Volumetric and Acoustic Studies of Binary Liquid Mixtures of Dipropylene Glycol Dimethyl Ether with Methyl Acetate, Ethyl Acetate and n-Butyl Acetate in the Temperature Range T = (288.15, 293.15, 298.15, 303.15, and 308.15) K

Densities and ultrasonic speeds have been measured over the whole composition range for binary liquid mixtures of dipropylene glycol dimethyl ether, CH₃(OC₃H₆)₂OCH₃, with methyl acetate, ethyl acetate, and n-butyl acetate using an Anton Paar DSA 5000 M density and speed sound analyzer at T = (288.15, 293.15, 298.15, 303.15, and 308.15) K and atmospheric pressure in order to evaluate the behavior of these binaries. From these data excess the molar volume, $ V_{m}^{\text{E}} $ , and deviation in isentropic compressibility, ?κ _S , have been calculated. These excess properties have been fitted with the Redlich–Kister type polynomial equation to get their coefficients and standard deviations which provide a base for discussing the forces operating in solutions.     

4,5-Dihydroxyimidazolidin-2-ones in an α-ureidoalkylation reaction of N-(carboxyalkyl)-, N-(hydroxyalkyl)-, and N-(aminoalkyl)ureas 3. α-Ureidoalkylation of N-[2-(dimethylamino)ethyl]urea

α-Ureidoalkylation of N-[2-(dimethylamino)ethyl]urea with 1,3-unsubstituted, 1,3-dialkyl-, and 1,3-dimethyl-4,5-diphenyl-4,5-dihydroxyimidazolidin-2-ones(thiones) was systematically studied. Hitherto unknown N-[2-(dimethylamino)ethyl]glycolurils and their hydrochlorides were synthesized. The yields of the target glycoluril hydrochlorides decreased on going from 1,3-H₂- to 1,3-dialkyl-4,5-dihydroxyimidazolidin-2-ones and increased with the introduction of phenyl groups at the positions 4 and 5 of the starting 4,5-dihydroxyimidazolidin-2-one. X-ray diffraction study showed that 2-[2-(dimethylamino)ethyl]glycoluril crystallizes in the form of a conglomerate.     

Synthesis and characterization of dinuclear p-, m- and o-xylyl bridged complexes of molybdenum and tungsten. The crystal structures of μ-p-xylyl- bis(η-pentamethyl-cyclopentadienyltri- carbonylmolybdenum) and μ-m-xylyl-bis(η- pentamethylcyclopentadienyltricarbonyltungsten)

The reactions of (M = Mo, W) with α,α′-p-, m- and o-dichloro-xylenes yielded p-, m- and o-xylyl bridged dinuclear complexes of in high yields. All of such new complexes are stable to air and water, even stable in dilute acids and bases.     

Complex salts trans-[Rh(β-Pic)4Cl2]X (X = Cl?, ReO 4? , and ClO 4? ): Synthesis, crystal structures, and thermal properties

Three novel complex salts containing the cation trans-[Rh(β-Pic)₄Cl₂]⁺ with the anions Cl⁻ (I), ReO₄⁻ (II), and ClO₄⁻ (III) were obtained and characterized by elemental analysis, X-ray diffraction, NMR spectroscopy, and IR spectroscopy. The complex trans-[Rh(β-Pic)₄Cl₂]ReO₄ crystallizes from DMF as a solvate in which solvent molecules fill the channels formed by the cations and anions. The thermal properties of complexes I, II, and II · DMF were examined by DTA. Final and some intermediate products of the thermolysis were isolated and characterized by physicochemical methods.     

Asymmetric synthesis of the natural erythro-(1R,2S)-8-O-4′-neolignan myrislignan

Abstract  

An efficient and practical asymmetric synthesis of erythro-(1R,2S)-8-O-4′-neolignan myrislignan was achieved by using vanillin and pyrogallic acid as the starting materials. Two key steps are involved: preparation of an enantiopure threo alcohol of predictable stereochemistry by dihydroxylation with AD-mix-β, and inversion of the absolute configuration from the threo to the erythro isomer using a Mitsunobu reaction. The route illustrates a new methodology for the synthesis of erythro-8-O-4′-neolignan.     

