1,2-Cyclic sulfite and sulfate furanoside diesters: improved syntheses and stability

The facile syntheses of 1,2- and 3,5-cyclic sulfite and sulfate furanoside diesters were conducted in molecular solvents and ionic liquids in the presence of immobilised morpholine. Molecular solvents and ionic liquids performed similarly with regards to overall yields. However, the use of ILs allowed for the reactions to be carried out under atmospheric conditions and showed good recyclability. Additionally, increases in product stability was achieved in ILs over organic solvents, in particular, in bis{(trifluoromethanesulfonyl)imide) and trispentafluoro-ethyltrifluorophosphate-based ionic liquids, which were also excellent media to control the hydrolysis of thionyl chloride and sulfuryl chloride. (C) 2009 Elsevier Ltd. All rights reserved.

Evaluation of Gas Solubility Prediction in Ionic Liquids using COSMOthermX

As the range of available ionic liquids increases, methods by which important engineering parameters such as gas solubilities can be estimated from simple structural information become ever more desirable. COSMO-based thermodynamic models, such as that used by COSMOthermX, allow the determination of such data for pure and mixed component systems. Herein, we evaluate the predictive capability of COSMOthermX through a comparison with literature data obtained from the IUPAC database which contains data for 15 gases in 27 ionic liquids, To determine any effect inherent to ionic liquids, gas solubility predictions were first performed for selected molecular solvents at constant temperature and pressure. Further estimations of gas solubility at temperatures ranging from (278 to 368) K at 0.1 MPa in water were performed for 14 gases. The Study has demonstrated that COSMOthermX is capable of predicting, qualitatively, gas solubilities in ionic liquids and, hence, reducing the amount of unnecessary experimental measurements prior to specific applications using ionic liquids.

Luminescence of LaF3:Ln(3+) Nanocrystal Dispersions in Ionic Liquids

Ionic liquids were used as solvents for dispersing luminescent lanthanide-doped LaF3:Ln(3+) nanocrystals (Ln(3+) = Eu3+ and Nd3+). To increase the solubility of the inorganic nanoparticles in the ionic liquids, the nanocrystals were prepared with different stabilizing ligands, i.e., citrate, N,N,N-trimethylglycine (betaine), and lauryldimethylglycine (lauryl betaine). LaF3:5%Ln(3+) :betaine could successfully be dispersed in 1-butyl-1-methylpyrrolidinium bis(tiifluoromethylsulfonyl)imide [C(4)mpyr][Tf2N], 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate [C(4)mpyr][TfO], and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C(4)mim][Tf2N] but only in limited amounts. Red photoluminescence was observed for the europium(III)-containing nanoparticles and near-infrared luminescence for the neodymium(III)-containing systems.

Phase transition and decomposition temperatures, heat capacities and viscosities of pyridinium ionic liquids

Ionic liquids are organic salts with low melting points. Many of these compounds are liquid at room temperature in their pure state. Since they have negligible vapor pressure and would not contribute to air pollution, they are being intensively investigated for a variety of applications, including as solvents for reactions and separations, as non-volatile electrolytes, and as heat transfer fluids. We present melting temperatures, glass transition temperatures, decomposition temperatures, heat capacities, and viscosities for a large series of pyridinium-based ionic liquids. For comparison, we include data for several imidazolium and quaternary ammonium salts. Many of the compounds do not crystallize, but form glasses at temperatures between 188 K and 223 K. The thermal stability is largely determined by the coordinating ability of the anion, with ionic liquids made with the least coordinating anions, like bis(trifluoromethylsulfonyl)imide, having the best thermal stability. In particular, dimethylaminopyridinium bis(trifluoromethylsulfonyl)imide salts have some of the best thermal stabilities of any ionic liquid compounds investigated to date. Heat capacities increase approximately linearly with increasing molar mass, which corresponds with increasing numbers of translational, vibrational, and rotational modes. Viscosities generally increase with increasing number and length of alkyl substituents on the cation, with the pyridinium salts typically being slightly more viscous than the equivalent imidazolium compounds. (c) 2005 Elsevier Ltd. All rights reserved.

Hydrogen abstraction from ionic liquids by benzophenone triplet excited states

The activation energy for hydrogen abstraction from imidazolium-based ionic liquids is significantly higher than that observed in conventional solvents.

Ionic liquids are not always green: hydrolysis of 1-butyl-3-methylimidazolium hexafluorophosphate

1-Butyl-3-methylimidazolium fluoride hydrate has been identified crystallographically as a decomposition product created during purification of the hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate. This highlights the need to treat ionic liquids much as one would any other research chemical with potentially hazardous properties, unknown toxicity and/or stability, particularly when searching for 'green solvents'.

