‘Living’ Controlled <i>in Situ</i> Gelling Systems: Thiol−Disulfide Exchange Method toward Tailor-Made Biodegradable Hydrogels

A ‘living’ controlled hydrogel formation method was first reported to create loose and compact in situ biodegradable hydrogels. The method executed under mild reaction conditions can conveniently tailor the hydrogel properties, and it has the potential to develop into a powerful tool for the design, synthesis, and self-assembly of novel tailor-made biomaterials and drug delivery systems

Synthesis of Novel Biodegradable Thermoresponsive Triblock Copolymers Based on Poly[(<i>R</i>)-3-hydroxybutyrate] and Poly(<i>N</i>-isopropylacrylamide) and Their Formation of Thermoresponsive Micelles

Novel thermoresponsive amphiphilic triblock copolymers with two hydrophilic poly(N-isopropylacrylamide) blocks flanking a central hydrophobic poly[(R)-3-hydroxybutyrate] block were synthesized by atom transfer radical polymerization. The copolymers were characterized by gel permeation chromatography (GPC) and 1H and 13C NMR spectroscopy. The thermal stability of the copolymer was investigated by thermogravimetric analysis (TGA), and crystallization behavior was studied by differential scanning calorimetry (DSC). The water-soluble copolymers formed core−corona-type micelle aggregates in water. The critical micelle concentrations of the triblock copolymers were in the range of 1.5 to 41.1 mg/L, and the partition coefficients were in the range of (1.64−20.42) × 105. Transmission electron microscopy showed that the self-assembled micelle aggregates had well-defined spherical shape. The temperature sensitivity of the micelles was demonstrated by the phase transition of a 0.5 mg/mL aqueous polymer solution at the lower critical solution temperature (LCST). Preliminary cytotoxicity studies showed that these micelles were nontoxic and could be potential candidates for the encapsulation and release of therapeutic drugs in the biological system

Light Emission of Gold Nanoparticles Induced by the Reaction of Bis(2,4,6-trichlorophenyl) Oxalate and Hydrogen Peroxide

Light emission at ∼415 nm was observed for gold particles with diameters of 2.6−6.0 nm dispersed in a solution containing bis(2,4,6-trichlorophenyl) oxalate and hydrogen peroxide. It was found that the light intensity was independent of the protecting reagents of the gold nanoparticles with similar size, the light intensity with gold nanoparticles of 5.0 and 6.0 nm in diameter was stronger than that with gold nanoparticles of 2.6 and 2.8 nm in diameter, and the light intensity increased linearly with the concentration of the gold nanoparticles using 6.0-nm gold nanoparticles. The gold nanoparticles were identified as emitting species, and the quantum yield was determined to be (2.8 ± 0.3) × 10-5 using 6.0-nm gold nanoparticles. The light emission is suggested to involve a sequence of steps:  the oxidation reaction of bis(2,4,6-trichlorophenyl) oxalate with hydrogen peroxide yielding an energy-rich intermediate 1,2-dioxetanedione, the energy transfer from this intermediate to gold nanoparticles, and the radiative relaxation of the as-formed exited-state gold nanoparticles. The observed luminescence is expected to find applications in the field of bioanalysis owing to the excellent biocompatibility and relatively high stability of gold nanoparticles

Facile Incorporation of Au Nanoparticles into an Unusual Twofold Entangled Zn(II)-MOF with Nanocages for Highly Efficient CO₂ Fixation under Mild Conditions

Herein, a new porous Zn­(II)-based metal–organic framework (MOF 1) has been prepared, the structure of which featured a twofold entangled motif based on two typical secondary building units (SBUs). The gas sorption studies indicated that MOF 1 may be explored as a useful platform to encapsulate metallic nanoparticles. Then the Au@1 composite has been prepared via a facile incorporation method without extra reducing agents. The Au@1 composite has been fully characterized by HRTEM, SEM-EDX, PXRD, gas sorption, XPS, ICP, etc. Catalytic experiments showed that the Au@1 composite had a perfect catalytic performance in CO2 fixation for epoxides with different substituents under mild conditions

Facile Incorporation of Au Nanoparticles into an Unusual Twofold Entangled Zn(II)-MOF with Nanocages for Highly Efficient CO₂ Fixation under Mild Conditions

Herein, a new porous Zn­(II)-based metal–organic framework (MOF 1) has been prepared, the structure of which featured a twofold entangled motif based on two typical secondary building units (SBUs). The gas sorption studies indicated that MOF 1 may be explored as a useful platform to encapsulate metallic nanoparticles. Then the Au@1 composite has been prepared via a facile incorporation method without extra reducing agents. The Au@1 composite has been fully characterized by HRTEM, SEM-EDX, PXRD, gas sorption, XPS, ICP, etc. Catalytic experiments showed that the Au@1 composite had a perfect catalytic performance in CO2 fixation for epoxides with different substituents under mild conditions

