IR and Raman spectra of two layered aluminium phosphates Co(en)3Al3P4O16 · 3H2O and [NH4]3[Co(NH3)6]3[Al2(PO4)4]2 · 2H2O

The FT IR and FT Raman spectra of Co(en)₃Al₃P₄O₁₆ · 3H₂O (compound I) and [NH₄]₃[Co(NH₃)₆]₃[Al₂(PO₄)₄]₂ · 2H₂O (compound II) are recorded and analysed based on the vibrations of Co(en)₃³⁺, Co(NH₃)₆³⁺, NH₄⁺, Al---O---P, PO₃, PO₂ and H₂O. The observed splitting of bands indicate that the site symmetry and correlation field effects are appreciable in both the compounds. In compound I, the overtone of CH₂ deformation Fermi resonates with its symmetric stretching vibration. The NH₄ ion in compound II is not free to rotate in the crystalline lattice. Hydrogen bonding of different groups is also discussed.     

Vibrational spectra of α-Ge(HPO4)2·H2O compound

We have measured Raman and infrared spectra of α-Ge(HPO₄)₂·H₂O compound at room temperature. The analysis of vibrational modes indicated the presence of two non-equivalent HPO₄²⁻ units in agreement with ³¹P nuclear magnetic resonance measurements. A tentative assignment of all the observed modes is proposed based on the previous works reported for other hydrogenphosphate-based compounds.     

Reaction of (±)-1,1′-binaphthyl-2,2′-diyl hydrogen phosphate {(±)-phosH} with copper(II), cobalt(II) and iron(II) compounds; Identification by x-ray diffraction of [Co(CH3OH)4(H2O)2][(+)-phos][(−)-phos]. 2CH3OH·H2O

[Cu₂(μO₂CCH₃)₄(H₂O)₂], [CuCO₃·Cu(OH)₂], [CoSO₄·7H₂O], [Co((+)-tartrate)], and [FeSO₄·7H₂O] react with excess racemic (±)- 1,1′-binaphthyl-2,2′-diyl hydrogen phosphate {(±)-PhosH} to give mononuclear Cu^II, Co^II and Fe^II products. The cobalt product, [Co(CH₃OH)₄(H₂O)₂]((+)-Phos)((−)-Phos) ·2CH₃OH·H₂O (7), has been identified by X-ray diffraction. The high-spin, octahedral Co^II atom is ligated by four equatorial methanol molecules and two axial water molecules. A (+)- and a (−)-Phos⁻ ion are associated with each molecule of the complex but are not coordinated to the metal centre. For the other Co^II, Cu^II and Fe^II samples of similar formulation to (7) it is also thought that the Phos⁻ ions are not bonded directly to the metal. When some of the Cu^II and Co^II samples are heated under high vacuum there is evidence that the Phos⁻ ions are coordinated directly to the metals in the products.     

Polarized emission from Ba[Pt(CN)4]·4H2O single crystals under high pressure

The emission spectra of single crystal Ba[Pt(CN)₄]·4H₂O were measured from 0 to 23 kbar for the two electronic transitions which are polarized with Ec and E;c. They exhibit a red-shift of −280 cm⁻¹/kbar and −195 cm⁻¹/kbar, respectively. 3he red-shift is explained by a pressure induced reduction of the intermolecular separation R in the direction of the linear chain (c-axis). The emission energies obtained at different pressures are compared with the results under normal conditions for various Me[Pt(CN)₄]·xH₂O salts (with different R). The close analogy between these two methods of R-reduction supports the importance of one-dimensional interaction for the interpretation of electronic properties of the tetracyano-platinates. Ba[Pt(CN)₄]·4H₂O shows a structural transition region in the pressure range studied here.     

