Theoretical and experimental study of fullerenol molecules and ions C60(OH)24 ? n(OL)n and C60(OH)24 ? n(OL)nL+ successively substituted by Alkali Metal atoms L (n = 1?24)

The equilibrium geometric parameters and the energetic characteristics of fullerenol molecules and ions C₆₀(OH)_{24 − n} (OL) _n and C₆₀(OH)_{24 − n} (OL) _n L⁺ successively substituted by alkali metal atoms L with the number of substitutions n = 1–24 have been calculated by the density functional theory B3LYP/6-31G* method. For all compounds, the structure of the covalent [C₆₀O₂₄] cage in which the oxygen atoms are bound to the C atoms of the six-membered [C₆] rings of the fullerene cage, six O atoms per [C₆] ring. The lithium derivatives have been considered in most detail. Computations have shown that the first four single substitutions of Li for H in the OH groups attached to the same C₆ ring require very low energy inputs, no more than 1 kcal/mol, and can spontaneously occur under common conditions. The further fifth and sixth single substitutions in the same C₆ ring are endothermic, but the required energy inputs are also modest (on the order of few kcal/mol). The first and second cooperative substitutions of Li for H simultaneously in all four hydroxylated C₆ rings require energy inputs of ∼3 and 11.6 kcal/mol, respectively; in the third and fourth fourfold substitutions, the energies increase by ∼15–16 kcal/mol. The mean partial energy per single substitution of Li for H in this series (n = 1−6) is ∼2 kcal/mol. Calculations have predicted that all C₆₀(OH)_{24 − n} (OLi) _n molecules with intermediated degrees of substitution (n = 1−16) can be obtained under the conditions of relatively low energy inputs (for example, under the conditions of the MALDI experiment) and can exist in the isolated state. For the sodium- and potassium-substituted analogues, the qualitative pattern persists, but the H/Na and H/K substitutions are somewhat more endothermic. The computational results are compared with the MALDI mass spectrum of the [C₆₀(OH) _x (ONa) _y -CH₃COONa) system.     

Synthesis and study of the properties of K2Y1 ? x ? yEuxTby(MoO4)(PO4) and K2Y1 ? x ? yEuxTby(MoO4)(PO4)1?δ(VO4)δ solid solutions

Al synthesized samples are isostructural and crystallize in the orthorhombic symmetry system, space group Ibca. Particles of the final product of ∼200 nm in size have been obtained. The introduction of the vanadate anion into the matrix composition leads to the lowering of the symmetry of the Eu³⁺ environment and to the rise of the defect luminescence at 450–550 nm because of the unit cell distortion. The luminescence of defects in terbium-europium-containing samples is determined by the sample surface area, which decreases on annealing. The τ, W ₀ and γ parameters of the luminescence kinetics of the samples have been determined.     

Structure and luminescence of [Tb0.5(C6NO2H5)3(H2O)2]2n·(H3O)4n(ZnCl5)n(ZnCl4)2n

A novel bimetallic 4f-3d metal-isonicotinic acid inorganic-organic hybrid complex [Tb_0.5(C₆NO₂H₅)₃(H₂O)₂]_2n ·(H₃O)_4n (ZnCl₅) _n (ZnCl₄)_2n (1) is synthesized. It has a one-dimensional polycationic chain-like structure. Photoluminescent investigation reveals that it displays interesting emissions in the violet, blue, green, and yellow regions.     

Ab initio study of the structure and stability of LaCl n(3 ? n)+ complexes (n = 1?8)

The structural and energetic characteristics of LaCl _n ^{(3 − n)+} (n = 1−8) complexes have been calculated by the ab initio MP2 method. Original Russian Text ? V.Yu. Buz’ko, Kh.B. Kushkhov, M.B. Buz’ko, V.T. Panyushkin, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 11, pp. 1899–1905.     

