Search results for " IONIC LIQUID"
showing 10 items of 88 documents
Catalytic Carbonylative Double Cyclization of 2-(3-Hydroxy-1-yn-1-yl)phenols in Ionic Liquids Leading to Furobenzofuranone Derivatives
2019
A catalytic carbonylative double cyclization method for the synthesis of furo[3,4-b]benzofuran-1(3H)-ones is reported. It is based on the reaction between readily available 2-(3-hydroxy-1-yn-1-yl)phenols, CO, and oxygen carried out in the presence of catalytic amounts of PdI2 (1 mol %) in conjunction with KI (20 mol %) and 2 equiv of diisopropylethylamine at 80 degrees C for 24 h under 30 atm of a 1:4 mixture of CO-air. Interestingly, the process was not selective when carried out in classical organic non-nucleophilic solvents (such as MeCN or DME), leading to a mixture of the benzofurofuranone derivative and the benzofuran ensuing from simple cycloisomerization, whereas it turned out chemo…
Superfluorinated ionic liquid crystals based on supramolecular, halogen-bonded anions
2016
Unconventional ionic liquid crystals in which the liquid crystallinity is enabled by halogen-bonded supramolecular anions [CnF2 n+1-I⋯I⋯I-CnF2 n+1]- are reported. The material system is unique in many ways, demonstrating for the first time 1) ionic, halogen-bonded liquid crystals, and 2) imidazolium-based ionic liquid crystals in which the occurrence of liquid crystallinity is not driven by the alkyl chains of the cation. Out of the ordinary: The high directionality of halogen bonds and the fluorophobic effect were exploited in the design and synthesis of a new family of unconventional superfluorinated ionic liquid crystals. The liquid crystallinity of the system is driven by halogen-bonded…
Ionic liquid crystals based on viologen dimers: tuning the mesomorphism by varying the conformational freedom of the ionic layer
2016
ABSTRACTWe investigated the liquid crystal behaviour of newly synthesised bistriflimide salts of symmetric viologen dimers. A smectic A phase was observed for intermediate spacer lengths and for relatively long lateral alkyl chains. The systems were characterised by thermal analysis, polarised optical microscopy, X-ray scattering and solid-state NMR. An intermediate ordered smectic phase was also exhibited by the compounds (except for systems with very short lateral chains) consisting of molten layers of alkyl chains and partially ordered ionic layers. These results, relating to the mesomorphic behaviour of viologen salts, are qualitatively compared to those of the more common imidazolium s…
Room temperature ionic liquids based on cationic porphyrin derivatives and tetrakis(pentafluorophenyl)borate anion
2011
A series of 11 low melting ionic liquids based on meso-substituted A3B -porphyrins and A2B2-porphyrins containing one or two pyridyl substituents have been synthesized in high yields. Three of them are liquids at room temperature. All these porphyrinic salts were characterized by1H NMR,19F NMR, MALDI-TOF mass spectrometry, elemental analysis and UV-visible spectroscopy. The thermal properties and conductivity values of these salt derivatives have been also measured. A specific conductivity value of up to 4 mS.cm-1could be obtained for a compound having the counter-anion B(C6F5)4-.
Graphene and ionic liquids new gel paste electrodes for caffeic acid quantification
2015
Abstract Graphene/ionic liquids nanocomposite gels were synthesized by an electrochemical etching approach and fully characterized under a morphological and structural point of view. For this purpose, several analytical techniques were applied, as HR-TEM/EDX (High Resolution-Transmission Electron Microscopy/Energy Dispersive X-Ray Analysis); FE-SEM/EDX (Field Emission-Scanning Electron Microscopy/Energy Dispersive X-Ray Analysis); XPS (X-Ray Photoelectron Spectroscopy); FT-IR (Fourier Transform-Infrared Spectroscopy) and electrochemical techniques. After the characterization study, nanocomposite-gel paste electrodes were assembled, exhibiting a selective and specific detection toward the ca…
Liquid structure of a water-in-salt electrolyte with a remarkably asymmetric anion
2021
Water-in-salt systems, i.e., super-concentrated aqueous electrolytes, such as lithium bis(trifluoromethanesulfonyl)imide (21 mol/kgwater), have been recently discovered to exhibit unexpectedly large electrochemical windows and high lithium transference numbers, thus paving the way to safe and sustainable charge storage devices. The peculiar transport features in these electrolytes are influenced by their intrinsically nanoseparated morphology, stemming from the anion hydrophobic nature and manifesting as nanosegregation between anions and water domains. The underlying mechanism behind this structure-dynamics correlation is, however, still a matter of strong debate. Here, we enhance the apol…
Ionic liquid gels and antioxidant carbon nanotubes: Hybrid soft materials with improved radical scavenging activity
2019
Hypothesis: Performances of materials are frequently affected by the action of radicals that can induce their degradation. To overcome the above issue, natural antioxidants (AOs) can be added during manufacturing. Considering the high instability of AOs, they have been adsorbed on carbon nanomaterials surface. However, the inclusion of functionalized carbon nanomaterials into gel matrix could enhance the antioxidant efficiency and represent an easy way to disperse and handle the active species.Experiments: Carboxypropyl functionalized carbon nanotubes (f-CNT), pure or with physically adsorbed alpha-tocopherol (f-CNT-VE) and quercetin (f-CNT-Q), were incorporated in some ionic liquid gels (I…
Ionic liquids/[bmim][N3] mixtures: promising media for the synthesis of aryl azides by SNAr
2008
The nucleophilic aromatic substitution of some activated aryl or heteroaryl halides has been performed in ionic liquid solution, using the 1-butyl-3-methylimidazolium azide as a nucleophile. The reaction course was studied varying the structures of both substrates and ionic liquids. In particular, in the latter case, the reaction of 2-bromo-5-nitrothiophene was carried out in five different ionic liquids ([bmim][BF 4], [bmim][PF 6], [bmim][NTf 2], [bm 2im][NTf 2], and [bmpyrr][NTf 2]). Finally, for all the substrates considered, a comparison with data obtained in MeOH solution in the presence of NaN 3 was also performed. Data collected indicate that in some cases it is possible to obtain ar…
The use of imidazolium group-containing Bronsted acids for masspectrometric determination of biogenic amines in alcoholic beverages
2017
Darbā ir izstrādāta metode sešu biogēno amīnu masspektrometriskai noteikšanai alkoholiskos dzērienos. Metodes pamatā ir kompleksu veidošanās starp biogēniem amīniem un imidazolija grupu saturošu Brensteda skābi, kas nodrošina ātru un selektīvu analīzi bez parauga sagatavošanas. Darba gaitā ir izpētīta vairāku masspektrometra parametru ietekme uz biogēno amīnu kompleksu rašanos, un izvēlētas specifiskās MRM pārejas. Metodes aprobācijai izvēlēti un analizēti astoņi alkoholiskie dzērieni.
New biocides based on imidazolinium-functionalised hybrid mesoporous silica nanoparticles
2022
Here, we report the development of a new biocide based on hybrid mesoporous silica nanoparticles (MSN). The MSN was synthesized by condensation method in emulsion followed by grafting with two different silylated ionic liquid moieties, namely butyl imidazolinium bromide and imidazolinium propansulfonate betaine. Features of nanoparticles were characterized by Thermogravimetry, Infrared and ss-NMR Spectroscopy, and Transmission Electron Microscopy. The antibacterial properties were tested against a Gram-positive bacterial strain previously isolated from artefacts of interest in the field of Cultural Heritage. Interestingly, the hybrid material presents an antibacterial activity higher than i…