Simultaneous Capillary Gas Chromatographic Determination of Cyproterone Acetate and 15β-Hydroxycyproterone Acetate in Urine

Abstract

The simultaneous capillary GC determination of underivatized antiandrogen cyproterone acetate (CPA) and its active metabolite 15β-hydroxycyproterone acetate (OH-CPA) in spiked urine was performed on a flexible VCOT quartz capillary column, coated with a non-polar CP-Sil 5 CB liquid phase. A split/splitless injector and a flame-ionization detector were used. Equilin was used as an internal standard, and resolution of all the compounds was achieved in 6 minutes. Limit of detection was 0.04 μg/μl of injected amount for both CPA and OH-CPA, the recoveries were between 91.35% and 105.56%, and the relative standard deviation varied from 3.35% to 7.38%. The method is applicable in analysis of these steroids in biological fluids.     

Molecular Interactions in 1,4-Dioxane,Tetrahydrofuran, and Ethyl Acetate Solutions of 1,1′-Bis(4-isopropyloxyacetylphenoxy)cyclohexane on Reological,Density, and Acoustic Behavior

Various thermo-acoustical parameters of 1,4-dioxane, tetrahydofuran and ethylacetae solutions of 1,1′-bis(4-isopropyloxyacetylphenoxy)cyclohexane were determined at different temperatures using density, viscosity and ultrasonic speed and correlated with concentration. Linear increase of ultrasonic speed, specific acoustical impedance, Rao’s molar sound function, Van der Waals constant and free volume with concentration C and decreased with temperature. Linear decrease of adiabatic compressibility, internal pressure, intermolecular free path length, classical absorption coefficient, and viscous relaxation time with concentration and increased with temperature indicated existence of strong molecular interactions in solutions and further supported by positive values of solvation number. Gibbs free energy of activation decreased with C in all three systems. It is decreased with T in 1,4-dioxane, while increased in tetrahydrofuran and ethyl acetate. Both enthalpy of activation and entropy of activation are increased gradually with C in 1,4-dioxane, while they are negative and remained practically independent of concentration in 1,4-dioxane and tetrahydofuran systems.     

Densities, Specific Heat Capacities, Apparent and Partial Molar Volumes and Heat Capacities of Glycine in?Aqueous Solutions of Formamide, Acetamide, and?N,N-Dimethylacetamide at T=298.15?K and?Ambient Pressure

Apparent molar volumes (V _2,φ ) and heat capacities (C _p2,φ ) of glycine in known concentrations (1.0, 2.0, 4.0, 6.0, and 8.0 mol⋅kg⁻¹) of aqueous formamide (FM), acetamide (AM), and N,N-dimethylacetamide (DMA) solutions at T=298.15 K have been calculated from relative density and specific heat capacity measurements. These measurements were completed using a vibrating-tube flow densimeter and a Picker flow microcalorimeter, respectively. The concentration dependences of the apparent molar data have been used to calculate standard partial molar properties. The latter values have been combined with previously published standard partial molar volumes and heat capacities for glycine in water to calculate volumes and heat capacities associated with the transfer of glycine from water to the investigated aqueous amide solutions, D[`(V)]<sub>2,tr</sub><sup>o</sup>\Delta\overline{V}_{\mathrm{2,tr}}^{\mathrm{o}} and D[`(C)]_p2,tr^o\Delta\overline{C}_{p\mathrm{2,tr}}^{\mathrm{o}} respectively. Calculated values for D[`(V)]<sub>2,tr</sub><sup>o</sup>\Delta\overline{V}_{\mathrm{2,tr}}^{\mathrm{o}} and D[`(C)]_p2,tr^o\Delta\overline{C}_{p\mathrm{2,tr}}^{\mathrm{o}} are positive for all investigated concentrations of aqueous FM and AM solutions. However, values for D[`(C)]_p2,tr^o\Delta\overline{C}_{p\mathrm{2,tr}}^{\mathrm{o}} associated with aqueous DMA solutions are found to be negative. The reported transfer properties increase with increasing co-solute (amide) concentration. This observation is discussed in terms of solute + co-solute interactions. The transfer properties have also been used to estimate interaction coefficients.     