Exchange coupling in alkoxy-polyoxovanadates [VIVnVV6?nO7(OR)12]4?n (n = 4, 3, 2)

The molecular structure and magnetic properties of alkoxy-polyoxovanadates [V^IV _n V^V _6−n O₇(OR)₁₂]⁴⁻ⁿ (n = 4, 3, 2) were studied within the framework of the DFT approach. The equilibrium geometric configurations of all complexes studied in this work are characterized by a distorted octahedral hexavanadate core; the unpaired d-electrons are localized on the metal centers (V^IV). The localized spin density distribution is also retained in the low-temperature crystal structures of the compounds whose magnetic properties are described by the Heisenberg-Dirac-van Vleck exchange spin Hamiltonian. The exchange parameters calculated using the broken symmetry formalism suggest predominance of ferromagnetic coupling between vanadium(IV) ions in the μ-OR bridged dimeric units {V^IVO(OR)V^IV} and in the diagonal pairs {V^IVOV^IV} (n = 4). The results obtained indicate that the magnitude and sign of the exchange parameters in the isostructural dimeric units within the hexavanadate core depend on the total number of unpaired electrons in the system.     

Synthesis, crystal structure and properties of [Nd(C6NO2H5)3(H2O)2]2n · (nH5O2)(nHgCl5)(2nHgCl4) · (nH2O) with unprecedented polycationic chains

A novel inorganic-organic hybrid complex, [Nd [Nd (C₆NO₂H₅)₃(H₂O)₂]_2n · (nH₅O₂)(nHgCl₅)(2nHgCl₄) · (nH₂O)(1), was obtained by hydrothermal reactions and structurally characterized by X-ray diffraction. The unit cell parameters are as follows: a = 9.579(1), b = 21.462(2), c = 15.801(1) ?, β = 102.339(6)^ℴ, V = 3173.5(5) ?³, Z = 4, space group P2₁/c. The crystal structure analysis reveals that the title complex is characteristic of a novel polycationic [Nd(C₆NO₂H₅)₃(H₂O)₂]_2n ⁶ⁿ⁺ one-dimensional chain-like structure. Photoluminescent investigation shows that the title complex displays strong emission in blue region, which is attributed to the intraligand π-π*-transition of nicotinic ligands. Optical absorption spectra of 1 reveal the presence of an optical gap of 3.45 eV. The article is published in the original.     

Spectral and electrochemical study of coordination molecules Cu4OX6L4: 3-Pyridylmethanol and 4-pyridylmethanol Cu4OBrnCl(6−n)(pm)4 complexes

The tetranuclear Cu₄OBr_nCl_(6−n)(pm)₄ complexes, where pm = 3-pyridylmethanol (3-pm), 4-pyridylmethanol (4-pm) and n = 0−6 with trigonal bipyramidal coordination of copper(II) were prepared and their infrared and electronic absorption spectra as well as cyclic voltammograms in nitromethane solutions were measured. The molecules exhibit strong single infrared Cu₄O stretching absorptions between 580 and 530 cm⁻¹ which are in linear correlations with the number of halides, n. Far infrared absorptions assigned to Cu-Br, Cu-Cl, and Cu-N stretching vibrations appear at higher wavenumbers for 3-pm complexes compared with those for 4-pm complex molecules. Two strongly overlapped d–d bands in the region 11300–13100 cm⁻¹ assigned to and e(d _xz, d _yz) → a ₁(d _z ²) transitions in the trigonal bipyramidal coordination of the copper(II) atoms were resolved by Gaussian analysis. Both, 3-pm and 4-pm ligands produce in the complex molecules almost the same ligand field. The maxima of the Gaussian d–d components vary with the parameter n and are for both series of the complexes deviated from linearity, more for the low-energy d–d bands than for high-energy analogues. The electrochemical reduction in nitromethane is significantly less reversible for 4-pm complex molecules compared with that of 3-pm analogues. Formal reduction potentials E′ _c for 3-pm complexes were observed in the range 478 (n = 0)−599 (n = 6) mV. The plot E′ _c vs. n is significantly deviated from linearity. It is suggested that the reducing electrons enter the half-filled d _z ² orbital of the copper(II) atom. The different spectral and electrochemical results obtained for 3-and 4-pm complexes are explained by different structural distortions, bond lengths, and charge distributions produced by halide ligand variations. The results are also discussed with previously reported data on analogous pyridine, 3-methylpyridine and 4-methylpyridine complexes.     

