Thiol-functionalized Ionic Liquid Research Articles

Immobilization of thiol-functionalized ionic liquids onto the surface of MIL-101(Cr) frameworks by S[sbnd]Cr coordination bond for biodiesel production

A novel functionalized MOF heterogeneous catalyst (MIL-101(Cr) @MBIAILs), 2-Mercaptobenzimidazole ILs with electron-rich SH groups immobilized onto the surface of the well-defined MIL-101(Cr) frameworks, was constructed and fabricated by the SCr coordination bond on the basis of the facile post-synthetic modification strategy. The heterogeneous catalyst was measured by XRD, FTIR, SEM, TEM, TGA, EA and N2 adsorption–desorption, and the catalytic behavior of the catalyst was assessed by the esterification about oleic acid and methanol as a model reaction. The results showed that MBIAILs have been successfully immobilized onto the surface of MIL-101(Cr) frameworks by SCr coordinate bonds. More importantly, the conversion of oleic acid just decreased from 91.0% to 82.1% when the catalyst had been reused six times. This exhibited the prepared catalyst had superior catalytic behavior and excellent reusability.

Microcontact Printing of Thiol-Functionalized Ionic Liquid Microarrays for “Membrane-less” and “Spill-less” Gas Sensors

Lab-on-a-chip systems have gained significant interest for both chemical synthesis and assays at the micro-to-nanoscale with a unique set of benefits. However, solvent volatility represents one of the major hurdles to the reliability and reproducibility of the lab-on-a-chip devices for large-scale applications. Here we demonstrate a strategy of combining nonvolatile and functionalized ionic liquids with microcontact printing for fabrication of "wall-less" microreactors and microfluidics with high reproducibility and high throughput. A range of thiol-functionalized ionic liquids have been synthesized and used as inks for microcontact printing of ionic liquid microdroplet arrays onto gold chips. The covalent bonds formed between the thiol-functionalized ionic liquids and the gold substrate offer enhanced stability of the ionic liquid microdroplets, compared to conventional nonfunctionalized ionic liquids, and these microdroplets remain stable in a range of nonpolar and polar solvents, including water. We further demonstrate the use of these open ionic liquid microarrays for fabrication of "membrane-less" and "spill-less" gas sensors with enhanced reproducibility and robustness. Ionic-liquid-based microarray and microfluidics fabricated using the described microcontact printing may provide a versatile platform for a diverse number of applications at scale.

Fabrication of a heated electrode modified with a thiol-functionalized ionic liquid for electrochemical/electrochemiluminescence sensors

A new heated thiol-functionalized ionic liquid (TFIL)/Au composite electrode, which possessed the advantages of a heated electrode technique and ionic liquids (ILs), was designed and fabricated in this study.

Thiopropyl-containing ionic liquid based periodic mesoporous organosilica as a novel and efficient adsorbent for the removal of Hg(ii) and Pb(ii) ions from aqueous solutions

In the present study, a novel thiol-functionalized ionic liquid based periodic mesoporous organosilica (PMO-IL-SH) is prepared, characterized and its efficiency for the removal of mercury and lead ions from aqueous solutions is investigated.

Immobilization of a thiol-functionalized ionic liquid onto HKUST-1 through thiol compounds as the chemical bridge

The IL@HKUST-1 catalyst was synthesized by a post-synthetic modification strategy. The introduction of ionic liquid greatly improved the acidity of the material, making it an efficient and recyclable catalyst for the esterification reaction.

π–π stacking interaction induced the assembly of gold nanorods

Gold nanorods have been recognized as a good candidate for developing novel nanomaterials due to their exceptional optical properties. However, their assemblies, especially with the assisted ionic liquid, have not been well characterized. In this paper, we report the self-assembly of gold nanorods using thiol-functionalized ionic liquid (1-methyl-3-(2′-mercaptoacetoxyethyl) imidazolium bromine) (TFIL). We found that gold nanorods can self-assemble via two different ways: From end-to-end to side-by-side with the increase of TFIL concentration. The shift of the absorption peak in UV–vis spectrum indicates the change of the assembly fashion. We propose that the π–π stacking interactions between the imidazole rings of TFIL molecules play the most important role in regulating the assembly process. The energy calculation further demonstrated that the face–face stacked orientation was the most stable geometry at high TFIL concentration, which supports the proposed mechanism. These gold nanorod assemblies were shown to yield the large SERS enhancements for Rhodamine 6G.

Soft materials composed with lanthanide (Eu3+, Tb3+) beta-diketonates and ZnO nanoparticles through ionic liquid linkage to integrate white luminescence

Abstract In this note, 3-(2-(2-mercaptoacetoxy)ethyl)-1-methyl-1H-imidazol-3-ium bromide (SH-IL), a kind of room temperature thiol-functionalized ionic liquid compound is synthesized and used to interact with ZnO nanoparticles for the chemical affinity between S of SH-IL and Zn of ZnO. And then an anion exchange reaction is performed to introduce europium(III) and terbium(III) tetrakis β-diketonates (thenoyltrifluoroacetonate (TTA) or acetylacetonate (AcAc)) to ILs functionalized ZnO matrices. Subsequently, novel series of photoactive composites are assembled with ZnO nanoparticles and lanthanide complexes through SH-IL as bridge. Especially, it is worthy point out that the integration to white luminescence can be realized for the composite systems by adjusting the ratio of different active building units (red color for Eu complex, green color for Tb complex and blue color for ZnO unit). This result provides useful data to develop white-luminescent composite phosphors.

