Synthesis,structure, and antibacterial properties of ternary rare-earth complexes with <Emphasis Type="Italic">o</Emphasis>-methylbenzoic Acid and 1,10-phenanthroline

Ternary rare-earth complexes with o-methylbenzoic acid (o-MBA) and 1,10-phenanthroline (Phen) Ln₂(o-MBA)₆(Phen)₂ · nH₂O(n = 0, 1) (Ln = La, Pr, Y, Yb) were synthesized and characterized by elemental analysis, IR, X-ray diffraction, and TG-DTG means. The complex La₂(o-MBA)₆(Phen)₂ · H₂O (I) is composed of two species of binuclear molecules in which the La³⁺ ion is coordinated with two nitrogen atoms of Phen and seven oxygen atoms of carboxylate groups. The carboxylate groups were bonded to La³⁺ in three modes: chelating-bidentate, bridging-bidentate, and chelating-bridging tridentate. The La³⁺ ion adopted a vigorous distorted monocapped square antiprism geometry. Complex I belongs to the triclinic crystal system, P space group, lattice parameters: a = 13.058(3), b = 12.7584(11), c = 20.773(4) Å, α = 101.18(3)°, β = 93.88(3)°, γ = 115.82(3)°, V = 3283.0(11)ų, Z = 2, ρ_calcd = 1.484 mg/m³, M _r = 1467.06, F(000) = 1476, μ = 1.350 mm^-1. The structure was refined to R _l = 0.0631 and wR ₂ = 0.1504. The antibacterial activity test indicates that these complexes exhibit better antibacterial ability against Escherichia coli and Staphylococcus aureus than the corresponding rare-earth chloride or o-MBA.     

Thermodynamic properties of lanthanum and lanthanide halides: III. Thermodynamic functions of LnF<Subscript>2</Subscript> (gas)

The molecular constants of LnF₂ (Ln = La-Lu) have been estimated based on the available spectro-scopic characteristics of lanthanum and lanthanide difluorides. These constants have been used for calculating the reduced Gibbs energy ?[G ⁰(T) ? H ⁰(0)]/T of the compounds in the ideal gas state in the range 298.15–3000 K at the standard pressure p ⁰ = 0.1 MPa. The electronic contribution to thermodynamic functions has been calculated taking into account the excitation energies of low-lying (<10 000 cm^?1) electronic states of Ln²⁺ ions. The splitting of the ground state term of Ln²⁺ in the ligand field is estimated.     

Syntheses and structures of 1d coordination polymers based on cluster anions [Re<Subscript>4</Subscript>Te<Subscript>4</Subscript>(CN)<Subscript>12</Subscript>]<Superscript>4–</Superscript> and cationic Ln<Superscript>3+</Superscript> (Ln = La,Gd) complexes with 1,10-phenanthroline

Two new porous coordination polymers based on cluster anions [Re₄Te₄(CN)₁₂]^4– and cationic Ln³⁺ (Ln = La, Gd) complexes with 1,10-phenanthroline (Рhen) are synthesized under hydrothermal conditions. The structures of the compounds are determined by X-ray diffraction analysis (CIF files CCDC 1437445 (I) and 1437446 (II)). Compound (РhenH)[{La(H₂O)₃(Рhen)₂}{Re₄Te₄(CN)₁₂}] · 1.5Рhen · 6H₂O (I) crystallizes in the space group \(P\bar 1\) (triclinic system): a = 13.322(3), b = 15.977(3), c = 18.576(4) Å, α = 71.34(3)°, β = 85.56(3)°, γ = 88.27(3)°, V = 3734.8(13) ų. Compound (PhenH)[{Gd(H₂O)₂(Phen)₂}{Re₄Te₄(CN)₁₂}] · 2Phen · 0.5H₂O (II) crystallizes in the space group C2/c (monoclinic crystal system): a = 18.146(1), b = 30.245(2), c = 13.455(2) Å, β = 97.858(2)°, V = 7315.4(1) ų. Structures I and II are based on polymer chains consisting of alternating fragments [Re₄Te₄(CN)₁₂]^4– and {Ln(H₂O) _n (Phen)₂}³⁺ (Ln = La, n = 3; Ln = Gd, n = 2) linked by the bridging CN ligands. The packings of the polymers contain extended channels due to the developed network of noncovalent interactions. The walls of the channels are formed by both hydrophilic (CN^–) and hydrophobic (Рhen) groups. The channels, whose volume is 25 and 15% for compounds I and II, respectively, are filled by disordered Phen molecules and PhenH⁺ cations, as well as by H₂O molecules.     

