Sungah Kang

Metal−Organic Framework@Microporous Organic Network: Hydrophobic Adsorbents with a Crystalline Inner Porosity

This work reports the synthesis and application of metal-organic framework (MOF)@microporous organic network (MON) hybrid materials. Coating a MOF, UiO-66-NH2, with MONs forms hybrid microporous materials with hydrophobic surfaces. The original UiO-66-NH2 shows good wettability in water. In comparison, the MOF@MON hybrid materials float on water and show excellent performance for adsorption of a model organic compound, toluene, in water. Chemical etching of the MOF results in the formation of hollow MON materials.

Microporous organic networks bearing metal-salen species for mild CO2 fixation to cyclic carbonates

This work shows that porous solid systems for catalytic carbon dioxide fixation can be developed by a direct assembly of metal-salen containing building blocks with organic connectors through a carbon–carbon bond formation reaction. For use as a dihalo building block, Al, Cr, Co-salen building blocks with two iodo groups were prepared. Sonogashira coupling of these building blocks with tetra(4-ethynylphenyl)methane resulted in microporous organic networks (MONs) bearing Al, Cr, and Co-salen species (Al-MON, Cr-MON, Co-MON). Scanning electron microscopy (SEM) showed that the materials had granular or spherical shapes. Brunauer–Emmett–Teller (BET) analysis revealed surface areas of up to 522–650 m2 g−1, and microporosity (<2 nm). The thermal stability of the materials was dependent on the degree of networking. Their chemical components were characterized by solid-phase 13C-nuclear magnetic resonance spectroscopy (NMR) and X-ray photoelectron spectroscopy (XPS). The materials containing metal-salen (M-MON) showed excellent chemical conversion of carbon dioxide with epoxide to cyclic carbonates under mild conditions (60 °C and 1 MPa CO2). Among the M-MONs, the Co-MON showed the best reactivity for carbon dioxide conversion to cyclic carbonates with 1400–1860 TON and 117–155 h−1 TOF. The size effect of epoxides in CO2 fixation was observed due to the microporosity of Co-MON.

Fe3O4 nanosphere@microporous organic networks: enhanced anode performances in lithium ion batteries through carbonization

Very thin microporous organic networks were formed on the surface of Fe3O4 nanospheres by Sonogashira coupling of tetra(4-ethynylphenyl)methane and 1,4-diiodobenzene. The thickness was controlled by screening the number of building blocks. Through carbonization, Fe3O4@C composites were prepared. The Fe3O4@C composites with 4-6 nm carbon thickness showed promising reversible discharge capacities of up to 807 mA h g(-1) and enhanced electrochemical stability.

Hollow and sulfonated microporous organic polymers: versatile platforms for non-covalent fixation of molecular photocatalysts

Sulfonated hollow microporous organic polymers (S-HMOP) were prepared by template synthesis and post synthetic approach. The S-HMOP showed excellent non-covalent fixation ability towards various cationic dyes through ionic interaction. Among various dye systems, Zn-porphyrin loaded S-HMOP showed promising activity and stability in the decomposition of 4-chlorophenol under visible light irradiation.