Lanthanide–Organic Frameworks Featuring Three-Dimensional Inorganic Connectivity for Multipurpose Hydrocarbon Separation

Abstract

Implementation of lanthanide−organic frameworks (LOFs) as solid adsorbents has been frequently handicapped by their permanent porosity being difficult to establish owing to the remarkable flexibility and diversity of lanthanide ions in terms of coordination number and geometry. Construction of robust LOFs with permanent porosity for industrially important hydrocarbon separation will greatly expand their application potential. In this work, by distributing N and O donors into an m-terphenyl skeleton, we rationally synthesized a heterofunctional linker, and constructed a pair of isostructural LOFs. Due to the inclusion of a rarely observed three-dimensional metal−carboxylate backbone serving as a highly connected inorganic secondary building unit, their permanent porosities were successfully established by diverse gas isotherms. They can be applied as separating media not only for natural gas purification and removal of carbon dioxide from C 2 hydrocarbons but also more importantly for single-step ethylene (C 2 H 4 ) purification from a three-component C 2 H n mixture during the adsorption process. The latter separation is very challenging and has been less reported in the literature. This work provides a unique example of LOFs featuring three-dimensional inorganic connectivity applied to multipurpose hydrocarbon separations.

Robust metal–organic framework with abundant large electronegative sites for removal of CO2 from a ternary C2H2/C2H4/CO2 mixture

“…The adsorption selectivity of the C 2 H 2 /CO 2 (1 : 1) mixture for JXNU-14 is comparable to those of leading MOFs such as JNU-1 (3), 44 SNNU-63 (2.7), 45 FJU-6-TATB (3.1), 46 and UTSA-68a (3.4) (Table S3 †). 47 The adsorption selectivity of the C 2 H 4 /CO 2 (1 : 1) mixture for JXNU-14 is also comparable in comparison with those of SNNU-95 (2.4), 48 ZJNU-120(Sm) (2.4), 33 and MOF-74(Zn) (3.3), 49 but smaller than those of Ni 2 (m-dobdc) (4.1) 32 and UTSA-74 (5.4) (Table S4 †). 49 The coadsorption of C 2 H 2 and C 2 H 4 suggests that JXNU-14 is a promising candidate for the removal of CO 2 from the C 2 H 2 /C 2 H 4 /CO 2 mixture.…”

“…25 However, most efforts are focused on the separation of binary gases such as C 2 H 2 / CO 2 [26][27][28][29][30][31] and C 2 H 4 /CO 2 . 32,33 Removal of one specific gas from the ternary mixtures would simplify the separation processes and is energy-saving. However, very limited MOFs have been reported for the separation of one gas from a ternary mixture.…”

Water-Stable Eu6-Cluster-Based fcu-MOF with Exposed Vinyl Groups for Ratiometric and Fluorescent Visual Sensing of Hydrogen Sulfide

“…Lanthanide metal–organic frameworks (LnMOFs), assembled from lanthanide-containing nodes or clusters and organic ligands through coordination bonds, − combine the lanthanide luminescence properties (e.g., long fluorescence lifetime, large Stokes shift, and narrow emission band) and the unique advantages of MOFs such as outstanding designability, permanent porosity, and tunable optical properties. − They have thus received much attention in the development of dual-emitting sensory materials for various sensing applications, such as temperature, ions, gases, small molecules, and pH. − However, studies on pure LnMOFs for H 2 S detection based on dual-emissive centers in combination with H 2 S-reactive sites, up to a point, are still far behind those hot topics. Specifically, dual-emitting probes constructed from the two independent emissions of single-lanthanide MOFs (S’LnMOFs) are very rare .…”

Amino-Functionalized Single-Lanthanide Metal–Organic Framework as a Ratiometric Fluorescent Sensor for Quantitative Visual Detection of Fluoride Ions

“…Lanthanide-based MOFs (LnMOFs), which are assembled by rationally coordinating lanthanide-containing nodes or clusters with multitopic organic molecules, have shown great promise in gas adsorption and separation, catalysis, electronics, and photonics. − Highlighted by the combination of the distinctive spectroscopy properties of lanthanide ions (e.g., large Stokes shift, narrow emission band, and long lifetime) and the features of porous MOFs (with intriguing topology and tunable structure), LnMOFs afford a wide platform to fabricate advanced luminescent materials for sensing temperature, gases, cations, anions, pH, volatile organic compounds, and biomarkers. − Most current ratiometric fluorescence probes for F – detection are based on the two independent emissions of mixed-lanthanide MOFs (M’LnMOFs) or dye-encapsulated MOFs. , Studies on pure single-lanthanide MOFs (S’LnMOFs) are still in their infancy. Presumably, this is because the majority of S’LnMOFs only display the lanthanide fluorescence generated by the efficient energy transfer of ligand to lanthanide ions (also called the “antenna effect”), as well as lack the recognition sites for F – ions.…”