Isophthalate–Hydrazone 2D Zinc–Organic Framework: Crystal Structure, Selective Adsorption, and Tuning of Mechanochemical Synthetic Conditions

Abstract

A new layered mixed-linker metal-organic framework [Zn(iso)(pcih)] (MOF) built from isophthalate ions (iso) and 4-pyridinecarbaldehyde isonicotinoyl hydrazone (pcih) was prepared using both solution and mechanochemical methods. By use of the latter, the 2D MOF is obtained either in a one-mortar three-component grinding or on the way of a two-step mechanosynthesis. Tuning of mechanochemical synthetic conditions allowed us to identify both necessary and favorable factors for the solid-state formation of the MOF. Single-crystal X-ray diffraction reveals the presence of interdigitated layers in the ABAB arrangement and interlayer 0D cavities filled with guest molecules. Upon thermal activation, the dynamic framework exhibits stepwise and selective adsorption of CO over N as well as high-pressure H adsorption reaching maximum excess of 1.15 wt% at 77 K. The mechanochemical synthetic protocol is expanded to a few other interdigitated structures.

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

“… 24 In situ PXRD provides global information about two-step structural transformation, while in situ IR and NMR shed light on the interaction between carbon dioxide and acylhydrazone group (−C(O)=N–NH−). 39 , 40 Moreover, one-component (CO 2 , CH 4 , Ar, O 2 , and N 2 ) and multicomponent (CH 4 /CO 2 ) equilibrium adsorption studies in a broad temperature range have shown high selectivity of JUK-8 toward carbon dioxide.…”

Interlinker Hydrogen Bonds Govern CO2 Adsorption in a Series of Flexible 2D Diacylhydrazone/Isophthalate-Based MOFs: Influence of Metal Center, Linker Substituent, and Activation Temperature

“… 44 Moreover, as can be seen from the above examples, major scientific efforts concerning flexible MOFs are directed toward understanding of 3D materials, 9 − 11 , 45 , 46 and the reports on 2D materials are still relatively rare and sought after. 20 , 42 , 47 − 51 …”

Sustainable Heterogeneous Catalysts for CO2 Utilization by Using Dual Ligand ZnII/CdII Metal–Organic Frameworks

“…Thes orption isotherms of CO 2 showed the typical typeIcharacter,i ndicating porous frameworks with retention of the microporous structures after the removal of guests from the crystalline samples and thew ide hysteresis may be caused by the guest-induced framework response. [91][92][93][94] Crystal and molecular structures of 1a nd 2…”

“…CO 2 absorption at 273 K revealed maximum uptakes 4 cm 3 g −1 and 6 cm 3 g −1 for 1 and 2 , respectively (Figure S8 in the Supporting Information). The sorption isotherms of CO 2 showed the typical type I character, indicating porous frameworks with retention of the microporous structures after the removal of guests from the crystalline samples and the wide hysteresis may be caused by the guest‐induced framework response …”