Crystal structure and thermodynamic stability of an acetone solvate of bis(trifluoroacetylacetonato)copper(II)

A solvate [Cu(CF₃COCHCOCH₃)₂(CH₃COCH₃)] has been synthesized and characterized for the first time. According to X-ray structural data (diffractometer X8 APEX BRUKER, radiation MoK _α, T = 150 K), it crystallizes in the monoclinic crystal system, space group P2₁/c, a = 8.9940(4) Å, b = 22.3966(11) Å, c = 8.1884(3) Å, β = 92.705(2)°, V = 1647.59(12) ų, Z = 4, d _calc = 1.725 g/cm³, final R = 0.0272. The structure is molecular. In the equatorial plane the atom Cu(II) is surrounded with four oxygen atoms of two chelating ligands (CF₃COCHCOCH₃)^?; Cu-O distances 1.927–1.937 Å, O-Cu-O angles 86.18–93.30° and 170.18–175.67°. Square coordination of Cu is complemented to the square-pyramidal one by the oxygen atom of an acetone molecule behaving as an axial ligand; Cu-O_acetone 2.342 Å, O-Cu-O_acetone 89.66–100.11°. In the studied compound disorder of one of the chelate ligands implies the co-existance of the molecules in the cis- and trans-configuration in the crystal under ratio 54.6:45.4. In air the solvate rapidly degrades losing acetone, while in a sealed vessel melts around 313 K. Temperature dependence of equilibrium vapor pressure of acetone over the complex was measured with the static spoon gauge technique, thermodynamic characteristics of its dissociation process being derived: [Cu(CF₃COCHCOCH₃)₂(CH₃COCH₃)]_s = [Cu(CF₃COCHCOCH₃)₂]_s + CH₃COCH_3g, ΔH _av ⁰ = 49.6(3) kJ/mol, ΔS _av ⁰ = 152(1) J/(mol K), ΔG _av ⁰ = 4.30(2) kJ/mol.     

Vapor pressure and crystal structure of platinum(II) <Emphasis Type="Italic">trans</Emphasis>-bis-(trifluoroketoiminate)

The temperature dependence of the saturated vapor pressure of the trans-Pt(ktf)₂ complex obtained from fluorinated β-ketoimine (CF₃-CO-CH₂-C(NH)-CH₃) was studied by the flow method. The standard thermodynamic parameters ΔH ₀ ^T and ΔS ₀ ^T of sublimation have been determined. Full crystal-chemical study has been performed for the complex. Crystal data for C₁₀H₁₀F₆N₂O₂Pt: a = 5.9790(8) Å, b = 7.373(2) Å, c = 8.5767(2) Å,α = 84.05(2)°, β = 72.43(1)°, γ = 67.14(1)°, V = 332.1(1) ų, Z = 1, d_calc = 2.496 g/cm³, triclinic, space group \(P\bar 1\). The structure is molecular and consists of isolated trans-Pt(ktf)₂ complexes. The Pt atom lies at the symmetry center and has a square planar environment of two oxygen and two nitrogen atoms; the distances Pt-O (1.984 Å) and Pt-N (1.969 Å) are similar within the limits of 2σ; the OPtN bond angle is 93.9°. Molecular packing in crystal is considered based on structural data; van der Waals energy of the crystal lattice of trans-Pt(ktf)₂ was calculated by the atom-atom potential method.     

Thermal properties of dimethylgold(III) 8-hydroxyquinolinate and 8-mercaptoquinolinate

Dimethylgold(III) complexes with 8-hydroxyquinoline Me₂Au(Ox) (I) and 8-mercaptoquinoline Me₂Au(Tox) (II) were synthesized and studied. Complex II obtained for the first time was identified from the elemental analysis, IR, ¹H NMR, and mass spectrometry data. The thermal properties of complexes I, II in condensed state were investigated by thermography. The temperature dependences of the saturated vapor pressure over crystals were measured by the Knudsen effusion method with mass spectrometric recording of the gas phase composition and the thermodynamic characteristics of the sublimation process were determined: for I, log P[Torr] = (14.6 ± 0.3) ? (6.34 ± 0.10) × 10³/(T, K), Δ H _subl ^o = 121.2 ± 1.9 kJ^?1, Δ S _subl ^o = 224.1 ± 4.6 J mol^?1 K^?1 (the temperature interval under study 80–115°C); for II, log P [Torr] = (13.3 ± 0.2) ? (6.30 ± 0.09) × 10³/(T, K), Δ H _subl ^o = 120.5 ± 1.7 kJmol^?1, ΔS _subl ^o = 199.3 ± 3.0 J mol^?1 K^?1 (86–145°C).     

