Surface tension of binary mixtures of imidazolium and ammonium based ionic liquids with alcohols, or water: cation, anion effect

The surface tensions were measured at atmospheric pressure, with use of a ring tensiometer, of a series of alcoholic solutions of closely related ionic liquids: 1-methyl-3-methylimidazolium methylsulfate, [MMIM][CH3SO4] in alcohol (methanol, or ethanol, or 1-butanol at 298.15 K), 1-butyl-3-methylimidazolium methylsulfate, [BMIM][CH3SO4] in alcohol (methanol, or ethanol, or 1-butanol at 298.15 K), 1-butyl-3-methylimidazolium octylsulfate, [BMIM][OcSO4] in alcohol (methanol, or 1-butanol at 298.15 K) and of 1-hexyloxymethyl-3-methylimidazolium tetrafluoroborate, [C6H(13)OCH2MIM][BF4], 1,3-dihexyloxymethylimidazolium tetrafluoroborate, [(C6H13OCH2)2IM][BF4] in alcohol (methanol, or 1-butanol, or 1-hexanol at 308.15 and 318.5 K) and hexyl(2-hydroxyethyl)dimethylammonium bromide, C6Br in 1-octanol at 298.15 K. The set of ammonium ionic liquids of different cations and anions (C2Br, C2BF4, C2PF6, C2N(CN)2, C3Br, C4Br and C6Br) was chosen to show the influence of small amount of the ammonium ionic liquid on the surface tension of water at 298.15 K. The influence of the cation, or anion alkyl chain length on the properties under study (densities and surface tension) was tested.     

5βH,6αH,7αH,10αCH3-eudesman-6,12-olides: A novel stereochemical group of natural sesquiterpene lactones. Stereostructure of isosilerolide

A new stereochemical group of eudesmanolides - 5βH,6αH,7αH,10αCH₃-eudesman-6,12-olides - was identified mainly on the basis of proton NMR spectroscopy and checked by X-ray analysis     

Correlations for the solubility of normal alkanoic acids ando-toluic acid in binary solvent mixtures

Reasonable estimates of ternary solid-liquid equilibrium can be obtained by application of the Wilson and UNIFAC models. The solubilities of octadecanoic, eicosanoic, docosanoic, and o-toluic acids in binary solvents consisting of a common component (cyclohexane) and a varying second component (heptane, ethanol, methanol, 2-propanol, and 1-butanol) have been measured by a dynamic method from 290 to 340 K. The systems containing cyclohexane-alcohols mixed solvents were found to exhibit a synergistic effect of solubility. The best prediction was obtained for the Wilson equation utilizing temperature dependent _ij parameters. For solubilities in nonpolar solvents, the standard deviations for predicted solubilities are comparable to the experimental errors.Presentation to First International Symposium on Solubility Phenomena, University of Western Ontario, London, Ontario, August 21–23, 1984.     

Local dipole interactions induce helicity of (<Emphasis Type="Italic">S</Emphasis>)-2-butyl-<Emphasis Type="Italic">N</Emphasis>-(1,8-naphthaloyl)-2-aminobenzoate molecules containing 1,8-naphthalimide rings utilized as a column building blocks: X-ray and quantum mechanical studies

In the crystal of triclinic symmetry the title compound contains four independent molecules, which differ in the conformation of the aliphatic carbon chain (T, G ⁺and G ⁻) and in the helicity (M or P) of the N-(1,8-naphthaloyl)-2-aminobenzoate (NAB) unit. Quantum chemical MP2 calculations showed that isolated molecules favor helicity of NAB bichromophores most likely due to attractive interactions between local dipoles formed along carbonyl bonds, such that the helical arrangement of O=C–C–C–N–C=O fragments is stabilized by intramolecular interactions between terminal anti-parallel local carbonyl dipoles. In the crystal structure, columnar stacking of the anti-parallel 1,8-naphalimide rings is observed. In a column the neighboring NAB units display opposite helicity.     