Densities, Viscosities, Speeds of Sound, FT-IR and 1H-NMR Studies of Binary Mixtures of n-Butyl Acetate with Ethanol, Propan-1-ol, Butan-1-ol and Pentan-1-ol at?298.15, 303.15, 308.15 and 313.15?K

Densities, viscosities and speeds of sound of binary mixtures of ethanol, propan-1-ol, butan-1-ol and pentane-1-ol with n-butyl acetate have been measured over the entire range of composition at temperatures of 298.15, 303.15, 308.15 and 313.15 K and atmospheric pressure. From the experimental densities, viscosities and speeds of sound, the excess molar volumes V ^E, deviations in viscosity ????, and deviations in isentropic compressibility ???? _S have been calculated. The excess molar volumes and deviations in isentropic compressibility are positive for all the binary systems studied over the whole composition, while deviations in viscosities are negative for all of the binary mixtures. The excess molar volumes, deviations in viscosity, and deviations in isentropic compressibility have been fitted to a Redlich?CKister type polynomial equation. FTIR and ¹H-NMR studies of these mixtures are also reported.     

Kamlet–Taft's Solvatochromic Parameters for Nonaqueous Binary Mixtures between n-Hexane and 2-Propanol, Tetrahydrofurane, and Ethyl Acetate

The π*, α, and β Kamlet–Taft solvatochromic solvent parameters have been determined for nonaqueous binary mixtures commonly used in normal-phase liquid chromatography (NPLC), such as ethyl acetate n-hexane, tetrahydrofurane n-hexane, and 2-propanol n-hexane from spectroscopic data by using several UV-visible absorbing probes. Because preferential solvation is almost nonexistent for the π* probes in the different binary mixtures, we conclude that the measured values reflect quite well the dipolarity–polarizability of the bulk solution. However, strong preferential solvation for the different α and β probes in all mixtures studied here shows that the solvent parameters obtained reflect the properties of the solvation shell more than the bulk properties. This observation does not necessarily mean that the α and β values obtained will not be useful in multiple linear regressions (MLR), but results should be interpreted with care and will depend on the particular situation. Actually, results will make sense only if the particular solute under study preferentially solvates in a fashion similar to that of the α and β solvatochromic probes.     

Synthesis, spectral and thermal properties, and crystal structure of catena-poly-μ-ethylenediamine(dipicolinato)zinc(II) trihydrate, {[Zn(dipic)(μ-en)]·3H2O}n

A novel metal–organic coordination polymer framework formulated as {[Zn(dipic)(μ-en)]·3H₂O} _n (1) (catena-poly-μ-ethylenediamine(dipicolinato)zinc(II) trihydrate) has been synthesized and characterized by spectral method (IR), elemental analysis, thermal analysis (TG, DTG, DTA) and single crystal X-ray diffraction techniques. It crystallizes in the triclinic system, space group P−1. The asymmetric unit contains three hydrogen-bonded water molecules and the Zn atom is five-coordinated by three N and two O atoms. In fact, it is a new one-dimensional zinc complex with the peculiarity of having the ethylenediamine ligand very unusually acting as bridge to form polymeric chains. In the crystal structure, intramolecular O–H···O and intermolecular O–H···O and N–H···O hydrogen bonds result in the formation of a supramolecular structure, in which they seem to be effective in the stabilization of the structure.     

Synthesis, Spectral and Structural Study of N-[1-(N,N,N′,N′-Tetramethylphosphoramidoyl)- 1H-Benzimidazol-2-yl]-Propionimidic Ethyl Ether

The preparation of N-[1-(N,N,N,N-tetramethylphosphoramidoyl)-1H-benzimidazol-2-yl]-proponimidic ethyl ester 2 has been achieved by the reaction of N-(1H-benzimidazol-2-yl)-proponimidic acid ethyl ester 1 with N,N,N,N-tetramethylchlorophosphoramide. The structure of compound 2 has been determined by X-ray diffraction. The results of (¹H, ¹³C, ³¹P) NMR, IR, EI-MS spectral data are consistent with those obtained from the X-ray diffraction. The compound crystallizes in the triclinic system, following the EsZ conformation. In the crystal, there are two weak C3–H3s1 and C15–H15sO1 intermolecular hydrogen bonds.     

