https://scholar.dgist.ac.kr/handle/20.500.11750/825 Sat, 04 Apr 2026 13:56:29 GMT 2026-04-04T13:56:29Z https://scholar.dgist.ac.kr/handle/20.500.11750/59328 Title: Cooperative Metal Ion Combinations in Ti-Based Multivariate Metal-Organic Frameworks Author(s): Seo, Eunho; Kim, Mijin; Byun, Asong; Lim, Subin; Moon, Dohyun; Oh, Hyunchul; Park, Jinhee Abstract: Multivariate metal-organic frameworks (MTV-MOFs), which incorporate multiple metal ions or organic linkers within a single framework, provide a powerful platform for investigating structure-composition-property relationships, which in turn enable the rational tuning of material performance. To establish such a correlation, it is critical to achieve precise compositional control while maintaining high crystallinity, thereby minimizing variability in crystallinity and disorder as confounding factors. We report a family of titanium-based multivariate metal-organic frameworks (MTV-MOFs), Ti2M4(mu 3-O)2pbpta3 (designated DGIST-14; M = Ni2+, Co2+, Mn2+), in which various combinations of transition metal ions are integrated into heterometallic clusters within highly crystalline soc-topology frameworks. Based on the hypothesis that Ti4+, a hard acid, can direct the formation of robust frameworks through strong interactions with hard basic carboxylate linkers, we aim to incorporate soft M2+ without compromising structural integrity. This approach facilitates the integration of diverse transition metal ions with precise control over metal ratios. The synergy among the metal centers leads to substantial improvements in structural stability, surface area (up to similar to 4600 m2/g), and gas uptake (up to similar to 1677 cm3/g). Notably, the controlled incorporation of Ni2+ and Mn2+ ions enables the selective generation of singlet oxygen under visible-light via a metal-composition-dependent pathway. This work establishes a structure-composition-function relationship in Ti-based MTV-MOFs and demonstrates a design strategy that leverages cooperative metal-ion combinations to simultaneously optimize framework stability and photoactivity. Fri, 31 Oct 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/59328 2025-10-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/58965 Title: Targeted Selenite Adsorption Using Defective Fe-BTC: Effective in Acidic and Alkaline Conditions Author(s): Byun, Asong; Lee, Byeoksong; Jeong, Yujin; Kang, Joongoo; Park, Jinkyu; Park, Jinhee Abstract: Amorphous Fe-BTC, characterized by entirely defective metal nodes, has been employed for the effective adsorption of toxic selenite anions from aqueous solutions. Remarkably, Fe-BTC maintains high adsorption efficiency across a broad pH range (2-12), achieving a maximum adsorption capacity of 491 mg g-1, ranking among the highest recorded for adsorbents, including MOFs. The adsorption process involves distinct chemical interactions depending on pH: weak and variable interactions under acidic conditions (pH 2) and strong, diverse coordination modes under alkaline conditions (pH 11). Notably, the strong coordination ability of selenite ensures high selectivity over selenate and competing anions such as Cl-, NO2-, NO3-, CO32-, SO42-, and PO43-. The abundance of metal defects endows Fe-BTC with superior adsorption capacity compared to crystalline Fe-MOF, MIL-100(Fe). This study provides a comparative analysis of selenite adsorption on Fe-BTC under acidic and alkaline conditions, emphasizing pH-dependent adsorption mechanisms and their implications for designing effective adsorbents for toxic species removal. Sun, 31 Aug 2025 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/58965 2025-08-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/57164 Title: Dual-functional metal-organic framework for chemisorption and colorimetric monitoring of cyanogen chloride Author(s): Lee, Byeongchan; Bae, Jaekyung; Go, Bogyeong; Kim, Min-Kun; Park, Jinhee Abstract: Given the growing concern over the deployment of toxic chemicals in warfare, the rapid and accurate removal and detection of cyanogen chloride (CK) as a blood agent has become increasingly critical. However, conventional physisorbents and chemisorbents used in military respirators are insufficient for the effective removal of CK. In this study, we demonstrate the chemisorption and sensing abilities of Co2(m-DOBDC) (m-DOBDC4− = 4,6-dioxo-1,3-benzenedicarboxylate) for CK via electrophilic aromatic substitution (EAS) in humid environments. Unlike the chemisorption in triethylenediamine (TEDA) impregnated carbon materials, which generates by-products through hydrolysis, the electron-rich C5 sites in m-DOBDC4− ligands give rise to cyano substitution with CK. This leads to the formation of stable C–C bonds and chloride ions (Cl−) coordinating with open Co2+ sites. Such a mechanism prevents the generation of toxic by-products like cyanic acid and hydrochloric acid. Breakthrough experiments conducted in a packed-bed system conclusively demonstrated the superior CK removal capacity of Co2(m-DOBDC) (1662 min/g), compared to TEDA-impregnated activated carbon (323 min/g) under humid conditions. Considering that MOF-74 series, isostructural with Co2(m-DOBDC), barely adsorb CK under similar conditions, this finding marks a significant advancement in developing novel sorbents for CK removal. Moreover, this chemisorption not only exhibited rapid and highly efficient CK removal but also enabled colorimetric monitoring via the distinctive color change induced by the coordination of Cl− acting as σ donors. These findings facilitate the development of adsorption and sensing equipment to protect military personnel from toxic chemical threats. © 2024 Elsevier Ltd Wed, 31 Jul 2024 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/57164 2024-07-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/56932 Title: Selective Sr2+ capture in an In3+-based anionic metal-organic framework Author(s): Kim, Yeonghun; Jin, Kangwoo; Park, In-Hyeok; Lee, Sanghyeop; Park, Jinkyu; Park, Jinhee Abstract: Strontium-90 (90Sr) has a long half-life (t1/2 = 28.8 years) and high β− decay energy (decay energy = 0.546 MeV), making it a hazardous radioactive pollutant. Various methods to remove 90Sr2+ from radioactive wastewater have been developed. Among them, the ion-exchange method has gained significant attention owing to its high capacity, simplicity, and cost-effectiveness. In this study, we synthesize a water-stable, anionic metal–organic framework, DGIST-12, assembled from In3+ and partially deprotonated 4,6-dihydroxy-1,3-benzenedicarboxylic acid. Furthermore, we evaluate the potential of DGIST-12 as a promising Sr2+ sorbent, highlighting its high porosity and a negatively charged In8 cluster. DGIST-12 effectively exchanges its counter cations, dimethylammonium, with Sr2+. Our findings suggest that the maximum Sr2+ uptake capacity of DGIST-12 is reached within 30 min of exposure, and this capacity is maintained across a broad pH range of 4–11. Importantly, DGIST-12 selectively adsorbs Sr2+ in the presence of various competing ions. Furthermore, the viability test performed on yeast cells exposed to Sr2+-containing media treated with DGIST-12 reveals that DGIST-12 can mitigate the harmful effects of Sr2+ toxicity on living organisms. These results underscore the promising prospects for creating innovative sorbent materials designed for the effective and discriminative removal of radioactive contaminants. © 2024 Elsevier B.V. Thu, 29 Feb 2024 15:00:00 GMT https://scholar.dgist.ac.kr/handle/20.500.11750/56932 2024-02-29T15:00:00Z