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Site Isolation in Metal-Organic Frameworks Enables Novel Transition Metal Catalysis.
Acc Chem Res 2018; 51(9):2129-2138AC

Abstract

Comprising periodically repeating inorganic nodes and organic linkers, metal-organic frameworks (MOFs) represent a novel class of porous molecular solids with well-defined pores and channels. Over the past two decades, a large array of organic linkers have been combined with many inorganic nodes to afford a vast library of MOFs. The synthetic tunability of MOFs distinguishes them from traditional porous inorganic materials and has allowed the rational design of many interesting properties, such as porosity, chirality, and chemical functionality, for potential applications in diverse areas including gas storage and separation, catalysis, light harvesting, chiral separation, and chemical sensing. In particular, the molecular functionality and intrinsic porosity of MOFs have rendered them attractive candidates as porous single-site solid catalysts for a large number of organic transformations. MOF catalysts offer several advantages over their homogeneous counterparts, including enhanced stability, recyclability and reusability, and facile removal of the toxic catalyst components from the organic products. Additionally, the highly ordered nature of MOFs leads to the generation of single-site solid catalysts, allowing for precise characterization of the catalytic sites through X-ray diffraction, X-ray absorption, and other spectroscopic interrogations and facilitating the elucidation of reaction mechanisms. Thus, MOF catalysis represents a fertile research area that is expected to witness continued growth in the foreseeable future. In this Account, we present our recent research progress in developing ligand-supported single-site MOF catalysts for challenging organic reactions. We present two complementary approaches to the design of ligand-supported MOF catalysts: direct incorporation of prefunctionalized organic linkers into MOFs and postsynthetic functionalization of orthogonal secondary functional groups of the organic linkers in MOFs. Monophosphine-, bipyridine-, β-diketimine-, and salicylaldimine-based ligands have been used to support both precious (Pd, Pt, Ir, Ru) and earth-abundant (Cu, Co, Fe) metals for a number of interesting catalytic reactions. The resulting MOF catalysts feature stable low-coordination species with minimum steric bulk around the active site-a feat that remains a challenge for homogeneous catalysts. For each ligand, we describe types of reactions catalyzed by the MOF in comparison with its homogeneous counterpart. In all cases, MOF catalysts outperformed their homogeneous counterparts in terms of catalyst stability, catalytic activity, and recyclability and reusability. Interestingly, several bipyridine- and salicylaldimine-ligated earth-abundant-metal-based MOF catalysts do not have homogeneous counterparts because the molecular compounds disproportionate or oligomerize to form inactive species in solution. This Account not only presents several interesting designs of ligand-supported single-site MOF catalysts but also provides illustrative examples of how site isolation in MOF catalysts shuts down deactivation pathways experienced by homogeneous systems. With precise knowledge of MOF structures and catalytically active sites, we envision the development of practically useful MOF catalysts comprising tailor-made building blocks that rationally optimize catalytic activities and selectivities.

Authors+Show Affiliations

Department of Chemistry , The University of Chicago , 929 East 57th Street , Chicago , Illinois 60637 , United States.Department of Chemistry , The University of Chicago , 929 East 57th Street , Chicago , Illinois 60637 , United States.Department of Chemistry , The University of Chicago , 929 East 57th Street , Chicago , Illinois 60637 , United States.