Stability of diammine and chloroammine gold(I) complexes in aqueous solution

The substitution equilibria AuCl ₂ ^? + iNH ₄ ⁺ = Au(NH₃)_iCl_{2 ? i} + iCl^? + iH⁺, β _i ^* . were studied pH-metrically at 25°C and I = 1 mol/L (NaCl) in aqueous solution. It was found that logβ ₁ ^* = ?5.10±0.15 and logβ ₂ ^* = ?10.25±0.10. For equilibrium AuNH₃Cl_solid = AuNH₃Cl, log K _s = ?3.1±0.3. Taking into account the protonation constants of ammonia (log K _H = 9.40), the obtained results show that for equilibria AuCl ₂ ^? + iNH₃ = Au(NH₃)_iCl_{2 ? i} + iCl^?, logβ₁ = 4.3±0.2, and logβ₂ = 8.55±0.15. The standard potentials E ₀ ^1/0 of AuNH₃Cl⁰ and Au(NH₃) ₂ ⁺ species are equal to 0.90±0.02 and 0.64±0.01 V, respectively.     

Thermodynamic parameters of phase transitions of perfluoro-N-(4-methylcyclohexyl)piperidine

The heat capacity of perfluoro-N-(4-methylcyclohexyl)piperidine (PMCP) was measured by low-temperature adiabatic calorimetry. The purity of the substance (N ₁ = 99.66 mol %), triple point temperature (T _tp = 293.26 K), and enthalpy of fusion (Δ_fus H _m ^° = 8.32 kJ/mol) were determined. The enthalpy of vaporization was measured by calorimetry at 298.15 K (Δ_vap H _m ^° (298.15 K) = 56.56 kJ/mol). The temperature dependence of the saturated vapor pressure of PMCP over the pressure range 6.2–101.6 kPa was determined by comparative ebulliometry. The normal boiling point (T _n.b. = 460.74 K), ehthalpies of vaporization (at various temperatures), and critical parameters of PMCP were calculated. The calculated and experimental values of Δ_vap H _m ^° (298.15 K) agree to within measurement errors, which proves the reliability of these values and pT parameters used in calculations.     

Structure and thermal properties of volatile copper(II) complexes with β-diimine derivatives of acetylacetone and the structure of 2-(methylamino)-4-(methylimino)-pentene-2 crystals

Copper(II) chelates with β-diimine derivatives of acetylacetone that have a general formula of Cu(R¹C(NR²)CHC(NR²)R¹)₂, where R¹, R² are alkyl substituents, are synthesized. The complexes were identified using elemental analysis, melting point measurements, and high-temperature mass spectrometry data. Knudsen technique is employed to determine the vapor pressure temperature dependence, and standard thermodynamic parameters of sublimation ΔH _T ⁰ and ΔS _T ⁰ are derived. A single crystal X-ray diffraction study is carried out for copper(II) complexes of Cu(CH₃-C(NCH₃)-CH-C(NCH³)-CH₃)₂ (a = 10.363(1) Å, b = 11.978(1) Å, c = 12.653(1) Å, V = 1570.6(3) ų, space group Pnc2, Z = 4, d _calc = 1.328 g/cm³, R = 0.027), Cu(CH₃-C(NC₂H₅)-CH-C(NC₂H₅)-CH₃)₂ (a = 11.782(4) Å, b = 13.951(8) Å, c = 25.591(8) Å, V = 4206(3) ų, space group C222¹, Z = 8, d _calc = 1.169 g/cm³, R = 0.10), and also 2-(methylamino)-4-(methylimino)-pentene-2 CH₃-(C=(NCH₃))-CH=(C-(NHCH₃))-CH₃ (a = 12.129(2) Å, b = 12.034(2) Å, c = 5.692(1) Å, β = 107.05(3)°, V = 794.3(3) ų, space group Cc, Z = 4, d _calc = 1.055 g/cm³, R = 0.06). Van der Waals lattice energy E _cryst is calculated for the cooper(II) complexes by the atom-atom potential technique. The calculated values are compared to experimental sublimation enthalpies Δ H _T ⁰ .     

