Hexaaquacobalt(II) and hexaaquacadmium(II) 4-nitro-2,3,5,6-tetraoxopyridinates [M(H2O)6](C5HN2O6)2 · 2H2O (M = Co and Cd): Synthesis, structures, and properties

The complexes [Cd(H₂O)₆](C₅HN₂O₆)₂ · 2H₂O (I) and [Co(H₂O)₆](C₅HN₂O₆)₂ · 2H₂O (II) were obtained in the crystalline state by reactions of cobalt chloride and cadmium chloride with ammonium 4-nitro-2,3,5,6-tetraoxopyridinate, (NH₄)₂ · (C₅HO₆N₂)₂. Their cocrystallization gave the heterometallic complex [Cd_0.32Co_0.68(H₂O)₆](C₅HN₂O₆)₂ · 2H₂O (III). The crystal and molecular structures of complexes I-III were determined by X-ray diffraction. It was demonstrated that the complexation reactions occur by replacement of two ammonium cations 4-nitro-2,3,5,6-tetraoxopyridinate by the complex cations [M(H₂O)₆]²⁺. The tetraoxopyridinate anions and the complex cations are hydrogen-bonded through the coordinated and crystallization water molecules as well as through the O atoms of the organic anion. The thermolysis of complexes I and II was examined by TGA.     

Synthesis and Crystal Structure of [Ni(H2O)6][Ni(H2O)2(C4H2O4)]·4H2O

Reaction of a freshly prepared Ni(OH)_{2?2 x} (CO₃) _x ·yH₂O with maleic acid in H₂O at room temperature afforded [Ni(H₂O)₆][Ni(H₂O)₂(C₄H₂O₄)]·4H₂O, which consists of [Ni(H₂O)₆]²⁺ cations, [Ni(H₂O)₂(C₄H₂O₄)]^2? anions and lattice H₂O molecules. Ni atoms in cations are octahedrally coordinated and Ni atoms in anions are each octahedrally coordinated by bidentate chelating maleato ligands and two water molecules at trans positions. Cations and anions are interlinked by hydrogen bonds to form 1D chains, which are hexagonally arranged and connected by the lattice water molecules. When heated in a flowing argon stream, the compound decomposes, with complete dehydration being followed by dissociation of nickel maleate into NiO and maleic anhydride.     

Synthesis and crystal structure of a novel tartrate copper(II) two-dimensional coordination polymer: {[Cu2(C4H4O6)2(H2O)2]·4H2O}∞

A new 2D coordination polymer, {[Cu₂(C₄H₄O₆)₂(H₂O)₂]·4H₂O}_∞ has been synthesized by the hydrothermal method and characterized by X-ray single crystal diffraction. Every copper(II) atom adopts a distorted octahedral geometry and coordinates with six oxygen atoms from one water molecule and three tartrate acid ions. The two tartrate acid ions have different coordination modes, one provides four oxygen atoms to coordinate with Cu(II) and another coordinates with all six oxygen atoms. Such a coordination mode generates a two-dimensional coordination polymer. In the solid state, the title compound forms a 3D network structure through hydrogen bonds.     

New 1D and 2D metal oxygen connectivities in Cu(II) succinato and glutarato coordination polymers: [Cu3(H2O)2(OH)2(C4H4O4)2] · 4H2O, [Cu4(H2O)2(OH)4(C4H4O4)2] · 5H2O and [Cu5(OH)6(C5H6O4)2] · 4H2O

Two Cu(II) hydroxo succinates [Cu₃(H₂O)₂(OH)₂(C₄H₄O₄)₂]?·?4H₂O (1) and [Cu₄(H₂O)₂(OH)₄(C₄H₄O₄)₂]?·?5H₂O (2) and one Cu(II) hydroxo glutarate [Cu₅(OH)₆(C₅H₆O₄)₂]?·?4H₂O (3) have been prepared and structurally characterized by single crystal X-ray diffraction methods. They feature 1D and 2D copper oxygen connectivity of elongated {CuO₆} octahedra in “4?+?1?+?1” and “4?+?2” coordination geometries. Within 1, linear trimers of three edge-sharing {CuO₆} octahedra are connected into copper oxygen chains, which are bridged by the anti conformational succinate anions to generate 2D layers with mono terminally coordinating gauche succinate anions on both sides. The layers are assembled into a 3D framework by interlayer hydrogen bonds with lattice H₂O molecules distributed in channels. Different from 1, the principal building units in 2 are linear tetramers of four edge-sharing {CuO₆} octahedra. The tetramers are condensed into copper oxygen chains and the succinate anions interlink them into a 3D framework with triangular channels filled by lattice H₂O molecules. The {CuO₆} octahedra in 3 are edge-shared to form unprecedented 2D inorganic layers with mono terminally coordinating glutarate anions on both sides. Interlayer hydrogen bonding interactions are responsible for supramolecular assembly of the layers into a 3D framework with lattice H₂O molecules in the channels. The inorganic layers in 3 can be described as hexagonal close packing of oxygen atoms with the Cu atoms in the octahedral cavities. The title compounds were further characterized by elemental analyses, IR spectra and thermal analyses.     

