Numerical Calculation of Permittivity and Dielectric Loss of Aqueous KF Solution Depending on State Parameters

Based on the analytical expressions for permittivity ε₁(ω) and dielectric loss ε₂(ω) are obtained by the kinetic equation method, the frequency spectra of these coefficients are analyzed for an aqueous KF solution in a wide variation range of the density ρ, the concentration C, and the temperature T. With a certain choice of the solution model, the potential interaction energy Φab(|r|), and the radial distribution function g_ab(|r|) of a- and b-type ions, ε₁(ω) and ε₂(ω) of an aqueous KF solution are numerically calculated depending on ρ, C, T, and ω.     

Two Mn(II) chloride complexes containing guest molecules

Two phenanthroline-manganese inclusion complexes with [MnCl(H₂O)(phen)₂]⁺ core have been synthesized and characterized by single crystal X-ray diffraction, elemental analyses, IR spectra, thermogravimetric analyses. Uncoordinated 2-mercaptothiazole (tzdtH) and 2-mercaptobenzothiazole (bztzH) as guest molecules are included in the complexes with formulas [MnCl(H₂O)(phen)₂]Cl·tzdtH (1) and {[MnCl(H₂O)(phen)₂]Cl}₂·bztzH (2). X-ray structural analyses for complexes revealed that the complex 1 is triclinic, space group P1 with a=9.724(1) Å, b=11.858(1) Å, c=12.644(2) Å; β=89.056(2)°; Z=2, D _c=1.513 Mg m^?3, F(000)=638 and the complex 2 is triclinic, space group P1 with a=9.861(1) Å, b=11.476(1) Å; c=12.908(3) Å; β=84.991(2)°; Z=1, D _c=1.511 Mg m^?3, F(000)=600. Two complexes exhibit high stability up to 650°C. The molar specific heat capacities for the two complexes 1 and 2 can be estimated as being 96.175±0.332 and 72.505±0.364 J mol^?1 K^?1 at 298.15 K by RD496-III microcalorimeter, respectively.     

XRD and EXAFS study of nitrato ammine complexes of nitrosyl ruthenium

The structure of trans-[RuNO(NH₃)₄(H₂O)](NO₃)₃ (I) and trans-[RuNO(NH₃)₄(NO₃)](NO₃)₂ (II) was determined by XRD. Crystallographic data are as follows: space group I4₁/a; a = b = 18.280(1) Å, c = 15.129(1) Å, R = 0.0244 (I), and space group Cm, a = 11.5620(3) Å, b = 7.9934(2) Å, c = 7.7864(2) Å, β = 127.124(1)°, R = 0.0139 (II). Interatomic distances for complex particles of fac- and mer- [RuNO(NH₃)₂(NO₃)₃] (III and IV, respectively) were determined by EXAFS.     

Interaction of hydantoins with transition metal ions: synthesis,structural, spectroscopic,thermal and magnetic properties of [M(H<Subscript>2</Subscript>O)<Subscript>4</Subscript>(phenytoinate)<Subscript>2</Subscript>] M = Ni(II), Co(II)

Complexes of Ni(II) and Co(II) of the formulae [Ni(H₂O)₄(pht)₂] (1) and [Co(H₂O)₄(pht)₂]·1,5NH₃·H₂O (2) (where pht = phenotoinate anion) were obtained and characterized physicochemically. [Ni(H₂O)₄(pht)₂] (1) crystallizes in a monoclinic space group P2₁/c; a = 11.7358(8), b = 11,1250(8), 11.4182(7) Å; β = 97.076(5)°; V = 1479.41 Å³; Z = 2. The environment around the nickel and cobalt ions can be described as a distorted octahedron. The metal ion was found to bind to four water molecules and two nitrogen atoms derived from two anions of the monodentate phenytoinate. Four intramolecular hydrogen bonds designated as S(6) graph set are found in one [Ni(H₂O)₄(pht)₂] (1) molecule. Two chain HB patterns, constructed by the [Ni(H₂O)₄(pht)₂] molecules extending along the c and b axes, respectively, have been observed. The cobalt complex precipitates with the additional solvent molecules: one and a half of ammonia and one water. The results document the preferential binding of hydantoins to the metal ions through N(3) atom.     

