Synthesis of an exceptional water-stable two-fold interpenetrated Zn(ii)-paddlewheel metal–organic framework

Abstract

Based on the ligands tetrakisIJ4-carboxyphenyl)silane (TCS) and 4,4′-bipy, a novel 3D doubly interpenetrated ZnIJII)-paddlewheel metal-organic framework Zn 2 TCSIJ4,4′-bipy) (1) was synthesized via facile conversion of its non-interpenetrated isomer (2) upon solvent removal at ambient temperature. It exhibits high CO 2 and CH 4 adsorption capacities and exceptional water stability.Metal-organic frameworks (MOFs) are a new class of porous materials that have received widespread attention due to their potential applications in gas storage, separation, catalysis, chemical sensors, semiconductors, fuel cells, supercapacitors and more. 1 However, one drawback of MOFs is that most of them are unstable in water and under humid conditions. Generally, MOFs containing tri-or tetravalent metal cations, such as Cr 3+ , Al 3+ , Fe 3+ , Ti 4+ and Zr 4+ , and ZIFs (zeolitic imidazolate frameworks) display a high degree of stability in water. 2-5 We recently calculated the pK a and NBO (Natural Bond Orbital) charges of many ligands applied in MOF synthesis and indicated that these data can be used to predict water stabilities of MOFs. 4 Ligands with higher NBO charges tend to form MOFs with better hydrothermal stability. CrystEngCommThis journal is † Electronic supplementary information (ESI) available: Experimental details, syntheses of 1-3, crystal data for 2 and 3·H 2 O, selected bond distances and angles for 2, PXRD patterns of 1-2, IR spectra of 1, fluorescence and diffuse reflectance UV-vis spectra of 1 and the ligand TCS, and CO 2 sorption isotherms for 1 measured at 298 K. CCDC 1034674, 1056672. For ESI and crystallographic data in CIF or other electronic format see

Engineered Bifunctional Luminescent Pillared‐Layer Frameworks for Adsorption of CO2 and Sensitive Detection of Nitrobenzene in Aqueous Media

“…Moreover, the desorption part of the isotherm does not trace the adsorption process, but a two‐step desorption occurs at P / P 0 ≈0.06 (gate‐closing pressure), resulting in a strong hysteresis loop. The maximum uptake of CO 2 is about 111 cm 3 g −1 (4.95 mmol g −1 ) for 1′ , 89 cm 3 g −1 (3.97 mmol g −1 ) for 2′ , 68 cm 3 g −1 (3.04 mmol g −1 ) for 3′ , 58 cm 3 g −1 (2.59 mmol g −1 ) for 4′ , and 45 cm 3 g −1 (2.01 mmol g −1 ) for 5′ at 195 K and P / P 0 =1, which are comparable with those of some reported paddlewheel Zn MOFs (Table S2 in the Supporting Information) [40–53] . At high temperature (Figure S5 in the Supporting Information), MOFs 1′ , 3′ , and 4′ exhibit significant CO 2 uptake at both 273 and 298 K, with capacities of 20–33 and 15–24 cm 3 g −1 , respectively; MOF 2′ reveals a significant CO 2 uptake of 22 cm 3 g −1 at 273 K, but negligible uptake capacity at 298 K; MOF 5′ displays no CO 2 uptakes at both temperatures.…”

Zinc Coordination Polymers Containing the m-(2-thiazolyl)benzoic Acid Spacer: Synthesis, Characterization and Luminescent Properties in Aqueous Solutions

“…Even if it is commonly thought that coordination polymers built by Zn II ‐carboxylate clusters [such as Zn 4 (O)(RCOO) 6 present in MOF‐5] undergo degradation in water, there are some specific cases where these compounds are water‐stable. The higher coordination number of zinc in paddlewheel SBUs (six instead of four as in MOF‐5) and the presence of weakly polar Zn−N bonds formed with pyridine‐containing auxiliary ligands like 4,4′‐dipyridyl are both responsible for the enhanced stability in aqueous solutions . In an attempt to determine the solution speciation, combined MALDI‐TOF and ESI mass spectrometry analyses were carried out on acidified (TFA, HCOOH) aqueous solutions.…”

Metal–Organic Frameworks Constructed from Group 1 Metals (Li, Na) and Silicon-Centered Linkers

“…Despite this, only a handful of MOFs have been synthesized using L1 and L2. [26][27][28] L3 has been used to synthesize MOFs with a variety of d-block, [29][30][31][32] and f-block metal nodes, [33][34][35][36] but the only MOFs with s-block metal nodes were reported by us using Mg 2+ or Ca 2+ . 37 Latterly, Moon and co-workers reported the synthesis of a MOF with L3 as linker and Li + -based nodes which was used as a precursor to porous lithium orthosilicate.…”