Syntheses and crystal structures of two Cd(II) coordination polymers: one-dimensional chain [Cd(C4H6N2)2(C4H2O4)(H2O)2] n and two-dimensional sheet [Cd(C4H6N2)(H2O)(C4H4O4)] n · n H2O

Two new Cd(II) coordination polymers, [Cd(C₄H₆N₂)₂(C₄H₂O₄)(H₂O)₂] _n (1) (where C₄H₆N₂?=?2-methylimidazole, C₄H₂O₄?=?fumarate), and [Cd(C₄H₆N₂)(H₂O)(C₄H₄O₄)] _n ?·?nH₂O (2), (where C₄H₄O₄?=?succinates), have been prepared and structurally characterized by single crystal X-ray diffraction. Complex 1 crystallizes in the triclinic space group P 1 in a one-dimensional chain structure, in which carboxy is monodentate; a three-dimensional supermolecular network structure was formed through hydrogen bonding. In complex 2, the coordination geometry of the Cd atoms is a pentagonal bipyramid, and a two-dimensional sheet is formed though carboxyl group bridging. In 1 and 2, IR spectra indicate the presence of bridging carboxyl groups, confirmed by structure analyses.     

Synthesis and Crystal Structure of (C6N3H18)2Ti4O4(C2O4)7·4H2O

The title compound (C6N3H18)2Ti4O4(C2O4)7(4H2O 1 (C13H22N3O18Ti2, Mr = 604.14) was synthesized by the reaction of Ti(SO4)2, H2C2O4(2H2O and N-(2-ammonioethyl)- piperazinium (AEPP) in aqueous solution. The single-crystal X-ray analysis has revealed that 1 crystallizes in the triclinic system, space group Pī with a = 9.1437(6), b = 11.4991(10), c = 11.6975(8)A, α = 96.2915(18), β = 107.998(3), γ = 104.276(4)°, V = 1110.35(14)A3, Z = 2, Dc = 1.807 g/cm3, F(000) = 618, μ = 0.815 mm－1, the final R = 0.0463 and wR = 0.1264 for 3718 observed reflections with I > 2σ(I). X-ray crystal-structure analysis suggests that compound 1 consists of [Ti4O4(C2O4)7]6－ anion and two protonated N-(2-ammonioethyl)piperazinium cations. The anions are linked into an infinite chain through Ti4O4(C2O4)8 by sharing the oxalates as bridging ligands.     

Synthesis,structure, and Mössbauer study of [Fe(H2O)(2)(C(9)O(6)H4)].H2O: a two-dimensional iron(II) trimellitate (MIL-67)

The two-dimensional (2D) iron trimellitate [Fe(H(2)O)(2)(C(9)O(6)H(4))].H(2)O, labeled MIL-67, has been obtained under hydrothermal conditions (473 K, 48 h). In the 2D structure of MIL-67, the Fe(2+) ions display two different octahedral environments: [FeO(4)(H(2)O)(2)] and [FeO(2)(H(2)O)(4)]. These octahedra share an apical water molecule to form infinite chains. The chains are linked by partly deprotonated C(9)O(6)H(4)(2-) anions to give hybrid organic-inorganic layers; the remaining acidic-CO(2)H group is dangling in the interlayer space. Below 8(1) K, MIL-67 displays a canted antiferromagnetic behavior, according to analyses via magnetic measurements and M?ssbauer spectroscopy. Crystal data for MIL-67 are as follows: triclinic; space group P1 (No. 2), with a = 6.9671(2) A, b = 7.3089(3) A, c = 12.5097(3) A, alpha = 78.758(1) degrees, beta = 89.542(2) degrees, and gamma = 65.197(1) degrees; volume V = 565.21(3) A(3); and Z = 2.     

