Study of Intra- and Intermolecular Interactions with Participation of α-Phosphorylated Amines and Alcohols in Different Solvents

Specific interactions of -hydroxy- and -aminophosphonates in chloroform and pyridine solutions were studied by theoretical (molecular mechanics) and experimental methods (calorimetry and IR spectroscopy). A competition between intra- and intermolecular interactions and effect of steric factor in molecules of organophosphorus compounds were revealed.     

Hydrodynamic Properties of “Pseudo-Dendrimer”

Summary: Hyperbranched polycarbosilane with terminal butyl groups is obtained by chemical modification of hyperbranched polyallylcarbosilane using the reaction of hydrosilylation with methyldichlorosilane, followed by treatment of the polychlorosilyl derivative with butyllithium. Its hydrodynamic and conformational properties are studied by the methods of light scattering, sedimentation-diffusion analysis, and viscosimetry in dilute solutions of methyl-tert-butyl ether, hexane, THF, chloroform, and toluene. The results obtained are compared with the data for the initial polyallylcarbosilane and carbosilane dendrimer with butyl terminal groups. It is demonstrated that branching regularity is the decisive factor determining the solution properties at fixed degree of the branching.     

Guest-Binding and Catalytic Properties of Immobilized β-Cyclodextrins

Abstract

Cyclodextrins¹(CyDs), cyclic oligomers of 6–8 glucose units, form inclusion complexes with guest compounds and have been used as catalyst for the selective syntheses.² Previously, immobilization of CyD with epichlorohydrin as crosslinking agent have been described.^3-4 Here, we report the first successful immobilization of β-CyD using various crosslinking agents. The guest binding abilities and the catalytic abilities of these immobilized β-CyDs are shown.     

The Viscosity of Dilute Solution of a Novel Polymer ‘Dextran’ in Different Solvents

Abstract

The viscosity of dilute solution of a water soluble polysaccharide “Dextran” has been studied in 6(M) Urea, 2(M) Glycine and 50% Glucose solution in three different temperatures - 40°C, 45°C and 50°C. From the solution viscosity measurement, thermo viscosity parameters like Huggins' constant (k′_H). Kraemer's constant (k″_H) and the viscosity concentration coefficient (a₂) have been estimated from viscosity concentration plots. The value of these parameters have been characterized and compared with the theoretical value. The evaluation of these constants enable to know the fate of polymer molecules in the solution.     

Solubility of 3-Caffeoylquinic Acid in Different Solvents at 291–340 K

Using a laser monitoring observation technique the solubilities of 3-caffeoylquinic acid in pure solvents, water, methanol, ethanol, 1-propanol, 1-butanol, and two mixed solvents, methanol + water, ethanol + water have been determined at temperature range from 291–340 K. The experimental data were correlated by the modified Apelblat equation, λh equation, and ideal model. The calculated solubilities were turned out very consistent with the experimental results, and the modified Apelblat equation shows the best agreement.     

Measurement and Correlation of the Solubility of N-Acetylglycine in Different Solvents at Temperatures from 278.15 to 319.15 K

The solubility of N-acetylglycine was measured in methanol, ethanol, propanol, isopropanol, n-butanol and ethyl formate in the temperature range between 278.15 and 319.15 K under atmospheric pressure by a gravimetric method. The solubility of N-acetylglycine in those selected solvents increases with increasing temperature. The solubility data were correlated with the van’t Hoff equation, the modified Apelblat equation and the λh equation to obtain the corresponding model parameters. The experimental results could be useful for optimizing the industrial process of purification of N-acetylglycine.     

Solute–Solvent Interactions of Methyl Violet in Different Solvents on Spectral Data

Spectroscopic studies of Methyl violet in protic (water, methanol, ethanol, isopropanol and n-butanol) and aprotic solvents (acetone, DMF) were carried out. UV-Visible absorption spectra of Methyl violet in protic solvents showed a hypsochromic shift, as the solvent polarity was changed from less polar to more polar, while a bathochromic shift was observed for aprotic solvents. Transition energy of Methyl violet in different solvents was correlated with solvatochromic parameters to study solute–solvents interactions. The Kamlet–Taft, Catalan and unified scale models were applied to investigate interactions between Methyl violet and solvents. The best agreement is found for the Catalan model.     

