Search

Chiral ionic liquids (CILs), or ionic liquids (ILs) with chiral additives, are very attractive chiral media for enantioselective electroanalysis, on account of their high chiral structural order at the electrochemical interphase. A family of molecular salts with CIL properties is now introduced, based on the chiral steroid building block of deoxycholic acid implemented either in the anion or cation. Testing them as chiral additives in a commercial achiral IL, they enable voltammetric discrimination of the enantiomers of a model chiral probe on disposable screen-printed electrodes in terms of peak potential differences, which is the most desirable transduction mode of the enantiorecognition event. The probe enantiomer sequence is the same for all selectors, consistent with their sharing the same chiral building block configuration. This proof-of-concept widens the application fields of bile acid derivatives as chiral selectors, while also enriching the still very few CIL families so far explored for applications in chiral electroanalysis. [ABSTRACT FROM AUTHOR]

Developing effective strategies to increase the chemical stability and to fine‐tune the physico‐chemical properties of melanin biopolymers by rational control of π‐electron conjugation is an important goal in materials science for biomedical and technological applications. Herein we report that poly‐1,8‐dihydroxynaphthalene (pDHN), a non‐nitrogenous, catechol‐free fungal melanin mimic, displays a high degree of structural integrity (from MALDI‐MS and CP/MAS 13C NMR analysis), a strong radical scavenging capacity (DPPH and FRAP assays), and an unusually intense EPR signal (g=2.0030). Morphological and spectral characterization of pDHN, along with deassembly experiments in ionic liquids, indicated amorphous aggregates of small globular structures with an estimated stacking distance of 3.9 Å and broadband absorption throughout the visible range. These results indicate that DHN‐based melanins exhibit a high structural integrity and enhanced antioxidant and free‐radical properties of potentially greater biomedical and technological relevance than for typical indole‐based eumelanins. [ABSTRACT FROM AUTHOR]

In recent years, the designer nature of ionic liquids (ILs) has driven their exploration and exploitation in numerous fields. Undoubtedly, the most attractive feature of ILs is their tunability and the incorporation of functional groups into the cations or anions is the most efficient way to impart a particular property. Functionalized ILs are generally named 'task-specific ionic liquids' (TSILs). In this review, we survey some of the classes of TSILs, generally characterized by the presence of only one 'common' functional group, arising from slight modifications (here, defined as 'point-functionalization') that can be achieved through simple synthetic procedures. In particular, we will discuss their synthesis, immobilization and applications in some specific fields. Among these, we consider their use as solvent catalysts in organic synthesis and metal-catalysed processes, and as fluids in metal extraction processes and gas capture, highlighting their possible uses in materials sciences. The aim of this review is to provide, through a careful survey of the literature, indications of sustainable and rational developments in this extremely prolific field. [ABSTRACT FROM AUTHOR]

Polymerizable ionic liquids (ILs) 1-methyl-3-(4-vinylbenzyl)imidazolium chloride, 1-hexyl-3-(4-vinylbenzyl)imidazolium chloride and 1-dodecyl-3-(4-vinylbenzyl)imidazolium chloride were prepared and used as new surfactants for the modification of montmorillonite (MMT). Functionalized MMTs were prepared by cationic exchange between sodium MMT and each of the ILs. Polystyrene (PS)/MMT composites were subsequently prepared by in situ intercalative free radical polymerization of styrene containing dispersed organophilic MMT. Exfoliation of MMT in the PS matrix was achieved only for MMT functionalized with the 1-dodecyl-3-(4-vinylbenzyl)imidazolium-based IL as revealed by X-ray diffraction and electron microscopy. The exfoliated composites showed good transparency and higher decomposition temperature than virgin polymer matrix, particularly pronounced under air atmosphere (Δ Tmax = 66 °C), data comparable to or even greater than those reported in the literature for exfoliated PS nanocomposites. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In order to rationalize the physicochemical behaviour of ionic liquids (ILs), quantitative structure–property relationship (QSPR) models have been derived for the conductivity and viscosity of a class of ILs based on the bis(trifluoromethylsulphonyl)imide anion. Data obtained at two different temperatures were analysed to assess the consistency of the derived relationships. Satisfactory correlations were found for both properties, although the QSPR derived for viscosity was heavily temperature dependent. ILs containing nitrile-functionalized cations could not be inserted into satisfactory QSPR. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The kinetics of the electrophilic bromination of three allylic ethers in a nonprotic solvent, 1,2-dichloroethane, has been investigated. Two of them followed a prevalent second-order pathway, while the third one exhibited a classical, clean third order. The second-order pathway in the first two olefins is attributed to electrophilic assistance of the ethereal oxygen to the attacking bromine molecule. In the molecular bromination of 2,4-cis-dimethyl-8-oxabicyclo[3.2.1]-6-octen-3-cis-ol, opposite temperature dependences were found for the two different kinetic pathways. An exoergonic process for the second-order reaction was explained by the lesser stability of the bromiranium–bromide ionic intermediate, compared to the bromiranium–tribromide in the third-order profile. © 2007 Wiley Periodicals, Inc. 39: 197–203, 2007 [ABSTRACT FROM AUTHOR]

Review: [158 refs. [ABSTRACT FROM AUTHOR]

Review: [91 refs. [ABSTRACT FROM AUTHOR]