Syntheses and structures of p-HOOCC6F4COOH · H2O (H2L · H2O) and luminescent coordination polymers [Tb2(H2O)4(L)3 · 2H2O] n and Tb2(Phen)2(L)3 · 2H2O

Compounds p-HOOCC₆F₄COOH · H₂O (H₂L · H₂O), [Tb₂(H₂O)₄(L)₃ · 2H₂O] _n (I), and Tb₂(Phen)₂(L)₃ · 2H₂O (II) are synthesized. According to the X-ray structure analysis data, the crystal structure of H₂L · H₂O is built of centrosymmetric molecules H₂L and molecules of water of crystallization. The crystal structure of compound I is built of layers of coordination 2D polymer [Tb₂(H₂O)₄(L)₃] _n and molecules of water of crystallization. The ligands are the L^2? anions performing both the tetradentate bridging and pentadentate bridging-chelating functions. The coordination polyhedron TbO₉ is a distorted three-capped trigonal prism. Acid H₂L manifests photoluminescence in the UV region (??_max = 368 nm). Compounds I and II have the green luminescence characteristic of the Tb³⁺ ions, and the band with ??_max = 545 nm (transition ⁵ D ₄?? ⁷ F ₅) is maximum in intensity. The photoluminescence intensity of compound II is higher than that for compound I.     

An analysis of the vibrational frequencies and amplitudes of the H5O+2 ion in H4SiW12O40·6H2O (TSA·6H2O) and H3PW12O40·6H2O (TPA·6H2O)

The infrared, Raman and inelastic neutron scattering (INS) spectra of TSA·6H₂O and TPA·6H₂O are in agreement with those expected for the presence of H₅O⁺₂ ions. Force fields for different assignment schemes are compared with the observed vibrational frequencies and the INS spectral profile. All but two schemes are eliminated. Whilst low-resolution INS spectroscopy cannot distinguish between these two schemes, the orientations of the vibrational ellipsoids for one scheme are in better agreement with those reported from low-temperature crystallographic studies of the H₅O⁺₂ ion.     

Synthesis and structure of two molybdovanadates containing coordinatively bound oxalato ligands: (NH4)6[Mo6V2O24(C2O4)2]·6H2O and (NH4)4[H2Mo2V2O12(C2O4)2]·2H2O

The compounds (NH₄)₆[Mo₆V₂O₂₄(C₂O₄)₂]·6H₂O (I) and (NH₄)₄[H₂Mo₂V₂O₁₂(C₂O₄)₂]·2H₂O (II) have been prepared from molybdenum(VI) oxide and ammonium vanadate in aqueous solution through the addition of ammonium oxalate, and their structures determined by X-ray structure analysis. Whereas the molybdovanadate anion [Mo₆V₂O₂₄(C₂O₄)₂]⁶⁻ found in (I) consists of six MoO₆ and two VO₆ edge-sharing octahedra of the γ-[Mo₈O₂₆]⁴⁻ type structure, the tetranuclear anion [H₂Mo₂V₂O₁₂(C₂O₄)₂]⁴⁻ of (II) adopts the structure with a M₄O₁₆ core. Both complexes contain bidentate oxalato ligands bonded to the vanadium ions. In both crystal structures the molybdovanadate anions are mutually hydrogen bonded by ammonium ions and water molecules.     

Synthesis and crystal structure of KBi(C6H4O7) · 3.5H2O

A novel compound, KBi(C₆H₄O₇) · 3.5H₂O (I), has been synthesized in the Bi(NO₃)₂-K₃(HCit) system (HCit^3? is an anion of citric acid C₆H₈O₇) at a component ratio (n) of 8 in a water-glycerol mixture, and its crystal structure has been determined. The crystals are unstable in air. The crystals are triclinic: a = 7.462 Å, b = 10.064 Å, c = 17.582 Å, α = 100.27°, β = 99.31°, γ = 105.48°, V = 1221.2 ų, Z = 2, space group $P\bar 1$ . In the structure of I, asymmetric binuclear fragments [Bi₂(Cit^4?)₂(H₂O)₂]^2? are linked through inversion centers into polymeric chain anions. Ions K⁺ and crystal water molecules are arranged in channels between the chains. The Bi(1)...Bi(2) distances in the binuclear fragment are 4.62 Å, and the Bi(1)...Bi(1) and Bi(2)...Bi(2) distances between bismuth atoms in the chain are 5.83 and 5.95 Å, respectively. The chains are linked through bridging oxygen atoms of the ligands Cit to form layers. In the centrosymmetric four-membered chelate ring Bi₂O₂ formed through Bi-O(Cit) bonds, the distances Bi(1)-Bi(1) are equal to 4.55 Å, and Bi(1)-O are 2.66 and 2.84 Å. The Bi-O bond lengths in I are in the range 2.12–3.16 Å. The Cit ligands act as hexadentate chelating/bridging ligands.     