Self‐Assembly Fractal Microstructures of HPAM/Chromium Acetate and HPAM/Phenolic Aldehyde Colloidal Dispersion Gel

Abstract

HPAM (partially hydrolyzed polyacrylamide)/chromium acetate and HPAM/phenolic aldehyde colloidal dispersion gels (CDGs) were investigated microscopically using atomic force microscope. The results show that the colloidal dispersion gels eventually form self‐assembly branch‐like fractal structures over a scanning range of micrometers. The fractal aggregates of single twigs formed by compact assembly of nanometer particles were observed over a smaller scanning range regardless of the concentration of HPAM and the crosslinking reagent. This indicated an HPAM‐dependence for the formation of the fractal structure and the crosslinking reagent independence of the geometrical morphology of the gel. Also, the results demonstrated that the elastic modulus (G′) of the fractal structure formed by the smaller (nanometer‐sized) colloidal particles was one order of magnitude higher than obtained for the micrometer‐sized particles. The elastic modulus (G′) and the dynamic stability of the gels increased with decreasing particle diameter.     

Synthesis of the Acetate of a New Phenolic Glycoside,Anacardoside,from Semecarpus anacardium and its Diastereomer

Anewphenolicglycoside1,anacardoside,1-O-β-D-glucopyranosyl-(1→6)-β-D-glucopyranosyloxy-3-hydroxy-5-methylbenzenewasrecentlyisolatedfromthefruitsofSemecarpusanacardium,whichhasbeenreportedtopossessanti-cancer,anti-inflammatory,anti-arihriticandanthelminticactivitiesz(2-8).Butthenaturalcontentofthenewphenolicglycosideisextremelysmall(0.0075%)andtheprocedureofextractionandseparationisverycomplicated'.Theimportantbiol0gicalimplication0ftheattachmentofsugarmoietiestoanaglyconaren0wbecondngmoreo…     

O,O'-二烷基-α-(4-三氟甲基苯基)氨基-取代苯基甲基膦酸酯的绿色合成研究

采用微波辐射﹑离子液体和无溶剂无催化剂三种绿色合成方法, 分别进行了以亚磷酸酯、邻氟苯甲醛和对三氟甲基苯胺为原料的类Mannich一锅法合成反应研究, 经合成筛选, 优选出控制反应温度100 ℃、无溶剂和无催化剂加热反应15 min的合成方法, 实验结果表明该方法经济、简便、产率高、反应时间短及对环境友好.     

1H, 13C, 15N NMR and 13C, 15N CPMAS studies of cobalt(III)-chloride-pyridine complexes, spontaneous py → Cl substitution in trans-[Co(py)4Cl2]Cl, and a new synthesis of mer-[Co(py)3Cl3]

trans-[Co(py)₄Cl₂]Cl·6H₂O, mer-[Co(py)₃Cl₃] and mer-[Co(py)₃(CO₃)Cl] were studied by UV-Vis, far-IR and ¹H, ¹³C, ¹⁵N NMR. The formation of Co-N bonds lead to variable in sign and magnitude changes of ¹H NMR chemical shifts, heavily dependent on proton position, coordination sphere geometry and character of auxiliary ligands. ¹³C nuclei were deshielded upon Co(III) coordination, while ¹⁵N NMR studies exhibited ca. 85–110 ppm shielding effects (ca. 15–25 ppm more expressed for nitrogens trans to N than trans to Cl or O). ¹³C and ¹⁵N CPMAS spectra revealed a slight inequivalency of formally identical Co-py bonds in trans-[Co(py)₄Cl₂]Cl·6H₂O and mer-[Co(py)₃Cl₃], suggesting for the latter complex an existence of distortion isomers. In chloroform, a spontaneous trans-[Co(py)₄Cl₂]Cl → mer-[Co(py)₃Cl₃] + py reaction was monitored by ¹H NMR and UV-Vis. This process of py → Cl substitution allowed the design of a more convenient and efficient method of mer-[Co(py)₃Cl₃] preparation.      