Novel crystal modification of <Emphasis Type="Italic">fac</Emphasis>-triamminetrinitrorhodium(III) — β-<Emphasis Type="Italic">fac</Emphasis>-[Rh(NO<Subscript>2</Subscript>)<Subscript>3</Subscript>(NH<Subscript>3</Subscript>)<Subscript>3</Subscript>]

The paper describes the preparation techniques for β-fac-[Rh(NO₂)₃(NH₃)₃]. The complex crystallizes as colorless prisms belonging to the monoclinic crystal system. Crystal data: a = 6.6338(2) Å, b = 11.0627(3) Å, c = 11.5314(3) Å; β = 96.608(1)°, V = 840.64(4) ų, space group P2₁/n, Z = 4, d_calc = 2.308 g/cm³. The structure is molecular and contains neutral complex molecules having the fac configuration. Crystal chemical analysis of the complex in comparison to α-fac-[Rh(NO₂)₃(NH₃)₃] is performed.     

Structure of the hexanuclear Cu(II) β-diketonate complex

The structure of the hexanuclear copper(II) β-diketonate complex with gfa (hexafluoroacetylacetone) and dpm (dipivalylmethanate) ligands was studied by low-temperature (T = 100 K) X-ray diffraction. Crystal data for Cu₆(gfa)₄(dpm)₄(OH)₄ [C₆₄H₈₄Cu₆F₂₄O₂₀]: a = 28.2364(7) Å, b = 12.8072(3) Å, c = 24.7199(7) Å, β= 115.900(1)°, V = 8041.5(4) ų, space group C2/m, Z = 4, d _calc 1.661 g/cm³. The coordination polyhedra of the copper atoms — squares and octahedra — are formed by the oxygen atoms of the gfa and dpm ligands and groups. In all cases, the Cu-O distances vary from 1.89 Å to 2.13 Å. The complexes follow the sites of the rhombohedral sublattice with the parameters a _c ≈ 14.4 Å and a _c ≈ 61.5°.     

Crystal structures of EuLnCuS<Subscript>3</Subscript> (Ln = Nd and Sm)

The compound sulfides EuLnCuS₃ (Ln = Nd and Sm) were obtained for the first time. Their crystal structures were determined from X-ray powder diffraction data. The crystals of both compounds are orthorhombic (space group Pnma). The compound EuNdCuS₃ is isostructural with BaLaCuS₃; the unit cell parameters are a = 11.0438(2) Å, b = 4.0660(1) Å, c = 11.4149(4) Å. The compound EuSmCuS₃ is isostructural with Eu₂CuS₃; the unit cell parameters are a = 10.4202(2) Å, b = 3.9701(1) Å, c = 12.8022(2) Å.     

Synthesis,structure and electrochemical properties of some thiosemicarbazone complexes of iridium

Reaction of thiosemicarbazones of salicylaldehyde and 2-hydroxyacetophenone (H₂L¹ and H₂L²) with [Ir(PPh₃)₃Cl] affords complexes of type [Ir(PPh₃)₂(L)(H)] (L = L¹ or L²) in ethanol. A similar reaction carried out in toluene affords the [Ir(PPh₃)₂(L)(H)] complexes along with complexes of type [Ir(PPh₃)₂(L)Cl], where a chloride is coordinated to iridium instead of the hydride. The structure of the [Ir(PPh₃)₂(L²)(H)] and [Ir(PPh₃)₂(L²)Cl] complexes has been determined by X-ray crystallography. Crystal data for [Ir(PPh₃)₂(L²)(H)]: space group, P2₁/c; crystal system, monoclinic; a=12.110(2) Å, b=17.983(4) Å, c=18.437(4) Å, β=103.42(3)°, Z=4; R ₁=0.0591, wR ₂=0.1107. Crystal data for [Ir(PPh₃)₂(L²)Cl]: space group, P2₁/c; crystal system, monoclinic; a=17.9374(11) Å, b=19.2570(10) Å, c=24.9135(16) Å, β=108.145(5)°, Z=4; R ₁=0.0463, wR ₂=0.0901. In all the complexes the thiosemicarbazones are coordinated to the metal center as dianionic tridentate O, N, S-donors and the two triphenylphosphines are trans. The complexes are diamagnetic (low-spin d? ⁶, S=0) and show intense MLCT transitions in the visible region. Cyclic voltammetry on all the [Ir(PPh₃)₂(L)(H)] and [Ir(PPh₃)₂(L)Cl] complexes shows a quasi-reversible Ir(III)–Ir(IV) oxidation within 0.55–0.78 V vs. SCE followed by an irreversible oxidation of the thiosemicarbazone within 0.91–1.27 V vs. SCE. An irreversible reduction of the thiosemicarbazone is also observed within ?1.10 to ?1.23 V vs. SCE.     

