Shuling Gong

Molecular design and synthesis of a calix[6]crown-based lithium-selective ionophore

Abstract Several 1,4-bridged calix[6]arene tetraesters were prepared from 1,4- p-tert -calix[6]crown-4’s by etherifying with ethyl bromoacetate. It was found that the 1,4- p-tert -calix[6]crown-4 tetraethylester ( 3a ) and the 1,4- p-tert -calix[6]benzocrown-4 tetramethylester ( 4b) exhibit very high selectivity toward lithium and sodium ions, respectively. The ion selectivity is very sensitive to the structure of polyoxyethylene spacer and the R in the ester moiety.

Pendant orientation and its influence on the formation of hydrogen-bonded thiacalixarene nanotubes

Five 1,3-alternatethiacalix[4]arene derivatives bearing carboxylic acid and/or urea hydrogen-bonding groups were prepared and their crystal structures were determined by single-crystal X-ray diffraction methods. In compound 1, where the pendant arms are all adorned with carboxylic acid groups, the pendants all orientate along the base of the molecular axis. An interesting three-dimensional network of “endo-inclusion” aquatubes is formed by stacking the water contained cavities of 1 up and down. While concerning to the other four compounds to which the urea groups are introduced, their pendant arms either orientate towards the inner side of the cavities, or orientate towards the outside, depending on the types of hydrogen-bonding groups and the position of these groups. When the urea groups are in the same side (compounds 2, 4 and 5), the opposite chains in the molecule will locate away from each other which may be due to the steric repulsions. But when the urea group and carboxylic acid group are in the same side (compounds 3 and 4), the opposite chains all orientate inwards because of the intramolecular, inter-chain hydrogen bonds between the opposite chains. Although these four compounds can also self-assemble through the cavity stacking motif, the inwardly orientated pendant arms which protrude into the thiacalixarene cavity obstruct the channels.

Synthesis, Characterization and Coordination Properties of a Novel Thiacalix[4]arene with Diagonal Quinolin-8-yloxy Pendants

A novel conic thiacalix[4]arene derivative (1) with diagonal quinolin-8-yloxy pendants via oxyethylene spacer has been synthesized in one step. The coordination properties of the new ligand towards Ni2 + , Co2 + and Zn2 + ions were studied by UV–vis, fluorescent spectra and 1H NMR titration. The results showed that 1 formed very stable complexes with the three metal ions, and the stoichiometries of 1-Ni2 + , 1-Co2 + and 1-Zn2 + were 1:1, 1:2 and 1:2, respectively.

Fibriform one-dimensional hydrogen-bonded network composed of 1,2-alt calix[4]arene tetra acetic acid

1,2-alt p-tert-Butylcalix[4]arene tetraacid can self-assemble via hydrogen-bonds into a one dimensional network with channel of diameter ca. 0.5 nm, and ethanol molecules were incorporated into the network playing roles of hydrogen bond donors and acceptors simultaneously.

Nano CaCO3: playing a special role in the monofunctionalization of calixarenes by epoxides

It was found that nano CaCO3 played an interesting role in the reaction of p-tert-butylcalixarene with epoxides. In the presence of nano CaCO3, a monosubstituted calixarene, a β ring-opening product of epoxide, was obtained regioselectively in good yield. When normal CaCO3 was used under the same conditions, the yield was less than 2%. The β ring-opening product of epichlorohydrin could convert to monoglycidyl calixarene by reacting with C2H5ONa in tetrahydrofuran at room temperature in moderate yield.

Invariant water inclusion property of 1,3-alternate p-tert-butylthiacalix[4]arene tetra-methyleneoxycarboxylic acid

The self-assembly behavior of 1,3-alternate p-tert-butylthiacalix[4]arene tetra-methyleneoxycarboxylic acid (I) and 1,3-alternate p-H-thiacalix[4]arene tetra-methyleneoxycarboxylic acid (II) in ethanol, acetone and in the existence of 4,4′-bipyridine were studied by single-crystal X-ray diffraction methods. Compound I maintains almost the same tubular shape molecular structure and the unique water inclusion property ([I ∩ 2H2O]) in the three different crystallization media because of the steric hindrance posed by the t-butyl groups. While for compound II, its molecular structure and water inclusion property are susceptible to the crystallization medium due to the absence of the t-butyl groups.

An approach to double thiacalixarene

Abstract A new double thiacalix[4]arene and a 1,3‐disubstituted thiacalix[4]arene were obtained by refluxing p‐tert‐butylthiacalix[4]arene in benzene with 2,6‐bis(bromomethyl)‐4‐methylanisole in the presence of Na2CO3 as a base under argon in 58% and 10% yield, respectively.

Aminolysis of p-tert-Butyl-tetrakis-[(ethoxycarbonyl)methoxy]thiacalix[4]arene

Abstract A convenient method for preparation of thiacalix[4]arene tetraamides in high to good yields by reacting conic or 1,3‐alt‐p‐tert‐butyl‐tetrakis[(ethoxycarbonyl)methoxy]‐thiacalix[4]arene with excess monoamines or diamines is reported. In most cases, corresponding tetraamides with original conformation were obtained. However, when the cone one was reacted with ethylenediamine or propylenediamine, the obtained tetraamides possessed partial conic conformation, which meant that conversion of conformation occurred.

Non-aqueous liquid membrane system

Abstract After analyzing the status quo and development of the research of liquid membrane, we put forward the possibility and necessity of establishment of a new type of liquid membrane system, i.e. non-aqueous liquid membrane system. The new liquid membrane system was founded by replacing water in former water–oil–water or oil–water–oil system with organic solvents or fluid polymer. Two types of non-aqueous liquid membrane system were successfully founded. The first is the modification of water–oil–water system without carrier, and another is the modification of oil–water–oil system with carrier. The carriers were synthesized from alkenyl crown ether or azacrown ether by hydrosilylation of methyldichlorosilane, followed by condensation with α,ω-dihydroxypolydimethylsiloxane. The transport of benzene, xylenes, benzonitrile, cyclohexanol and propanediol in the non-aqueous liquid membrane systems were investigated. It was found that the carriers can facilitate the substance through a non-aqueous liquid membrane, and can transport 1,2-propanediol from the mixture of 1,2-propanediol and 1,3-propanediol slightly selectively.

Preparation and Properties of High Solid Content and Low Viscosity Waterborne Polyurethane—Acrylate Emulsion with a Reactive Emulsifier

High solid content waterborne polyurethane-acrylate (WPUA) emulsions have been successfully synthesized in two steps. Firstly, we prepared a waterborne polyurethane emulsion, then reacted it with acrylate monomer by emulsion polymerization using the semi-continuous seeded method. The effects of the type and amount of emulsifier, the amount of dimethylolpropionic acid (DMPA), the choice of capping group, the ratio of PU/PA, and the method of adding a water-soluble monomer to the properties of the composite emulsion were investigated. The reactive emulsifier replaced the traditional emulsifier and there were no metal ions introduced to the reaction, whether by the emulsifier or the initiator. Through a variety of tests, we proved that the prepared emulsion has the advantages of small particle size, narrow distribution, good stability, good performance of the film, and solid content of 46%.