Synthesis and crystal structure of new one-dimensional copper(II) complex [Cu4(En)2(μ1,1-N3)4(μ1,1,1-N3)2(μ1,3-N3)2]n

A new polymer azido-bridged copper(II) complex [Cu₄(En)₂(μ_1,1-N₃)₄(μ_1,1,1-N₃)₂(μ_1,3-N₃)₂] _n (I) (En = ethylenediamine) has been synthesized and crystallography characterized. Complex I shows one-dimensional coordination polymeric structure based on a tetranuclear cluster unit [Cu₄(En)₂(μ_1,1-N₃)₄(μ_1,1,1-N₃)₂(μ_1,3-N₃)₂], in which the azido ions display three different bridging modes.     

Complex potassium yttrium molybdate phosphates K2Y1 ? xEux(MoO4)(PO4)0.9(VO4)0.1: Synthesis and study of luminescent properties

Samples with various dopant contents were obtained using solid-state and sol-gel methods. The resulting single-phase samples have the formula K₂Y_{1 − x} Eu _x (MoO₄)(PO₄)_0.9(VO₄)_0.1 (x = 0, 0.005, 0.01, 0.02, 0.03) and are isostructural with K₂Y(MoO₄)(PO₄). The possibility of formation of complex molybdate vanadates M₂^IM^III(MoO₄)(VO₄). was studied. Unlike their precursor K₂Y(MoO₄)(PO₄), the complex potassium yttrium molybdate phosphates obtained are deliquescent. Their structures contain no water molecules. The absorption and emission spectra of the compounds under study were recorded. In all the spectra, the electric dipole transition ⁵ D ₀−⁷ F ₂ (616 nm) is appreciably more intense than the magnetic dipole transition ⁵ D ₀−⁷ F ₁ (590 nm). This suggests that the coordination environment of the Eu³⁺ ion keeps asymmetric. The excitedstate lifetimes of anhydrous and humidified samples were determined. The average lifetime is the same for all samples (≈1.5 ms), which is due to the stability of their structures.     

EPR study of solid solutions of [Cr(NH3)5Cl]x[Rh(NH3)5Cl]1?x[PdCl4]·nH2O and [Cr(NH3)5Cl]x[Rh(NH3)5Cl]1?x[PtCl4] compounds

In order to determine the features of the structure of double complex salts (DCSs) of [Cr(NH₃)₅Cl]×[MCl₄]·nH₂O, where M = Pd, Pt, n = 0, 1, the DCS solid solutions of palladium and platinum with isostructural DCSs containing the chloropentaammine rhodium cation, [Cr(NH₃)₅Cl] _x [Rh(NH₃)₅Cl]_1−x [MCl₄]·nH₂O, where x = 0.01–0.2, are synthesized and studied by the EPR method. DCSs with the isostructural chloropentaammine rhodium cation are used as a diluter for magneto concentrated systems. It is shown that DCS of platinum and anhydrous DCS of palladium have the identical environment of chromium ions. The EPR spectra of chromium ions for these compounds are described by the following spin Hamiltonian parameters: S = 3/2, g _xx = 1.987, g _yy = 1.987, g _zz = 1.985, D = 1660 Gs, E = 235 Gs. For the palladium complex containing crystalline water, the EPR spectra of chromium ions are described by the parameters: S = 3/2, g _xx = 1.984, g _yy = 1.984, g _zz = 1.984, D = 1060 Gs, E = 350 Gs. A decrease in the crystal field parameters for the aqueous palladium complex is caused by a redistribution of the electron density to the oxygen atom in the second sphere of the chromium ion environment.     

