Publications by authors named "Chang Seop Hong"

Hydrogen is a clean-burning fuel that can be converted to other forms. of energy without generating any greenhouse gases. Currently, hydrogen is stored either by compression to high pressure (>700 bar) or cryogenic cooling to liquid form (<23 K).

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Article Synopsis
  • - The article discusses a new type of adsorbent made from microporous organic polymers (POPs) that selectively separates ethane (C2H6) from ethylene (C2H4) gas mixtures, presenting a more efficient alternative to traditional cryogenic distillation methods.
  • - The designed POP adsorbent features specific pore sizes and coordinated copper(I) ions, which allow it to preferentially adsorb ethylene (C2H4) while limiting the adsorption of ethane (C2H6), achieving high selectivity and performance at various temperatures.
  • - Computational studies indicate that the interaction between the POP's copper and ethylene enhances its adsorption capacity, confirming the effectiveness of the adsorbent through both
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  • Diamine-functionalized metal-organic frameworks (MOFs) like Mg(dobpdc) are effective CO adsorbents but struggle with diamine loss at high desorption temperatures.
  • A new study introduces Mn(dobpdc) modified with diaminopropane derivatives, which allows CO to be desorbed at lower temperatures and prevents diamine loss.
  • The research also reveals unique adsorption structures in MOFs with primary-tertiary diamine, enhancing our understanding of how metal ions affect diamine stability in these adsorbents.
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The film-forming capability of the host plays a crucial role in effectively forming a light-emitting layer through a solution process in organic light-emitting diodes (OLEDs). In this study, we synthesized two side-chain polymer hosts, and , consisting of carbazole and dibenzothiophene. The synthesis was carried out through radical polymerization using styrene-based host monomers.

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Purifying CH from a ternary CH/CH/CH mixture poses a substantial industrial challenge due to their close physical and chemical properties. In this study, we introduce an innovative design approach to regulate and optimize the nitration degree of a hypercrosslinked polymer to achieve targeted separation performance. We synthesized a porous organic polymer (HCP) using the solvent knitting method and carried out its postsynthetic nitration, resulting in HCP-NO-1 and HCP-NO-2 with different nitration degrees.

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Direct air capture (DAC) shows considerable promise for the effective removal of CO; however, materials applicable to DAC are lacking. Among metal-organic framework (MOF) adsorbents, diamine-Mg(dobpdc) (dobpdc = 4,4-dioxidobiphenyl-3,3'-dicarboxylate) effectively removes low-pressure CO, but the synthesis of the organic ligand requires high temperature, high pressure, and a toxic solvent. Besides, it is necessary to isolate the ligand for utilization in the synthesis of the framework.

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Hydrogen storage is crucial in the shift toward a carbon-neutral society, where hydrogen serves as a pivotal renewable energy source. Utilizing porous materials can provide an efficient hydrogen storage solution, reducing tank pressures to manageable levels and circumventing the energy-intensive and costly current technological infrastructure. Herein, two highly porous aromatic frameworks (PAFs), C-PAF and Si-PAF, prepared through a Yamamoto C─C coupling reaction between trigonal prismatic monomers, are reported.

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In this study, two novel multiple resonance (MR) emitters, DtCzBN and Cy-DtCzBN, were designed based on the well-known BCzBN structure and synthesized for narrowband solution-processed organic light-emitting diodes (OLEDs). Cy-DtCzBN possesses a dimeric V-shaped structure formed by coupling two individual DtCzBN units via a nonconjugated cyclohexane linker. When compared with DtCzBN, Cy-DtCzBN, as a medium-sized molecule, was found to maintain the optical and photophysical properties of the corresponding monomeric unit, DtCzBN, but exhibits high thermal stability, excellent solubility, and good film-forming ability.

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Postsynthetic modifications (PSMs) of metal-organic frameworks (MOFs) play a crucial role in enhancing material performance through open metal site (OMS) functionalization or ligand exchange. However, a significant challenge persists in preserving open metal sites during ligand exchange, as these sites are inherently bound by incoming ligands. In this study, for the first time, we introduced alkoxides by exchanging bridging chloride in NiClBTDD (BTDD=bis (1H-1,2,3,-triazolo [4,5-b],-[4',5'-i]) dibenzo[1,4]dioxin) through PSM.

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Metal-organic frameworks (MOFs), a sort of crystalline porous coordination polymers composed of metal ions and organic linkers, have been intensively studied for their ability to take up nonpolar gas-phase molecules such as ethane and ethylene. In this context, interpenetrated MOFs, where multiple framework nets are entwined, have been considered promising materials for capturing nonpolar molecules due to their relatively higher stability and smaller micropores. This study explores a solvent-assisted reversible strategy to interpenetrate and deinterpenetrate a Cu(II)-based MOF, namely, MOF-143 (noninterpenetrated form) and MOF-14 (doubly interpenetrated forms).

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Among the various metal-organic framework (MOF) adsorbents, diamine-functionalized Mg(dobpdc) (dobpdc = 4,4-dioxidobiphenyl-3,3'-dicarboxylate) shows remarkable carbon dioxide removal performance. However, applying diamine-functionalized Mg(dobpdc) in practical applications is premature because it shows persistent performance degradation under real flue gas conditions containing water vapor owing to diamine loss during wet cycles. To address this issue, we employed hydrophobic carbonate compounds to protect diamine groups in een-Mg(dobpdc) (, een = N-ethylethylenediamine).