The crystal structure of Hg2FeF5(OH)2 · H2O

The new compound Hg₂FeF₅(OH)₂ · H₂O was prepared by evaporation of an aqueous 40% HF solution containing HgO and FeF₃ in the stoichiometric ratio. The material is orthorhombic, space group Cmmm, with a = 7.505(1) Å, b = 11.823(3) Å, c = 3.941(2)Å, and Z = 2. The crystal structure was determined from single crystal intensity data obtained by means of an automated four-circle diffractometer and refined to the conventional values R = 0.0621 and R_w = 0.0566 for 451 observed reflections. The structure is characterized by infinite straight chains of FeF₆ octahedra sharing trans F atoms in the direction [001]. These chains are linked by rutile-type chains of HgF₄(OH)₂ octahedra also running along [001]. Water molecules are statistically distributed on half of the 4i positions; they are off-centered in the channels parallel to [001] allowing O---H ··· F bonding. The structure is compared to that of HgFeF₅ · 2H₂O and to that of the hexagonal tungsten bronze.     

A novel 2D layer structure constructed from sandwich-type transition metal substituted tungstates and nickel coordination fragments: {[Ni(enMe)2]2[Ni(enMe)2(H2O)]2[As2W18Ni4(enMe)2O68]}·2H3O·2H2O

A novel polyoxometalate {[Ni(enMe)₂]₂[Ni(enMe)₂(H₂O)]₂[As₂W₁₈Ni₄(enMe)₂O₆₈]}·2H₃O·2H₂O (1) (enMe = 1,2-propylenediamine) has been synthesized and characterized, which is the first high-dimensional structure constructed from sandwich-type transition metal substituted tungstates and transition metal coordination groups.     

Single-crystal characterization of Co7(OH)6(H2O)3(C4H4O4)47H2O; A new cobalt succinate identified through high-throughput synthesis

A new form of cobalt succinate has been discovered using high-throughput methods and its structure was solved by single crystal X-ray diffraction. Co₇(C₄H₄O₄)₄(OH)₆(H₂O)₃7H₂O crystallizes in the monoclinic space group P2₁/c with cell parameters: a=7.888(2) Å, b=19.082(6) Å, c=23.630(7) Å, β=91.700(5)°, V=3555(2) Å³, R₁=0.0469. This complex structure, containing 55 crystallographically distinct non-hydrogen atoms, is compared to the previously reported nickel phase, characterized using ab initio structure solution from synchrotron powder diffraction data.     

A new compound of uranium VI with formamide UO3 · HCONH2 · 0.5H2O

A new compound of uranium VI has been prepared by thermolysis of uranyl formate diammoniate in an ammonia environment. Chemical analysis and infrared spectrophotometry favor the formula UO₃ · HCONH · 0.5H₂O. X-Ray analysis is in agreement with an orthorhombic lattice having parameters a = 6.88 Å, b = 23.46 Å, c = 24.67 Å. The photoluminescence spectra of this compound are presented.     

Cation → anion energy transfer in [Cr(en)3][Cr(CN)6]·2H2O

Energy transfer from Cr(en)₃³⁺ to Cr(CN)₆³⁻ has been observed in [Cr(en)₃][Cr(CN)₆]·2H₂O with an efficiency close to unity. The ⁴T₂ & rt arrow-wavy; ²E intersystem crossing efficiency in Cr(en)₃³⁺ is also unity.     

Système ternaire : H2O–Fe(NO3)3–Co(NO3)2 isotherme : 30 °C

Ternary system: H₂O–Fe(NO₃)₃–Co(NO₃)₂ isotherm: 30 °C. The H₂O–Co(NO₃)₂ binary system has been investigated in the –28 to 50 °C temperature range. The solid–liquid equilibria of the ternary system H₂O–Fe(NO₃)₃–Co(NO₃)₂ were studied by using a synthetic method based on conductivity measurements. One isotherm is established at 30 °C, and the stable solid phases that appear are iron nitrate nonahydrate: Fe(NO₃)₃·9 H₂O, iron nitrate hexahydrate: Fe(NO₃)₃·6 H₂O, cobalt nitrate hexahydrate: Co(NO₃)₂·6 H₂O, and cobalt nitrate trihydrate: Co(NO₃)₂·3 H₂O. To cite this article: B. El Goundali et M. Kaddami, C. R. Chimie 9 (2006).     

