Zeolitic imidazolate framework-8
shares the same topology with
sodalite zeolite but consists of Zn nodes bridged by imidazolate linkers
to form a neutral open-framework structure. ZIF-8 has been recognized
as a unique molecular sieving material with a flexible framework enabling
interesting “gate-opening” functionality. Controlling
the crystal size and shape is crucial for regulating the structural
flexibilities and mass transport properties. The present study demonstrates
that an aqueous-system-enabled spray-drying process enables the shape
engineering of ZIF-8 with a hollow polycrystalline structure. It is
notable that our synthesis route produces an amorphous zinc complex
compound, which possesses a continuous random network partially with
crystalline fillers, after spray drying followed by an amorphous-to-crystal
transition via activation treatment using polar organic solvents.
The size of primary ZIF-8 crystals consisting of secondary polycrystals
depends on the kind of the organic solvent. The macro-/microscopic
structures of hollow polycrystalline ZIF-8 significantly structurally
enhanced the adsorption capacity and uptake rate. The large-scale,
rapid production and enhanced adsorption performances make this continuous
method a very promising candidate for industrial applications and
shaping of MOF.
A lipophilic diphosphonium salt 1 having binaphtyl-type axial chirality was developed as a novel ion-pair extractant. By use of (R)-1, (−)-di-O-benzoyltartrate ((−)-DBT) was extracted more effectively than (+)-DBT. The enantioselectivity (α=D(−)⁄D(+); D: distribution ratio) was 1.3–1.4. When monophosphonium-type extractants (2 and 3) having structures similar to that of 1 were used, the enantioselectivity was heavily lowered. Equilibrium studies revealed that the extraction occurs via formation of a 1 : 1 ion-pair complex between 1 and DBT at pH 7.5–8.0. The effects of pH, ionic strength, and temperature on the extractability and the enantioselectivity were investigated. The enantioselectivity decreased with lowering pH, and was higher at lower temperatures. The optical purity of DBT in the aqueous phase was gradually enhanced by multistage extraction. From an NMR analysis of the 1·DBT complex, the resonances of methylene-protons adjacent to phosphonium in the more extractable complexes ((R)-1·-(−)-DBT and (S)-1·(+)-DBT) shifted to a higher field compared to those of the less extractable complexes ((R)-1·(+)-DBT and (S)-1·(−)-DBT).
A polyaniline
(PANI) composite was prepared through chemical polymerization
of aniline in the cholesteric liquid crystal (CLC) state of hydroxypropyl
cellulose (HPC). Polymerization and composite formation were simultaneously
performed. Polarizing optical microscopy, scanning electron microscopy,
electrochemistry, and optical spectroscopy were used to characterize
the composite. Electron spin resonance and a superconducting quantum-interference
device were used to investigate the composite’s magnetic properties.
PANI in the composite exhibited a helical structure of the main chain
as a result of the main chain growing in the direction of the LC orientation.
The main chains of PANI were secondarily doped, thus they exhibited
moderate electrical conductivity as a conducting polymer (PANI)/insulating
polymer composite. Polarons (radical cations) distributed along the
main chain with a helical structure are responsible for the composite’s
magnetic spins. Consequently, the spins, like the helical structure,
are delocalized. Because of the doping–dedoping of the PANI
component, the composite exhibits excellent redox properties. The
PANI/HPC composite’s potential applications in capacitors,
electrochemical transistors, thermistors, and optical fibers were
investigated.
We developed a new Bach-type reaction in the presence of oxy-hemoglobin as an oxygen supplier to synthesize polyazobenzene by traditional Bach reaction. The resultant product is a form of polymeric dye/hemoglobin copolymer. The advantage of this research is that it involves a new reaction using the function of biomolecules, as well as the formation of plastics and biomaterials. The bio-based material may have good affinity with life forms, which may lead to applications in medical science.
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