Ionothermal synthesis of calcium-based metal–organic frameworks in a deep eutectic solvent

Abstract

The unprecedent use of a deep eutectic solvent (DES) for the ionothermal synthesis of Ca(II) based metal-organic frameworks (MOFs) has been explored. The 1:2 choline chloride:e-urea DES (e-urea = 2-imidazolidinone,...

Impact of urea-based deep eutectic solvents on Mg-MOF-74 morphology and sorption properties

“…While 4 is structurally reminiscent of the reported [M(dobdcH2)(H2O)4] (M = Ni, Co) chains,[40] it is worth noting that intermediate phases on the way to Mg-MOF-74 have been recently described showing also deprotonation solely at the carboxylate units [41]. Partial deprotonation to the dobdcH2 ligand has also been observed for Ca-MOFs prepared in the ChCl:e-urea (1:2) DES [42]. 3.3.2.…”

“…Such features may also be impacted by (i) the viscosity of DESs, which has a potential impact on the diffusion of the reactants during the reaction time; and (ii) the DES stabilization of water-sensitive materials, which allows the formation of MOFs that are usually prone to hydrolysis. [28,42,47] Thus, we hypothesize that a labile phase may be produced in the initial stages of MOF formation, this phase may assist the assembly of the sliced morphology for Mg-MOF-74, in a similar way as the PCN-74 assisted the formation of Mg-MOF-74-II. This hypothesis is also in accordance with the above-mentioned recent report of intermediate phases towards Mg-MOF-74 incorporating the ligand exclusively deprotonated at the carboxylic acid moieties when using a higher concentration of the reagents in DMF/ethanol/water.…”

Crystalline chalcogenidometalate-based compounds from uncommon reaction media

“…49 ILs have enjoyed increasing attention in many research fields, in particular in the area of ionothermal synthesis, that is, reactions in ionic liquids under slightly elevated temperatures in sealed reaction containers -yet well below supercritical conditions. This afforded the synthesis of well-defined crystalline materials, especially functional zeolites, 50,51 metal organic frameworks, 52,53 and crystalline chalcogenides. 54 As illustrated in Fig.…”