Gas-phase synthesis of terbium and lutetium carboxylates

Gas-phase ligand exchange between volatile lanthanide dipivaloylmethanates (Ln(dpm)₃; Hdpm is dipivaloylmethane, Ln = Tb, Lu) and o-substituted aromatic carboxylic acids (HCarb = Hsal is o-hydroxybenzoic acid, Habz is o-aminobenzoic acid, Hpobz is o-phenoxybenzoic acid, Hpa is o-anilinobenzoic acid). The gas-phase reaction involves the formation of the mixed-ligand complex Ln (dpm)_3?n (Carb)n, which is subsequently converted into tris-carboxylate (Ln(Carb)₃) on heating of the product in vacuum.     

Structure and charge-transport properties of LnBaCuCoO<Subscript>5 + δ</Subscript> (Ln = Y,Dy) cuprocobaltites

LnBaCuCoO_{5 + δ} (Ln = Y, Dy) cuprocobaltites were prepared. Their unit cell parameters were determined and their thermal expansion, electrical conductivity (σ), and Seebeck coefficient (S) were studied in air in the range 300–1100 K. The compounds have tetragonal structures (space group P4/mmm). Their unit cell parameters are a = 0.3867(2) nm, c = 0.7550(7) nm, V = 112.9(2) × 10^?3 nm³ for YBaCuCoO_4.98; and a = 0.3872(2) nm, c = 0.7562(7) nm, V = 113.4(2) × 10^?3 nm³ for DyBaCuCoO_5.01. They are p-type semiconductors. The electrical conductivity of DyBaCuCoO_{5 + δ} is slightly lower and its Seebeck coefficient is 1.5–2 times higher than the respective values for YBaCuCoO_{5 + δ} apparently because of different electronic configurations of the rare-earth cations in LnBaCuCoO_{5 + δ} (4d ⁰ for Y³⁺ and 4f ⁹ for Dy³⁺). Dilatometric measurements show that the LnBaCuCoO_{5 + δ} phases in the range 300–1100 K do not experience structural phase transitions, and their linear thermal expansion coefficients (LTEC) are 14.3 × 10^?6 K^?1 for Ln = Y and 14.7 × 10^?6 K^?1 for Ln = Dy.     

Chloro- und Azidokomplexe des Vanadyl(IV)-Ions in Acetonitril,Propandiol-1,2-carbonat,Trimethylphosphat und Dimethylsulfoxid

The formation of chloro- and azidocomplexes of VO²⁺(IV) is investigated in acetonitrile (AN), propanediol-1,2-carbonate (PDC), trimethyl phosphate (TMP) by spectrophotometric, potentiometric and conductometric methods. The following coordination forms are indicated: [VOCl]⁺ inAN, PDC andDMSO), [VOCl₂] (inAN, PDC andTMP), [VOCl₃]^? (inPDC andTMP[?]), [VOCl₄]^2? (inAN, PDC andTMP); [VON₃]⁺ (inAN, PDC andDMSO), [VO(N₃)₂] (inAN, PDC, TMP andDMSO), [VO(N₃)_2+n]^n? (inAN, PDC, TMP andDMSO). The results are interpreted by the donor numbers and sterical properties of the solvent molecules.     

