Influence of Ionic Liquids on the Crystalline Structure of nanoColloids (original) (raw)
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Recent Developments in Ionic Liquids and Nanomaterials
Rasayan Journal of Chemistry, 2021
In this paper, the development of Ionic Liquids to synthesize various types of nanoparticles having commercial and viable uses in 21st century is discussed. Nanotechnology is a promising methodology that generates various types of nanoparticles. Research-based on Ionic Liquids is in the progressive stage and by amalgamating it in nanotechnology, amazing results can be accomplished. Thus, efforts must be made to develop advanced techniques to synthesize nanoparticles with desired structures and morphologies in eco-friendly and sustainable Ionic Liquids to reduce environmental pollution in the future. With this perspective, various developments and efforts made by the scientists in the domain of Nanomaterials and Ionic Liquids have been reviewed.
Journal of Physical Chemistry C, 2016
This work reports the influence of anion structure (Br-, NO 3-, BF 4-, and SCN-) in the aggregation process of ionic liquids (ILs), derived from 1,8-bis(3-methylimidazolium-1-yl)octane, in 4.75% ethanol-water solution (v/v). The aggregation behavior was investigated using small angle x-ray scattering (SAXS), nuclear magnetic resonance (NMR), dynamic light scattering (DLS), and transmission electron microscopy (TEM). Spin-lattice relaxation times (T1), obtained by NMR, indicated that the molecular mobility of the ILs changed when aggregates are formed. 1 H-NMR showed distinct chemical shifts as a function of the concentration of [BisOct(MIM) 2 ][2X] (in which X = Br, NO 3 , SCN, and BF 4) in solution. This change was associated with different chemical environments experienced by the hydrogen atoms when the aggregation process occurs. This behavior was characterized by the different types of interactions in the aggregates, in accordance with the anion of the IL structure. The SAXS measurements demonstrated that the distance between two molecules, which function as scattering centers, was dependent on the anion hydrophobicity. Less hydrophobic anions resulted in shorter distances between scattering centers due to their better solvating ability. Due to the lower solvating ability of hydrophobic anions, a larger distance between two scattering centers was observed. Furthermore, ILs with more hydrophobic anions (e.g., BF 4-) resulted in closely-packed aggregates.
Coordination polymer nano-objects into ionic liquids: Nanoparticles and superstructures
A new exploit of ionic liquids as an alternative reaction media in the synthesis of cyano-bridged coordi- nation polymers nano-objects such as nanoparticles and their superstructures is discussed. Stable colloidal solutions containing nanoparticles of cyano-bridged coordination polymers Cu3[Fe(CN)6]2/ [Cn-MIM][An] (where n = 2, 4; An = BF4, Cl) or their superstructures were prepared in the corresponding 1-R-3-methylimidazolium salts [Cn-MIM][An] which acts as both the stabilizing agent and the solvent. Different conditions, such as temperature, nature of the ionic liquid counter anion and N-alkyl substi- tuted chain length, water content and microwave action have been varied in order to check their influ- ence on the size, the shape and the organisation of the nanoparticles. A special emphasis is devoted to detailed studies of the magnetic properties of these frozen colloids. The dynamic study shows that the relaxation of magnetisation for the nanoparticles and their superstructures is influenced by interparticle interactions leading to appearance of a cluster-glass-like behaviour in these systems.
Nanostructure self-organization of ionic liquids
Russian Journal of Physical Chemistry A, 2010
The theory of integral equations was applied to investigate the formation of structures in ionic liq uids (ILs). The effect of temperature and the length of the cation tails on the structural properties of a system was studied. An intermediate type of ordering in ILs as compared with common liquids was observed. The formation of polar and nonpolar domains was revealed, with the distribution of the polar domains having the shape of a three dimensional net coexisting with nonpolar domains. The characteristic scale of intermediate ordering was shown to increase as a power function without disturbing the shape of the distribution of polar domains as the length of the cation tails grew.