Crystal structure,luminescent and thermochromic properties of bis(tetraethylammonium) hexachlorotellurate(IV)

The crystal structure of (C₂H₅)₄N)₂TeCl₆ was determined by X-ray diffraction (a = 14.130(2) Å, b = 14.547(2)Å, c = 13.296(2)Å, β= 90.356(3)°; space group C2/c, Z = 4, ρ_(calcd) = 1.387 g/cm³). The crystal structure is composed of the [TeCl₆]^2? anions and tetraethylammonium cations ((C₂H₅)₄N)⁺. The electronic and geometric aspects that determine the spectral luminescence and thermochromic properties of the complex are discussed.     

Synthesis,crystal structures,and characterization of a new substituted 1,2,4-triazole and its two Co(II)/Mn(II) complexes

A new triazole-substituted ligand H₂L (H₂Trza = 3-amino-1H-1,2,4-triazole-5-acetate) and its two new isomorphic compounds [M(HTrza)₂(_H2O)₂] ? 2H₂O (Co(I) and Mn(II)) have been synthesized and characterized structurally. Their X-ray crystal structures (CIF files CCDC nos. 906893 for I and 906892 for II) show that H₂L belongs to a tetragonal system; space group P4₃ with a = b = 5.0445(13), c = 27.054(10) Å; Z = 4. Complex I belongs to a monoclinic system; space group P2₁/n with a = 7.6543(8), b = 7.3453(8), c = 13.6283(14) Å; β = 91.5990(10)°, Z = 2. Complex II belongs to a triclinic system; space group with a = 6.8550(15), b = 8.0630(18), c = 15.173(4) Å; α = 84.794(4)°, β = 79.005(3)°, γ = 73.779(4)°, Z = 2. X-ray analysis demonstrates that compound H₂L is found to contain a H₂Trza and a lattic water molecule; complexes I and II are discrete mononuclear species. The central Co(II) and Mn(II) atoms exhibit octahedral coordinations, type 4 + 2. In two compounds, the coordination entities are further organized via hydrogenbonding interactions to generate uniform supramolecular networks. Thermal stabilities of two compounds were examined by thermogravimetric analysis.     

The frequency dispersion of dynamic transfer coefficients and elastic moduli of magnetic liquids

The analytic equations for viscosity coefficients and the corresponding elastic moduli obtained in [3] were used to calculate these values over a wide range of reduced frequency values (ω* ≈ 10^?7?10). The volume η _v (ω) and shear η _s (ω) viscosity coefficients decreased as the frequency increased. The dispersions η _v (ω) and K _r (ω) were only caused by the contribution of structural relaxation, and the dispersions η _s (ω) and μ(ω), by translational and structural relaxation. The shear elastic modulus μ(ω) and relaxation volume elastic modulus K _r (ω) increased as the frequency grew. The results obtained were in satisfactory agreement with the conclusions from general relaxation theory.     

Synthesis of spiro[(6-phenyl-3,4-dihydro-2H-1,3-dioxine)-2<Emphasis Type="Italic">R</Emphasis>(<Emphasis Type="Italic">S</Emphasis>), 3′-(19′,28′-oxidooleanan)]-4-ones and X-ray diffraction analysis of their configuration

The structure of two stereoisomeric spiroadducts of allobetulone with 5-phenyl-2,3-dihydrofuran-2,3-dione was established by X-ray diffraction (XRD) analysis. The crystals of the 2R isomer are orthorhombic, P2₁2₁2₁, a = 10.825(5) Å, b = 12.849(6) Å, c = 23.358(9) Å; V = 3249(2) ų, Z = 4, d _calc = 1.200 g/cm³; the crystals of the 2S isomer hemihydrate are triclinic, P1, a = 11.505(7) Å, b = 12.192(8) Å, c = 13.123(8) Å; α = 103.35(5)°, β = 100.80(5)°, γ = 90.98(5)°; V = 1756(2) ų, Z = 2, d _calc = 1.127 g/cm³. The molecular structure of the spiroadducts is discussed.     

Crystal structure of the co-crystal ALA-VAL·ALA·H<Subscript>2</Subscript>O: A layered inclusion compound

A co-crystal of L-alanyl-L-valine (AV) and L-alanine (A), AV·A·(H₂O), has been prepared and characterized by single crystal XRD analysis. Crystal data: C₁₁H₂₅N₃O₆; M = 295.3; orthorhombic, space group P2(1)2(1)2(1); a = 16.4773(17) Å, b = 18.3932(19) Å, c = 5.0398(5) Å, V = 1527.4(3) ų, Z = 4; d _calc = 1.284 g/cm³. Experimental parameters: T = 100 K; diffractometer, radiation: Kappa APEX II, graphite-monochromatized MoK _α ; R ₁ = 0.046, wR ² = 0.120 for 4639 unique reflections and 214 refinement parameters. The L-alanyl-L-valine dipeptide molecules assemble to form a parallel β-sheet through hydrogen bonds, while the L-alanine molecules fill the large channels located in the interlayer space. AV·A·(H₂O) is the first layered structure based on a representative of hydrophobic dipeptides that form hexagonal tubular structures in the solid state, as well as the first inclusion compound of AV with a chiral guest.     