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Article Synopsis
  • The MOF-type Ni(dobpdc) exhibits high stability and capacity for sulfur dioxide (SO) capture, achieving 4.3 mmol/g at low pressure (0.05 bar) and room temperature (298 K).
  • It demonstrates excellent cycling performance, indicating durability over repeated use.
  • Fluorescence and time-resolved photoluminescence experiments reveal its effective SO detection capabilities and suggest a possible mechanism for this detection.
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The nuclear industry will continue to develop rapidly and produce energy in the foreseeable future; however, it presents unique challenges regarding the disposal of released waste radionuclides because of their volatility and long half-life. The release of radioactive isotopes of iodine from uranium fission reactions is a challenge. Although various adsorbents have been explored for the uptake of iodine, there is still interest in novel adsorbents.

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In reticular chemistry, topology is a powerful concept for defining the structures of covalent organic frameworks (COFs). However, due to the lack of diversity in the symmetry and reaction stoichiometry of the monomers, only 5% of the two-dimensional topologies have been reported to be COFs. To overcome the limitations of COF connectivity and pursue novel topologies in COF structures, two aminal-linked COFs, KUF-2 and KUF-3, are prepared, with dumbbell-shaped secondary building units.

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The development of adsorbents for Kr and Xe separation is essential to meet industrial demands and for energy conservation. Although a number of previous studies have focused on Xe-selective adsorbents, stimuli-responsive Xe/Kr-selective adsorbents still remain underdeveloped. Herein, a Hofmann-type framework Co(DABCO)[Ni(CN) ] (referred to as CoNi-DAB; DABCO = 1,4-diazabicyclo[2,2,2]octane) that provides a temperature-dependent switchable Xe/Kr separation performance is reported.

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Engineering excitation wavelength of photosensitizers (PSs) for enhanced reactive oxygen species (ROS) generation has inspired new windows for opportunities, enabling investigation of previously impracticable biomedical and photocatalytic applications. However, controlling the wavelength corresponding to operating conditions remains challenging while maintaining high ROS generation. To address this challenge, we implement a wavelength-engineerable imidazolium-based porous organic photocatalytic ROS generation system (KUP system) via a cost-effective one-pot reaction.

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We proposed a new strategy to maximize the density of acidic groups by modulating the electronic effects of the substituents for high-performance proton conductors. The conductivity of the sulfonated 1-MeL40-S with methyl group corresponds to 2.29×10  S cm at 80 °C and 90 % relative humidity, remarkably an 22100-fold enhancement over the nonsulfonated 1-MeL40.

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Although porous organic polymer (POP) has been explored as a promising photosensitizer, its powdered form makes it unfavorable for practical applications. Here, we demonstrate a protocol for fabricating imidazoline-based POP composites using fabric and sponge as substrates. This fabrication is limited to POPs with aldehyde containing organic building blocks.

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Correction for 'Post-synthetic modifications in porous organic polymers for biomedical and related applications' by Ji Hyeon Kim , , 2022, , 43-56, https://doi.org/10.1039/D1CS00804H.

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Although diamine-appended metal-organic framework (MOF) adsorbents exhibit excellent CO adsorption performance, a continuous decrease in long-term capacity during repeated wet cycles remains a formidable challenge for practical applications. Herein, we present the fabrication of diamine-appended Mg(dobpdc)-alumina beads (-; een = -ethylethylenediamine; = number of carbon atoms attached to epoxide) coated with hydrophobic silanes and alkyl epoxides. The reaction of epoxides with diamines in the portal of the pore afforded sufficient hydrophobicity, hindered the penetration of water vapor into the pores, and rendered the modified diamines less volatile.

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Ammonia is a promising energy vector that can store the high energy density of hydrogen. For this reason, numerous adsorbents have been investigated as ammonia storage materials, but ammonia adsorbents with a high gravimetric/volumetric ammonia capacity that can be simultaneously regenerated in an energy-efficient manner remain underdeveloped, which hampers their practical implementation. Herein, we report Ni_acryl_TMA (TMA = thiomallic acid), an acidic group-functionalized metal-organic framework prepared via successive postsynthetic modifications of mesoporous NiClBTDD (BTDD = bis(1-1,2,3,-triazolo [4,5-],-[4',5'-]) dibenzo[1,4]dioxin).

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Ammonia is useful for the production of fertilizers and chemicals for modern technology, but its high toxicity and corrosiveness are harmful to the environment and human health. Here, we report the recyclable and tunable ammonia adsorption using a robust imidazolium-based MOF (JCM-1) that uptakes 5.7 mmol g of NH at 298 K reversibly without structural deformation.

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Porous organic polymers (POPs) are prepared by crosslinked polymerization of multidimensional rigid aromatic building blocks. Generally, POPs can be classified into crystalline covalent organic frameworks (COFs) and other poorly crystalline or amorphous porous polymers. Due to their remarkable intrinsic properties, such as high porosity, stability, tunability, and presence of numerous building blocks, several new POPs are being developed for application across various scientific fields.

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Article Synopsis
  • A new compound called calix[]triazolium was created that specifically detects AMP (adenosine monophosphate).
  • The compound binds with chromenolate anions to form a non-fluorescent complex that can then switch to a fluorescent state when AMP is present.
  • This system effectively differentiates AMP from similar molecules like ADP and ATP based on fluorescence changes, making it unique in its sensing capabilities.
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Diamine-appended metal-organic frameworks (MOFs) exhibit exceptional CO adsorption capacities over a wide pressure range because of the strong interaction between basic amine groups and acidic CO. Given that their high CO working capacity is governed by solvent used during amine functionalization, a systematic investigation on solvent effect is essential but not yet demonstrated. Herein, we report a facile one-step solvent exchange route for the diamine functionalization of MOFs with open metal sites, using an efficient method to maximize diamine loading.

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