正辛烷为稀释剂不对称N-甲基-N-辛基烷基酰胺萃取铀(Ⅵ)的研究(英)

The extraction of uranyl nitrate was studied with newly synthesized unsymmetrical alkylamides, Nmethyl-N-octyloctylamide (MOOA), N-methyl-N-octyldecanamide (MODA), and N-methyl-N-octyldodecanamide (MODOA), employing n-octane as diluent. The effect of the concentrations of nitric acid, sodium nitrate and extractants on the extraction was investigated and the extraction mechanism was suggested. The effect of temperature on the extraction was also studied and the related thermodynamic functions were calculated. The extracted species were characterized by FTIR spectrometry。     

Synthesis, crystal and electronic structures, and thermodynamic characteristics of BaCe1 ? xInxO3 ? x/2 solid solutions

New perovskite oxide phases BaCe_{1 − x} In _x O_{3 − x/2} (x = 0.1–0.8) (space group Pbnm) have been synthesized. The unit cell volume of the resulting solid solutions monotonically decreases with an increase in the degree of substitution of indium for cerium due to the contraction of octahedra in perovskite blocks. The thermodynamic stability of the compound BaCe_0.75In_0.25O_2.875 was studied by the solution calorimetry method, and barium cerates were shown to be thermodynamically stable with respect to binary oxides at room temperature. The structure of occupied and vacant states in BaCe_{1 − x} In _x O_{3 − x/2} was determined on the basis of X-ray emission, absorption, and photoelectron spectra, and the energy gap was estimated at ∼2 eV.     

Synthesis and Crystal Structure of an Acetate Radical Bridged Dinuclear Copper(Ⅱ) Complex

A new acetate radical bridged dinuclear copper(Ⅱ ) complex (C8H9NO2)2-Cu2(CH3COO)4 has been synthesized by the reaction of Cu(OAc)2 with pyridine-3-ethyl formate and further characterized by X-ray single-crystal diffraction. Crystal data for the title compound: triclinic system,space group P1,with a=8.1654(14),b=9.7010(16),c=9.9005(17) ,α= 83.266(2),β=78.887(2),γ=72.881(2)o,V=733.9(2) 3,Mr=665.58,Z=1,Dc=1.506 g/cm3,F(000)=342,μ=1.510 mm-1,the final R=0.0392 and wR=0.1005. According to the structural determination,each unit of the title compound is composed of two Cu(Ⅱ) atoms,two pyridine-3-ethyl formate molecules and four acetate ions. Each Cu(Ⅱ) coordinates to oxygen atoms of acetate and nitrogen atoms of pyridine-3-ethyl formate ligand to give a six-coordinate distorted octahedral geometry. It is worth mentioning that strong Cu–Cu bond can be observed in the title compound.     

Theoretical study of the structure and stability of cage-substituted icosahedral closo-boranes, alanes, and gallanes MiM′12 ? iH 122? (M, M′ = B, Al, and Ga; i = 0–12)

The equilibrium geometric parameters and energetic and spectroscopic characteristics of low-lying conformers for several series of model cage-substituted (mixed) borane, alane, and gallane closo-dianions M _i M′_{12 − i} H₁₂²⁻(M, M′ = B, Al, Ga), as well as of “bare” gallium-aluminum anions Ga _i Al_12−i ⁻ with i = 0–12, were calculated within the B3LYP approximation of the density functional theory using 6–31G* and 6–311+G** basis sets. Differences in structure and stability between alanoborane clusters of similar composition are revealed. In clusters where the M and M’ heteroatoms are close in size and electronegativity (in gallonoalanes and gallium-aluminum anions), successive substitutions of M′ for M are accompanied by small energy changes and occur quasi-stochastically in different positions of the cage. When the substituents are significantly different (in alanoboranes), mixed clusters are unstable against disproportionation into homonuclear “predecessors” M₁₂H₁₂²⁻ and M′₁₂H₁₂²⁻, and the most favorable M _i M′_{12 − i} H₁₂²⁻ structures among them are those in which M _i M′_{12 − i} the cages are subdivided into homonuclear “subclusters” M _i and M′t′_12−i with a maximal number of homonuclear bonds (M-M and M′-M′) and a minimal number of heteronuclear bonds (M-M′).