Visualization of Iodine Chemisorption Facilitated by Aryl C–H Bond Activation

Abstract

The ability to chemisorb iodine is important for the safe longterm storage of fission products from nuclear reactors. Herein, we successfully used single-crystal X-ray diffraction analysis to crystallographically visualize I 2 binding sites in two isostructural metal−organic frameworks, viz. Co 2 (m-DOBDC) (m-DOBDC 4− = 4,6-dioxo-1,3-benzenedicarboxylate) and Co 2 (p-DOBDC) (p-DOBDC 4− = 2,5-dioxo-1,4-benzenedicarboxylate), with increasing I 2 loading. Interestingly, the C−H bond at the electron-rich carbon (C5) of m-DOBDC 4− is activated toward electrophilic aromatic substitution, forming an aryl C−I bond and I − or I 3 − that coordinates to unsaturated open Co sites. Cooperation between the ligand and the open Co sites leads to rapid chemisorption of I 2 even under mild adsorption conditions, such as room temperature. In contrast, molecular I 2 coordinates to the open Co sites of Co 2 (p-DOBDC).Owing to the chemisorption of I 2 , I 2 @Co 2 (m-DOBDC) decomposes at a much higher temperature than I 2 @Co 2 (p-DOBDC), as revealed by thermogravimetric analysis.

Ti‐Based Oxide Anode Materials for Advanced Electrochemical Energy Storage: Lithium/Sodium Ion Batteries and Hybrid Pseudocapacitors

“…Except for TiO 2 and Li 4 Ti 5 O 12 , many other Ti‐based oxides also showed promising prospects for LHCs applications. Lee's group reported a novel carbon/AlPO 4 hybrid‐coated H 2 Ti 12 O 25 pseudocapacitors, exhibiting an enhanced rate capability and long‐term cycle stability. Moreover, the hybrid coating significantly inhibits the swelling phenomenon caused by gas generation from electrolyte decomposition …”

Effect of Functional Groups on the I2 Sorption Kinetics of Isostructural Metal–Organic Frameworks

“…We previously reported the I 2 adsorption of the isostructural MOFs, Co 2 (m-DOBDC) (m-DOBDC 4− = 4,6dioxo-1,3-benzenedicarboxylate) and Co 2 (p-DOBDC) (p-DOBDC 4− = 2,5-dioxo-1,4-benzenedicarboxylate), and found that they followed different I 2 adsorption mechanisms, chemisorption and physisorption, respectively (Figure 1 (b)). 22 ) is formed by the interaction of an I 2 molecule with an I − ion. In this study, these findings were extended to examine the I 2 sorption by an isostructural M 2 (m-DOBDC) series (M = Mg 2+ and Ni 2+ ).…”

Thermo-Responsive and Shape-Adaptive Hydrogel Actuators from Fundamentals to Applications

“…However, challenges still remain. Since hydrogels are typically isotropic materials that usually undergo uniform volumetric expansion and contraction in response to external stimuli, they are difficult to achieve asymmetrical shape changes such as bending, twisting, and [21][22][23][24][25] folding. Use of single polymer materials or simple polymer structures are unlikely to selectively trigger site-specific swelling or contraction, leading to shape adaptability and transformation in a controllable manner.…”