Nickel(II) complex with 1,4,7-tris(2-aminoethyl)-1,4,7-triazacyclononane

A nickel(II) complex, [Ni(taetacn)](ClO₄)₂ ? H₂O, where taetacn = 1,4,7-tris(2-aminoethyl)-1,4,7-triazacyclononane was synthesized. The crystal structure was determined by the single-crystal X-ray diffraction method at 293 K. The complex crystallizes in the orthorhombic space group Pna2₁ with a = 16.004(2) Å, b = 10.186(1) Å, c = 13.937(2) Å, V = 2271.9(5) ų, D_x = 1.56 g cm^?3, D_m = 1.59 g cm^?3 (floatation method), and Z = 4. The R₁ [I > 2σ(I)] and wR₂ (all data) values are 0.0636 and 0.1672, respectively, for all 4845 independent reflections. The compound is composed of octahedral nickel(II) cation with three 2-aminoethyl pendant groups of taetacn, tetrahedral ClO ₄ ^? anion, and a water molecule of crystallization. Electronic spectra are consistent with the octahedral geometry. Temperature dependence of the magnetic susceptibility (4.5–300 K) can be interpreted considering the zero-field splitting of the nickel(II) ion (g = 2.14, D = 3.72 cm^?1, and Nα = 300 × 10^?6 cm³ mol^?1). Cyclic voltammetry in DMF showed quasi-reversible and irreversible oxidation waves (E_pa = 0.54 V, E_pc = 0.45 V; E_pa = 1.16 V, E_pc = 0.71 V vs. Ag/Ag⁺).     

Structure of the Oxonium Compound of Pefloxacinium Hexachloridostannate(IV)

The structure of tris{hexachloridostannate(IV)}-hexachloride-tetrakis(pefloxacinium)-tetraoxonium undecahydrate (CCDC 1551760) 4PefH ₃ ²⁺ , 4H₃O⁺, 3SnCl ₆ ^2? , 6Cl^?, 11H₂O (I), (PefH is pefloxacin) is determined. The I crystals are triclinic: a = 13.5474(10) Å, b = 15.2859(11) Å, c = 15.6586(11) Å, α = 94.467(1)°, β = 105.477(1)°, γ = 111.560(1)°, V = 2849.9(4) ų, space group Pī, Z = 1. The structure is stabilized by multiple intermolecular hydrogen bonds and π–π-interactions between the PefH₃²⁺ ions.     

Stability of gold(I) glycinate complexes in aqueous solution

The stepwise substitution equilibrium AuCl ₂ ^? +iX^?=AuCl_2?i X _i ^? +iCl^?, β_i, where X^? is the glycinate ion (H₂N-CH₂-COO^?), i = 1 or 2, at 25°C in an aqueous solution with I = 1.0 mol/L (NaCl) has been studied pH-metrically. The corresponding constants are logβ₁ = 3.60 ± 0.10, and logβ₂ = 6.2 ± 0.2.     

Thermochemical study of the complex formation of mercury(II) with nitrilotriacetic acid in an aqueous solution

The formation constant of the Hg(Nta) ₂ ^4? complex, where Nta^3? is the nitrilotriacetate ion, is determined by pH-metric titration at 298.15 K and ionic strength I = 0.5 (KNO₃) (logβ = 21.49 ± 0.10). The thermal effects for the formation of the Hg(NTa) _i2?3i complexes (i = 1, 2) are determined by a direct calorimetric method (?56.69 ± 1.04 and ?85.88 ± 1.32 kJ/mol for i = 1 and 2, respectively).     

