Thermodynamic studies and hydride transfer reactions from a rhodium complex to BX3 compounds

Michael T. Mock, Robert G. Potter, Donald M. Camaioni, Jun Li, William G. Dougherty, W. Scott Kassel, Brendan Twamley, Daniel L DuBois

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

This study examines the use of transition-metal hydride complexes that can be generated by the heterolytic cleavage of H2 gas to form B-H bonds. Specifically, these studies are focused on providing a reliable and quantitative method for determining when hydride transfer from transition-metal hydrides to three-coordinate BX3 (X = OR, SPh, F, H; R = Ph, p-C 6H4OMe, C6F5, tBu, Si(Me)3) compounds will be favorable. This involves both experimental and theoretical determinations of hydride transfer abilities. Thermodynamic hydride donor abilities (ΔG°H-) were determined for HRh(dmpe)2 and HRh(depe)2, where dmpe ) 1,2-bis(dimethylphosphinoethane) and depe ) 1,2-bis(diethylphosphinoethane), on a previously established scale in acetonitrile. This hydride donor ability was used to determine the hydride donor ability of [HBEt3]- on this scale. Isodesmic reactions between [HBEt3]- and selected BX3 compounds to form BEt3 and [HBX3]- were examined computationally to determine their relative hydride affinities. The use of these scales of hydride donor abilities and hydride affinities for transition-metal hydrides and BX3 compounds is illustrated with a few selected reactions relevant to the regeneration of ammonia borane. Our findings indicate that it is possible to form B-H bonds from B-X bonds, and the extent to which BX3 compounds are reduced by transition-metal hydride complexes forming species containing multiple B-H bonds depends on the heterolytic B-X bond energy. An example is the reduction of B(SPh)3 using HRh(dmpe)2 in the presence of triethylamine to form Et 3N-BH3 in high yields.

Original languageEnglish
Pages (from-to)14454-14465
Number of pages12
JournalJournal of the American Chemical Society
Volume131
Issue number40
DOIs
Publication statusPublished - Oct 14 2009

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Rhodium
Coordination Complexes
Thermodynamics
Hydrides
Metals
Boranes
Ammonia
Regeneration
Gases
Transition metals
Acetonitrile
acetonitrile
triethylamine

ASJC Scopus subject areas

  • Chemistry(all)
  • Catalysis
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Thermodynamic studies and hydride transfer reactions from a rhodium complex to BX3 compounds. / Mock, Michael T.; Potter, Robert G.; Camaioni, Donald M.; Li, Jun; Dougherty, William G.; Kassel, W. Scott; Twamley, Brendan; DuBois, Daniel L.

In: Journal of the American Chemical Society, Vol. 131, No. 40, 14.10.2009, p. 14454-14465.

Research output: Contribution to journalArticle

Mock, MT, Potter, RG, Camaioni, DM, Li, J, Dougherty, WG, Kassel, WS, Twamley, B & DuBois, DL 2009, 'Thermodynamic studies and hydride transfer reactions from a rhodium complex to BX3 compounds', Journal of the American Chemical Society, vol. 131, no. 40, pp. 14454-14465. https://doi.org/10.1021/ja905287q
Mock, Michael T. ; Potter, Robert G. ; Camaioni, Donald M. ; Li, Jun ; Dougherty, William G. ; Kassel, W. Scott ; Twamley, Brendan ; DuBois, Daniel L. / Thermodynamic studies and hydride transfer reactions from a rhodium complex to BX3 compounds. In: Journal of the American Chemical Society. 2009 ; Vol. 131, No. 40. pp. 14454-14465.
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