Calorimetric study and thermal analysis of [Gd4/3Y2/3(Gly)6(H2O)4](ClO4)6·5H2O and [ErY(Gly)6(H2O)4](ClO4)6·5H2O (Gly: glycin)

Two solid-state coordination compounds of rare earth metals with glycin, [Gd_4/3Y_2/3(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O and [ErY(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O were synthesized. The low-temperature heat capacities of the two coordination compounds were measured with an adiabatic calorimeter over the temperature range from 78 to 376 K. [Gd_4/3Y_2/3(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O melted at 342.90 K, while [ErY(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O melted at 328.79 K. The molar enthalpy and entropy of fusion for the two coordination compounds were determined to be 18.48 kJ mol⁻¹ and 53.9 J K⁻¹ mol⁻¹ for [Gd_4/3Y_2/3(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O, 1.82 kJ mol⁻¹ and 5.5 J K⁻¹ mol⁻¹ for [ErY(Gly)₆(H₂O)₄](ClO₄)₆·5H₂O, respectively. Thermal decompositions of the two coordination compounds were studied through the thermogravimetry (TG). Possible mechanisms of the decompositions are discussed.     

Reversible photomagnetic properties of the molecular compound [{Cu(bipy)2}2{Mo(CN)8}]·9H2O·CH3OH

The optical and photomagnetic properties of [{Cu^II(bipy)₂}₂{Mo^IV(CN)₈}]·9H₂O·CH₃OH (1) have been reinvestigated. A comparison between spectra in solution and in the solid state revealed the presence of an intervalence band (or Metal–Metal Charge Transfer, hereafter noted MMCT) at 570 nm. The photomagnetic properties have been performed in a Superconducting QUantum Interference Device at 10 K with irradiation in the range of the MMCT: 488 nm, 520 nm and 647 nm at 10 K. An important increase of the magnetic signal has been measured after 1 h of irradiation at 488 nm, whereas a weaker increase has been obtained for the irradiation at 520 nm in the same conditions. Moreover, after an excitation at 488 nm, an irradiation at 647 nm has induced a decrease of the magnetic moment, which corresponds to a partial deexcitation. The complete characterization of the photoproduct has been realised after an irradiation of 4 h at 488 nm. The photomagnetic properties have shown an increase of the paramagnetism of 1 at low temperature. After a thermal heating at 300 K, the material goes back to its initial state before irradiation. It is the first time that a fully reversible photomagnetic behaviour for the compound [{Cu^II(bipy)₂}₂{Mo^IV(CN)₈}]·9H₂O·CH₃OH has been described. The observed properties have been discussed in terms of an electron transfer mechanism Mo → Cu.     

Compounds containing layers of composition [(SbF)XO4] (X = P, As). Crystal structures of Na(SbF)PO4 · 1.5H2O, Na(SbF)AsO4, NH4(SbF)PO4 · H2O, and NH4(SbF)AsO4 · 3H2O

The title compounds have been prepared in water by reaction of SbF₃ with dihydrogen phosphates or arsenates and characterized by single crystal X-ray work, IR, Raman, and Mössbauer spectroscopy. They have identical layer structures. Layers of composition [(SbF)XO₄]⁻ (X = P, As) were formed by sharing four corners between XO₄ tetrahedra and SbFO₄ pseudooctahedra. The lengths of the terminal Sb---F bond (with the lone pair in a trans-position) and the Sb---O bonds are 192 and 219 pm, respectively. The stacking of the layers and the interlayer distance depend on the cations and the number of intercalated water molecules. In Na(SbF)AsO₄ the Na⁺ ion is coordinated by only two oxygen atoms within 300 pm. Crystal data: Na(SbF)PO₄ · 5H₂O, monoclinic, P2₁/m, A = 656.2(5), B = 654.1(5), C = 867.9(3) pm, β = 92.43(1)°, 889 reflections, 81 parameters, R = 0.044, R_w = 0.046. NH₄(SbF)PO₄ · H₂O, tetragonal, I4/m, A = 656.6(3), C = 1439.8(5) pm, 680 reflections, 31 parameters, R = 0.023, R_w = 0.021. Na(SbF)AsO₄, tetragonal, P4/ncc, A = 671.8(1), C = 1756.4(4) pm, 1056 reflections, 28 parameters, R = 0.052, R_w = 0.065. NH₄(SbF)AsO₄ · 3H₂O, tetragonal, P4/ncc, A = 683.8(2), C = 1873.0(7) pm, 1194 reflections, 30 parameters, R = 0.042, R_w = 0.050.     

