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Title: Heterolysis of H2 Across a Classical Lewis Pair, 2,6-Lutidine-BCl3: Synthesis, Characterization, and Mechanism

We report on a combined computational and experimental study of the activation of hydrogen using for 2,6-lutidine (Lut)/BCl3 Lewis pairs. Herein we describe the synthetic approach used to obtain a new FLP, Lut-BCl3 that activates molecular H2 at ~10 bar, 100 °C in toluene or lutidine as the solvent. The resulting compound is an unexpected neutral hydride, LutBHCl2, rather than the ion pair, which we attribute to ligand redistribution. The mechanism for activation was modeled with density functional theory and accurate G3(MP2)B3 theory. The dative bond in Lut-BCl3 is calculated to have a bond enthalpy of 15 kcal/mol. The separated pair is calculated to react with H2 and form the [LutH+][HBCl3–] ion pair with a barrier of 13 kcal/mol. Metathesis with LutBCl3 produces LutBHCl2 and [LutH][BCl4]. The overall reaction is exothermic by 8.5 kcal/mol. An alternative pathway was explored involving lutidine–borenium cation pair activating H2. This work was supported by the U.S. Department of Energy's (DOE) Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences, and Geosciences, and was performed in part using the Molecular Science Computing Facility (MSCF) in the William R. Wiley Environmental Molecular Sciences Laboratory, a DOE national scientific user facility sponsored by the Department ofmore » Energy's Office of Biological and Environmental Research and located at the Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for DOE.« less
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Publication Date:
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Report Number(s):
Journal ID: ISSN 1521-3765; KC0302010
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Chemistry - A European Journal (Online); Journal Volume: 21; Journal Issue: 4
ChemPubSoc Europe
Research Org:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
Sponsoring Org:
Country of Publication:
United States