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Zhang W, Lucier BEG, Terskikh VV, Chen S, Huang Y. Understanding Cu(i) local environments in MOFs via63/65Cu NMR spectroscopy. Chem Sci 2024; 15:6690-6706. [PMID: 38725502 PMCID: PMC11077522 DOI: 10.1039/d4sc00782d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 02/26/2024] [Indexed: 05/12/2024] Open
Abstract
The field of metal-organic frameworks (MOFs) includes a vast number of hybrid organic and inorganic porous materials with wide-ranging applications. In particular, the Cu(i) ion exhibits rich coordination chemistry in MOFs and can exist in two-, three-, and four-coordinate environments, which gives rise to many structural motifs and potential applications. Direct characterization of the structurally and chemically important Cu(i) local environments is essential for understanding the sources of specific MOF properties. For the first time, 63/65Cu solid-state NMR has been used to investigate a variety of Cu(i) sites and local coordination geometries in Cu MOFs. This approach is a sensitive probe of the local Cu environment, particularly when combined with density functional theory calculations. A wide range of structurally-dependent 63/65Cu NMR parameters have been observed, including 65Cu quadrupolar coupling constants ranging from 18.8 to 74.8 MHz. Using the data from this and prior studies, a correlation between Cu quadrupolar coupling constants, Cu coordination number, and local Cu coordination geometry has been established. Links between DFT-calculated and experimental Cu NMR parameters are also presented. Several case studies illustrate the feasibility of 63/65Cu NMR for investigating and resolving inequivalent Cu sites, monitoring MOF phase changes, interrogating the Cu oxidation number, and characterizing the product of a MOF chemical reaction involving Cu(ii) reduction to Cu(i). A convenient avenue to acquire accurate 65Cu NMR spectra and NMR parameters from Cu(i) MOFs at a widely accessible magnetic field of 9.4 T is described, with a demonstrated practical application for tracking Cu(i) coordination evolution during MOF anion exchange. This work showcases the power of 63/65Cu solid-state NMR spectroscopy and DFT calculations for molecular-level characterization of Cu(i) centers in MOFs, along with the potential of this protocol for investigating a wide variety of MOF structural changes and processes important for practical applications. This approach has broad applications for examining Cu(i) centers in other weight-dilute systems.
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Affiliation(s)
- Wanli Zhang
- Department of Chemistry, The University of Western Ontario 1151 Richmond Street London Ontario N6A 5B7 Canada
| | - Bryan E G Lucier
- Department of Chemistry, The University of Western Ontario 1151 Richmond Street London Ontario N6A 5B7 Canada
| | - Victor V Terskikh
- Metrology, National Research Council Canada Ottawa Ontario K1A 0R6 Canada
| | - Shoushun Chen
- College of Chemistry and Chemical Engineering, Lanzhou University Lanzhou 730000 China
| | - Yining Huang
- Department of Chemistry, The University of Western Ontario 1151 Richmond Street London Ontario N6A 5B7 Canada
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Fu Y, Yao Y, Forse AC, Li J, Mochizuki K, Long JR, Reimer JA, De Paëpe G, Kong X. Solvent-derived defects suppress adsorption in MOF-74. Nat Commun 2023; 14:2386. [PMID: 37185270 PMCID: PMC10130178 DOI: 10.1038/s41467-023-38155-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 04/14/2023] [Indexed: 05/17/2023] Open
Abstract
Defects in metal-organic frameworks (MOFs) have great impact on their nano-scale structure and physiochemical properties. However, isolated defects are easily concealed when the frameworks are interrogated by typical characterization methods. In this work, we unveil the presence of solvent-derived formate defects in MOF-74, an important class of MOFs with open metal sites. With multi-dimensional solid-state nuclear magnetic resonance (NMR) investigations, we uncover the ligand substitution role of formate and its chemical origin from decomposed N,N-dimethylformamide (DMF) solvent. The placement and coordination structure of formate defects are determined by 13C NMR and density functional theory (DFT) calculations. The extra metal-oxygen bonds with formates partially eliminate open metal sites and lead to a quantitative decrease of N2 and CO2 adsorption with respect to the defect concentration. In-situ NMR analysis and molecular simulations of CO2 dynamics elaborate the adsorption mechanisms in defective MOF-74. Our study establishes comprehensive strategies to search, elucidate and manipulate defects in MOFs.
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Affiliation(s)
- Yao Fu
- Department of Physical Medicine and Rehabilitation, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, 310027, PR China
- Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou, 310027, PR China
- Univ. Grenoble Alpes, CEA, IRIG-MEM, Grenoble, France
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA
| | - Yifeng Yao
- Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou, 310027, PR China
| | - Alexander C Forse
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA
- Department of Chemistry, University of Cambridge, Cambridge, CB2 1EW, UK
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Jianhua Li
- Department of Physical Medicine and Rehabilitation, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, 310027, PR China
| | - Kenji Mochizuki
- Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou, 310027, PR China
| | - Jeffrey R Long
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Jeffrey A Reimer
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94720, USA
| | - Gaël De Paëpe
- Univ. Grenoble Alpes, CEA, IRIG-MEM, Grenoble, France
| | - Xueqian Kong
- Department of Physical Medicine and Rehabilitation, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, 310027, PR China.
- Key Laboratory of Excited-State Materials of Zhejiang Province, Department of Chemistry, Zhejiang University, Hangzhou, 310027, PR China.
- Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240, China.
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