Synthesis, XRD structure and properties of diaqua(p-toluidine-N,N-di-3-propionato)copper(II) dihydrate [Cu(p-Tdp)(H2O)2]·2H2O

The copper(II) complex [Cu(p-Tdp)(H₂O)₂]·2H₂O, where p-Tdp is the anion of p-toluidine-N,N-di-3-propionic acid (or N,N-di(2-carboxyethyl)-p-toluidine), has been synthesized and characterized by X-ray diffraction. Three crystallographically independent [Cu(p-Tdp)(H₂O)₂] molecules have a similar structure. The Cu atoms have a square pyramidal environment (4+1) with a small trigonal bipyramidal distortion. The ortho-H atom of the benzene ring blocks up the sixth coordination position of the Cu polyhedron. The basal plane is formed by the donor atoms of the tridentate ligand and by the water molecule (average bond length Cu---N 2.03, Cu---O 1.93, Cu---O_w 2.00 Å), the apex is occupied by another water molecule (Cu---O_w 2.27 Å). The Cu atoms are located 0.20–0.30 Å out of the mean planes of the four basal atoms towards the apical O_w atom. The IR and electronic absorption spectra of p-Tdp and the title compound have been described. UV–Vis reflectance spectra shows that the complex has the same square pyramidal geometry in the crystal state and in solution. The protonation constants of the ligand log K₁=6.87(2), log K₂=3.75(2), log K₃=2.57(2) and stability constants log K_CuH(p-Tdp)=2.13(5), log K_Cu(p-Tdp)=6.38(3) were determined by pH-titration at 25.0 °C and I=0.1 M KNO₃.     

Synthesis and crystal structure of KNa3[Fe3O(CH3COO)6(H2O)2]3 [α-P2W17Fe(H2O)O61]·32.5H2O

A complex of the composition KNa₃[Fe₃O(CH₃COO)₆(H₂O)₃]₃ [α-P₂W₁₇Fe(H₂O)O₆₁]·32.5H₂O (I) was obtained by interaction of FeCl₃·6H₂O and phosphotungstate K₁₀[α₂-P₂W₁₇O₆₁]·20H₂O in an acetate buffer with a yield of 52%. Compound I was characterized by single crystal X-ray phase analysis and IR spectroscopy. In the crystal structure, the Na and K cations bind [Fe₃O(CH₃COO)₆(H₂O)₃]⁺ trinuclear cations and [α-P₂W₁₇Fe(H₂O)O₆₁]⁷⁻ heteropolytungstate anions into infinite zigzag chains. Original Russian Text Copyright ? 2005 by N. V. Izarova, M. N. Sokolov, A. V. Virovets, H. G. Platas, and V. P. Fedin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 46, No. 1, pp. 149–155, January–February, 2005.     

Conductivities of the Ternary Systems Y(NO3)3+La(NO3)3+H2O, La(NO3)3+Ce(NO3)3+H2O, La(NO3)3+Nd(NO3)3+H2O and Their Binary Subsystems at Different Temperatures

Electrical conductivities were measured for the ternary systems Y(NO₃)₃+La(NO₃)₃+H₂O, La(NO₃)₃+Ce(NO₃)₃+H₂O, La(NO₃)₃+Nd(NO₃)₃+H₂O, and their binary subsystems Y(NO₃)₃+H₂O, La(NO₃)₃+H₂O, Ce(NO₃)₃+H₂O, and Nd(NO₃)₃+H₂O at (293.15, 298.15 and 308.15) K. The measured conductivities were used to test the generalized Young’s rule and the semi-ideal solution theory. The comparison results show that the generalized Young’s rule and the semi-ideal solution theory can yield good predictions for the conductivities of the ternary electrolyte solutions, implying that the conductivities of aqueous solutions of (1:3 + 1:3) electrolyte mixtures can be well predicted from those of their constituent binary solutions by the simple equations.     