Gelation of ionic liquids using a cross-linked poly(ethylene glycol) gel matrix

Conductive ionic liquid -poly(ethylene glycol) (IL-PEG) gels have been prepared by gelation of the hydrophobic ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [(C(6)mim] [NTf2]) by the cross-linking reaction of disuccinimidylpropyl PEG monomers with four-arm tetraamine PEG cross-linkers. This is the first time that a crosslinked PEG matrix, such as this, has been used to gel nonaqueous solvents. Initial studies screening other ionic liquids as solvents indicate that the gelation of the ionic liquid is both cation and anion dependent with smaller, coordinating cations disrupting or preventing gel formation.

Industrial applications of ionic liquids

The potential to use Ionic Liquids (ILs) as novel solvents or fluids for a diverse range of applications has become increasingly rent as researchers in academia and try respond to challenges from atmospheric emissions and disposal of many common solvents by evaluating novel reaction media. The intrinsic non-volatile nature of ILs provides an opportunity to reduce, or even completely eliminate, hazardous and toxic emissions to the atmosphere, thus providing the promise for significant environmental benefits. In synthesis and catalysis, ILs have been used as solvents (or solvents and catalysts), with the greatest current effort on using the ILs as alternatives to VOCs. In contrast, electrochemical studies hove utills'ed the fact that ILs are liquid rather than solids to provide liquid electrolytes without needing to odd an additional solvent. is overview appraiso an appraisal of potential to use ILs in industrial applications, illustrating some areas where practical uses are being developed, and how, throuqh understanding ionic liquids in a conceptuo level, new opportunities ore continuing to evolve.

Using Caenorhabditis elegans to probe toxicity of 1-alkyl-3-methylimidazolium chloride based ionic liquids

Ionic liquids are gaining attention as new solvents within the green chemistry community; however this attention has quickly outstripped current environmental and toxicological data available. In the present communication, we establish the use of Caenorhabditis elegans as a model organism for inexpensively and quickly exploring toxicological effects of 1-alkyl-3-methylimidazolium chloride ionic liquids.

Rare-earth complexes of ferrocene-containing ligands: Visible-light excitable luminescent materials

The ferrocene-derivatives bis(ferrocenyl-ethynyl)-1,10-phenanthroline (Fc(2)phen) and ferrocenoyltrifluoroacetone (Hfta) have been used to synthesize ferrocene-containing rare-earth beta-diketonate complexes. The complexes [Ln(tta)(3)(Fc(2)phen)] and [Ln(fta)(3)(phen)] (where Ln = La, Nd, Eu, Yb) show structural similarities to the tris(2-thenoyltrifluoroacetonate)(1,10-phenanthroline)lanthanide(III) complexes, [Ln(tta)(3)(phen)]. The coordination number of the lanthanide ion is 8, and the coordination sphere can be described as a distorted dodecahedron. However, the presence of the ferrocene moieties shifts the ligand absorption bands of the rare-earth complexes to longer wavelengths so that the complexes can be excited not only by ultraviolet radiation but also by visible light of wavelengths up to 420 nm. Red photoluminescence is observed for the europium(III) complexes and near-infrared photoluminescence for the neodymium(III) and ytterbium(III) complexes. The presence of the ferrocene groups makes the rare-earth complexes hydrophobic and well-soluble in apolar organic solvents.

Long-lived near-infrared luminescent lanthanide complexes of imidodiphosphinate

Near-infrared emitting complexes of Nd(III), Er(III), and Yb(III) based on hexacoordinate lanthanide ions with an aryl functionalized imidodiphosphinate ligand, tpip, have been synthesized and fully characterized. Three tpip ligands form a shell around the lanthanide with the ligand coordinating via the two oxygens leading to neutral complexes, Ln(tpip)(3). In the X-ray crystal structures of Er(III) and Nd(III) complexes there is evidence of CH-pi interactions between the phenyl groups. Photophysical investigations of solution samples of the complexes demonstrate that all complexes exhibit relatively long luminescence lifetimes in nondeuteurated solvents. Luminescence studies of powder samples have also been recorded for examination of the properties of NIR complexes in the solid state for potential material applications. The results underline the effective shielding of the lanthanide by the twelve phenyl groups of the tpip ligands and the reduction of high-energy vibrations in close proximity to the lanthanide, both features important in the design of NIR emitting lanthanide complexes.

Cobalt(II) Complexes of Nitrile-Functionalized Ionic Liquids

A series of nitrile-functionalized ionic liquids were found to exhibit temperature-dependent miscibility (thermomorphism) with the lower alcohols. Their coordinating abilities toward cobalt(II) ions were investigated through the dissolution process of cobalt(II) bis(trifluoromethylsulfonyl)imide and were found to depend on the donor abilities of the nitrile group. The crystal structures of the cobalt(II) solvates [Co(C1C1CNPyr)2(Tf2N)4] and [Co(C1C2CNPyr)6][Tf2N]8, which were isolated from ionic-liquid solutions, gave an insight into the coordination chemistry of functionalized ionic liquids. Smooth layers of cobalt metal could be obtained by electrodeposition of the cobalt-containing ionic liquids.