Carboxylate–Hydrazone Mixed‐Linker Metal–Organic Frameworks: Synthesis, Structure, and Selective Gas Adsorption

Abstract

New mixed-linker metal-organic framework (MOF) materials incorporating both carboxylate and hydrazone linkers were prepared. The zinc-based 3D MOFs were obtained by utilizing a presynthesized aroylhydrazone [4-pyridinecarbaldehyde isonicotinoyl hydrazone (PCIH)] and para-dicarboxylic acids [1,4-benzenedicarboxylic acid (H 2 BDC) and 4,4′-biphenyldicarboxylic acid (H 2 BPDC)]. Single-crystal X-ray diffraction revealed the interpenetrated, pillar-layered structures of the MOFs, including

Water-Stable Metal–Organic Framework with Three Hydrogen-Bond Acceptors: Versatile Theoretical and Experimental Insights into Adsorption Ability and Thermo-Hydrolytic Stability

“…The average occupation profiles confirm that the most probable location of CO 2 is in the proximity of polar −C­(O)N–NH– and SO 2 groups lining the framework walls (red regions in Figure b) and thus form the evidence for the key role of the acylhydrazone linker in the observed higher CO 2 uptake. Analogous behavior with regard to CO 2 and N 2 adsorption was observed for recently reported Zn-acylhydrazone/dicarboxylate-frameworks. − …”

“…The framework 1 is the first 3D noninterpenetrated example of MOFs incorporating both carboxylate and acylhydrazone linkers as contrasted to the previously reported layered materials [Zn 2 (Xiso) 2 (pcih) 2 ] n 18,19 as well as a group of 3D interpenetrated MOFs [M 2 (pcdx) 2 (pcih) 2 ] n (M = Cd 2+ , Zn 2+ ; pcdx = 1,4-benzenedicarboxylate, 2-amino-1,4benzenedicarboxylate acid, or 4,4′-biphenyldicarboxylate). 20,21 By use of a V-shaped dicarboxylic acid (H 2 sdb) the interpenetration could be prevented leading to the largest voids among all carboxylate/acylhydrazone MOFs reported. Simultaneously, introducing sulfonyl groups on the pore walls rendered the resulting Cd-MOF moderately hydrophilic through adding hydrogen-bond acceptors between hydrophobic phenyl rings.…”

Collective Breathing in an Eightfold Interpenetrated Metal–Organic Framework: From Mechanistic Understanding towards Threshold Sensing Architectures

“…The resulting geometric complementarity of −COO and −NH− functional groups is realized through interpenetration and internetwork interactions. However, as was previously shown for rigid interpenetrated frameworks with analogous dual internetwork −COO⋅⋅⋅H−N− hydrogen bonds, the presence of such a steric complementarity of subnetworks does not guarantee switchability, and extra supramolecular interactions with guest molecules that is, chemical stimuli are required to induce structural transformations. Our highly hydrolytically stable zinc‐based MOF represents the first interpenetrated MOF featuring distinct water vapor stimulated switching transitions.…”

Combining In Situ Techniques (XRD, IR, and 13C NMR) and Gas Adsorption Measurements Reveals CO2-Induced Structural Transitions and High CO2/CH4 Selectivity for a Flexible Metal–Organic Framework JUK-8

“…The acylhydrazone MOFs are a novel and developing group of metal–organic frameworks that bear the −C­(O)N–NH– motif on the pore surface. Members of this family show very interesting properties, such as extraordinary stability, structural transformation, excellent catalytic reactivity in CO 2 fixation to epoxides, proton conductivity, as well as sensing activity .…”