Synthesis and characterization of cobalt(II) and manganese(II) xylaratogermanates: The molecular and crystal structures of the [M(H2O)6][Ge(μ3-L)2{M(H2O)2}2] · 4H2O · nCH3CN Complexes (M = Co, n = 0; M = Mn, n = 1)

A synthetic procedure was developed, and heteropolynuclear coordination compounds—the products of the interaction of germanium tetrachloride with xylaric (trihydroxyglutaric) acid HOOC-CH(OH)-CH(OH)-CH(OH)-COOH (H₅L) and the acetates of the 3d metals Mn(II) and Co(II)—were prepared. The compounds were characterized by elemental analysis, thermogravimetry, and IR spectroscopy. The X-ray diffraction analysis of the [M(H₂O)₆][Ge(μ₃-L)₂{M(H₂O)₂}₂] · 4H₂O · nCH₃CN complexes, where M = Co, n = 0 (I) and M = Mn, n = 1 (II), was performed. The crystals of I are monoclinic, a = 10.752(2) Å, b = 11.830(2) Å, and c = 10.772(2) Å, β = 94.741(3)°, V = 1365.4(5) ų, Z = 2, space group P2₁/n, R1 = 0.0309 for 3200 reflections with I > 2σ(I). The crystals of II are triclinic, a = 9.5330(17) Å, b = 9.7415(17) Å, and c = 10.3935(18) Å, α = 115.024(2)°, β = 97.580(3)°, γ = 111.535(3)°, V = 764.9(2)ų, Z = 1, space group $P\bar 1$ , R1 = 0.0621 for 3028 reflections with I > 2σ(I). The bimetallic anions [Ge(μ₃-L)₂{M(H₂O)₂}₂]^2?, the cations [M(H₂O)₆]²⁺, and crystal water molecules form the basis of compounds I and II (the acetonitrile molecule is also a constituent of compound II). In the centrally symmetrical trinuclear complex anion, the Ge(1) atom is bound to two M(1) atoms through two completely deprotonated bridging ligands. The Ge(1) atom is coordinated to the six alcohol oxygen atoms of two ligands L^5? at the apexes of a distorted octahedron (the average Ge(1)-O distances in I and II are 1.8858(14) and 1.892(3)Å, respectively). The coordination polyhedron of the M(1) atom in the complex anion is a strongly distorted octahedron. The base of the coordination polyhedron is formed by the two bridging alcohol oxygen atoms (the average M(1)-O distances in I and II are 2.1756(14) and 2.255(3) Å, respectively) of two L^5? ligands and by the oxygen atoms of two water molecules (the average M(1)-O distances in I and II are 2.0693(17) and 2.175(4) Å, respectively). In the centrally symmetrical complex cation, the coordination polyhedron of the M(2) atom is a somewhat distorted octahedron. The M(2)-O(H₂O) bond lengths in I and II vary in the ranges of 2.0137(17)-2.1555(17) and 2.140(5)-2.172(4) Å, respectively (the average lengths are 2.0375(17) and 2.166(4) Å, respectively). The cations and anions are joined by a branched system of hydrogen bonds.     

An infrared and raman spectroscopic study of pyrazinecadmium (II) tetracyanometalate (II) Benzene (1/1) clathrates: Cd(C4H4N2)Cd(CN)4⁗C6H6 and Cd(C4H4N2)Hg(CN)4⁗C6H6

Two new benzene clathrates of the form Cd(Pyrazine)M(CN)₄C₆H₆, where M = Cd or Hg, have been prepared and their infrared and Raman spectra are reported.     

Tetranuclear bismuth complexes Bi4(O)2(O2CC6H2F3-3,4,5)8 · 2C6H6 and Bi4(O)2(O2CC6H2F3-3,4,5)8 · 2C6H4Me2-1,4: Synthesis and structures

X-ray diffraction study of tetranuclear organobismuth complexes Bi₄(O)₂(O₂CC₆H₂F₃-3,4,5)₈ · 2⁶-C₆H₆ and Bi₄(O)₂(O₂CC₆H₂F₃-3,4,5)₈ · 2(C₆H₄Me₂-1,4) revealed four Bi atoms connected through the bridging carboxylate ligands and the O atoms. The coordination sphere of the terminal Bi atoms includes the chelate carboxylate ligand and the 6-arene molecule. The bridging O atoms are tricoordinated, the distances between the terminal Bi atom and the center of benzene molecule (1,4-dimethylbenzene) are 3.024 Å(3.131 Å).Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 1, 2005, pp. 4–11.Original Russian Text Copyright © 2005 by Sharutin, Egorova, Sharutina, Ivanenko, Adonin, Starichenko, Pushilin, Gerasimenko.     

