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The present paper discusses the electrodeposition of nano-Aluminum using aromatic cation based ionic liquids. Three imidazolium chloride salts were employed, in ultrapure quality: l-ethyl-3-methyl-imidazolium chloride [EMIm]Cl, l-benzyl-3-methyl-imidazolium chloride [BzMIm]Cl and l,3-dibenzyl-imidazolium chloride [DBzIm]Cl, respectively. Anhydrous Aluminum chloride (AlCl 3 ) salt was used as a source of Aluminum ions in the ionic liquids. This research aims to achieve this goal by investigating the Aluminum coatings on gold substrate and study the effect of changing the organic cation on the properties of the resulting Al-coatings. SEM-EDAX analyses were used to determine the film composition. It was found that the particle size of the Al-deposites was dramatically reduced from the micrometer regime down to the nanometer regime with a change in the substituents of the imidazolium cations from EMIm to DBzIm, respectively. This means that the more the aromatic rings in the cation, the finer the particle size. Thickness and adhesion of the Al-deposits were decreased in the presence of the aromatic rings. [ABSTRACT FROM AUTHOR]

Description of the local microscopic structure in ionic liquids (ILs) is a prerequisite to obtain a comprehensive understanding of the influence of the nature of ions on the properties of ILs. The local structure is mainly determined by the spatial arrangement of the nearest neighboring ions. Therefore, the main interaction patterns in ILs, such as cation-anion H-bond-like motifs, cation-cation alkyl tail aggregation, and ring stacking, were considered within the framework of the nearest-neighbor approach with respect to each particular interaction site. We employed classical molecular dynamics (MD) simulations to study in detail the spatial, radial, and orientational relative distribution of ions in a set of imidazolium-based ILs, in which the 1-butyl-3-methylimidazolium (C4mim+) cation is coupled with the acetate (OAc-), chloride (Cl-), tetrafluoroborate (BF4 -), hexafluorophosphate (PF6 -), trifluoromethanesulfonate (TfO-), or bis(trifluoromethanesulfonyl)amide (TFSA-) anion. It was established that several structural properties are strongly anion-specific, while some can be treated as universally applicable to ILs, regardless of the nature of the anion. Namely, strongly basic anions, such as OAc- and Cl-, prefer to be located in the imidazolium ring plane next to the C-H2/4-5 sites. By contrast, the other four bulky and weakly coordinating anions tend to occupy positions above/below the plane. Similarly, the H-bond-like interactions involving the H² site are found to be particularly enhanced in comparison with the ones at H4-5 in the case of asymmetric and/or more basic anions (C4mimOAc, C4mimCl, C4mimTfO, and C4mimTFSA), in accordance with recent spectroscopic and theoretical findings. Other IL-specific details related to the multiple H-bond-like binding and cation stacking issues are also discussed in this paper. The secondary H-bonding of anions with the alkyl hydrogen atoms of cations as well as the cation-cation alkyl chain aggregation turned out to be poorly sensitive to the nature of the anion. [ABSTRACT FROM AUTHOR]

The terahertz and infrared frequency vibration modes of room-temperature ionic liquids with imidazolium cations and halogen anions were extensively investigated. There is an intermolecular vibrational mode between the imidazolium ring of an imidazolium cation, a halogen atomic anion with a large absorption coefficient and a broad bandwidth in the low THz frequency region (13–130 cm–1), the intramolecular vibrational modes of the alkyl-chain part of an imidazolium cation with a relatively small absorption coefficient in the mid THz frequency region (130–500 cm–1), the intramolecular skeletal vibrational modes of an imidazolium ring affected by the interaction between the imidazolium ring, and a halogen anion with a relatively large absorption coefficient in a high THz frequency region (500–670 cm–1). Interesting spectroscopic features on the interaction between imidazolium cations and halogen anions was also obtained from spectroscopic studies at IR frequencies (550–3300 cm–1). As far as the frequency of the intermolecular vibrational mode is concerned, we found the significance of the reduced mass in determining the intermolecular vibration frequency. [ABSTRACT FROM AUTHOR]