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30129753

Citation

Drake, Tasha, et al. "Site Isolation in Metal-Organic Frameworks Enables Novel Transition Metal Catalysis." Accounts of Chemical Research, vol. 51, no. 9, 2018, pp. 2129-2138.
Drake T, Ji P, Lin W. Site Isolation in Metal-Organic Frameworks Enables Novel Transition Metal Catalysis. Acc Chem Res. 2018;51(9):2129-2138.
Drake, T., Ji, P., & Lin, W. (2018). Site Isolation in Metal-Organic Frameworks Enables Novel Transition Metal Catalysis. Accounts of Chemical Research, 51(9), pp. 2129-2138. doi:10.1021/acs.accounts.8b00297.
Drake T, Ji P, Lin W. Site Isolation in Metal-Organic Frameworks Enables Novel Transition Metal Catalysis. Acc Chem Res. 2018 09 18;51(9):2129-2138. PubMed PMID: 30129753.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Site Isolation in Metal-Organic Frameworks Enables Novel Transition Metal Catalysis. AU - Drake,Tasha, AU - Ji,Pengfei, AU - Lin,Wenbin, Y1 - 2018/08/21/ PY - 2018/8/22/pubmed PY - 2018/8/22/medline PY - 2018/8/22/entrez SP - 2129 EP - 2138 JF - Accounts of chemical research JO - Acc. Chem. Res. VL - 51 IS - 9 N2 - Comprising periodically repeating inorganic nodes and organic linkers, metal-organic frameworks (MOFs) represent a novel class of porous molecular solids with well-defined pores and channels. Over the past two decades, a large array of organic linkers have been combined with many inorganic nodes to afford a vast library of MOFs. The synthetic tunability of MOFs distinguishes them from traditional porous inorganic materials and has allowed the rational design of many interesting properties, such as porosity, chirality, and chemical functionality, for potential applications in diverse areas including gas storage and separation, catalysis, light harvesting, chiral separation, and chemical sensing. In particular, the molecular functionality and intrinsic porosity of MOFs have rendered them attractive candidates as porous single-site solid catalysts for a large number of organic transformations. MOF catalysts offer several advantages over their homogeneous counterparts, including enhanced stability, recyclability and reusability, and facile removal of the toxic catalyst components from the organic products. Additionally, the highly ordered nature of MOFs leads to the generation of single-site solid catalysts, allowing for precise characterization of the catalytic sites through X-ray diffraction, X-ray absorption, and other spectroscopic interrogations and facilitating the elucidation of reaction mechanisms. Thus, MOF catalysis represents a fertile research area that is expected to witness continued growth in the foreseeable future. In this Account, we present our recent research progress in developing ligand-supported single-site MOF catalysts for challenging organic reactions. We present two complementary approaches to the design of ligand-supported MOF catalysts: direct incorporation of prefunctionalized organic linkers into MOFs and postsynthetic functionalization of orthogonal secondary functional groups of the organic linkers in MOFs. Monophosphine-, bipyridine-, β-diketimine-, and salicylaldimine-based ligands have been used to support both precious (Pd, Pt, Ir, Ru) and earth-abundant (Cu, Co, Fe) metals for a number of interesting catalytic reactions. The resulting MOF catalysts feature stable low-coordination species with minimum steric bulk around the active site-a feat that remains a challenge for homogeneous catalysts. For each ligand, we describe types of reactions catalyzed by the MOF in comparison with its homogeneous counterpart. In all cases, MOF catalysts outperformed their homogeneous counterparts in terms of catalyst stability, catalytic activity, and recyclability and reusability. Interestingly, several bipyridine- and salicylaldimine-ligated earth-abundant-metal-based MOF catalysts do not have homogeneous counterparts because the molecular compounds disproportionate or oligomerize to form inactive species in solution. This Account not only presents several interesting designs of ligand-supported single-site MOF catalysts but also provides illustrative examples of how site isolation in MOF catalysts shuts down deactivation pathways experienced by homogeneous systems. With precise knowledge of MOF structures and catalytically active sites, we envision the development of practically useful MOF catalysts comprising tailor-made building blocks that rationally optimize catalytic activities and selectivities. SN - 1520-4898 UR - https://www.unboundmedicine.com/medline/citation/30129753/Site_Isolation_in_Metal_Organic_Frameworks_Enables_Novel_Transition_Metal_Catalysis_ L2 - https://dx.doi.org/10.1021/acs.accounts.8b00297 DB - PRIME DP - Unbound Medicine ER -