Conformational Composition and Spin Properties of β-Phosphone Nitroxyl Radicals in Gaseous Phase and Solutions

Abstract

As part of our studies of the extremely high sensitivity to substitutients A,B,R, temperature and solvents of phosphorus hyperfine splitting in ESR spectra of β-phosphone nitroxyl radicals ABP(O)CR₂N(Î)Bu¹, we have studied them theoretically. The conformational composition and spin delocalization in H₂(O)CH₂N(Î)Í, (ÌåÌ)₂P(O)CÌå₂N(Î)Ìå and (ÍÎ)₂P(O)CÌ?₂N(Î)Bu' has been studied by UHF/6-31G& and MNDO (GAMESS). Solvent effects on conformational equilibrium, rotational and inversion barriers, charge distributions and spin properties of β-phosphone nitroxyl were calculated by SCRF UHF/6-31G* method.     

The Up-conversion Laser Properties of a Non-polar Organic Dye and the Influence of Solvents and Pumping Wavelengths

The research on up-conversion photoluminescence of organic materials is a hot topic1, most recently, the up-conversion laser properties of organic materials with big two- photon absorption cross section have been noticed especially2. According to the prev…     

Comments on “Solubility and Dissolution Thermodynamic Data of Cefpiramide in Pure Solvents and Binary Solvents”

Errors are found in the mathematical correlation based on the combined Jouyban–Acree and Modified Apelblat models for describing the variation in the mole fraction solubility of cefpiramide with temperature and solvent composition for the binary aqueous–ethanol solvent system. The equation coefficients given by Tang and coworkers, when substituted into the model equation, do not yield the authors’ calculated mole fraction solubilities of cefpiramide.     

Solubility of Omeprazole Sulfide in Different Solvents at the Range of 280.35–319.65 K

Solubility data were measured for omeprazole sulfide in ethanol, 95 mass-% ethanol, ethyl acetate, isopropanol, methanol, acetone, n-butanol and n-propanol in the temperature range from 280.35 to 319.65 K by employing the gravimetric method. The solubilities increase with temperature and they are in good agreement with the calculated solubility of the modified Apelblat equation and the λh equation. The experimental solubility and correlation equation in this work can be used as essential data and model in the purification process of omeprazole sulfide. The thermodynamic properties of the solution process, including the Gibbs energy, enthalpy, and entropy were calculated using the van’t Hoff equation.     

Miceliization and Surface Adsorption of Tetraethylammonium Perfluorooctanesulfonate in Mixed Solvents

The surface tension and cenductivity of tetracthylarnmomum perfluorooctanesulfonate (TEPFOS) solu-tions in mixed solvents were determined The criticsl micelle concentrations (cmc) and surface adsorption of TEPFOS in various solvents (Dimetbylsulfoxlde and DMSO, formamide and FA, and DMSO-H2O and FA H2O mixtures) were calculated from the above experimental date. The results show that the surface activity of TEPFOS is much higher than that of typical hydrocarbon surfactant, sodium dodecylsulfate (SDS); the melecalar interaction (in terms of colubility araneter or surface tension) of solvent is the decisive factor in sffecting the cmc of TEPFOS , in the apretic solvent DMSO, the value of entropy change during micelliza-tion of TEPFOS may beecme subsantially negative; the surfaof adsorption amount of TEPFOS is the largest in H2O, smaller in FA , and the smallest in DMSO.     