Quantum-chemical study of chlorophosphoranes: II. Structure of molecules of (Cl2)aP(ClnX3?n)e series, and mutual influence of axial and equatorial substituents

The quantum-chemical calculations of the (C₆H₅)₂PCl₃ molecule were performed by the methods RHF/6-31G(d) and MP2/6-31G(d) with complete and partial optimization of its geometry. The results of calculations were used for evaluating the NQR frequencies of ³⁵Cl and the parameters of asymmetry of the of electric field gradient on the ³⁵Cl nuclei of this molecule. According to the results of calculations with the partial optimization of geometry and to the experimental data of ³⁵Cl NQR the bond lengths were found of central atom P in the solid state of this compound. The mutual influence of its axial and equatorial bonds was studied. It is shown that in chlorophosphoranes the ³⁵Cl NQR frequencies of the axial and equatorial chlorine atoms decrease with the decrease in the bond lengths of phosphorus atom.     

Synthesis and crystal structure of [Mo3S4(Dppen)3Cl3]PF6 · 1.5CH2Cl2 and [W3S4(Dppe)3Br3]2ZnBr4 · 5.5CH3CN

New cluster complexes [Mo₃S₄(Dppen)₃Cl₃]PF₆ · 1.5CH₂Cl₂ (Dppen = cis-Ph₂PCH=CHPPh₂) (I) and [W₃S₄(Dppe)₃Br₃]₂(ZnBr₄)₂ · 5.5CH₃CN (Dppe = Ph₂PCH₂CH₂PPh₂) (II) were synthesized. Their molecular and crystal structures were determined by X-ray diffraction. Diphoshine ligands in the complexes I and II are coordinated in the bidentate mode, providing an arrangement of three chelate rings, giving rise to chirality.     

Subsolidus binary phase diagram of (n-CnH2n+1NH3)2ZnCl4 (n?=?14, 16, 18)

The thermotropic phase solid–solid transitions compound (n-C _n H_2n+1NH₃)₂ZnCl₄ (n = 14, 16, 18) were studied, and a series of their mixtures were prepared. These laminar materials contain bilayers sandwiched between metal halide layers. The low temperature crystal structures of the pure salts are characteristic of the piling of sandwiches in which a two-dimensional macro-anion ZnCl₄ ²⁻ is sandwiched between two alkylammonium layers. These layers become conformationally disordered in the high temperature phases. The subsolidus binary phase diagrams of (n-C₁₄H₂₉NH₃)₂ZnCl₄-(n-C₁₈H₃₇NH₃)₂ZnCl₄ and (n-C₁₆H₃₃NH₃)₂ZnCl₄-(n-C₁₈H₃₇NH₃)₂ZnCl₄ were established by differential thermal analysis and X-ray diffraction. In each phase diagram, an intermediate compound and two eutectoid invariants were observed. There are three noticeable solid solution ranges (α, β, γ) at the left boundary, right boundary, and middle of the phase diagram.     

Novel chromium trinuclear trifluoroacetate complexes Cr3(μ3-O)(CF3COO)6(CH3COOH)2(CF3COO) and Cr3(μ3-O)(CF3COO)6(CH3COOH)2(THF): Synthesis and crystal structure

Novel anhydrous trinuclear ₃-oxo complexes of Cr(III), Cr₃(₃-O)(CF₃COO)₆(CH₃COOH)₂(CF₃COO) (I) and of Cr(III,III,II), Cr₃(₃-O)(CF₃COO)₆(CH₃COOH)₂(THF) (II) (where THF is (CH₂)₄O) are synthesized by anodic dissolution of metallic chromium in solutions of trifluoroacetic acid in acetonitrile and in tetrahydrofuran and their structures are studied by X-ray diffraction analysis. Complex I forms orthorhombic crystals with space group Pna2₁, a = 9.778(1) , b = 16.042(2) , c = 22.851(4) , Z = 4, R ₁ = 0.0332; complex II crystallizes in monoclinic system: space group P2₁/c, a = 9.866(1) , b = 17.895(2) , c = 21.167(4) , = 100.75(2)°, Z = 4, R = 0.0422. The average Cr-(₃-O) distances in compounds I and II are almost equal (1.943(3) and 1.927(3) ). An average length of the Cr-O bond in octahedral surrounding of metal atoms is different in complexes I and II (1.985(4) and 2.003(3) , respectively), which is specified by different oxidation states of the metal atom. The CrCr distances lie in an interval of 3.366(1)–3.337(1) .__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 4, 2005, pp. 266–272.Original Russian Text Copyright © 2005 by Glazunova, Boltalin, Troyanov.     

