Dongbin Zhao

Bio: Dongbin Zhao is an academic researcher from École Polytechnique Fédérale de Lausanne. The author has contributed to research in topics: Ionic liquid & Nitrile. The author has an hindex of 24, co-authored 34 publications receiving 2850 citations.

From dysfunction to bis-function: on the design and applications of functionalised ionic liquids

Abstract: Some of the recent developments concerning the synthesis, properties and applications of functionalised ionic liquids are highlighted. Various strategies are presented, including functionalisation of the cation, anion or both cation and anion in the same ionic liquid, leading to what has been termed dual-functionalised ionic liquids. Particular attention is given to the application of functionalised ionic liquids as reaction media, to stabilise nanoparticles/modify surfaces and to generate porous materials.

Nitrile-functionalized pyridinium ionic liquids: Synthesis, characterization, and their application in carbon-carbon coupling reactions

Abstract: A series of relatively low-cost ionic liquids, based on the N-butyronitrile pyridinium cation [C(3)CNpy](+), designed to improve catalyst retention, have been prepared and evaluated in Suzuki and Stille coupling reactions. Depending on the nature of the anion, these salts react with palladium chloride to form [C(3)CNpy](2)[PdCl(4)] when the anion is Cl(-) and complexes of the formula [PdCl(2)(C(3)CNpy)(2)][anion](2) when the anion is PF(6)(-), BF(4)(-), or N(SO(2)CF(3))(2)(-). The solid-state structures of [C(3)CNpy]Cl and [C(3)CNpy](2)[PdCl(4)] have been established by single-crystal X-ray diffraction. The catalytic activity of these palladium complexes following immobilization in both N-butylpyridinium and nitrile-functionalized ionic liquids has been evaluated in Suzuki and Stille coupling reactions. All of the palladium complexes show good catalytic activity, but recycling and reuse is considerably superior in the nitrile-functionalized ionic liquid. Inductive coupled plasma spectroscopy reveals that the presence of the coordinating nitrile moiety in the ionic liquid leads to a significant decrease in palladium leaching relative to simple N-alkylpyridinium ionic liquids. Palladium nanoparticles have been identified as the active catalyst in the Stille reaction and were characterized using transmission electron microscopy.

Brønsted Acidic Ionic Liquids and Their Zwitterions: Synthesis, Characterization and pKa Determination

Abstract: Imidazolium chlorides with one or two carboxylic acid substituent groups, 1-methyl-3-alkylcarboxylic acid imidazolium chloride, [Me{(CH2)(n)COOH}im]Cl (n=l, 3), and 1,3-dialkylcarboxylic acid imidazolium chloride, [{(CH2)(n)COOH}(2)im]Cl (n=1, 3), have been synthesized via their corresponding acid esters. Deprotonation of the carboxylic acid functionalized imidazolium chlorides with triethylamine affords the corresponding zwitterions [Me{(CH2)(n)COO}im] (n=1, 3) and [{(CH2),COOH}{(CH2)(n)COO}im] (n= 1, 3). Subsequent reaction of the zwitterions with strong acids gives the new imidazolium salts [Me{(CH2)(n)COOH }im]X (n=1, 3; X=BF4, CF3SO3) and [{(CH2)(n)COOH)(2)im]X (n=1, 3; X=BF4, CF3SO3), which exhibit melting points as low as -61 degreesC. The solidstate structures of two of the carboxylic acid functionalized imidazolium salts have been determined by single-crystal X-ray diffraction analysis. Extensive hydrogen bonding is present between the chloride and the imidazolium, with eight (ClH)-H-... interactions below 3Angstrom. The pK(a) values of all the salts, determined by potentiometric titration, lie between 1.33 and 4.59 at 25 degreesC.

Synthesis and characterization of ionic liquids incorporating the nitrile functionality

Abstract: A series of imidazolium salts with the nitrile functional group attached to the alkyl side chain, viz. [CnCNmim][X] (where CnCNmim is the 1-alkylnitrile-3-methylimidazolium cation and Cn = (CH2)n, n = 1−4; X = Cl, PF6, and BF4) and [C3CNdmim][X] (where CnCNdmim is the 1-alkylnitrile-2,3-dimethylimidazolium cation and Cn = (CH2)n, n = 3; X = Cl, PF6, and BF4), have been prepared and characterized using spectroscopic methods. The majority of the nitrile-functionalized imidazolium salts can be classed as ionic liquids since they melt below 100 °C. Four of the imidazolium salts have been characterized in the solid state using single-crystal X-ray diffraction analysis to reveal an extensive series of hydrogen bonds between H atoms on the cation and the anion. The relationship between the solid-state structure and the melting point is discussed. Key physical properties (density, viscosity, and solubility in common solvents) of the low melting ionic liquid have been determined and are compared with those of the ...

A Synthetic Zwitterionic Water Channel: Characterization in the Solid State by X‐ray Crystallography and NMR Spectroscopy

Abstract: Keywords: transition mas nmr ; coordination polymers ; magic-angle ; magnetic-resonance ; molecular-dynamics ; spectra ; resolution ; chains ; zinc ; selectivity Reference LCOM-ARTICLE-2005-015doi:10.1002/anie.200500207View record in Web of Science Record created on 2005-11-09, modified on 2017-05-12

Dye-Sensitized Solar Cells

Abstract: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...

Nanoparticles as Recyclable Catalysts: The Frontier between Homogeneous and Heterogeneous Catalysis

Abstract: Interest in catalysis by metal nanoparticles (NPs) is increasing dramatically, as reflected by the large number of publications in the last five years. This field, "semi-heterogeneous catalysis", is at the frontier between homogeneous and heterogeneous catalysis, and progress has been made in the efficiency and selectivity of reactions and recovery and recyclability of the catalytic materials. Usually NP catalysts are prepared from a metal salt, a reducing agent, and a stabilizer and are supported on an oxide, charcoal, or a zeolite. Besides the polymers and oxides that used to be employed as standard, innovative stabilizers, media, and supports have appeared, such as dendrimers, specific ligands, ionic liquids, surfactants, membranes, carbon nanotubes, and a variety of oxides. Ligand-free procedures have provided remarkable results with extremely low metal loading. The Review presents the recent developments and the use of NP catalysis in organic synthesis, for example, in hydrogenation and C--C coupling reactions, and the heterogeneous oxidation of CO on gold NPs.

Catalysis in ionic liquids

Abstract: 2.5. Stabilization of IL Emulsions by Nanoparticles 2623 3. Hydrogenations in ILs 2623 3.1. Hydrogenation on IL-Stabilized Nanoparticles 2623 3.1.1. Hydrogenation of 1,3-Butadiene 2623 3.1.2. Hydrogenation of Alkenes and Arenes 2624 3.1.3. Hydrogenation of Ketones 2624 3.2. Homogeneous Catalytic Hydrogenation in ILs 2624 3.3. Hydrogenation of Functionalized ILs 2625 3.3.1. Selective Hydrogenation of Polymers 2625 3.4. Asymmetric Hydrogenations 2626 3.4.1. Enantioselective Hydrogenation 2626 3.5. Role of the ILs Purity in Hydrogenation Reactions 2628