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Title: Tuning Zr 6 Metal–Organic Framework (MOF) Nodes as Catalyst Supports: Site Densities and Electron-Donor Properties Influence Molecular Iridium Complexes as Ethylene Conversion Catalysts

Abstract

The Zr 6 nodes of the metal–organic frameworks (MOFs) UiO-66 and UiO-67 are metal oxide clusters of atomic precision and can be used as catalyst supports. The bonding sites on these nodes—that is, hydrogen-bonded H 2O/OH groups on UiO-67 and non-hydrogen-bonded terminal OH groups on UiO-66—were regulated by modulation of the MOF syntheses. Ir(C 2H 4) 2(C 5H 7O 2) complexes reacted with these sites to give site-isolated Ir(C 2H 4) 2 complexes, each anchored to the node by two Ir–Onode bonds. The supported iridium complexes on these sites have been characterized by infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectroscopies and density functional theory calculations. The ethylene ligands on iridium are readily replaced by CO, and the ν CO frequencies of the resultant complexes and those of comparable complexes reported elsewhere show that the support electron-donor tendencies increase in the order HY zeolite << UiO-66 < UiO-67 (= NU-1000) < ZrO 2 < MgO. The sharpness of the IR ν CO bands shows that the degree of uniformity of the support bonding sites decreases in the order ZrO 2 ≈ UiO-67 ≈ NU-1000 < MgO < UiO-66 << HY zeolite. The reactivity of supported Ir(CO) 2 complexesmore » with C2H4 to form Ir(C 2H 4)(CO) and Ir(C 2H 4) 2(CO) is influenced by the support electron-donor properties, with the reactivity increasing in the order MgO = ZrO 2 = NU-1000 (not reactive) < UiO-66 < UiO-67 << HY zeolite. Density functional theory calculations characterizing the complexes supported on NU-1000, UiO-66/67, and HY zeolite concur with the use of the calculated ν CO bands as indicators of electron-donor properties of the supported metal catalysts. Our calculations also show that the reactivity of the supported Ir(CO) 2 complexes with C 2H 4 is correlated with the electron-donor properties of the iridium center. Lastly, the supported Ir(C 2H 4) 2 samples are precatalysts for ethylene hydrogenation and ethylene dimerization, with the activity for each reaction increasing with increasing electron-withdrawing strength of the support.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Energy Frontier Research Center for Inorganometallic Catalyst Design (ICDC)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1370933
DOE Contract Number:  
SC0012702
Resource Type:
Journal Article
Journal Name:
ACS Catalysis
Additional Journal Information:
Journal Volume: 6; Journal Issue: 1; Related Information: ICDC partners with University of Minnesota(lead); Argonne National Laboratory; Clemson University; Dow Chemical Company; Northwestern University; Pacific Northwest National Laboratory; University of California Davis; University of Washington; Journal ID: ISSN 2155-5435
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalyst supports; ethylene dimerization; ethylene hydrogenation; iridium carbonyl complexes; iridium ethylene complexes; metal−organic framework nodes

Citation Formats

Yang, Dong, Odoh, Samuel O., Borycz, Joshua, Wang, Timothy C., Farha, Omar K., Hupp, Joseph T., Cramer, Christopher J., Gagliardi, Laura, and Gates, Bruce C. Tuning Zr6 Metal–Organic Framework (MOF) Nodes as Catalyst Supports: Site Densities and Electron-Donor Properties Influence Molecular Iridium Complexes as Ethylene Conversion Catalysts. United States: N. p., 2016. Web. doi:10.1021/acscatal.5b02243.
Yang, Dong, Odoh, Samuel O., Borycz, Joshua, Wang, Timothy C., Farha, Omar K., Hupp, Joseph T., Cramer, Christopher J., Gagliardi, Laura, & Gates, Bruce C. Tuning Zr6 Metal–Organic Framework (MOF) Nodes as Catalyst Supports: Site Densities and Electron-Donor Properties Influence Molecular Iridium Complexes as Ethylene Conversion Catalysts. United States. doi:10.1021/acscatal.5b02243.
Yang, Dong, Odoh, Samuel O., Borycz, Joshua, Wang, Timothy C., Farha, Omar K., Hupp, Joseph T., Cramer, Christopher J., Gagliardi, Laura, and Gates, Bruce C. Mon . "Tuning Zr6 Metal–Organic Framework (MOF) Nodes as Catalyst Supports: Site Densities and Electron-Donor Properties Influence Molecular Iridium Complexes as Ethylene Conversion Catalysts". United States. doi:10.1021/acscatal.5b02243.
@article{osti_1370933,
title = {Tuning Zr6 Metal–Organic Framework (MOF) Nodes as Catalyst Supports: Site Densities and Electron-Donor Properties Influence Molecular Iridium Complexes as Ethylene Conversion Catalysts},
author = {Yang, Dong and Odoh, Samuel O. and Borycz, Joshua and Wang, Timothy C. and Farha, Omar K. and Hupp, Joseph T. and Cramer, Christopher J. and Gagliardi, Laura and Gates, Bruce C.},
abstractNote = {The Zr6 nodes of the metal–organic frameworks (MOFs) UiO-66 and UiO-67 are metal oxide clusters of atomic precision and can be used as catalyst supports. The bonding sites on these nodes—that is, hydrogen-bonded H2O/OH groups on UiO-67 and non-hydrogen-bonded terminal OH groups on UiO-66—were regulated by modulation of the MOF syntheses. Ir(C2H4)2(C5H7O2) complexes reacted with these sites to give site-isolated Ir(C2H4)2 complexes, each anchored to the node by two Ir–Onode bonds. The supported iridium complexes on these sites have been characterized by infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectroscopies and density functional theory calculations. The ethylene ligands on iridium are readily replaced by CO, and the νCO frequencies of the resultant complexes and those of comparable complexes reported elsewhere show that the support electron-donor tendencies increase in the order HY zeolite << UiO-66 < UiO-67 (= NU-1000) < ZrO2 < MgO. The sharpness of the IR νCO bands shows that the degree of uniformity of the support bonding sites decreases in the order ZrO2 ≈ UiO-67 ≈ NU-1000 < MgO < UiO-66 << HY zeolite. The reactivity of supported Ir(CO)2 complexes with C2H4 to form Ir(C2H4)(CO) and Ir(C2H4)2(CO) is influenced by the support electron-donor properties, with the reactivity increasing in the order MgO = ZrO2 = NU-1000 (not reactive) < UiO-66 < UiO-67 << HY zeolite. Density functional theory calculations characterizing the complexes supported on NU-1000, UiO-66/67, and HY zeolite concur with the use of the calculated νCO bands as indicators of electron-donor properties of the supported metal catalysts. Our calculations also show that the reactivity of the supported Ir(CO)2 complexes with C2H4 is correlated with the electron-donor properties of the iridium center. Lastly, the supported Ir(C2H4)2 samples are precatalysts for ethylene hydrogenation and ethylene dimerization, with the activity for each reaction increasing with increasing electron-withdrawing strength of the support.},
doi = {10.1021/acscatal.5b02243},
journal = {ACS Catalysis},
issn = {2155-5435},
number = 1,
volume = 6,
place = {United States},
year = {2016},
month = {1}
}