Transition states of spin-forbidden reactions

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

Spin-orbit coupling plays an important role in determining the mechanisms and kinetics of spin-forbidden reactions and many reactions exhibiting two-state reactivity. Spin-orbit coupling can allow the system to change its spin state, especially when potential energy surfaces (PESs) of two spin states approach each other. Here, we introduce a convenient new approximation method for locating stationary points on the lowest mixed-spin potential energy surface along a reaction pathway by using density functional calculations. The mixing of different spin states is achieved by introducing the spin-orbit coupling into the electronic Hamiltonian using a pre-defined coupling constant. Two examples are given using the new methodology: (a) a CO association reaction with the coordinatively unsaturated Fe(CO)4 complex and (b) an α-H elimination reaction of a model complex containing W. We computed a Gibbs free energy of activation of 2.8 kcal mol-1 for the CO association reaction, which is reasonably consistent with the experimentally measured reaction rate. For the H elimination reaction, the spin change occurs at a relatively low energy, and the present treatment allows one conclude that kinetics of the reaction can be reasonably well described without spin-orbit coupling.

Original languageEnglish (US)
Pages (from-to)4129-4136
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume20
Issue number6
DOIs
StatePublished - 2018

Bibliographical note

Publisher Copyright:
© 2018 the Owner Societies.

Fingerprint

Dive into the research topics of 'Transition states of spin-forbidden reactions'. Together they form a unique fingerprint.

Cite this