Different J-Type Aggregates of meso-Tetrakis （4-hydroxyphenyl） porphyrin （H2THPP） Formed in Different Solvents

The aggregation of meso-tetrakis(4-hydroxyphenyl)porphyrin (H2THPP) in dimethylformamide (DMF)-water solution and in DMF-chloroform solution was studied by UV-vis absorption spectroscopy. The red shift of Soret band indicates the formation of J-type aggregates of H2THPP in these two solutions. However, different shift extent of Sorer band, 12 nm in DMF-water solution and 32 nm in DMF-chloroform solution, implies structural difference between these two J-type aggregates. The hydrogen bond between hydroxyl group and N-H bonds in porphyrin ring is thought as the main cause to the formation of J-type aggregate in DMF-chloroform solution, whereas the π-Q interaction between two adjacent porphyrin cores is thought as the main cause of the formation of J-type aggregate in DMF-water solution     

Optical and Electronic Properties of Different Kinds of Water‐Soluble Porphyrin Films

Water‐soluble porphyrin‐porphyrin and porphyrin‐CdSe nanoparticle monolayer films were self‐assembled on different substrates. The influence of substrates, types of films, and heat treatment temperature on fluorescence of different kinds of porphyrin films was investigated. The SEM images showed the formation of monolayer films on porous alumina foil. The films assembled on porous alumina foil possessed higher fluorescence intensity and thermal stability. The result of conductance measurement indicated that the interaction of trimethylamidophenylporphyrin iodide (TAPPI) molecules with hydroxyl groups on porous alumina foil was weakened after CdSe nanoparticles assembled with TAPPI.     

Deuterium isotope effects in the thermal decomposition of β hydroxy ketones and β-hydroxy esters

Small primary and cumulative secondary isotope effects a determined experimentally by thermolysis of various β-hydroxy ketones and β-hydroxy esters.     

Synthesis and Mesomorphic Properties of Novel γ-Substituted β-Diketonates

The synthesis and mesomorphic properties of two series of novel γ-substituted β-diketonates have been reported. All of the compounds 2,4-dioxo-3-pentyl 4-[[4-(n-alkoxyl) cinnamoyl]oxy]cinnamatetes Ia-If (n=7-12) exhibit two monotropic phases(N and Sc) and have a wider mesophase range than the compounds 2,4-dioxo-3-pentyl 4-[[4-(n-alkoxyl) benzoyl]oxy] cinnamatetes Ⅱa-Ⅱf (n=7-12), which display one monotropic nematic phase (n=7-10) or an enantiotropic nematic phase for n=11 or two enantiotropic phases (N and Sc)for n=12.     

Synthesis,Structure Characterization and Optical Properties of β Lithium Zinc Phosphate

β-LiZnPO_4 single crystal was successfully synthesized via hydrothermal method. It crystallizes in the trigonal space group R3 with a = b = 13.6490 ?, c = 9.1123 ?, γ = 120.00° and Z = 18. Structure of the crystal is constructed by LiO_4, ZnO_4 and PO_4 tetrahedral units to form a three-dimensional(3 D) framework. The crystal has a high transmission ranging from 350 to 800 nm with UV cut-off edge at 220 nm. The nonlinear optical efficiency of the as-prepared β-LiZnPO_4 is about 1.2 times as large as that of KDP(KH_2PO_4) standard. Additionally, band structure and density of states calculations for β-LiZnPO_4 were performed using the total-energy code CASTEP, based on density functional theory(DFT).     

Stereochemistry in alkylations of dianions of β-hydroxysulfoxides and β-hydroxysulfones

Alkylations of dianions of β-hydroxysulfoxides and β-hydroxysulfones have been found to be affected by chelation of a Li cation with a sulfinyl group and by coordination of the cation with tetrahydrofuran rather than a sulfonyl group, respectively.     

Study on the Intramolecular Cyclization through Opening of Epoxide Ⅳ. Cyclization of N-Methyl-N-benzoylmethylene β-Methyl-a, β- epoxypropionamide in Aprotic and Protic Solvents

Intramolecular cyclization of β -methyl substituted epoxide under aprotics （e.g. LDA in benzene） and protic conditions （e.g. LiOH in MeOH/H2O）both gave a mixture of β-,γ-, δ- and ε-lactam but in different ratio.     

Two—photon Up—conversion Luminescent Properties of HMASPS and HEASPS in Three Different Polymer Matrices

Three dye-doped polymer rods in different matrices were synthesized in which wcak hydrogen bond, strong hydrogen bond and covalent bond existed between the dye and the polymer chain. And the two-photon up-conversion luminescent properties of HMASPS and HEASPS in three different microenvironments were studied.