Crystal structure of a complex of nickel(II) with 2-amino-4-imino-2-pentene

The structure of a nickel(II) complex with 2-amino-4-iminopentane is determined by X-ray crystallography at 150 K. Crystal data for C₁₀H₁₈N₄Ni are: a = 10.9802(3)Å, b = 13.5780(4)Å, c = 8.0935(2)Å, β = 107.304(1)°, space group P2₁/c, V = 1152.04(5) ų, Z = 4, d _x = 1.459 g/cm³, R = 0.0283. The structure is molecular; the metal atom is coordinated by four nitrogen atoms of two β-diimine ligands. The Ni-N distances in Ni(NacNac)₂ fall within 1.8571–1.8623 Å. The molecules in the crystal are joined by only van der Waals interactions.     

Solution Thermodynamics of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis><Superscript>/</Superscript>-Ethylenebis-(salicylideneiminato)-diaquochromium(III) Chloride in Aqueous Dimethylsulphoxide

The densities, viscosities and refractive indices of N,N ^/-ethylene-bis(salicylideneiminato)-diaquochromium(III) chloride, [Cr(salen)(H₂O)₂]Cl, in aqueous dimethylsulfoxide (DMSO) with different mass fractions (w ₂ = 0.20, 0.40, 0.60, 0.80 and 1.00) of DMSO were determined at 298.15, 308.15 and 318.15 K under atmospheric pressure. From measured densities, viscosities and refractive indices the apparent molar volumes (V _φ ), standard partial molar volume (V _φ ⁰ ), the slope (S _V ^* ), standard isobaric partial molar expansibility (φ _E ⁰ ) and its temperature dependence (?φ _E ⁰ /?T) _p , the viscosity B-coefficient, its temperature dependence (?B/?T), solvation number (S _n ) and apparent molar refractivity (R _D ^φ ), etc., were calculated and discussed on the basis of ion–ion and ion–solvent interactions. These results revealed that the solutions are characterized by ion–solvent interactions rather than by ion–ion interactions and the complex behaves as a long range structure maker. Thermodynamics of viscous flow was discussed in terms of transition state theory.     

X-Ray diffraction data for new ferrites ErMFe<Subscript>2</Subscript>O<Subscript>5</Subscript> (M = Li,Na, K)

New ferrites ErMFe₂O₅ (M = Li, Na, K) were synthesized from erbium and iron(III) oxides and lithium, sodium, and potassium carbonates by solid-state annealing. According to X-ray powder diffraction, these compounds crystallize in the orthorhombic system with the following unit cell parameters: ErLiFe₂O₅, a = 10.510 Å, b = 10.776 Å, c = 14.270 Å, V ⁰ = 1616.16 ų; Z = 16, V _subcell ⁰ = 101.01 ų, ρ_X = 6.01 g/cm³, ρ_pycn = 5.97 ± 0.05 g/cm³; ErNaFe₂O₅, a = 10.519 Å, b = 10.785 Å, c = 15.510 Å, V ⁰ = 1759.56 ų, Z = 16, V _subcell ⁰ = 109.90 ų, ρ_X = 5.77 g/cm³, ρ_pycn = 5.72 ± 0.08 g/cm³; ErKFe₂O₅, a = 10.050 Å, b = 11.320 Å, c = 15.480 Å, V ⁰ = 1937.33 ų, Z = 16, V _subcell ⁰ = 121.08 ų, ρ_X = 5.46 g/cm³, ρ_pycn = 5.41 ± 0.04 g/cm³.     

