An Isomeric Copper‐Diisophthalate Framework Platform for Storage and Purification of C₂H₂and Exploration of the Positional Effect of the Methyl Group

Abstract

Three isostructural metal-organic frameworks (MOFs) based on dicopper paddlewheels and dimethyl-functionalized linear diisophthalate ligands were solvothermally constructed, with the aim to investigate their performance regarding acetylene (C 2 H 2 ) storage as well as separation and purification and to further understand the positional effect of the weakly polarized methyl functionality. Isotherm measurements and IAST selectivity analyses revealed that the three compounds exhibited the promising potential for storing C 2 H 2 and recovering C 2 H 2 from carbon dioxide (CO 2 ) and methane (CH 4 ) at ambient conditions. Furthermore, their C 2 H 2 adsorption properties can be tailored and optimized by altering the relative position of the methyl substituents immobilized in the organic linkers. At 298 K and 1 atm, the C 2 H 2 uptake capacities vary from 173.0 to 183.6 cm 3 (STP) g À 1 , while the C 2 H 2 /CH 4 and C 2 H 2 /CO 2 adsorption selectivities are in the range of 24.5-26.6 and 4.34-4.70 for the equimolar gas mixtures. The ortho-dimethyl-modified MOF outperformed better than the other two MOF isomers. The results indicate that rational arrangement of functional groups can to some extent improve gas adsorption properties. Although the property discrepancy caused by the less-polar methyl group is not as large as that by Lewis-basic nitrogen atoms, this is the first experimental demonstration of the positional effect of methyl group on C 2 H 2 adsorption.

Rational Construction and Performance Regulation of an In(III)–Tetraisophthalate Framework for One-Step Adsorption-Phase Purification of C2H4 from C2 Hydrocarbons

“…Furthermore, the resulting frameworks are ionic, and their physiochemical properties can be facilely fine-tuned by postsynthetic ion exchange. In terms of organic ligands, we designed and synthesized an unexploited bithiophene-based tetraisophthalate ligand (Scheme ), as part of our continuing efforts to develop polyisophthalate framework compounds for light hydrocarbon storage and separation. − The aromatic-rich nature of the ligands provides the resulting MOFs with the “inert” pore surface, while the thiophene sulfur and carboxylate oxygen atoms can function as hydrogen-bonding acceptors to enforce the ability to recognize C 2 H 2 and C 2 H 6 in preference to C 2 H 4 . It should be mentioned that compared to diisophthalate and triisophthalate ligands, the tetraisophthalate linker is quite rarely reported presumably due to the synthetic difficulty, solubility issue, and poor availability of the starting building blocks. − …”

A novel 3D terbium metal–organic framework as a heterogeneous Lewis acid catalyst for the cyanosilylation of aldehyde

“… 1 Due to the unlimited coordinated bonds through the metal ions/clusters and the organic linkers, they usually appear as infinite multiple dimension networks, which endow the MOFs with diversified structures and functional applications. 2 Meanwhile they usually have high porosity, large surface area and considerable capacity, 3 which offer a wide range of potential applications in gas storage, 4 gas capture, 5 separation, 6 chemical catalysis, 7 luminescence, 8 magnetism, 9 drug delivery, 10 and so on.…”

CoS2/MoS2 Hollow Heterostructure as High‐efficiency Bifunctional Electrocatalyst for Overall Water Splitting

“…As shown in Figure 3E, the electrolyzer needs a cell voltage of 1.62 V to ChemistrySelect achieve a current density of 10 mA cm À 2 , which is very close to that of Pt/C + RuO 2 , and comparable to many other similar electrocatalysts reported recently. [33][34][35] In addition, the electrolyzer can stably splitting water for at least 20 hours without obvious voltage change, demonstrating the good stability of CoS 2 /MoS 2 -2 (Figure 3F).…”