Dihydrogen activation by antiaromatic pentaarylboroles

J Am Chem Soc. 2010 Jul 21;132(28):9604-6. doi: 10.1021/ja105075h.

Abstract

Facile metal-free splitting of molecular hydrogen (H(2)) is crucial for the utilization of H(2) without the need for toxic transition-metal-based catalysts. Frustrated Lewis pairs (FLPs) are a new class of hydrogen activators wherein interactions with both a Lewis acid and a Lewis base heterolytically disrupt the hydrogen-hydrogen bond. Here we describe the activation of hydrogen exclusively by a boron-based Lewis acid, perfluoropentaphenylborole. This antiaromatic compound reacts extremely rapidly with H(2) in both solution and the solid state to yield boracyclopent-3-ene products resulting from addition of hydrogen atoms to the carbons alpha to boron in the starting borole. The disruption of antiaromaticity upon reaction of the borole with H(2) provides a significant thermodynamic driving force for this new metal-free hydrogen-splitting reaction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Boron / chemistry*
  • Hydrogen / chemistry*
  • Hydrogen Bonding
  • Models, Molecular
  • Thermodynamics

Substances

  • Hydrogen
  • Boron