Reduction kinetics of glycinate complexes of palladium(II) on a dropping-mercury electrode in acid perchlorate solutions

Polarograms for the reduction of glycinate complexes of palladium(II) (5 × 10^?5 M) are obtained in equilibrium solutions of pH 0.8–3.0 with different protonated-glycine concentrations c _Hgly (supporting electrolyte, 0.5 M NaClO₄). It is established that the irreversible wave of reduction of complexes Pd(gly)₂ corresponds to the diffusion limiting current I _d ⁽²⁾ . A similar wave at pH 1.5 and c _Hgly = 0.005 M, as well as at pH 1.0 and c _Hgly = 0.05–0.5 M is preceded by the diffusion limiting current I _d ⁽¹⁾ . Values of the I _d ⁽²⁾ /I _d ⁽¹⁾ ratio are close to the ratio between equilibrium concentrations of Pd(gly)₂] and [Pdgly⁺], calculated using the step stability constant for Pd(gly)₂. This fact testifies to the reduction of complexes Pdgly⁺ in the vicinity of I _d ⁽¹⁾ and complexes Pd(gly)₂, in the vicinity of I _d ⁽²⁾ . At pH 0.8–1.2 and [H₂gly⁺] = 1 × 10^?4 to 5 × 10^?3 there is observed the diffusion-kinetic limiting current of the first wave I ₁ ⁽¹⁾ , which increases with increasing [H⁺] and decreasing [H₂gly⁺]. The nature of the slow preceding chemical stage that occurs during the reduction of complexes Pdgly⁺ is discussed.     

Synthesis and X-ray diffraction study of ferrites ErM<Superscript>I</Superscript>Fe<Subscript>2</Subscript>O<Subscript>5</Subscript> (M<Superscript>I</Superscript> = Li,Na, K,Cs)

Ferrites of composition ErM^IFe₂O₅ (M^I = Li, Na, K, Cs) were synthesized by a solid-phase method. The structure of the ferrites was for the first time studied by X-ray powder diffraction. Crystal systems, unit cell parameters, and X-ray and pycnometric densities were determined. For ErLiFe₂O₅, a = 10.510 Å, c = 14.270 Å, V°= 1616.16 ų, Z = 16, V _subcell ^° = 101.01 ų, ρ_x = 6.01 g/cm³, ρ_pyc = 5.97 ± 0.04 g/cm³; for ErNaFe₂O₅, a = 10.519 Å, c = 15.510 Å, V° = 1759.56 ų, Z = 16, V _subcell ^° = 109.90 ų, ρ_x = 5.77 g/cm³, ρ_pyc = 5.72 ± 0.08 g/cm³; for ErKFe₂O₅, a = 11.050 Å, c = 15.480 Å, V° = 1937.33 ų, Z = 16, V _subcell ^° = 121.08 ų, ρ_x = 5.46 g/cm³, ρ_pyc = 5.41 ± 0.04 g/cm³; and for ErCsFe₂O₅, a = 10.78 Å, c = 16.01 Å, V° = 1905.37 ų, Z = 16, V _subcell ^° = 119.09 ų, ρ_x = 6.86 g/cm³, ρ_pyc = 6.61 ± 0.01 g/cm³.     

(18-Crown-6)(hydrogennitrato)potassium: Synthesis and crystal structure

A new complex, [K(18-crown-6)(NO₃)(HNO₃)] (I), is synthesized, and its crystal structure is studied using X-ray diffraction analysis: space group P \(\bar 1\), a = 8.253 Å, b = 9.277 Å, c = 13.903 Å, α = 95.89°, β = 104.30°, γ = 91.89°, Z = 2. The triclinic structure of compound I was solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.059 for all 3573 independent reflections (CAD4 automated diffractometer, γMoK _α radiation). The structure of compound I contains two independent halves of two centrosymmetric complex molecules with different coordination modes of the K⁺ cations. Two NO ₃ ^? and HNO₃ ligands are randomly disordered relative to the symmetry center and are presented by two average independent H_0.5N ₃ ^1/2? , ligands, which are also orientationally disordered.     

4,7,13,16,21,24-Hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane Penta(nitrato)lanthanate(III): Synthesis and Crystal Structure

A new complex salt, 4,7,13,16,21,24-hexaoxa-1,10-diazoniabicyclo[8.8.8]hexacosane penta(nitrato)lanthanate(III) (H₂(Crypt-222)]²⁺ · [La(NO₃)₅]^2?), is synthesized. Its crystal structure is studied using X-ray diffraction analysis (space group Pbcm, a = 9.517 Å, b = 13.358 Å, c = 24.585 Å, Z = 4; direct method, full-matrix least-squares in the anisotropic approximation, R = 0.039 for 4650 measured independent reflections). The [La(NO₃)₅]^2? complex anion lies on the m plane, and the 2 axis passes through the 2.2.2-cryptand dication with two protonated nitrogen atoms. The coordination polyhedron of the La³⁺ cation (coordination number 11) is a distorted octahedron with five bifurcated vertices, each containing two O atoms from the same NO ₃ ^? . ligand. The [La(NO₃)₅]^2? anions are joined into infinite polymer chains along the y axis through the NO ₃ ^? bridging ligand.     

