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Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
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Dynamic-dependent selectivity in a bisphosphine iron spin crossover C-H insertion/π-coordination reaction
Michael T Davenport1, Justin K Kirkland1, Daniel H Ess1
1Department of Chemistry and Biochemistry, Brigham Young University Provo Utah USA 84604 dhe@chem.byu.edu.
Chemical Science
|September 15, 2023
Summary
Pathway selectivity in organometallic reactions is not governed by transition states or minimum energy crossing points. Instead, dynamic motion during reactive collisions dictates outcomes in spin crossover reactions.
Area of Science:
- Organometallic Chemistry
- Computational Chemistry
- Reaction Dynamics
Background:
- Reaction pathway selectivity is typically governed by competing transition states.
- Organometallic reactions can be complicated by electronic spin state changes, modeled as minimum energy crossing points (MECPs).
Purpose of the Study:
- To investigate the factors controlling pathway selectivity in the reaction between bisphosphine iron and ethylene, involving spin state crossover.
- To determine if transition states or MECPs accurately model experimental observations.
Main Methods:
- Utilized quasiclassical trajectory simulations.
- Examined both single and mixed spin state trajectories.
- Analyzed the reaction dynamics of bisphosphine iron and ethylene.
Main Results:
- Neither transition states nor MECPs accurately predicted pathway selectivity.
- Quasiclassical trajectories revealed nonstatistical intermediates.
- Pathway selectivity (C-H insertion vs. π-coordination) was determined by dynamic motion during collisions.
Conclusions:
- Dynamic motion during reactive collisions, not transition states or MECPs, governs selectivity in this spin crossover organometallic reaction.
- Introduced a new selectivity model for organometallic reactions with spin crossover, emphasizing dynamic control.
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