nb(η5-C5H4R)2{AuP(C6H5)3}2]+ with R = H or Si(CH3)3

Triangular “NbAu₂” cluster compounds have been prepared by the reaction of [Nb(η⁵-C₅H₄R)₂H₃] (R = H, Si(CH₃)₃) with gold(I) salts and the structure of [Nb{η⁵-C₅H₄Si(CH₃)₃}₂{AuP(C₆H₅)₃}₂] PF₆ has been determined by X-ray diffraction.     

Energetic materials composed of coordination polymers: {[Zn(μ-atrz)3](ClO4)2·2H2O}n and {[Cu(μ-atrz)3](NO3)2·2H2O}n

An improved synthetic pathway for trans-4,4′-azo-1,2,4-triazole (atrz) was discovered. Pure atrz was obtained directly without any other separation step in an environment friendly process. Treatment of atrz with zinc perchlorate and cupric nitrate led to the isolation of {[Zn(μ-atrz)₃](ClO₄)₂·2H₂O}_n and {[Cu(μ-atrz)₃](NO₃)₂·2H₂O}_n, which were well characterized. Their structures were determined by X-ray crystallographic analysis. The calculation results of the formation of {[Zn(μ-atrz)₃](ClO₄)₂ 2H₂O}_n and {[Cu(μ-atrz)₃](NO₃)₂ 2H₂O}_n indicates that the perfect crystal structures in spite of much resistance. A fundamental understanding of the structure and thermal properties involves factors, such as conjugated system, crystal structure, and inorganic metallic compounds that affect their thermal behavior. The high energy of the coordination compounds consists of chemical, electronic, and potential energy. The potential for the improvement of the coordination polymer opens up a new world for research of energetic materials.     

From an {Fe4S4}-cluster to {Fe2S2}- and {Fe3S}-carbonyls. Crystal structure of [Fe3S(CO)9]2−

We report the electrochemical and chemical synthesis of the first isolable iron carbonyls obtained directly from an {Fe₄S₄}-cluster and carbon monoxide: the structure of one product of chemical reduction, [Fe₃S(CO)₉]²⁻, had been determined by X-ray crystallography.     

Tris(pyrazolyl)borate half-sandwich complexes of trivalent uranium incorporating the [C8H6{SiiPr3-1,4}2]2− and [C8H4{SiiPr3-1,4}2]2− ligands

The reaction of UI₃ in THF with KTp^Me2 and the subsequent addition of [K₂(C₈H₆{SiⁱPr₃-1,4}₂)] or [K₂(C₈H₄{SiⁱPr₃-1,4}₂)] yields dark red [U(κ³-Tp^Me2)(C₈H₆{SiⁱPr₃-1,4}₂)] 1 and purple [U(κ³-Tp^Me2)(C₈H₄{SiⁱPr₃-1,4}₂)] 2, respectively. The ¹H NMR of 1 at room temperature suggests a rigid structure, whereas 2 is fluxional in solution on the NMR timescale. 1 is unreactive towards CO, CO₂ and MeNC under mild conditions; density functional calculations were used to compare the electronic and steric effects of the Tp^Me2 vs. Cp* ligands in mixed sandwich complexes of the type [U(L)(C₈H₆{SiH₃-1,4}₂)] (L = Cp* or (κ³-Tp^Me2)). On heating at 80 °C, 1 reacts with excess MeNC to yield [U(C₈H₆{SiⁱPr₃-1,4}₂)(κ²-dmpz)₂(η¹-CNMe)] 3. The structures of 1–3 have been determined by single crystal X-ray diffraction.