Synthesis,crystal structure,and thermal behavior of dimethylgold(III) acetate

A dimethylgold(III) compound with an acetate fragment [(CH₃)₂AuOCOCH₃]₂ has been synthesized. The complex was identified from the melting point, IR, ¹H NMR, and mass spectrometry data. The temperature dependence of saturated vapor pressure over crystals has been measured and the thermodynamic parameters of sublimation have been determined by Knudsen’s effusion method with mass spectrometric measurements of the composition of the gas phase: ΔH _subl = 100.87 kJ·mol^?1, ΔS _subl = 216.67 J·mol^?1·K^?1. The thermal behavior of the solid compound was investigated by differential thermal analysis. The compound was studied by X-ray diffraction. Crystal data for C₈H₁₈Au₂O₄: a = 12.214(5) Å, b = 14.307(3) Å, c = 7.6635(15) Å; β = 103.39(3)°, Z = 4, d _calc = 2.917 g/cm³, space group P2(1)/c, R = 0.0261. The [(CH₃)₂AuOCOCH₃]₂ dimer complex with an Au...Au distance of 2.989 Å is the structural unit. The gold atom has a square plane environment of two carbon and two oxygen atoms; the Au-O distances vary from 2.118 Å to 2.139 Å. The molecules are arranged in chains linked by van der Waals interactions.     

4,7,13,16,21,24-Hexaoxa-1,10-diazoniabicyclo[8.8.8]-hexacosane Bis(nitrate-hydrogennitrate): Synthesis and crystal structure

A crystalline adduct of 2.2.2-cryptand and nitric acid, [H₂(Crypt-222)]²⁺·2(NO ₃ ^? ·HNO₃) (I), is synthesized and studied using X-ray diffraction analysis. The monoclinic structure of compound I (space group C2/c, a = 13.326 Å, b = 15.262 Å, c = 15.020 Å, β = 98.96°, Z = 4) is solved by a direct method and refined by the full-matrix least-squares method in the anisotropic approximation to R = 0.067 for 2647 independent reflections (CAD4 automated diffractometer, λMoK _α radiation). In the structure of compound I, the 2.2.2-cryptand dication lies on an axis 2 and has an endo-endo conformation, for which two H atoms at two protonated N atoms are directed inside the cavity. One of the NO ₃ ^? ·HNO₃ dimers is situated in the inversion center, and the other dimer lies on another axis 2 and is disordered over three orientations. All H atoms in the NO ₃ ^? ·HNO₃ dimers are equiprobably disordered over two close sites. Each of the two NO ₃ ^? ·HNO₃ dimers is formed by the very strong disordered N-O-H···O=N hydrogen bond between the nitric acid molecule and nitrate anion.     

3D Supramolecular structure of the coordination polymer [Ag(2-MePyz)ReO<Subscript>4</Subscript>]

The complex [Ag(2-MePyz)ReO₄] (I) is synthesized, and its structure is determined. The crystals are monoclinic, space group P 2₁/c, a = 7.234(1), b = 15.451(1), c = 8.036(3) Å, β = 92.56(1)°, V = 897.3(2) ų, ρ_calcd = 3.347 g/cm³, Z = 4. Structure I consists of cationic polymer chains [Ag(2-MePyz)] _∞ ⁺ . Anions ReO ₄ ^? are weakly bound to Ag⁺ (Ag...O_average 2.693 Å) and join the latter into a supramolecular framework. The Ag⁺ ion has a linear coordination (NAgN 177.9(2)°, distances Ag-N 2.223(5) and 2.242(5) Å).