Related Experiment Video
Updated: Sep 29, 2025
07:20
Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents
Published on: May 28, 2014
14.1K
Dinitrogen Coordination to a High-Spin Diiron(I/II) Species
Juan F Torres1, Collin H Oi1, Ian P Moseley2
1Center for Catalysis and Florida Center for Heterocyclic Chemistry, Department of Chemistry, University of Florida, Gainesville, FL 32611, USA.
Angewandte Chemie (International Ed. in English)
|March 18, 2022
Summary
Researchers developed a novel high-spin iron-dinitrogen complex, mimicking nitrogenase enzymes. This mixed-valent diiron(I/II) complex exhibits unique electronic properties and slow magnetic relaxation, advancing dinitrogen coordination chemistry.
Area of Science:
- Inorganic Chemistry
- Bioinorganic Chemistry
- Materials Science
Background:
- Dinitrogen coordination to iron is crucial for industrial (Haber-Bosch) and biological nitrogen fixation (nitrogenase enzymes).
- Existing iron-dinitrogen chemistry predominantly involves low-valent states, unlike the high-spin centers in nitrogenase enzymes.
- Bridging the gap between synthetic iron-dinitrogen complexes and enzymatic systems remains a key challenge.
Purpose of the Study:
- To synthesize and characterize a high-spin, mixed-valent diiron complex capable of dinitrogen coordination.
- To investigate the electronic structure and magnetic properties of the novel iron-dinitrogen complex.
- To explore the potential of such complexes as models for nitrogenase active sites.
Main Methods:
- Synthesis of a novel bis(β-diketiminate) cyclophane ligand and its corresponding diiron complex.
- Characterization using field-applied Mössbauer spectroscopy to probe iron's oxidation states and spin states.
- Magnetic susceptibility measurements (dc and ac) to determine magnetic properties and relaxation behavior.
- Computational methods (e.g., DFT) to support experimental findings and elucidate electronic structure.
Main Results:
- A high-spin mixed-valent cis-(μ-1,2-dinitrogen)diiron(I/II) complex, [(FeBr)2 (μ-N2 )Lbis ]-, was successfully synthesized.
- Spectroscopic and magnetic data confirm a delocalized S=7/2 Fe2 N2 unit.
- The complex exhibits slow magnetic relaxation, characterized by a zero-field splitting parameter D=-5.23 cm-1.
Conclusions:
- This study reports the first high-spin, mixed-valent diiron complex featuring a μ-1,2-dinitrogen bridge.
- The findings provide insights into the electronic structure and magnetic behavior of iron-dinitrogen systems relevant to nitrogenase enzymes.
- The complex's properties, including slow magnetic relaxation, open avenues for developing new catalysts and molecular magnetic materials.
More Related Videos
Related Concept Videos
03:02Colors and Magnetism
12.4K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
12.4K
02:42Valence Bond Theory
9.8K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
9.8K
02:51Metal-Ligand Bonds
21.6K
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
21.6K
02:54Coordination Compounds and Nomenclature
22.6K
In most main group element compounds, the valence electrons of the isolated atoms combine to form chemical bonds that satisfy the octet rule. For instance, the four valence electrons of carbon overlap with electrons from four hydrogen atoms to form CH4. The one valence electron leaves sodium and adds to the seven valence electrons of chlorine to form the ionic formula unit NaCl (Figure 1a). Transition metals do not normally bond in this fashion. They primarily form coordinate covalent bonds, a...
22.6K
02:34Structural Isomerism
19.8K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
Isomers are different chemical species that have the same chemical formula. Structural isomerism of coordination compounds can be divided into two subcategories, the linkage isomers and coordination-sphere isomers.
Linkage isomers occur when the coordination compound contains a ligand that can bind to the transition metal center through two different atoms. For example, the CN− ligand can bind through the carbon atom or through the nitrogen atom. Similarly, SCN− can...
19.8K
02:57Coordination Number and Geometry
16.9K
For transition metal complexes, the coordination number determines the geometry around the central metal ion. Table 1 compares coordination numbers to molecular geometry. The most common structures of the complexes in coordination compounds are octahedral, tetrahedral, and square planar.
16.9K