Intrinsicality of Guest Molecule Coordination in MOF

Abstract: 

Open metal sites within metal-organic frameworks (MOFs), typically hosting Lewis-basic guest molecules through coordination bonding, exhibit pivotal characteristics in their chemical reactivity.  In this talk, we elucidate the intrinsic nature of coordinative bonds established at MOF's open metal sites, dependent on the strength of bonding with guest molecules, differentiating between (i) weak and (ii) strong coordination bonds.

For instance, the exchange of relatively stronger coordination bonds, such as water, methanol, ethanol, and DMF, with chloroalkanes results in weak coordination bonding, leading to the activation of metal centers.^1-5  This activated state, induced by chloroalkanes, augments the catalytic activity of these metal centers.  In contrast, strong coordination bonding with compounds like hydroquinone and aniline initiates catalytic reactions, such as the "coordinative reduction" of the framework metals or the "catalytic polymerization" of coordinated substances.⁶  Specifically, hydroquinone induces the coordinative reduction of Cu(II) ions within the Cu₃BTC₂ MOF (BTC=benzenetricarboxylate), while aniline triggers polymerization. Furthermore, we demonstrate that the polymerized aniline (pAni) substantially enhances the hydrolytic stability of the Cu₃BTC₂, which is inherently vulnerable to humid conditions due to its low coordination valency.  Finally, we illustrate how the stabilized Cu₃BTC₂ significantly enhances its performance in atmospheric water harvesting.

References

1. J. Am. Chem. Soc. 2015, 137, 10009.

2. ACS Appl. Mater. Interfaces 2017, 9, 24743. 

3. Chem. Commun. 2018, 54, 6458.

4. Bull. Kor. Chem. Soc. 2021, 42, 658-666.

5. J. Mater. Chem. A. 2022, 10, 23499-23508.

6. J. Am. Chem. Soc. 2019, 141, 7853- 7864.

20241024_대학원 세미나_정낙천 교수.pdf