In-Situ X-ray Diffraction Studies of Host−Guest Properties in Nanoporous Zinc-Triazolate-Based Framework Materials

Abstract

Two nanoporous metal-organic framework materials incorporating the exotridentate bridging ligand 3-amino-1,2,4triazolate (AmTAZ) have been synthesized through variation of secondary bridging anions: [Zn 3 (AmTAZ) 3 S](NO 3 )) crystallizes in the cubic space group I23 and is constructed from triangular Zn 3 S units that are bridged through AmTAZ ligands into a cationic three-dimensional (3D) network with nitrate and water molecules residing in the cavities. 2 • 2(EtOH) crystallizes in the monoclinic space group C2/c and shows a complex 3D network constructed from seven crystallographically unique zinc centers bridged by AmTAZ, carbonate, and hydroxide anions. The porous nature of both materials has been explored by thermogravimetric analysis, nitrogen sorption, and in situ synchrotronbased powder X-ray diffraction.

Local Deprotonation Enables Cation Exchange, Porosity Modulation, and Tunable Adsorption Selectivity in a Metal–Organic Framework

“…Using the augmented nets is useful in (i) describing the exact structural feature of MOF structures (shown above for the distinction of Zn 4 O and Zn 3 O SBUs), (ii) distinguishing MOF structures that are closely related but different in symmetry, and (iii) predicting new theoretical nets for the design of MOFs (many of this type are collected in RCSR) . For (ii), another interesting example is [Zn 3 S­(AmTAZ) 3 ]­·NO 3 ·H 2 O (HAmTAZ = 3-amino-1,2,4-triazole), which exhibited a similar Zn 3 S SBU, but it has a cationic framework filled with charge-balancing nitrate anions. At first glance, the Zn 3 S SBU is also 6-coordinated, and thus the framework has a pcu topology, but the framework has two types of embedded cages.…”

In Situ Single-Crystal Diffraction Studies of the Structural Transition of Metal−Organic Framework Copper 5-Sulfoisophthalate, Cu-SIP-3

“…Variable-temperature powder diffraction data are commonly used in MOF materials to track the changes in unit cell parameters on the application of an external stimulus such as temperature or solvent. ,− Studies on single crystals mostly relate to changes of metal coordination or framework flexibilities on removal of solvent, or inclusion of other guest molecules. There are several reports of single-crystal to single-crystal reactions studied by diffraction reporting the changes of structure on exposure to different solvent conditions. ,,,− Fewer studies have been done to characterize transformations which involve significant coordination changes and large atomic movements, due to the problems associated with retaining crystallinity when there is significant movement in the crystal. Herein we report an in situ single-crystal analysis to examine the mechanism of transformation in the framework Cu-SIP-3, when both thermal and gaseous stimuli are used to induce major coordination changes in the framework.…”

“…Variable-temperature powder diffraction data are commonly used in MOF materials to track the changes in unit cell parameters on the application of an external stimulus such as temperature or solvent. 23,[27][28][29][30][31] Studies on single crystals mostly relate to changes of metal coordination or framework flexibilities on removal of solvent, or inclusion of other guest molecules. There are several reports of singlecrystal to single-crystal reactions studied by diffraction reporting the changes of structure on exposure to different solvent conditions.…”

Chemistry of Metal-organic Frameworks Monitored by Advanced X-ray Diffraction and Scattering Techniques

“…The structural changes upon guest-adsorption was investigated by in-situ powder diffraction on Zn-triazolate system, where high anisotropic structural flexing upon water or ethanol adsorption/desorption could be observed. 118 The crystal-tocrystal transformations upon guest removal on Ca-MOFs (AEPF-1) based on the 4,4'-(hexafluoroisopropylidene) bis(benzoic acid) ligand and Ca-terephthalate (Ca(BDC) (DMF)(H 2 O) were investigated by XRPD. 119,120 Structure response upon exposure to different solvents were investigated on pyrene-based JUC-118(Zn,Co).…”