Multivariate Sulfonic-Based Titanium Metal–Organic Frameworks as Super-protonic Conductors

Abstract

The proton-conducting performances of a microporous Ti-based metal–organic framework (MOF), MIP-207, were successfully tuned using a multicomponent ligand replacement strategy to gradually introduce a controlled amount of sulfonic acid groups as a source of Brönsted acidic sites while keeping the robustness and ecofriendly synthesis conditions of the starting material. Typically, multivariate sulfonic-based solids MIP-207-(SO3H-IPA) x -(BTC)1–x were prepared by combining various ratios of trimesate 1,3,5-benzenetricarboxylate (BTC) moieties and 5-SO3H-isophthalate (SO3H-IPA). The best sulfonic-MOF candidate that combines structural integrity with high proton conductivity values (e.g., σ = 2.6 × 10–2 S cm–1 at 363 K/95% relative humidity) was further investigated using ab initio molecular dynamics simulations. These calculations supported that the −SO3H groups act as proton donors and revealed that the proton transfer mechanism results from the solvation structure of protons through the fast Zundel/hydronium interconversion along the continuous H-bonded network connecting the adsorbed water molecules.

Computational Exploration of a Metal(II) Catecholate-Functionalized UiO-66 Nanoporous Metal–Organic Framework for Effective NOx Capture

“…The NO and NO 2 single-component adsorption isotherms for both UiO-66 and UiO-66-CatFe­(II) were calculated by GCMC simulations by implementing the force field discussed above (eq ) using CADSS software . Both pristine UiO-66 and UiO-66-CatFe­(II) incorporating four CatFe­(II) units per unit cell (corresponding to a Zr/Fe metalation ratio of 1:0.17 similar to 1:0.21 reported previously for the analogue UiO-66-CatFe­(III)-OCH 3 ) were DFT-geometry-optimized.…”

“…The NO and NO 2 single-component adsorption isotherms for both UiO-66 and UiO-66-CatFe(II) were calculated by GCMC simulations by implementing the force field discussed above (eq 2) using CADSS software. 65 Both pristine UiO-66 and UiO-66-CatFe(II) incorporating four CatFe(II) units per unit cell (corresponding to a Zr/Fe metalation ratio of 1:0.17 similar to 1:0.21 reported previously for the analogue UiO-66-CatFe(III)-OCH 3 49 ) were DFT-geometry-optimized. A simulation box consisting of eight unit cells (2 × 2 × 2) was considered for both MOFs, and the atomic positions of the MOF frameworks were held fixed during the adsorption and trial moves for the guest molecules including, i.e., translational, rotational, creation, and deletion.…”

Microwave-Assisted Rapid Synthesis of Nanoscale MOF-303 for Hydrogel Composites with Superior Proton Conduction at Ambient-Humidity Conditions

“…The Nyquist plots at selected temperatures and 98% RH are show in Figure S7, and the calculated proton conductivities are presented in Figure a. MeSA@MOF-303 has a room-temperature proton conductivity of 4.38 × 10 –3 S cm –1 , which is high enough to compete with the well-known proton conductive MOFs, e.g., MIP-207-(SO 3 H-IPA) 0.16 -(BTC) 0.84 (1.2 × 10 –3 S cm –1 at 298 K and 98% RH), CFA-17 (3.3 × 10 –3 S cm –1 at 295 K and 94% RH), and MOF-801 (1.88 × 10 –3 S cm –1 at 298 K and 98% RH) . With increasing temperature, the proton conductivity of MeSA@MOF-303 reaches 1.04 × 10 –2 S cm –1 at 323 K and further attains a maximum value of 3.11 × 10 –2 S cm –1 at 343 K. Furthermore, the proton conductivity of MeSA@MOF-303 is maintained without significant loss after 16 h (Figure S8), showing good long-term stability.…”

Multivariate zeolitic imidazolate frameworks with an inverting trend in flexibility

“…This has been shown to be a powerful tool of modifying pore structure and chemistry in rigid frameworks. 25 In this work, we explored the ability to synthetically modify the step-shaped adsorption behavior of flexible CdIF-13 by employing this mixed-linker approach. We selected CdIF-13 for this study because: (i) its desirable capacity and step shape, (ii) both the open and closed phases are well characterized by single-crystal X-ray diffraction (SCXRD), and (iii) the adsorption process has been thoroughly studied by in situ powder XRD (PXRD).…”