Formation of Nanoparticles Assisted by Ionic Liquids
Handbook of Green Chemistry - Volume 8 – Green Processes – Green Nanoscience, 2012
Imidazolium ionic liquids (ILs) have proven to be a suitable medium for the generation of a myriad of soluble metal nanoparticles (NPs). In particular, transition-metal NPs with small size and a narrow size distribution have been mainly prepared by reduction of organometallic compounds with molecular hydrogen or by decomposition of complexes in the zerovalent state in ILs. The formation and stabilization of nanoparticles in these fluids occurs with reorganization of the hydrogen bond network and the generation of nanostructures with polar and non-polar regions where the NPs are included. The IL forms a protective layer that is probably composed of imidazolium aggregate anions located immediately adjacent to the NP surface-providing the Columbic repulsion and countercations that provide the charge balance. These stable transition metal NPs immobilized in the ILs are considered efficient green catalysts for general reactions in multiphase systems. In this chapter, the synthesis, stabilization, and catalytic applications of metal NPs in ILs and the recyclability of these systems are discussed. 1.1 Metal Nanoparticles in Ionic Liquids: Synthesis Generally, stable and well-dispersed metal NPs have been prepared in ILs by the simple reduction of the M(I-IV) complexes or thermal decomposition of the organometallic precursors in the formal zero oxidation state. Recently, other methods such as the phase transfer of preformed NPs in water or organic solvents to the IL and the bombardment of bulk metal precursors with deposition on the ILs have been reported. However, one of the greatest challenges in the NPs field is to synthesize reproducibly metal NPs with control of the size and shape. Selected studies of the preparation of metal NPs in ILs that, in some cases, provide NPs with different sizes and shapes are considered in this section.
Ionic liquids for nano-and microstructures preparation. Part 1: Properties and multifunctional role
Advances in Colloid and Interface Science, 2015
Keywords: Ionic liquids Nanoparticle interaction Nanomaterial synthesis Microstructure preparation Ionic liquids (ILs) are a broad group of organic salts of varying structure and properties, used in energy conversion and storage, chemical analysis, separation processes, as well as in the preparation of particles in nano-and microscale. In material engineering, ionic liquids are applied to synthesize mainly metal nanoparticles and 3D semiconductor microparticles. They could generally serve as a structuring agent or as a reaction medium (solvent). This review deals with the resent progress in general understanding of the ILs role in particle growth and stabilization and the application of ionic liquids for nano-and microparticles synthesis. The first part of the paper is focused on the interactions between ionic liquids and growing particles. The stabilization of growing particles by steric hindrance, electrostatic interaction, solvation forces, viscous stabilization, and ability of ILs to serve as a soft template is detailed discussed. For the first time, the miscellaneous role of the ILs in nano-and microparticle preparation composed of metals as well as semiconductors is collected, and the formation mechanisms are graphically presented and discussed based on their structure and selected properties. The second part of the paper gives a comprehensive overview of recent experimental studies dealing with the applications of ionic liquids for preparation of metal and semiconductorbased nano-and microparticles. A wide spectrum of preparation routes using ionic liquids are presented, including precipitation, sol-gel technique, hydrothermal method, nanocasting, and microwave or ultrasound-mediated methods.
Nanostructural Organization in Ionic Liquids
Journal of Physical Chemistry B, 2006
Nanometer-scale structuring in room-temperature ionic liquids is observed using molecular simulation. The ionic liquids studied belong to the 1-alkyl-3-methylimidazolium family with hexafluorophosphate or with bis(trifluoromethanesulfonyl)amide as the anions, [C n mim][PF 6 ] or [C n mim][(CF 3 SO 2 ) 2 N], respectively. They were represented, for the first time in a simulation study focusing on long-range structures, by an all-atom force field of the AMBER/OPLS_AA family containing parameters developed specifically for these compounds. For ionic liquids with alkyl side chains longer than or equal to C 4 , aggregation of the alkyl chains in nonpolar domains is observed. These domains permeate a tridimensional network of ionic channels formed by anions and by the imidazolium rings of the cations. The nanostructures can be visualized in a conspicuous way simply by color coding the two types of domains (in this work, we chose red ) polar and green ) nonpolar). As the length of the alkyl chain increases, the nonpolar domains become larger and more connected and cause swelling of the ionic network, in a manner analogous to systems exhibiting microphase separation. The consequences of these nanostructural features on the properties of the ionic liquids are analyzed.
Inorganic Chemistry, 2008
Stable silver nanoparticles are obtained reproducibly by hydrogen reduction of different inorganic precursors from Ag I X salts (X ) BF 4 , PF 6 , OTf) dissolved in the ionic liquids BMim + BF 4 -, BMim + PF 6 -, BMim + OTf -, or BtMA + NTf 2 -[BMim + ) n-butylmethylimidazolium, BtMA + ) n-butyltrimethylammonium, NTf 2 ) N(O 2 SCF 3 ) 2 , and OTf ) O 3 SCF 3 ] in the presence of n-butylimidazole (Bim) as the scavenger for the HX acid byproduct and with a narrow size distribution in the diameter range of 2.8−26.1 nm, which increases linearly with the molecular volume of the ionic liquid anion (transmission electron microscopy characterization).