Three N–H Functionalized Metal–Organic Frameworks with Selective CO₂ Uptake, Dye Capture, and Catalysis

Three N–H functionalized metal–organic frameworks, Pb-DDQ, Zn-DDQ, and Cu-DDQ, were synthesized with a new flexible dicarboxylate ligand based on quinoxaline (H2DDQ = N,N′-dibenzoic acid-2,3-diaminoquinoxaline). CO2 adsorptions indicate that Zn-DDQ and Cu-DDQ have greatly enhanced the CO2 uptake due to the opposite N–H groups on pyrazine. With very small adsorption of N2, Cu-DDQ shows high selectivity for CO2 and N2. The three MOFs also have large adsorptions of some selected dyes, while Zn-DDQ and Cu-DDQ with large but different shapes of pores are demonstrated to be promising materials for fast separation of MB/other and CV/other mixtures, respectively. The cyanosilylation of aldehydes and ketones with high yields in a short reaction time for Cu-DDQ indicates that Cu-DDQ has a higher Lewis acidity than the other two MOFs

High CO₂ Uptake Capacity and Selectivity in a Fascinating Nanotube-Based Metal–Organic Framework

An unusual porous metal–organic framework has been synthesized by using Pb­(II) and rigid V-shaped 4,4′-(pyri­dine-3,5-diyl)­diiso­phthalic acid (H4L). Structure analysis reveals that there exist 1D cylindrical 14.26 Å and triangular prism 10.69 × 10.69 × 10.69 Å3 nanotubes in the framework. Gas sorption behavior of the nanoporous MOF shows a relatively high capacity and selectivity of CO2 over CH4

Three N–H Functionalized Metal–Organic Frameworks with Selective CO₂ Uptake, Dye Capture, and Catalysis

Three N–H functionalized metal–organic frameworks, Pb-DDQ, Zn-DDQ, and Cu-DDQ, were synthesized with a new flexible dicarboxylate ligand based on quinoxaline (H2DDQ = N,N′-dibenzoic acid-2,3-diaminoquinoxaline). CO2 adsorptions indicate that Zn-DDQ and Cu-DDQ have greatly enhanced the CO2 uptake due to the opposite N–H groups on pyrazine. With very small adsorption of N2, Cu-DDQ shows high selectivity for CO2 and N2. The three MOFs also have large adsorptions of some selected dyes, while Zn-DDQ and Cu-DDQ with large but different shapes of pores are demonstrated to be promising materials for fast separation of MB/other and CV/other mixtures, respectively. The cyanosilylation of aldehydes and ketones with high yields in a short reaction time for Cu-DDQ indicates that Cu-DDQ has a higher Lewis acidity than the other two MOFs

Three N–H Functionalized Metal–Organic Frameworks with Selective CO₂ Uptake, Dye Capture, and Catalysis

Three N–H functionalized metal–organic frameworks, Pb-DDQ, Zn-DDQ, and Cu-DDQ, were synthesized with a new flexible dicarboxylate ligand based on quinoxaline (H₂DDQ = <i>N</i>,<i>N</i>′-dibenzoic acid-2,3-diaminoquinoxaline). CO₂ adsorptions indicate that Zn-DDQ and Cu-DDQ have greatly enhanced the CO₂ uptake due to the opposite N–H groups on pyrazine. With very small adsorption of N₂, Cu-DDQ shows high selectivity for CO₂ and N₂. The three MOFs also have large adsorptions of some selected dyes, while Zn-DDQ and Cu-DDQ with large but different shapes of pores are demonstrated to be promising materials for fast separation of MB/other and CV/other mixtures, respectively. The cyanosilylation of aldehydes and ketones with high yields in a short reaction time for Cu-DDQ indicates that Cu-DDQ has a higher Lewis acidity than the other two MOFs

High CO₂ Uptake Capacity and Selectivity in a Fascinating Nanotube-Based Metal–Organic Framework

An unusual porous metal–organic framework has been synthesized by using Pb­(II) and rigid V-shaped 4,4′-(pyri­dine-3,5-diyl)­diiso­phthalic acid (H₄L). Structure analysis reveals that there exist 1D cylindrical 14.26 Å and triangular prism 10.69 × 10.69 × 10.69 ų nanotubes in the framework. Gas sorption behavior of the nanoporous MOF shows a relatively high capacity and selectivity of CO₂ over CH₄