Design of a Humidity-Stable Metal–Organic Framework Using a Phosphonate Monoester Ligand

Abstract

Phosphonate monoesters are atypical linkers for metal-organic frameworks, but they offer potentially added versatility. In this work, a bulky isopropyl ester is used to direct the topology of a copper(II) network from a dense to an open framework, CALF-30. CALF-30 shows no adsorption of N2 or CH4 however, using CO2 sorption, CALF-30 was found to have a Langmuir surface area of over 300 m(2)/g and to be stable to conditions of 90% relative humidity at 353 K owing to kinetic shielding of the framework by the phosphonate ester.

Gas-Phase Dimerization of Ethylene under Mild Conditions Catalyzed by MOF Materials Containing (bpy)NiII Complexes

“…Combining NU-1000 with a DMSO solution of 1·HCl for 12 h (Figure 1; also see SI, section S4) readily afforded the desired NU-1000-bpyHCl material as an orange solid. [23][24] This solvent-assisted linker incorporation (SALI) methodology took advantage of the ability of the Zr 6 (µ 3 -OH) 8 (OH) 8 nodes of NU-1000 to be readily modified through reaction between the free Zr-OH moieties (or missing-linker sites) on the node and incoming carboxylic [23][24] or phosphonic acid- 25,26 containing functionalities. In contrast to the modifications with carboxylic acids, [23][24] it was necessary to use a dilute solution and only a moderate excess (2.5-3 equiv/Zr 6 node) of the phosphonic acid ligand 1 to prevent decomposition of the NU-1000 framework during ligand incorporation.…”

Hydrophobic Metal–Organic Frameworks: Assessment, Construction, and Diverse Applications

“…Shimizu's group reported a series of MOFs derived from phosphonate monoesters, some of which have been proven as hydrophobic . In 2012, they reported a barium tetraethyl‐1,3,6,8‐pyrenetetraphosphonate MOF, CALF‐25, from the solvothermal reaction of BaBr 2 and the ligand optp, which turned into a phosphonate monoester by in situ partial hydrolysis .…”

“…Shimizu and co‐workers later reported another copper(II) phosphonate monoester CALF‐30, formulated as [Cu 3 (btp‐ i Pr) 2 ], obtained by using the phosphonic acid monoester ligand H 3 btp‐ i Pr . CALF‐30 was synthesized as a microcrystalline blue powder, and it was proposed to be a 2D layered structure possessing small hexagonal pores of 3.57 Å that were defined by isopropyl ester groups.…”

“…Shimizu's group reported a series of MOFs derived from phosphonate monoesters, some of which have been proven as hydrophobic. [85,159,160,187,188] In 2012, they reported a barium tetraethyl-1,3,6,8-pyrenetetraphosphonate MOF, CALF-25, from the solvothermal reaction of BaBr 2 and the ligand optp, which turned into a phosphonate monoester by in situ partial hydrolysis. [85] CALF-25 is a 3D framework structure consisting of 1D barium phosphonate chains crosslinked with four neighboring chains by the ligands.…”

“…Shimizu and co-workers later reported another copper(II) phosphonate monoester CALF-30, formulated as [Cu 3 (btp-i Pr) 2 ], obtained by using the phosphonic acid monoester ligand H 3 btp-i Pr. [159] CALF-30 was synthesized as a microcrystalline blue powder, and it was proposed to be a 2D layered structure possessing small hexagonal pores of 3.57 Å that were defined by isopropyl ester groups. The gas adsorption studies for CALF-30 revealed no essential uptakes for N 2 (77 K), H 2 (77 K), Ar (195 K), and CH 4 (195 and 273 K), but an uptake of ≈55 cm 3 g −1 for CO 2 at 195 K. The BET and Langmuir surface areas were estimated to be 244 and 312 m 2 g −1 ,…”