Structural analysis of modulated crystals. A new structure of Ce<Subscript>4</Subscript>Pd<Subscript>13.6</Subscript>Sn<Subscript>5.9</Subscript>

Incommensurate modulated structure of Ce₄Pd_13,6Sn_5,9 intermetallic is studied by (3+1)D analysis in a rhombic basic cell a = 2.08458(4) nm, b = 0.47129(1) nm, and c = 0.92874(1) nm; q = 0,2407(1)b*. Xmmm(0β0)000 group determines the symmetry of the crystal. The superspace analysis is compared to the analysis of the superstructure with a, 4b, and c periods in three dimensions.     

Synthesis and structural investigation of hafnium(IV) complexes with acetylacetone and trifluoroacetylacetone

Two volatile hafnium(IV) complexes with acetylacetone and trifluoroacetylacetone (HL) have been prepared and their structures have been studied at ?30°C. Crystal data for C₂₀H₂₈HfO₈: a = 21.5493(4) Å, b = 8.36720(10) Å, c = 13.9905(3) Å; β = 116.5550(10)°, space group C2/c, Z = 4, d _calc = 1.692 g/cm³, R = 0.015. Crystal data for C₂₀H₁₆F₁₂HfO₈: a = 8.1039(12) Å, b = 11.4499(14) Å, c = 15.790(2) Å; α = 99.341(4)°, β = 103.175(4)°, γ = 108.185(4)°, space group P?1, Z = 2, d _calc = 2.003 g/cm³, R = 0.074. Both structures are molecular and comprise isolated complex molecules HfL₄. The hafnium atom is coordinated with eight oxygen atoms of four β-diketonate ligands, Hf-O distances varying from 2.153 Å to 2.191 Å. The molecules make van der Waals contacts in the structures.     

Synthesis and crystal structure of two {M(4,4′-dpdo)<Subscript>2</Subscript>[N(CN)<Subscript>2</Subscript>]<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)<Subscript>2</Subscript>} complexes (M = Co(II), Mn(II); 4,4′-dpdo = 4,4′-bipyridyl-N,N′-dioxide)

The ligand 4,4′-bipyridyl-N,N′-dioxide (4,4′-dpdo) was used in the synthesis of two complexes, {Co(4,4′-dpdo)₂[N(CN)₂]₂(H₂O)₂} (1) and {Mn(4,4′-dpdo)₂[N(CN)₂]₂(H₂O)₂} (2). The complexes were found to be isostructural, triclinic, space group P-1 with Z = 1 and the following unit cell parameters: a = 8.158(8) Å, b = 8.865(8) Å, c = 9.477(9) Å; α = 70.988(13)°, β = 78.778(13)°, γ = 71.964(10)°; V = 612.8(10) ų for 1; a = 8.247(14) Å, b = 9.001(16) Å, c = 9.707(17) Å; α = 71.02(2)°, β = 78.63(2)°, γ = 72.62(2)°; V = 646(2) ų for 2. Final R-values were 0.075 and 0.083 for 1 and 2, respectively. In the molecules of the complexes, Co(II) or Mn(II) cation is coordinated by two O-atoms of two 4,4′-dpdo ligands, two terminal N-atoms of two dicyanamides, and two O-atoms of water molecules. The crystals are molecular, with adjacent complex molecules linked through a system of O-H...N and O-H...O hydrogen bonds.     

X-ray structural study of fluorinated β-diketonate complexes of zirconium(IV)