Homogeneity regions of neodymium,samarium, and europium manganites in air

XRD phase analysis of homogeneous phases and heterogeneous compositions of general formula Ln_2?x Mn_xO_3±δ (Ln = Nd, Sm, Eu; 0.90 ≤ x ≤ 1.20; Δx = 0.22) prepared by ceramic synthesis from oxides in air at 900–1400°C was used to determine the solubility boundaries for Ln₂O₃ oxides and maganese oxides in LnMnO_3±δ. The results were represented as fragments of the phase diagrams for the Ln-Mn-O systems in air. It was assumed that the solubility of Ln₂O₃ oxides in LnMnO_3±δ is determined by lattice defects, while that of manganese oxides, in addition to above mechanism, by the disproportionation reaction 2Mn³⁺ = Mn²⁺ + Mn⁴⁺ followed by the partial substitution of divalent magnesium for Ln³⁺ at cuboctahedral positions of the perovskitelike crystal lattice.     

3D metal-organic frameworks based on lanthanide-seamed dimeric pyrogallol[4]arene nanocapsules

Two novel 3D metal-organic frameworks(MOFs)with cds network,{[Me NH_3]_7[Ln_8(Pg C_2)_2(H_2O)_y(HCOO)_7]}_n·x(Solvent)(FJI-Y4,FJI=Fujian Institute,Ln=Gd,y=12;FJI-Y5,Ln=Dy,y=11;Pg C_2=C-ethylpyrogallol[4]arene),based on unprecedented dimeric pyrogallol[4]arene-based Ln_8metal-organic nanocapsule(MONC)supramolecular building blocks and formate linkers,have been prepared under solvothermal conditions.To our best of knowledge,they present not only the first two examples of 3D hierarchical structures constructed from MONCs in metal-pyrogallol[4]arene system,but also the first two examples of MOFs based on lanthanide MONCs.Remarkably,the inner cavity volume of the Ln_8capsule in FJI-Y4 and FJI-Y5 is approximately151?~3,which is larger than those found in previous transition metal-seamed dimeric Pg C_n-based MONCs.Magnetic investigation on FJI-Y4 suggests a significant magnetocaloric effect(23.97 J kg~(-1)K~(-1),ΔH=7 T,2.5 K),while FJI-Y5 exhibits slow relaxation of the magnetization.     

Mixed ligand acetate,propionate, and pivalate complexes of rare earth metals with monoethanolamine: A new approach to the synthesis,composition, structure,and use for the preparation of oxide materials

Compositions of mixed ligand acetate, propionate, and pivalate complexes of rare earth metals of the cerium and yttrium groups with monoethanolamine are predetermined by the synthesis conditions and the nature of the carboxylate ligand and rare earth metal ion. Solid mixed ligand complexes [Ln(Piv)₅(MEAH)][MEAH] and [Ln(Piv)₃(MEA)], homoligand complexes [Ln(Piv)₃] (HPiv is 2,2-dimethylpropionic (pivalic) acid), and gel-like hydroxo complexes [Ln(Carb)_3–x–y (NO₃) _x -(OH) _y (MEA) _w (H₂O) _z ] (HCarb is acetic (HAc) or propionic (HProp) acid) are isolated using original synthesis procedures involving ion pairs [MEAH]⁺[Carb]^– (MEA is monoethanolamine). The compounds are studied by IR spectroscopy, ¹H NMR spectroscopy, elemental and thermal analyses, and mass spectrometry. Specific features for the complex formation of rare earth metal pivalates with MEA are additionally studied using quantum-chemical simulation.     