Thermal decomposition and kinetic data of Cd(BF4)2·6H2O

The thermal dehydration and decomposition of Cd(BF₄)₂·6H₂O were studied by means of DTA, TG, DSC and X-ray diffraction methods and the end products of the thermal decomposition were identified. The results of thermal analysis show that the compound is fused first, then it is dehydrated until Cd(BF₄)₂·3H₂O is obtained, which has not been described in the literature so far. The enthalpy of phase transition is H _ph.tr.=115.6 kJ mol^–1 Separation of the compound is difficult since it is highly hygroscopic. Then, dehydration and decomposition take place simultaneously until CdF₂ is obtained which is proved by X-ray diffraction. On further increasing the temperature, CdF₂ is oxidized to CdO and the characteristic curve assumes a linear character.Based on TG data, kinetic analyses were carried out separately for both parts of the curve: first until formation of the trihydrate and then — until formation of CdF₂. The formal kinetic parameters are as follows:for the first phase:E ^*=45.3 kJ mol^–1; rate equationF=^2/3; correlation coefficient 0.9858 for the second phase:E ^*=230.1 kJ mol^–1; rate equationF=(1–)^2/3[1-(1–)^1/3]^–1; correlation coefficient 0.9982.     

Syntheses and Crystal Structures of Two Cyano-bridged Bimetallic Complexes [Ce(DMSO)4(H2O)3Fe(CN)6]·H2O and [La(DMSO)4(H2O)3Co(CN)6]·H2O (DMSO = Dimethylsulfoxide)

Two new bimetallic cyano-bridged complexes [Ce(DMSO)4(H2O)3Fe(CN)6]·H2O 1 and [La(DMSO)4(H2O)3Co(CN)6]·H2O 2 have been prepared by the ball milling reaction method and structurally characterized by X-ray single-crystal structure analyses. Crystallographic data for 1:C14H32CeFeN6O8S4, Mr = 736.67, monoclinic, space group P21/n, a = 14.952(1), b =13.7276(9), c = 15.392(1) (A), β = 108.288(1)°, V = 2999.6(4) (A)3, Z = 4, Dc= 1.631 g/cm3,μ =2.304 mm-1, F(000) = 1480, R = 0.0593 and wR = 0.1611; and those for 2: C14H32CoLaN6O8S4,Mr=738.54, monoclinic, space group P21/n, a = 14.945(3), b = 13.731(3), c = 15.300(3) (A), β=107.806(1)°, V= 2989.3(11) (A)3, Z = 4, Dc = 1.641 g/cm3,μ = 2.288 mm-1, F(000) = 1480, R =0.0383 and wR = 0.1132. In both complexes the lanthanide ion is eight-coordinated in a square antiprism arrangement, and the Fe(Ⅲ) or Co(Ⅲ) ion in a nearly regular octahedral environment.The [LnM(CN)6(DMSO)4(H2O)3]·H2O (Ln = Ce and M = Fe for 1; Ln = La and M = Co for 2)species are held together via hydrogen bonds by coordinated water molecules, lattice water molecules and nitrogen atoms of cyanide groups to form a three-dimensional framework.     

Thermal and calorimetric studies of M(IO3)2·6H2O and M(IO3)2·6D2O forM 2+=Ca2+ and Sr2+

Thermal and calorimetric studies were carried out on M(IO₃)₂·6H₂O and M(IO₃)₂·6D₂O forM ²⁺=Ca²⁺ and Sr²⁺, using DTA and DSC methods. The thermal behaviour of the ordinary and deuterated hydrates is outlined and the differences observed between them are discussed. The enthalpies of the phase transitions were determined. The H _f ^o for Ca(IO₃)₂·6H₂O, Ca(IO₃)₂·6H₂O(D₂O) and Sr(IO₃)₂·6H₂O(D₂O) were calculated from the H _deh data and comments are made on the isotope effect observed.

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Zusammenfassung Mittels DTA- und DSC-Methoden wurden Me(IO₃)₂·6H₂O und Me(IO₃)₂·6D₂O (mitMe ²⁺=Ca²⁺ und Sr²⁺) thermisch und kalorimetrisch untersucht. Es wird ein Überblick über das thermische Verhalten ordentlicher und deuterierter Hydrate gegeben, in dem auch die Unterschiede zwischen beiden diskutiert werden. Die Enthalpien der untersuchten Phasenumwandlungen wurden bestimmt. Aus den Daten für H_deh wurde H_f von Ca(IO₃)₂·6H₂O, Ca(IO₃)₂H₂O(D₂O) und Sr(IO₃)₂·6H₂O(D₂O) berechnet und Bemerkungen zum beobachteten Isotopeneffektes gemacht.