Conservation of [(C2H4NH3)3N]2·(ZrF7)2·H2O layers during the topotactic dehydration of [(C2H4NH3)3N]2·(ZrF7)2·9H2O

Tren amine cations [(C₂H₄NH₃)₃N]³⁺ and zirconate or tantalate anions adopt a ternary symmetry in two hydrates, [H₃tren]₂·(ZrF₇)₂·9H₂O and [H₃tren]₆·(ZrF₇)₂·(TaOF₆)₄·3H₂O, which crystallise in R32 space group with a_H = 8.871 (2) Å, c_H = 38.16 (1) Å and a_H = 8.758 (2) Å, c_H = 30.112 (9) Å, respectively. Similar [H₃tren]₂·(MX₇)₂·H₂O (M = Zr, Ta; X = F, O) sheets are found in both structures; they are separated by a water layer (O_w(2)-O_w(3)) in [H₃tren]₂·(ZrF₇)₂·9H₂O. Dehydration of [H₃tren]₂·(ZrF₇)₂·9H₂O starts at room temperature and ends at 90 °C to give [H₃tren]₂·(ZrF₇)₂·H₂O. [H₃tren]₂·(ZrF₇)₂·H₂O layers remain probably unchanged during this dehydration and the existence of one intermediate [H₃tren]₂·(ZrF₇)₂·3H₂O hydrate is assumed. O_w(1) molecules are tightly hydrogen bonded with -NH₃⁺ groups and decomposition of [H₃tren]₂·(ZrF₇)₂·H₂O occurs from 210 °C to 500 °C to give successively [H₃tren]₂·(ZrF₆)·(Zr₂F₁₂) (285 °C), an intermediate unknown phase (320 °C) and ZrF₄.     

Synthesis, structural characterization and properties of a 3D infinitely extended structural rare earth coordination compound of K3{[Sm(H2O)7]2Na[α-SiW11O39Sm(H2O)4]2} · 14 H2O· 14 H2O

A 3D infinitely extended structural rare earth coordination compound with a formula of K₃{[Sm(H₂O)₇]₂Na[α-SiW₁₁O₃₉Sm(H₂O)₄]₂}·14H₂O has been synthesized by reaction of Sm₂O₃, HClO₄, NaOH with α-K₈SiW₁₁O39·nH₂O, and characterized by IR, UV spectra, ICP, TG-DTA, cyclic voltammetry, variable-temperature magnetic susceptibility and X-ray single-crystal diffraction. X-ray single-crystal diffraction indicates that the title compound crystallizes in a triclinic lattice, Pī space group, with a = 1.2462(3) nm, b = 1.2652(3) nm, c = 1.8420(4) nm, α = 87.45(3)°, β = 79.91(3)°, γ= 82.57(3)°, Z = 1, R₁ = 0.0778, wR₂ = 0.1610. Structural analysis reveals that Sm³⁺(1) coordination cation has incorporated into the vacant site of [α-SiW11O₃₉]⁸⁻ entity, forming the [α- SiW₁₁O₃₉Sm(H₂O)₄]⁵⁻ subunit. The two adjacent [α-SiW₁₁O₃9Sm(H₂O)4]⁵⁻ subunits are combined with each other through two Sm(1)-O-W bridges accompanying the formation of dimmer structural unit [α-SiW₁₁O₃₉Sm(H₂O)₄]₂ ¹⁰⁻ of the title compound. The neighboring dimmer structural units [α-SiW₁₁O₃₉Sm(H₂O)₄]₂ ¹⁰⁻ are linked to form the 1D chainlike structure by means of two Sm³⁺(2) and a Na⁺(1) coordination cations. The K⁺(1) cations connect the 1D packing chains constructing the 2D netlike structure, and adjacent netlike layers are also grafted by K⁺(2) cations to build the novel 3D infinitely extended structure. The result of TG-DTA curves manifests that the decomposition temperature of the title polyanionic framework is 554°C. The cyclic voltammetry measurements show that the title polyanion has the two-step redox processes in aqueous solution with pH = 3.1. Variable temperature magnetic susceptibility indicates the title compound obeys the Cruie-Weiss Law in the higher temperature range from 110 to 300 K, while in the lower temperature range from 2 to 110 K the comparatively strong antiferromagnetism interactions can be observed.     