Polysiloxane microspheres functionalized with imidazole groups as a palladium catalyst support

Polysiloxane microspheres containing a large number of silanol groups were obtained by an emulsion process of modified polyhydromethylsiloxane. N‐substituted imidazole groups were grafted on these microspheres by the silylation of their silanol groups with N‐[γ‐(dimethylchlorosilyl)propyl]imidazole hydrochloride. The progress of the reaction was monitored using ²⁹Si and ¹³C magic angle spinning (MAS) NMR and its impact on microsphere morphology was studied using scanning electron microscopy (SEM). The usefulness of the imidazole‐functionalized microspheres as a support for a metal catalyst was demonstrated by their reaction with PdCl₂(PhCN)₂. In this way a new heterogenized catalyst, Pd(II) complex with imidazole ligands supported on polysiloxane microspheres, was generated. This catalyst, MPd , was characterized using ¹³C and ²⁹Si MAS NMR, X‐ray photoelectron, Fourier transform infrared and far‐infrared spectroscopies, X‐ray diffraction, SEM–energy‐dispersive X‐ray spectroscopy and wide‐angle X‐ray scattering. The catalyst appears in two structures, as Pd(II) complex and Pd(0) nanoclusters. Its catalytic activity was tested using a model reaction, the hydrogenation of cinnamaldehyde, and compared with that of an analogous complex operating in a homogeneous system. MPd showed a high activity in the promotion of hydrogenation of cinnamaldehyde. The activity in the substrate conversion was stable at least in five cycles of this reaction. The main product was hydrocinnamaldehyde which could be obtained with a yield above 70%. A mechanism of the reaction is proposed. Copyright © 2016 John Wiley & Sons, Ltd.     

An expedient synthesis and conformational features of acylhydrazone macrocycles derived from tartaric acid: evidence of water and π aromatic hydrogen bond interactions

Tartaric acid dihydrazides with acetal protected hydroxy groups react with terephthalaldehyde to preferentially form [2+2] bisacylhydrazone macrocycles. The structures of these macrocycles display all anti N–N and CN bonds. Both trans- and cis-C(O)–NH bonds are present in the macrocycle thus allowing the formation of a rather compact macrocyclic structure. The structures of the acylhydrazone macrocycle are shown to be different in the crystal and in the isolated molecule due to the structure determining role of water included in the crystal lattice: in the former all of the OC–C–H bonds are anti, while in the latter both syn- and anti-bonds are present. Both the non-planarity of the bisacylhydrazone molecules and their chiral interchromophoric interactions contribute to the rotatory power of the molecule. The low-temperature X-ray crystal structure of this compound provides direct evidence for hydrogen bonding between water and the aromatic π-electrons in the solid state.     

Synthesis and antibacterial activity of some novel N2‐hydroxymethyl and N2‐aminomethyl derivatives of 4‐aryl‐5‐(3‐chlorophenyl)‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thione

In this investigation, several novel N2‐hydroxymethyl and N2‐aminomethyl derivatives of 5‐(3‐chlorophenyl)‐4‐(4‐methylphenyl)‐2,4‐dihydro‐ 3H‐1,2,4‐triazole‐3‐thione and 4‐(4‐bromophenyl)‐ 5‐(3‐chlorophenyl)‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐ thione were prepared. All synthesized compounds were screened for their antibacterial activity against six Gram‐positive and four Gram‐negative bacterial strains. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:737–743, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20737     

Temperature and composition dependence of the density and viscosity of binary mixtures of (hyperbranched polymer,B-U3000 + 1-alcohol,or ether)

Density and viscosity were determined for binary mixtures of {hyperbranched polymer, a fatty acid modified dendritic polymer Boltorn U3000 (B-U3000) + 1-alcohol (1-butanol, 1-hexanol, and 1-octanol)} at T = (298.15, 308.15, 318.15, 328.15, and 338.15) K and of {B-U3000 + tert-butyl-methylether (MTBE)} at T = (298.15, 308.15, and 318.15) K and ambient pressure. The temperature dependence of density and viscosity for these systems can be described by linear regression and by the Vogel–Fucher–Tammann equation, respectively. Excess volumes were discussed in a function of mass fractions. Viscosity deviations were calculated and correlated by the Redlich–Kister polynomial expansions using also the mass fractions. The polynomial correlations describe the variation of viscosity with composition. A qualitative discussion on these quantities in terms of molecular interactions is reported.