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Two-state reactivity in C-H activation by a four-coordinate iron(0) complex
Anne K Hickey1, Sean A Lutz1, Chun-Hsing Chen1
1Department of Chemistry, Indiana University, 800 E. Kirkwood Ave., Bloomington, IN 47405, USA. smith962@indiana.edu.
Chemical Communications (Cambridge, England)
|January 10, 2017
Summary
The iron complex [Ph2B(tBuIm)2Fe(CO)2]- exhibits a trigonal pyramidal ground state, with a square planar state accessible at higher temperatures. Two-state reactivity was observed, leading to an iron(II) product via C-H oxidative addition.
Area of Science:
- Organometallic chemistry
- Coordination chemistry
- Computational chemistry
Background:
- The study investigates the electronic structure and reactivity of a specific iron complex, [Ph2B(tBuIm)2Fe(CO)2]-.
- Understanding the interplay between different spin states and molecular geometries is crucial in catalysis and materials science.
Purpose of the Study:
- To determine the ground state structure and accessible geometries of the [Ph2B(tBuIm)2Fe(CO)2]- complex.
- To investigate the mechanism of C-H oxidative addition and explore the concept of two-state reactivity.
Main Methods:
- High-level electronic structure calculations were employed.
- Calculations were calibrated against experimental data.
- Analysis of potential energy surfaces for different spin states.
Main Results:
- The ground state structure was identified as trigonal pyramidal with a spin state S = 1.
- A thermally accessible square planar geometry (S = 0) was found.
- Evidence for two-state reactivity was established, with C-H oxidative addition occurring on the singlet surface.
Conclusions:
- The iron complex exhibits rich electronic behavior with accessible spin states influencing its reactivity.
- Two-state reactivity, involving both singlet and triplet surfaces, plays a key role in the observed C-H functionalization.
- This work provides insights into the design principles for iron-based catalysts with tunable reactivity.
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