Differential guest location by host dynamics enhances propylene/propane separation in a metal-organic framework

Energy-efficient approaches to propylene/propane separation such as molecular sieving are of considerable importance for the petrochemical industry. The metal organic framework NbOFFIVE-1-Ni adsorbs propylene but not propane at room temperature and atmospheric pressure, whereas the isostructural SIFSIX-3-Ni does not exclude propane under the same conditions. The static dimensions of the pore openings of both materials are too small to admit either guest, signalling the importance of host dynamics for guest entrance to and transport through the channels. We use ab initio calculations together with crystallographic and adsorption data to show that the dynamics of the two framework-forming units, polyatomic anions and pyrazines, govern both diffusion and separation. The guest diffusion occurs by opening of the flexible window formed by four pyrazines. In NbOFFIVE-1-Ni, (NbOF5)2- anion reorientation locates propane away from the window, which enhances propylene/propane separation

Supramolecular Isomers of Metal–Organic Frameworks Derived from a Partially Flexible Ligand with Distinct Binding Motifs

Three novel metal–organic frameworks (MOFs) were isolated upon reacting heterofunctional ligand 4-(pyrimidin-5-yl)­benzoic acid (4,5-pmbc) with mixed valence Cu­(I,II) under solvothermal conditions. X-ray crystal structural analysis reveals that the first compound is a layered structure composed of one type of inorganic building block, dinuclear paddlewheel [Cu₂(O₂C−)₄], which is linked through 4,5-pmbc ligands. The two other supramolecular isomers are composed of the same Cu­(II) dinuclear paddlewheel and a dinuclear Cu₂I₂ cluster, which are linked via the 4,5-pmbc linkers to yield two different 3-periodic frameworks with underlying topologies related to <b>lvt</b> and <b>nbo</b>. The observed structural diversity in these structures is due to the distinct coordination modes of the two coordinating moieties (the carboxylate group on the phenyl ring and the N-donor atoms from the pyrimidine moiety)

A Fine-Tuned MOF for Gas and Vapor Separation: A Multipurpose Adsorbent for Acid Gas Removal, Dehydration, and BTX Sieving

International audienc

Introducing a Cantellation Strategy for the Design of Mesoporous Zeolite-like Metal–Organic Frameworks: Zr-sod-ZMOFs as a Case Study

International audienc

The solid-state structures of organic salts formed by calix[4]arene dihydroxyphosphonic acid with nucleic bases cations: adeninium, cytosinium, guaninium and uracilium

International audienc

A Fine-Tuned Metal–Organic Framework for Autonomous Indoor Moisture Control

Conventional adsorbents, namely zeolites and silica gel, are often used to control humidity by adsorbing water; however, adsorbents capable of the dual functionality of humidification and dehumidification, offering the desired control of the moisture level at room temperature, have yet to be explored. Here we report Y-<b>shp</b>-MOF-5, a hybrid microporous highly connected rare-earth-based metal–organic framework (MOF), with dual functionality for moisture control within the recommended range of relative humidity (45%–65% RH) set by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). Y-<b>shp</b>-MOF-5 exhibits exceptional structural integrity, robustness, and unique humidity-control performance, as confirmed by the large number (thousand) of conducted water vapor adsorption–desorption cycles. The retained structural integrity and the mechanism of water sorption were corroborated using in situ single-crystal X-ray diffraction (SCXRD) studies. The resultant working water uptake of 0.45 g·g^–1 is solely regulated by a simple adjustment of the relative humidity, positioning this hydrolytically stable MOF as a prospective adsorbent for humidity control in confined spaces, such as space shuttles, aircraft cabins, and air-conditioned buildings