White luminescent hybrid soft materials of lanthanide (Eu3 +, Sm3 +) beta-diketonates and Ag/Ag2S nanoparticles based with thiol-functionalized ionic liquid bridge

Thiol-ionic liquid (SHIL) is prepared and used as bridge to prepare multi-component soft hybrids materials Ag(Ag2S)-SHIL-Ln(L)4 (Ln=Eu, Sm, L=TTA (thenoyltrifluoroacetylacetone), TAA (trifluoroacetylacetone), DBM (1,3-diphenyl-1,3-propanepione)) for its good solubility and functionality. Luminescence color of these soft hybrid materials can be adjusted through controlling different proportion of beta-diketonates (TTA, TAA, DBM) and silver species (Ag, Ag2S). Especially the white luminescence can be realized for the special composition of Ag/Ag2S and lanthanide beta-diketonate. The result can be expected to prepare luminescent soft materials to obtain the multi-color and white luminescence.

Enhanced Photochemical Stability of CdSe/CdS Quantum Dots Capped by Imidazolium-Based Ionic Liquids

The novel thiol-functionalized ionic liquids (ILs), 1-(10-mercaptodecyl)-3-methylimidazolium chloride ([HS-C10mim]Cl) and 1-(4-mercaptobutyl)-3-methylimidazolium chloride ([HS-C4mim]Cl), were synthesized by introducing thiol groups onto the alkyl chains in imidazolium-based ILs. The ILs exhibit strong affinity toward CdSe/CdS quantum dots (QDs), and can readily transfer the QDs from organic phases to aqueous phase. The IL-capped CdSe/CdS QDs are extremely soluble in water, and their photochemical stability was measured by absorption spectra. It is shown that the [HS-C10mim]Cl-capped QDs in water present much better anti-photooxidation than [HS-C4mim]Cl-capped those. The measurements of Zeta potential and hydrodynamic diameter reveal that the enhanced mechanism of [HS-C10mim]Cl depends mainly on the specific physico-chemical properties of the ILs. In particular, CdSe/CdS QDs with high surface potential, small hydrodynamic diameter, and optimal photochemical stability can be harvested by the solubilization of free [HS-C10mim]Cl in ligand shells of the QDs.

Gold Nanoparticles Grown on Ionic Liquid-Functionalized Single-Walled Carbon Nanotubes: New Materials for Photothermal Therapy

Gold nanoparticles were grown on single-walled carbon nanotubes (SWNTs) coated with a thiol-functionalized ionic liquid resulting in the formation of core-shell structures referred to as SWNT-IL-Au nanohybrid materials. The nanohybrid materials were characterized by high-resolution transmission electron microscopy (HR-TEM), Raman-, and UV/Vis absorption spectroscopy. The nanohybrid materials were found to enter lysosomes in HeLa cells and show negligible cytotoxicity. Interestingly, they have an enhanced NIR absorption that is effectively transferred into heat to cause localized hyperthermia, resulting in rapid cell death; overall, the material appears to have excellent properties for photothermal therapeutic applications.

Preparation, characterization, and application of a new thiol-functionalized ionic liquid for highly selective extraction of Cd(II)

A highly selective thiol-functionalized ionic liquid (thiol-FIL) was synthesized and characterized by FT-IR and ESI mass spectroscopy. The capability of thiol-FIL to extract Cd(II), Ni(II), Cr(III) and Pb(II) was evaluated. It is found that thiol-FIL possesses high selectivity for Cd(II), and this has led to a method for determination of Cd(II) by flame atomic absorption spectrometry that is free of interferences by up to a 1,000-fold excess of Na(I), Mg(II), Ca(II), Mn(II), Fe(III), Al(III), Cu(II), Zn(II), Ni(II), Cr(III), Co(II), As(III), Pb(II), and Hg(II). With extraction equilibrium time of 1 min, a good linearity (r = 0.9998) and a detection limit of 0.39 μg L−1 were obtained. The precision (RSD) for 11 replicate measurements of 10 μg L−1 Cd was 1.6%. The method was validated using certified reference materials. The recoveries of cadmium in spiked real samples ranged from 97% to 102%.

Enhanced electrochemiluminescence of luminol-O 2 system at gold–hydrophobic ionic liquid|water interface

A hydrophobic thiol-functionalized ionic liquid (IL) was synthesized and immobilized tightly on a gold electrode surface via Au–S bond to construct a stable Au–IL|water interface. At the Au–IL|water interface, the electrochemiluminescence (ECL) of luminol-O 2 system was investigated. The ECL intensity of luminol-O 2 system at the Au–IL|water interface was much larger and more stable than that at Au|water interface. The enhanced ECL mechanism at the Au–IL|water interface was studied and discussed in details.

