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Title: Thermodynamic Hydricity of Transition Metal Hydrides

Transition metal hydrides play a critical role in stoichiometric and catalytic transformations. Knowledge of free energies for cleaving metal hydride bonds enables the prediction of chemical reactivity, such as for the bond-forming and bondbreaking events that occur in a catalytic reaction. Thermodynamic hydricity is the free energy required to cleave an M-H bond to generate a hydride ion (H -). Three primary methods have been developed for hydricity determination: the hydride transfer method establishes hydride transfer equilibrium with a hydride donor/acceptor pair of known hydricity, the H 2 heterolysis method involves measuring the equilibrium of heterolytic cleavage of H 2 in the presence of a base, and the potential-pK a method considers stepwise transfer of a proton and two electrons to give a net hydride transfer. Using these methods, over 100 thermodynamic hydricity values for transition metal hydrides have been determined in acetonitrile or water. In acetonitrile, the hydricity of metal hydrides spans a range of more than 50 kcal/mol. Finally, methods for using hydricity values to predict chemical reactivity are also discussed, including organic transformations, the reduction of CO 2, and the production and oxidation of hydrogen.
Authors:
 [1] ;  [2] ;  [2] ;  [1] ;  [2] ;  [1]
  1. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  2. Univ. of North Carolina, Chapel Hill, NC (United States). Dept. of Chemistry
Publication Date:
Grant/Contract Number:
SC0014255; CHE-1205189
Type:
Published Article
Journal Name:
Chemical Reviews
Additional Journal Information:
Journal Volume: 116; Journal Issue: 15; Journal ID: ISSN 0009-2665
Publisher:
American Chemical Society
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1280195
Alternate Identifier(s):
OSTI ID: 1313998

Wiedner, Eric S., Chambers, Matthew B., Pitman, Catherine L., Bullock, R. Morris, Miller, Alexander J. M., and Appel, Aaron M.. Thermodynamic Hydricity of Transition Metal Hydrides. United States: N. p., Web. doi:10.1021/acs.chemrev.6b00168.
Wiedner, Eric S., Chambers, Matthew B., Pitman, Catherine L., Bullock, R. Morris, Miller, Alexander J. M., & Appel, Aaron M.. Thermodynamic Hydricity of Transition Metal Hydrides. United States. doi:10.1021/acs.chemrev.6b00168.
Wiedner, Eric S., Chambers, Matthew B., Pitman, Catherine L., Bullock, R. Morris, Miller, Alexander J. M., and Appel, Aaron M.. 2016. "Thermodynamic Hydricity of Transition Metal Hydrides". United States. doi:10.1021/acs.chemrev.6b00168.
@article{osti_1280195,
title = {Thermodynamic Hydricity of Transition Metal Hydrides},
author = {Wiedner, Eric S. and Chambers, Matthew B. and Pitman, Catherine L. and Bullock, R. Morris and Miller, Alexander J. M. and Appel, Aaron M.},
abstractNote = {Transition metal hydrides play a critical role in stoichiometric and catalytic transformations. Knowledge of free energies for cleaving metal hydride bonds enables the prediction of chemical reactivity, such as for the bond-forming and bondbreaking events that occur in a catalytic reaction. Thermodynamic hydricity is the free energy required to cleave an M-H bond to generate a hydride ion (H-). Three primary methods have been developed for hydricity determination: the hydride transfer method establishes hydride transfer equilibrium with a hydride donor/acceptor pair of known hydricity, the H2 heterolysis method involves measuring the equilibrium of heterolytic cleavage of H2 in the presence of a base, and the potential-pKa method considers stepwise transfer of a proton and two electrons to give a net hydride transfer. Using these methods, over 100 thermodynamic hydricity values for transition metal hydrides have been determined in acetonitrile or water. In acetonitrile, the hydricity of metal hydrides spans a range of more than 50 kcal/mol. Finally, methods for using hydricity values to predict chemical reactivity are also discussed, including organic transformations, the reduction of CO2, and the production and oxidation of hydrogen.},
doi = {10.1021/acs.chemrev.6b00168},
journal = {Chemical Reviews},
number = 15,
volume = 116,
place = {United States},
year = {2016},
month = {8}
}