Related Experiment Video
Updated: Apr 23, 2026
13:21
Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging
Published on: July 21, 2011
14.6K
Strongest exchange coupling in gadolinium(III) and nitroxide coordination compounds.
Takuya Kanetomo1, Takayuki Ishida
1Department of Engineering Science, The University of Electro-Communications , Chofu, Tokyo 182-8585, Japan.
Inorganic Chemistry
|September 27, 2014
Summary
Researchers synthesized a novel molecule, [Gd(hfac)3(6bpyNO)], exhibiting strong antiferromagnetic coupling. This finding supports the design principle that planar chelates enhance magnetic interactions in lanthanide complexes.
Area of Science:
- Coordination Chemistry
- Magnetochemistry
- Materials Science
Background:
- Antiferromagnetic coupling is crucial for developing advanced magnetic materials.
- Lanthanide complexes offer unique magnetic properties due to their electronic structure.
- Molecular design plays a key role in controlling magnetic interactions.
Purpose of the Study:
- To synthesize and characterize a novel lanthanide complex with strong antiferromagnetic coupling.
- To investigate the relationship between molecular structure and magnetic properties.
- To validate the empirical design strategy for enhancing antiferromagnetic interactions.
Main Methods:
- Single-crystal X-ray diffraction for structural determination.
- Magnetic susceptibility measurements to quantify magnetic coupling.
- Quantum chemical calculations to support experimental findings.
Main Results:
- The synthesized complex [Gd(hfac)3(6bpyNO)] displayed a significant antiferromagnetic coupling parameter of 2J/kB = -15.9(2) K.
- Structural analysis revealed a short Gd-O bond attributed to the tridentate coordination of the nitroxide ligand.
- The planar nature of the chelate ligand was confirmed to favor stronger antiferromagnetic coupling.
Conclusions:
- The study successfully demonstrates a new molecule with strong antiferromagnetic coupling.
- The findings validate the empirical design rule linking chelate planarity to coupling strength.
- This work provides a foundation for designing future molecular magnets with tailored properties.
Related Concept Videos
02:42Valence Bond Theory
8.8K
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...
8.8K
02:34Structural Isomerism
16.8K
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,...
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,...
16.8K
03:02Colors and Magnetism
12.0K
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...
12.0K
02:51Metal-Ligand Bonds
19.2K
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...
19.2K
02:57Coordination Number and Geometry
15.5K
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.
15.5K
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
1.5K
Two NMR-active nuclei bonded to a central atom can be involved in geminal or two-bond coupling. Geminal coupling is commonly seen between diastereotopic protons in chiral molecules and unsymmetrical alkenes, among others.
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
The central atom need not be NMR-active because its electrons are affected by the electron polarization of the spin-active atoms. However, spin information is transmitted less effectively than in one-bond coupling, and 2J values are usually weaker than 1J values. The energy of...
1.5K