Gold nanoparticles prepared by sonochemical method in thiol-functionalized ionic liquid

A convenient sonochemical method in preparation of gold nanoparticles capped by thiol-functionalized ionic liquid (TFIL) using hydrogen peroxide as a reducing agent was described in this paper. The obtained gold nanoparticles (GNPs) were characterized by ultraviolet–visible (UV–vis) absorption spectra, transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectra. It is found that the molar ratio of gold atom in chloroauric acid to thiol group in TFIL (Au/S) has great effects on the particles size and distribution of GNPs. The FT-IR spectra reveal that the function of thiol-containing ionic liquids is to form the bond of S–Au for stabilization of the gold cluster. Small gold nanoparticles size of 2.7 ± 0.3 nm with narrow uniform distributions can be obtained at the molar ratio of Au/S = 1:2 under ultrasound irradiation for 12 h. The reported method, which is performed in ionic liquid and hydrogen peroxide solution under ultrasound irradiation, is friendly to environment.

One-phase preparation of palladium nanoparticles using thiol-functionalized ionic liquid

Thiol-functionalized ionic liquid (TFIL: 1,3-di(2’,3’-dimercaptoacetoxypropyl) imidazolium, 3′’-mercapto1 ″-propanesulfonic acid) as a stabilizer for preparing palladium (Pd) nanoparticles was synthesized. The suggested TFIL was designed to have thiol groups on both cation and anion as well as on symmetrical positions in cation. Transmission electron microscopy (TEM) shows that the average diameter of the palladium nanoparticles was 3.0 nm and that the standard deviation was 0.15 nm. The overall results strongly suggest that this potential TFIL can act as a highly effective stabilizer for the preparation of Pd nanoparticles

Palladium nanowires stabilized by thiol-functionalized ionic liquid: seed-mediated synthesisand heterogeneous catalyst for Sonogashira coupling reaction

With the recent surge of the use of room-temperature ionic liquids in the synthesesof inorganic nanomaterials, we have successfully integrated the advantages of athiol-functionalized ionic liquid and the seed growth method to generate palladiumnanowires at room temperature. Moreover, the as-prepared palladium nanowires showvery high catalytic activity and stability for the Sonogashira coupling reaction.

Synthesis of Thiol-Functionalized Ionic Liquids and Formation of Self-Assembled Monolayer on Gold Surfaces: Effects of Alkyl Group and Anion on the Surface Wettability.

Twenty four thiol-functionalized ionic liquids based on imidazolium cation, 1-(12-mercaptododecyl)-3alkylimidazolium salts, have been synthesized, and utilized to investigate the effects of alkyl-chain length and anion on the wettability of Au surfaces on the basis of self-assembled monolayers presenting [(CnSAMIM)X], where n = 1-6, X = Br, BF4, PF4 and NTf2. Water wettabilities of the surfaces were measured as a water contact angle by contact angle goniometry. It was found that water wettab ility of the Au su rfaces coated with imidazolium ions was largely dependent not only on counter anions but also on the length of alkyl chains. In the case of SAMs of N-alkylimidazolium ions having short length of N-alkyl chain (C1-C4), anions played great role in determining water wettability of the surfaces.

Synthesis of Thiol-Functionalized Ionic Liquids and Formation of Self-Assembled Monolayer on Gold Surfaces: Effects of Alkyl Group and Anion on the Surface Wettability

Twenty four thiol-functionalized ionic liquids based on imidazolium cation, 1-(12-mercaptododecyl)-3alkylimidazolium salts, have been synthesized, and utilized to investigate the effects of alkyl-chain length and anion on the wettability of Au surfaces on the basis of self-assembled monolayers presenting [(CnSAMIM)X], where n = 1-6, X = Br, BF4, PF4 and NTf2. Water wettabilities of the surfaces were measured as a water contact angle by contact angle goniometry. It was found that water wettab ility of the Au su rfaces coated with imidazolium ions was largely dependent not only on counter anions but also on the length of alkyl chains. In the case of SAMs of N-alkylimidazolium ions having short length of N-alkyl chain (C1-C4), anions played great role in determining water wettability of the surfaces.

Size-Selective Synthesis of Gold and Platinum Nanoparticles Using Novel Thiol-Functionalized Ionic Liquids

One-phase synthesis of gold and platinum nanoparticles using new thiol-functionalized ionic liquids (TFILs) is described for the first time. TFILs as stabilizing agents for gold and platinum nanoparticles were designed to have thiol groups on either the cation or anion and symmetrical or unsymmetrical positions only in the cation. Transmission electron microscopy, electron diffraction, and NMR were used for the characterization of nanoparticles. The metal nanoparticles formed using TFILs are crystalline structures with face-centered cubic packing arrangements and have small sizes (the average diameters are 3.5, 3.1, and 2.0 nm for Au and 3.2, 2.2, and 2.0 nm for Pt, respectively) and uniform distributions (the standard deviations are 0.7, 0.5, and 0.1 nm for Au and 1.1, 0.2, and 0.1 for Pt, respectively). It is believed that the nanoparticle size and distribution depend on the number and position of thiol groups in the IL.