Abstract
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 bond-breaking 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. 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.
| Original language | English |
|---|---|
| Pages (from-to) | 8655-8692 |
| Number of pages | 38 |
| Journal | Chemical Reviews |
| Volume | 116 |
| Issue number | 15 |
| DOIs | |
| Publication status | Published - Aug 10 2016 |
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ASJC Scopus subject areas
- Chemistry(all)
Cite this
Thermodynamic Hydricity of Transition Metal Hydrides. / Wiedner, Eric; Chambers, Matthew B.; Pitman, Catherine L.; Bullock, R Morris; Miller, Alexander J M; Appel, Aaron.
In: Chemical Reviews, Vol. 116, No. 15, 10.08.2016, p. 8655-8692.Research output: Contribution to journal › Review article
}
TY - JOUR
T1 - Thermodynamic Hydricity of Transition Metal Hydrides
AU - Wiedner, Eric
AU - Chambers, Matthew B.
AU - Pitman, Catherine L.
AU - Bullock, R Morris
AU - Miller, Alexander J M
AU - Appel, Aaron
PY - 2016/8/10
Y1 - 2016/8/10
N2 - 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 bond-breaking 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. 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.
AB - 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 bond-breaking 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. 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.
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U2 - 10.1021/acs.chemrev.6b00168
DO - 10.1021/acs.chemrev.6b00168
M3 - Review article
VL - 116
SP - 8655
EP - 8692
JO - Chemical Reviews
JF - Chemical Reviews
SN - 0009-2665
IS - 15
ER -