Quantum-chemical study of lutetium,ytterbium, and gadolinium phthalocyaninates PcLnCl

Structural parameters and IR spectra of the (¹A₁//C_4v)-PcLuCl, (²B₂//C_4v)-PcYbCl, and (⁸A₂//C_4v)-PcGdCl molecules, (²A₂//C_4v)-Pc⁺LuCl, (3B₁//C_4v)-Pc⁺YbCl, and (⁹A₁//C_4v)-Pc⁺GdCl cations, (¹A_g//D_2h)-PcLuCl₂LuPc dimer, and PcLuCl···PcLuCl coaxial molecular pair have been simulated using the DFT (U) PBE0/SDD method. The PcLnCl (Ln = Lu, Yb, Gd) molecules have exhibited the equilibrium Ln–N bond length of 222, 223, and 230 pm, the Ln–Cl bond length of 245, 246, and 253 pm, the dipole moment of 4.73, 4.57, and 4.84 D directed from Cl to Ln, and ionization potential of 6.6 eV. β-Decay (¹A₁//C_4v)-Pc¹⁷⁷LuCl → (¹A₁//C_4v)-(Pc^177mHfCl)⁺ occurs with no significant change of the charge on the metal atom.     

Crystal structure of EuLnAgS<Subscript>3</Subscript> (Ln = Gd and Ho) compounds

The crystal structures of the first prepared EuLnAgS₃ (Ln = Gd and Ho) compounds, which have two polymorphs, were determined by X-ray powder diffraction. α-EuLnAgS₃ phases are isostructural to BaErAgS₃ (monoclinic crystal system, space group C2/m): a = 17.3168(10) Å, b = 3.9683(2) Å, c = 8.3174(4) Å, β = 103.94° (EuGdCuS₃); a = 17.1729(12) Å, b = 3.9367(3) Å, c = 8.2905(6) Å, β = 103.9° (EuHoCuS₃). β-EuLnAgS₃ phases belong to the AgBiS₂ structure type (cubic crystal system, space group Fm-3m): a = 5.739(2) Å (EuGdCuS₃) and a = 5.678 Å (EuHoCuS₃). In the α-EuLnAgS₃ crystal structure, LnS₆ octahedra and AgS₅ trigonal bipyramids share edges to form a three-dimensional (3D) structure with channels accommodating Eu²⁺ ions. A decrease in Ln³⁺ ionic radius gives rise to the crystal-chemical contraction of the 3D structure.     

Microbial Transformation of Curcumin to Its Derivatives with a Novel <Emphasis Type="Italic">Pichia kudriavzevii</Emphasis> ZJPH0802 Strain

Curcumin, a polyphenolic compound, has shown a wide range of pharmacological activities and has been widely used as a food additive. However, the clinical use of curcumin is limited to some extent because of its poor water solubility and low bioavailability. To overcome these problems, many approaches have been attempted and structural modification of curcumin by microbial transformation has been proven to be an alternative. In this study, we isolated a novel yeast strain Pichia kudriavzevii ZJPH0802 from a soil sample, which is capable of converting curcumin to its derivatives. The transformed products by this strain were evaluated by HPLC, (+) electrospray ionization (ESI)-MSⁿ, and ¹H nuclear magnetic resonance methods. Compared with controls, two new peaks of the transformed broth appeared at retention times of 26 min (I) and 62 min (II) by HPLC analysis. The two transformed products were then further identified by (+) ESI-MSⁿ. The spectrum showed that compound I had an accurate [M+H+NH₃]⁺ ion at m/z 392, [M+H]⁺ ion at m/z 375, [M+H–H₂O]⁺ ion at m/z 357, and (+) ESI-MS³ spectrum showed that ion at m/z 357 could further form fragment ions at m/z 339, 177, and 163; compound II had an accurate [M+H]⁺ ion at m/z 373, [M+H–H₂O]⁺ ion at m/z 355, and (+) ESI-MS³ spectrum showed that ion at m/z 355 could further form fragment ions at m/z 219, 179, 177, 163, and 137. These two transformed products thereby were confirmed as hexahydrocurcumin (I) and tetrahydrocurcumin (II).     

