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

Abstract

In this work, the effect of functional groups on I 2 sorption kinetics is investigated using two different types of isostructural metal-organic frameworks, UiO-66-X series (X = H, Br, NO 2 , NH 2 , (OH) 2 , and (COOH) 2) and M 2 (m-DOBDC) series, (M = Co2+, Mg2+, and Ni2+; m-DOBDC 4− = 4,6-dioxo-1,3benzenedicarboxylate). Among the UiO-66-X series, UiO-66-(COOH) 2 exhibits the fastest sorption kinetics and the highest sorption capacity due to dipole-induced dipole interactions between carboxylic acid groups and I 2 molecules. In addition, faster I 2 chemisorption is observed in M 2 (m-DOBDC) because of electrophilic aromatic substitution of m-DOBDC 4− with I 2. The I 2 sorption mechanisms are further supported by fitting the I 2 adsorption kinetics data to pseudo-first-order and pseudo-second-order kinetic models.

Capture of Gaseous Iodine in Isoreticular Zirconium‐Based UiO‐n Metal‐Organic Frameworks: Influence of Amino Functionalization, DFT Calculations, Raman and EPR Spectroscopic Investigation

“…Previous experimental adsorption investigations [26] of molecular iodine in cyclohexane liquid phase, have shown similar results concerning the UiO-66-H, UiO-66-Br and UiO-66-NO 2 members. But they differed for the UiO-66-(OH) 2 and UiO-66-NH 2 compounds, for which identical higher iodine uptakes were reported.…”

“…The redox I 2 !I 3 À conversion was unexpected in our system and was observed in a few previous studies, [24] but was not mentioned in other works. [22,26] This reaction will be further characterized by Raman and EPR spectroscopies.…”

“…[24] These reports dealt with the use of iodine vapor generated in a closed cell, in contact with the considered powdered UiO-n compounds, which are then weighted for the estimation of iodine uptake. For this UiO-n series, other works also described the influence of defects in the UiO-66 (Hf) solids [25] or the effects of the nature of a wide variety of functional organic groups decorating the ditopic ligands in UiO-66, [26] by analyzing the iodine sorption from liquid phase using cyclohexane as solvent.…”

Cluster‐Based Crystalline Materials for Iodine Capture

“…Subsequently in 2021, in order to systematically study the effect of functional groups on the kinetics of I 2 adsorption. Lee and Park tested the iodine adsorption behavior of two different types of isostructural organic frameworks, UiO‐66‐X series (X=H, Br, NO 2 , NH 2 , (OH) 2 , and (COOH) 2 ) and M 2 (m‐DOBDC) series [92] . Among all groups, the carboxylic acid group (−COOH) exhibits the fastest adsorption kinetics and highest adsorption capacity.…”

Solvent‐mediated single‐crystal‐to‐single‐crystal transformation of metal–organic cage self‐assembly

“…Unlike the extended structural metal–organic frameworks (MOFs) and covalent organic frameworks, which are constructed by periodic (dative) covalent bonds between building blocks, the self‐assemblies of cages are typically solvent‐mediated 21–27 . Additionally, the interactions present such as van der Waals, dipole–dipole, and hydrogen bonds are relatively weak.…”