Calorimetric Study of the Activation of Hydrogen by Tris(pentafluorophenyl)borane and Trimesitylphosphine
| Autor: | Tom Autrey, Adrian Y. Houghton |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Exothermic reaction
Standard enthalpy of reaction 010405 organic chemistry Chemistry 010402 general chemistry Photochemistry 01 natural sciences Heterolysis Frustrated Lewis pair Isothermal process 0104 chemical sciences chemistry.chemical_compound Reaction rate constant Kinetic isotope effect Physical chemistry Tris(pentafluorophenyl)borane Physical and Theoretical Chemistry |
| Zdroj: | The Journal of Physical Chemistry A. 121:8785-8790 |
| ISSN: | 1520-5215 1089-5639 |
| DOI: | 10.1021/acs.jpca.7b08582 |
| Popis: | The mechanism of H2 heterolysis by the frustrated Lewis pair of B(C6F5)3 and P(mes)3 was investigated by isothermal reaction calorimetry in the temperature range from 30 to 90 °C. The experimental heat curves were modeled in Berkeley Madonna to obtain both kinetic and thermodynamics data simultaneously. The H2 activation reaction is treated as a single, termolecular step with a rate constant of 0.61 M–2 s–1 at 303 K with an exothermic enthalpy of reaction, ΔHH2 = −141 kJ/mol. An Eyring analysis gave activation parameters of ΔH‡ = 13.6(9) kJ mol–1 and ΔS‡ = −204(85) J K–1 mol–1. Using D2 gas in place of H2 gas provided an opportunity to measure the relative rates of D2 versus H2 heterolysis to yield a the kinetic isotope effect, KIE = 1.1(1). |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|