Thermodynamic properties of some lanthanum and lanthanide halides: II. Thermodynamic functions of gaseous molecules LnX (Ln = Ce−Lu,X = F,Cl)

The molecular constants of LnF (Ln = Ce?Lu) for the ground state have been estimated based on the available spectroscopic characteristics of lanthanum and lanthanide monofluorides. These constants have been used for calculating the reduced Gibbs energy (?[G ⁰(T) ? H ⁰(0)]/T) of the compounds in the ideal gas state in the range 298.15–3000 K at the standard pressure p ⁰ = 0.1 MPa. The rigid rotator-harmonic oscillator approximation with additional inclusion of the anharmonicity of oscillations (by the method of Mayer and Goeppert-Mayer) and correction for centrifugal stretching have been used. The contribution made by electronic excitation has been calculated by two methods: based on the energies of the excited states of molecules and based on the electronic excitation energy of the free Ln⁺ ion. Analogous data are reported for lanthanide monochlorides.     

Thermochemistry of the Reaction of Solvated Sodium Ion Clusters with Thymine in the Gas Phase: An Example of the Reaction in Microcosmic Environment

The thermochemistry of the reaction of the microsolvated Na⁺ such as [Na(H₂O) _n ; n?=?1?6]⁺, [Na(NH₃) _n ; n?=?1?6]⁺ and [Na(H₂O) _n (NH₃) _m ; n?+?m?=?2?6]⁺ with thymine (Thy), as an example of a reaction in the microcosmic environment, have been studied in this work, theoretically. It was found that the increase of the number of solvent molecules in the structure of microsolvated Na⁺ is accompanied by the decrease of the standard enthalpy (\(\Delta H_{r}^{^\circ }\)) and Gibbs free (\(\Delta G_{r}^{^\circ }\)) energies of the reaction (Thy?+?[Na(X) _n ]⁺→Thy-Na(X) _n ⁺ ; X?=?solvent molecule). Also, the calculations showed that the electronic intermolecular interaction (?E_int) between the Thy and microslovated Na⁺ decreased with the increase of solvent molecules. For the interaction of the [Na(H₂O) _n ; n?=?4, 5 and 6]⁺ ions with the Thy, there was the probability of forming of the hydrogen bond between water molecules in the structure of solvated Na⁺ and the Thy. The gas phase infrared (IR) spectra of the complexes of the microsolvated Na⁺ with the Thy for different values of n were calculated and compared with each other to follow the change in the frequency of the stretching vibration of the interaction path between the C=O group of the Thy and Na (O…Na) with n. Using the calculated values of \(\Delta G_{r}^{^\circ }\) of the reactions, the mole fractions of the complexes of microsolvated Na⁺ ions with the Thy were calculated at different humidity.     

Mass Spectrometric Detection of Charged Silver Nanoclusters with Hydrogen Inclusions Formed by the Reduction of AgNO<Subscript>3</Subscript> in Ethylene Glycol

In the problem of the production silver nanoparticles, mass spectrometry allows one to identify nanoclusters as nuclei or intermediates in the synthesis of nanoparticles and to understand the mechanisms of their formation. Using low-temperature secondary emission mass spectrometry, we determined the cluster composition of a system formed in the microwave treatment of a solution of AgNO₃ in ethylene glycol (M). Along with silver ion–ethylene glycol associates М _m ? Ag⁺ (m = 1–5) and small silver clusters AgM _n ⁺ (n = 1–9), unusual silver clusters with one hydrogen atom [Ag _n H]⁺ (n = 2, 4) were observed. Possible pathways for the formation of silver nanoparticles taking into account hydrogen-containing cluster intermediates are discussed.     