{[Cu4(nip)4(4，4′-bipy)4(DMF)4]·CH3OH}n配合物的合成与晶体结构

A coordination polymer, {[Cu₄(nip)₄(4，4′-bipy)₄(DMF)₄]·CH₃OH}_n, have been synthesized by the layer method using 5-nitroisophthalic acid (H₂nip), Cu(CH₃COOH)₂ and 4,4′-bipyridine(4,4′-bipy) with three solutions in a marrow tube and structurally characterized by X-ray single-crystal structure analysis. The results indicated that the nip ligand has a μ₂ mono-atomic bridging-monodentate coordination mode and the structure is a two-dimensional network. CCDC: 623420.     

Synthesis and X-ray diffraction study of complex oxides of the Zn2 ? x(ZraSnb)1 ? xFe2xO4 composition

A multicomponent system of complex refractory oxides of the composition Zn_{2 − x} (Zr _a Sn _b )_{1 − x} Fe_2x O₄ (a + b = 1; a: b = 1: 5, 1: 4, 1: 3, 1: 2, 1: 1, 2: 1, 3: 1, 4: 1; x = 0−1.0; Δx = 0.05) was studied by X-ray diffraction. The samples were prepared from oxides of appropriate metals by low-temperature plasma synthesis (hydrogen-oxygen flame). Two phases with wide homogeneity ranges were identified: α phase crystallized in the crystal system of inverse cubic spinel and β phase with the structure of tetragonal spinel. The phase boundaries were found. Structural data are presented for about 100 solid solutions.     

Structure of complex salts [Co(NH3)6][Rh(NO2)6] and [Co(NH3)6][(NO2)3Rh(μ-NO2)1+x(μ-OH)2?xRh(NO2)3]·(2-x)(H2O), x = 0.17

The structures of two salts [Co(NH₃)₆][Rh(NO₂)₆] (I) and [Co(NH₃)₆][(NO₂)₃Rh(μ-NO₂)_1+x (μ-OH)_2−x Rh(NO₂)₃]·(2−x)(H₂O), x = 0.17 (II) are solved. Single crystals of the salts are obtained by the counter diffusion method through the gel of aqueous solutions of [Co(NH₃)₆]Cl₃ and Na₃[Rh(NO₂)₆]. The structure of [Co(NH₃)₆][Rh(NO₂)₆] is consistent with the diffraction data for a polycrystalline sample of poorly soluble fine salt formed in the exchange reaction between aqueous solutions of [Co(NH₃)₆]Cl₃ and Na₃[Rh(NO₂)₆]. The structure of [Co(NH₃)₆][(NO₂)₃Rh(μ-NO₂)_1+x (μ-OH)_2−x Rh(NO₂)₃]·(2−x)(H₂O), x = 0.17 exhibits the stabilizing effect of a large cation in the formation of novel, unknown previously coordination ions: [(NO₂)₃Rh(μ-NO₂)(μ-OH)₂Rh(NO₂)₃]³⁻ and [(NO₂)₃Rh(μ-NO₂)₂(μ-OH)Rh(NO₂)₃]³⁻.     

Theoretical study on homoleptic mononuclear and binuclear ruthenium carbonyls Ru(CO)n (n= 3–5) and Ru2(CO)n (n = 8, 9)