Metal(II)-promoted hydrolysis of pyridine-2-carbonitrile to pyridine-2-carboxylic acid. The structure of [Cu(pyridine-2-carboxylate)2] · 2H2O

Pyridine-2-carbonitrile (2-CNpy) undergoes Cu(II) or Co(II)-promoted hydrolysis to pyridine-2-carboxamide (piaH) and/or pyridine-2-carboxylic acid (pycH). The pathway of pycH formation depends on the presence of 2-amino-2-hydroxymethyl-1,3-propanediol (AL¹) and on the central atom. In the absence of AL¹, Co(II) or Cu(II) ions mediate piaH formation under mild reaction conditions in the first hydrolytic step. Cu(II) ions assist in piaH transformation to pycH by subsequent reflux. In the presence of AL¹ and Co(II), a Co(II) complex containing pyoxaL¹ (2-(2-pyridinyl)-4,4-bis(hydroxymethyl)-2-oxazoline) is formed in the first stage; subsequent decomposition of pyoxaL¹ under the reflux yields pycH. Under similar conditions, no solid Cu(II) complex with pyoxaL¹ can be isolated, but a Cu(II) complex with coordinated pyc⁻ anions precipitates from the reaction mixture. The synthesis, spectral and magnetic properties of the complexes [Co(H₂O)₂ (piaH)₂]Cl₂, [Co(H₂O)₂(pyc)₂] · 2H₂O, [Cu(H₂O)₂(piaH)₂]Cl₂, [Cu(pyc)₂] and [Cu(pyc)₂] · 2H₂O, including the structure determination of the latter one, are described.     

一个新的夹心型杂多钨酸盐Na6(C5N2H7){[Na(H2O)2]3Co(H2O)5-[Co(H2O)]3(AsW9O33)2}•27H2O的晶体结构及性质

在pH＝7.5的水溶液中, Na₂WO₄•2H₂O, NaAsO₂, CoCl₂•6H₂O与对氨基吡啶反应, 得到了一种新的夹心型杂多钨酸盐Na₆(C₅H₇N₂){[Na(H₂O)₂]₃Co(H₂O)₅[Co(H₂O)]₃(AsW₉O₃₃)₂}•27H₂O单晶, 用X射线单晶衍射法及元素分析确定了其结构, 晶体属三斜晶系, P 空间群, 其晶胞参数为: a＝1.3276(8) nm, b＝1.7581(10) nm, c＝2.4381(14) nm, α＝70.954(9)°, β＝86.663(9)°, γ＝72.885(9)°, V＝5.136(5) nm³, Z＝2, R₁＝0.0608, wR₂＝0.0848 [I＞2σ(I)]. 在{[Na(H₂O)₂]₃Co(H₂O)₅[Co(H₂O)]₃(AsW₉O₃₃)₂}^7－阴离子中, 一个Co^2＋与聚阴离子{[Na(H₂O)₂]₃[Co(H₂O)]₃(AsW₉O₃₃)₂}^9－的一个端基氧共价连接, Co^2＋呈现出5和6两种配位数, 质子化的氨基吡啶正离子作为抗衡离子存在于晶体之中. 对标题化合物进行了IR, UV-Vis, TG-DSC表征. 对该化合物、Na₂WO₄•2H₂O及CoCl₂•6H₂O催化H₂O₂氧化乙醛的活性进行了比较研究, 该化合物的催化活性远优于简单化合物Na₂WO₄•2H₂O和CoCl₂•6H₂O.