35203-44-2Relevant articles and documents
On the mesophase formation of 1,3-dialkylimidazolium ionic liquids
Yang, Mei,Mallick, Bert,Mudring, Anja-Verena
, p. 3068 - 3077 (2013)
A series of seven different 1,3-dialkylimidazolium-based ion-pair salts with the same molecular weight and size but different symmetries was synthesized. For all salts, bromide was chosen as the counterion, giving the series ([CnIMCm][Br]), where IM = imidazolium and Cn and Cm are varying N-alkyl substituents with n + m = 13. Thus, the effect of symmetry on the physicochemical properties, such as thermal transitions, densities and viscosities and particularly mesophase formation, is investigated herein. All salts are fully characterized by NMR spectroscopy and mass spectrometry, and their physicochemical properties such as thermal transitions, densities, and viscosities are reported. Single crystal X-ray structure analysis is reported for 1-tridecylimidazolium bromide ([C0IMC13][Br]) and 1-ethyl-3- undecylimidazolium bromide ([C2IMC11][Br]). Salts 1-tridecylimidazolium bromide ([C0IMC13][Br]) and 1-dodecyl-3-methylimidazolium bromide ([C1IMC12][Br]) exhibit thermotropic liquid crystal behavior, confirmed by differential scanning calorimetry, polarized optical microscopy, and small-angle X-ray diffraction to be the SmA mesophase. A structure with interdigitation of alkyl chains is observed for all of [C0IMC13][Br], [C1IMC12][Br], and [C2IMC11][Br], despite the absence of thermotropic liquid crystalline behavior for the latter (and all other isomers with an alkyl chain length less than 12 carbon atoms). This allows us to draw the conclusion that for the liquid crystal phase of an ionic liquid to exist, not only are the calamitic shape and integral length of a molecule important but a minimal alkyl chain length of n = 12 is also required. Therefore, a dodecyl group could be considered as the functional group responsible for liquid crystalline behavior.
In-situ synthesis of mercury(II)-N-heterocyclic carbene complexes by using “oxide route”, structural characterization and their photo-catalytic degradation activity for dyes
Altaf, Muhammad Faisal,Chaudhary, Sidra,Hasnain, Muhammad,Imran, Muhammad,Iqbal, Muhammad Adnan,Latif, Shoomaila
, (2021/12/30)
N-alkylated imidazole derivatives (1a-1b), mono-azolium salts (SL2-SL3) and their symmetrically (SC2) and non-symmetrically (SC3) substituted mercury(II)-N-heterocyclic carbene (Hg(II)-NHC) complexes were synthesized by using “oxide route”. The characterization was done by using physical (i.e., solubility, melting point determination, compound microscopic analysis) and spectral (i.e., UV-Visible spectroscopy, FT-IR spectroscopy, 1H and 13C NMR spectroscopy) methods. Chemical equilibrium between monomeric and dimeric structures of bromide-bridging Hg(II)-NHC complexes was also observed in the presence of solvent. Photo-catalytic degradation rate of two environmentally polluting dyes i.e., methylene blue (MR) and congo red (CR), was investigated by using compound 1 (SC2) and compound 2 (SC3) which demonstrated that the compound 2 had maximum degradation rate in the range of 70–80% as compared to the compound 1 (60–70% ).
On the effects of head-group volume on the adsorption and aggregation of 1-(n-hexadecyl)-3-Cm-imidazolium bromide and chloride surfactants in aqueous solutions
Keppeler, Nicolas,Galgano, Paula D.,da Silva Santos, Soraya,Malek, Naved I.,El Seoud, Omar A.
, (2021/02/09)
The effects of the length of alkyl side chain (Cm) of ionic liquid-based surfactants (ILBSs) on their adsorption at the water/air interface, and aggregation in aqueous solutions were investigated for the series 1-(n-hexadecyl)-3-Cm-imidazolium bromides and chlorides, where Cm = C1-C4 for the bromides, and C1-C5 for the chlorides. These physicochemical properties were calculated from surface tension, conductivity, and fluorescence data. It was found that increasing the length of Cm (i.e., volume of the head group) leads to enhancement of surface activity, increase in the area per surfactant molecule at the water/air interface (Amin) and the degree of counter-ion dissociation (αmic). Our data also indicated that increasing the volume of the head group results in a decrease of the critical micelle concentration (cmc), Gibb's free energy of adsorption and micellization, and microscopic polarity of interfacial water. In order to delineate the effects of the presence of unsaturation in the HG, we included members that carry Cm = vinyl and allyl in the bromide series. The effect of these groups was found to be similar to removing a methylene group from Cm. The dependence of the solubilization of a lipophilic dye (Sudan IV) and a drug (nitrendipine) on the length of Cm was also studied.
N-Functionalised Imidazoles as Stabilisers for Metal Nanoparticles in Catalysis and Anion Binding
Beer, Paul D.,Cookson, James,Serpell, Christopher J.
, p. 683 - 690 (2020/07/03)
Metal nanoparticles (NPs) have physicochemical properties which are distinct from both the bulk and molecular metal species, and provide opportunities in fields such as catalysis and sensing. NPs typically require protection of their surface to impede aggregation, but these coatings can also block access to the surface which would be required to take advantage of their unusual properties. Here, we show that alkyl imidazoles can stabilise Pd, Pt, Au, and Ag NPs, and delineate the limits of their synthesis. These ligands provide an intermediate level of surface protection, for which we demonstrate proof-of-principle in catalysis and anion binding.