Homoleptic mononuclear and binuclear ruthenium carbonyls Ru(CO) _n (n = 3–5) and Ru₂(CO) _n (n = 8,9) have been investigated using density functional theory. Sixteen isomers are obtained. For Ru(CO)₅, the lowest-energy structure is the singlet D _3h trigonal bipyramid. Similar to Os(CO)₅, the distorted square pyramid isomer with C _2v symmetry lies ∼7 kJ·mol⁻¹ higher in energy. For the unsaturated mononuclear ruthenium carbonyls Ru(CO)₄ and Ru(CO)₃, a singlet structure with C _2v symmetry and a C _s bent T-shaped structure are the lowest-energy structures, respectively. The global minimum for the Ru₂(CO)₉ is a singly bridged (CO)₄Ru(μ-CO)Ru(CO)₄ structure. A triply bridged Ru₂(CO)₆(μ-CO)₃ structure analogous to the known Fe₂(CO)₉ structure is predicted to lie very close in energy to the global minimum. For Ru₂(CO)₈, the doubly bridged C ₂ structure is predicted to be the global minimum. For the lowest-energy structures of M₂(CO) _n (M = Fe, Ru, Os, n = 9,8), it is found that both iron and ruthenium are favored to form structures containing more bridging carbonyl groups, while osmium prefers to have structures with less bridging carbonyl groups. The study of dissociation energy shows that the dissociation of Ru₂(CO)₉ into the mononuclear fragments Ru(CO)₅ + Ru(CO)₄ is a less energetically demanding process than the dissociation of one carbonyl group from Ru₂(CO)₉ to give Ru₂(CO)₈.     

Synthesis and Crystal Structure of the Heterovalent Copper(I,II) π-Complex Cu7Br6.48Cl1.52 ? 2C3N3(OC3H5)3

Single crystals of the heterovalent Cu^I,Cu^II π,σ-complex Cu₇Br_6.48Cl_1.52 ⋅ 2C₃N₃(OC₃H₅)₃ are synthesized by the ac electrochemical method from an ethanol solution containing 2,4,6-triallyloxy-1,3,5-triazine, CuCl₂ ⋅ 2H₂O, and CuBr₂. The unit cell parameters of the crystals are: space group , a = 8.271(3) Å, b = 11.391(3) Å, c = 11.821(3) Å, α = 67.43(1)°, β = 84.41(2)°, γ = 85.14(2)°, V = 1022(1) ų, and R(F) = 0.0714. The copper and halogen atoms form unique moieties Cu₆X₆ linked by bridging fragments [Cu²⁺ (C₃N₃(OC₃H₅)₃)₂]X₂ into infinite chains. Each inorganic moiety Cu₆X₆ is linked with four 2,4,6-triallyl- oxy-1,3,5-triazine molecules. The ligand molecule is coordinated to one Cu^II atom through the nitrogen atom of the triazine cycle and to two Cu^I atoms through the C=C bonds of two allyl groups. The Br content equal to 0.57 in the X(4) position linking the Cu^I and Cu^II atoms differs markedly from a value of 0.85–0.91 for the X(1), X(2), and X(3) positions linked only with the Cu(I) atoms.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 6, 2005, pp. 455–461.Original Russian Text Copyright © 2005 by Goreshnik, Schollmeyer, Mys’kiv.     

Synthesis,X-ray crystal structure and thermal decomposition of two peroxovanadium complexes with coordinated ammonia molecules: [{VO(O2)2(NH3)}2{μ-Cu(NH3)4}] and [Zn(NH3)4][VO(O2)2(NH3)]2

The compounds [{VO(O₂)₂(NH₃)}₂{μ-Cu(NH₃)₄}] (1) and [Zn(NH₃)₄][VO(O₂)₂(NH₃)]₂ (2) were prepared and characterized by elemental analysis and infrared spectra. The single crystal X-ray study revealed that the structure of 1 consists of trinuclear complex molecules [(NH₃)OV(O₂)₂{μ-Cu(NH₃)₄}(O₂)₂VO(NH₃)] with a rare heterobimetalic peroxo bridge: copper(II)–peroxo ligand–vanadium(V). The structure of 2 is composed of tetraamminezinc(II) cations and ammineoxodiperoxovanadate(V) anions. In course of thermal decomposition of 1 performed up to 620 °C, the following intermediate products: [Cu(NH₃)₂(VO₃)₂], and subsequently a mixture of V₂O₅ with monoclinic β-Cu₂V₂O₇, were gradually formed. The final product of decomposition is Cu(VO₃)₂. The thermal decomposition of 2 is a two-step process. In the first stage, [Zn(NH₃)₃(VO₃)₂] as supposed intermediate was formed, which transformed at higher temperatures by release of ammonia molecules to the monoclinic modification of Zn(VO₃)₂.