Chlorokomplexe von 3 d5-Ionen in nichtwäßrigen Lösungen

The chloro systems of Mn²⁺ and Fe³⁺ were investigated in acetonitrile (AN), propanediole-1,2-carbonate (PDC) and trimethylphosphate (TMP) by spectrophotometric, potentiometric and conductometric methods. The following coordination forms seem to be present: MnCl₂ (inAN, PDC andTMP), [MnCl₄]^2? (tetrahedral inAN, octahedral inTMP), [MnCl₆]^4? (octahedral inPDC andTMP); [FeCl]²⁺ (tetrahedral inAN andPDC), [FeCl₂]⁺ (tetrahedral inTMP), FeCl₃ (tetrahedral inAN andPDC), [FeCl₄]^? (tetrahedral inAN, PDC andTMP).     

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 properties of lanthanum and lanthanide halides: IV. Enthalpies of atomization of LnCl,LnCl<Superscript>+</Superscript>, LnF,LnF<Superscript>+</Superscript>, and LnF<Subscript>2</Subscript>

The results of measurement of equilibrium constants of 30 reactions involving lanthanum and lanthanide fluorides (LnF, LnF₂, and LnF₃) and 14 reactions involving lanthanum and lanthanide monochlorides (Ln = La-Lu) have been summarized. These constants have been used for calculating the enthalpies of reactions by the second and third laws, from which the enthalpies of atomization Δ_at H ₀ ⁰ of LnCl, LnF, and LnF₂ have been determined. Comparison of the calculation results shows that the thermodynamic functions of LnCl and LnF (Ln = Ce-Yb) in which the electronic excitation contribution has been calculated from the excitation energies of Ln⁺ ions allow one to adequately determined the Δ_at H ₀ ⁰ values from experimental data. Using the trends in the change in Δ_at H ₀ ⁰ as a function of the atomic number of a lanthanide, the enthalpies of atomization of compounds for which experimental data are lacking have been estimated. The Δ_at H ₀ ⁰ values for LnCl⁺ ions have been calculated. The reliability of the Δ_at H ₀ ⁰ values for LnF⁺ ions have been assessed.     

Electronic Structure and Relative Stabilities of 10- and 12-Vertex. <Emphasis Type="Italic">Closo</Emphasis>and <Emphasis Type="Italic">Nido</Emphasis>-Heteroborane Clusters of Ga,Ge, and As Elements

A DFT method with the B3LYP functional and the 6-311++G(d,p) diffuse basis set is used to predict geometries, relative stabilities, electronic structures, and the bonding of closo- and nido-Ga_mB_n–mH _n ^2? , Ge_mB_n–mH _n ^m?2 , and As_mB_n–mH _n ^{2 m?2} (n = 10, 12 and m = 1, 2) Clusters are obtained by replacing BH with isolobal GaH, GeH⁺, and AsH²⁺ fragments, keeping the same skeleton electron pairs (SEP). Based on the polyhedral skeletal electron pairs theory (PSEPT), closo and nido structures are predicted and can be of significant interest for experimentalists working in the field of heteroboranes. Different cluster stabilities are studied according to Gimarc′s and Williams′ rules, where our calculations show that the monosubstituted clusters deviate from these rules, giving rise to open structures. As₂B₈H _n ²⁺ as 10-vertex structures lead to nido-type clusters, however, Ge_mB_n–mH _n ^m?2 (n = 10, 12 and m = 1, 2) give rise to closo isomers with close energies. All optimized structures exhibit large HOMO–LUMO gaps suggesting a good kinetic stability, thus predicting their isolation and characterization.     

Electron affinity and substituent effects in radical anions

The first vertical electron affinities EA of 13 series of molecules and free radicals D(X _i ) _n are related to the inductive (σ _I ), resonance (σ _R ^? ), and polarization (σ_α) parameters of substituents X _i by the dependences EA = EA _H + aΣσ _I + bΣσ _R/? + cΣσ_α: In radical anions D^+·(X _i ) _n , compared to radical cations D^+·(X _i ) _n , the polarization interaction is weaker or similar in magnitude but has an opposite sign. The previously unknown resonance parameters σ _R ^? of substituents SiMe₃ and CH₂SiMe₃ bound to the radical anion center H₂C=CH^?· were calculated.