Calorimetric Study of the Activation of Hydrogen by Tris(pentafluorophenyl)borane and Trimesitylphosphine

Journal Article · Wed Nov 08 04:00:00 EST 2017 · Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory

DOI:https://doi.org/10.1021/acs.jpca.7b08582· OSTI ID:1430435

Houghton, Adrian Y. ^[1]; Autrey, Tom ^[1]

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1. Pacific Northwest National Laboratory, 902 Battelle Boulevard, P.O. Box 999, Richland, Washington 99352 United States

The mechanism of H2 activation by B(C6F5)3 and P(mes)3 was investigated by isothermal reaction calorimetry, and the heat curves generated were modelled in Berkeley Madonna. The reaction is treated as a single, termolecular step, and an Eyring analysis gave activation parameters of ΔH‡ = 13.6(9) kJ mol-1 and ΔS‡ = -204(85) J K-1 mol-1. The enthalpy of the reaction was found to be -141 kJ mol-1. The kinetic isotope effect was measured as 1.1, consistent with a four-center transition state containing two isotopically exchangeable atoms.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1430435
• Report Number(s): PNNL-SA-128390; KC0302010
• Journal Information: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory, Journal Name: Journal of Physical Chemistry. A, Molecules, Spectroscopy, Kinetics, Environment, and General Theory Journal Issue: 46 Vol. 121; ISSN 1089-5639
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

activation energy
enthalpy
frustrated Lewis pairs
kinetic isotope effect
metal-free hydrogen activation