Three novel complexes of zirconium(IV) are prepared and characterized by single crystal X-ray diffraction: zirconium(IV) pivaloyltrifluoroacetonate Zr(ptac)₄, zirconium(IV) trifluoroacetylacetonate Zr(tfac)₄, and zirconium(IV) hexafluoroacetylacetonate Zr(hfac)₄. Crystal data for C₃₂H₄₀F₁₂ZrO₈: a = 19.9842(6) Å, b = 11.8417(3) Å, c = 16.4831(5) Å; β = 95.2880(10)°, monoclinic, space group Cc, Z = 4, d _calc = 1.491 g/cm³, R = 0.061. Crystal data for C₂₀H₁₆F₁₂ZrO₈: a = 21.5063(15) Å, b = 7.9511(5) Å, c = 16.0510(10) Å; β = 113.736(4)°, monoclinic, space group C2/c, Z = 4, d _calc = 1.860 g/cm³, R = 0.047. Crystal data for C₂₀H₄F₂₄ZrO₈: a = 15.3533(13) Å, b = 20.2613(15) Å, c = 19.6984(17) Å; β = 95.828(2)°, monoclinic, space group P2₁/c, Z = 2, d _calc = 2.004 g/cm³, R = 0.078. All the structures are molecular and include isolated mononuclear Zr(β-dik)₄ complex molecules. Coordination environment of zirconium atom is made by eight oxygen atoms of four β-diketonates; the coordination polyhedron is an almost regular square antiprism. The Zr-O distances fall within 2.14–2.23 Å. Complexes in the structures are joined by van der Waals interactions. Using the structural data, the van der Waals energies of crystal lattices of the studied compounds are calculated by the atom-atom potential method.     

New approaches to the calculation and interpretation of asymmetry factors of chromatographic peaks

The suitability of the determination of the asymmetry factor of chromatographic peaks by the ratio of areas of two components separated by a perpendicular dropped from the maximum of the peak to the base-line, A _s * = S _b /S _a , where symbol a corresponds to the leading edge of the peak and b is for its tailing slope, is discussed. It is demonstrated that this method enables the estimation of the asymmetry of even partially separated chromatographic signals, including those eluted “in the tail” of intense peaks of solvents. The concepts of the asymmetry index I(A _s *) and its increment ΔI(A _s *) = (A _s *)–I(A _s *) are introduced, which ensures the characterization of the asymmetry of peaks of polar analytes with respect to the asymmetry of nonpolar reference components, that is, the separation of the effects of the polarity of analytes and their quantities injected into the chromatographic column on this parameter. For the first time we revealed a correlation of the asymmetry factors of compounds of different chemical nature with such a characteristic of their polarity as the difference in chromatographic separation temperature and the normal boiling point of analytes.     

Crystal structure of magnesio-ferri-hornblendite □Ca<Subscript>2</Subscript>(Mg<Subscript>4</Subscript>Fe<Superscript>3+</Superscript>)[(Si<Subscript>7</Subscript>Al)O<Subscript>22</Subscript>](OH)<Subscript>2</Subscript> as a potentially new mineral of the amphibole supergroup

A sample of magnesio-ferri-hornblendite, a potential new mineral of the amphibole supergroup, was studied by X-ray diffraction and IR spectroscopy. The crystal chemical formula is (Z = 2): ^AK_0.04^M(4) (Ca_1.92Na_0.08) ^C[^M(1)(Mg_1.78Fe_0.22⁴⁺) ^M(2)(Mg_1.62Fe_0.26³⁺Al_0.12) ^M(3)(Mg_0.64Fe_0.32²⁺Mn_0.04)] [^T(Si_7.44Al_0.56)O₂₂] ^W(OH)₂. The monoclinic unit cell parameters are a = 9.855(1) Å, b = 18.084(1) Å, c = 5.289(1) Å, β = 104.853(2)°; V = 911.1(2) ų; space group C2/m; Z = 2. The crystal structure was refined to R = 2.82% in the anisotropic approximation for atomic displacement parameters using 1166 reflections with I > 2σ(I). The magnesio-ferri-hornblendite structure is generally similar to the structures of other monoclinic calcium amphiboles, and its key distinctive features are the predominance of Мg among C²⁺ cations and Fe³⁺ among C³⁺ cations.     

Synthesis,crystal structure,and thermal analysis of a copper(II) complex with imidazo[4,5-<Emphasis Type="Italic">f</Emphasis>]1,10-phenantroline

A new complex, [Cu₂(μ ₂-Cl)₂(IP)₂Cl₂] · 4H₂O (IP = imidazo[4,5-f]1,10-phenathroline), was synthesised and characterised by elemental analysis, thermal analysis, IR spectra, and X-ray crystallography. The results showed that the complex crystallises in the monoclinic space group P \(\bar 1\); a = 7.880 (2) Å, b = 9.227(2) Å, c = 10.694(2) Å; α = 97.788(4)°, β = 100.637(4)°, γ = 95.841(3)°; V = 750.7(3) ų, and Z = 1. The complex is further stabilised by H-bonds and a π-π stacking interaction between the pyridine and benzene rings of two neighbouring molecules with the centroid.centroid distance of 3.498(3) Å, leading to a 3D supramolecular architecture. Thermal decomposition procedure of the complex explored by TG-DTG has three stages, and the final product is Cu in residual rate of 16.18 % (calculated to be 16.26 %).