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Title: Evidence for Redox Mechanisms in Organometallic Chemisorption and Reactivity on Sulfated Metal Oxides

The chemical and electronic interactions of organometallic species with metal oxide support materials are of fundamental importance for the development of new classes of catalytic materials. Chemisorption of Cp*(PMe 3)IrMe 2 on sulfated alumina (SA) and sulfated zirconia (SZ) led to an unexpected redox mechanism for deuteration of the ancillary Cp* ligand. Evidence for this oxidative mechanism was provided by studying the analogous homogeneous reactivity of the organometallic precursors toward trityl cation ([Ph 3C] +), a Lewis acid known to effect formal hydride abstraction by one-electron oxidation followed by hydrogen abstraction. Organometallic deuterium incorporation was found to be correlated with surface sulfate concentration as well as the extent of dehydration under thermal activation conditions of SA and SZ supports. Surface sulfate concentration dependence, in conjunction with a computational study of surface electron affinity, indicates an electron-deficient pyrosulfate species as the redox-active moiety. Furthermore, these results provide further evidence for the ability of sulfated metal oxides to participate in redox chemistry not only toward organometallic complexes but also in the larger context of their application as catalysts for the transformation of light alkanes.
Authors:
ORCiD logo [1] ;  [1] ; ORCiD logo [1] ;  [1] ;  [1] ;  [2] ; ORCiD logo [3] ; ORCiD logo [4] ; ORCiD logo [1]
  1. Argonne National Lab. (ANL), Lemont, IL (United States)
  2. Ames Lab., Ames, IA (United States)
  3. Ames Lab. and Iowa State Univ., Ames, IA (United States)
  4. Argonne National Lab. (ANL), Lemont, IL (United States); Illinois Institute of Technology, Chicago, IL (United States)
Publication Date:
Report Number(s):
IS-J-9600
Journal ID: ISSN 0002-7863
Grant/Contract Number:
AC02-06CH11357; AC02-07CH11358
Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 140; Journal Issue: 20; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
Ames Laboratory (AMES), Ames, IA (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1435752
Alternate Identifier(s):
OSTI ID: 1460729

Klet, Rachel C., Kaphan, David M., Liu, Cong, Yang, Ce, Kropf, A. Jeremy, Perras, Frederic A., Pruski, Marek, Hock, Adam S., and Delferro, Massimiliano. Evidence for Redox Mechanisms in Organometallic Chemisorption and Reactivity on Sulfated Metal Oxides. United States: N. p., Web. doi:10.1021/jacs.8b00995.
Klet, Rachel C., Kaphan, David M., Liu, Cong, Yang, Ce, Kropf, A. Jeremy, Perras, Frederic A., Pruski, Marek, Hock, Adam S., & Delferro, Massimiliano. Evidence for Redox Mechanisms in Organometallic Chemisorption and Reactivity on Sulfated Metal Oxides. United States. doi:10.1021/jacs.8b00995.
Klet, Rachel C., Kaphan, David M., Liu, Cong, Yang, Ce, Kropf, A. Jeremy, Perras, Frederic A., Pruski, Marek, Hock, Adam S., and Delferro, Massimiliano. 2018. "Evidence for Redox Mechanisms in Organometallic Chemisorption and Reactivity on Sulfated Metal Oxides". United States. doi:10.1021/jacs.8b00995.
@article{osti_1435752,
title = {Evidence for Redox Mechanisms in Organometallic Chemisorption and Reactivity on Sulfated Metal Oxides},
author = {Klet, Rachel C. and Kaphan, David M. and Liu, Cong and Yang, Ce and Kropf, A. Jeremy and Perras, Frederic A. and Pruski, Marek and Hock, Adam S. and Delferro, Massimiliano},
abstractNote = {The chemical and electronic interactions of organometallic species with metal oxide support materials are of fundamental importance for the development of new classes of catalytic materials. Chemisorption of Cp*(PMe3)IrMe2 on sulfated alumina (SA) and sulfated zirconia (SZ) led to an unexpected redox mechanism for deuteration of the ancillary Cp* ligand. Evidence for this oxidative mechanism was provided by studying the analogous homogeneous reactivity of the organometallic precursors toward trityl cation ([Ph3C]+), a Lewis acid known to effect formal hydride abstraction by one-electron oxidation followed by hydrogen abstraction. Organometallic deuterium incorporation was found to be correlated with surface sulfate concentration as well as the extent of dehydration under thermal activation conditions of SA and SZ supports. Surface sulfate concentration dependence, in conjunction with a computational study of surface electron affinity, indicates an electron-deficient pyrosulfate species as the redox-active moiety. Furthermore, these results provide further evidence for the ability of sulfated metal oxides to participate in redox chemistry not only toward organometallic complexes but also in the larger context of their application as catalysts for the transformation of light alkanes.},
doi = {10.1021/jacs.8b00995},
journal = {Journal of the American Chemical Society},
number = 20,
volume = 140,
place = {United States},
year = {2018},
month = {4}
}