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A Stable Homoleptic Organometallic Iron(IV) Complex
Om Prakash1, Pavel Chábera2, Nils W Rosemann2
1Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Box 124, Lund, 22100, Sweden.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|May 6, 2020
Summary
A stable iron(IV) N-heterocyclic carbene complex, [Fe(phtmeimb)2](PF6)2, was synthesized. Its triplet ground state and excited-state dynamics, including a 0.8 ps lifetime, were characterized for the first time.
Area of Science:
- Organometallic Chemistry
- Inorganic Chemistry
- Materials Science
Background:
- Iron complexes are crucial in catalysis and materials science.
- Understanding the electronic structure and excited-state dynamics of high-valent iron complexes is essential for developing new functional materials and catalysts.
- N-heterocyclic carbenes (NHCs) offer robust ligand platforms for stabilizing reactive metal centers.
Purpose of the Study:
- To synthesize and characterize a novel homoleptic organometallic iron(IV) complex.
- To investigate the electronic structure, spin state, and excited-state dynamics of the synthesized Fe(IV) complex.
- To explore the potential of NHC ligands in stabilizing high-valent iron species.
Main Methods:
- Synthesis and isolation of the [Fe(phtmeimb)2](PF6)2 complex.
- Characterization using various spectroscopic (NMR, Mössbauer, UV-Vis), analytical (HR-MS, elemental analysis), and structural (scXRD) techniques.
- Electrochemical studies and magnetic susceptibility measurements to determine electronic properties.
- Quantum chemical calculations to support experimental findings.
- Time-resolved spectroscopy to study excited-state dynamics.
Main Results:
- A stable homoleptic iron(IV) complex, [Fe(phtmeimb)2](PF6)2, was successfully synthesized and isolated.
- Mössbauer spectroscopy and magnetic susceptibility confirmed a triplet Fe(IV) low-spin S=1 ground state.
- Electronic absorption revealed intense ligand-to-metal charge transfer (LMCT) bands in the red and near-infrared regions.
- The excited-state dynamics of a Fe(IV) complex were studied for the first time, showing a 3LMCT excited state lifetime of approximately 0.8 ps.
Conclusions:
- The synthesized [Fe(phtmeimb)2](PF6)2 complex represents a stable platform for studying high-valent iron chemistry.
- The detailed characterization provides fundamental insights into the electronic structure and spin state of Fe(IV) NHC complexes.
- The study opens new avenues for exploring the photophysical properties and potential applications of iron-NHC complexes in catalysis and materials science.
Keywords:
N-heterocyclic carbeneshigh-valent ironorganometallic complexesphotophysicstransient absorption spectroscopyMore Related Videos
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