Related Experiment Video
Updated: Jul 1, 2025
06:31
Preparation of SNS CobaltII Pincer Model Complexes of Liver Alcohol Dehydrogenase
Published on: March 19, 2020
7.1K
Magneto-Structural Correlation of Five-Coordinate Trigonal Bipyramidal High Spin Cobalt(II) Complexes
Peng Zhang1,2, Yao-Cheng Tian3, Zhenxing Wang4
1State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|March 4, 2024
Summary
High spin cobalt(II) complexes with D3h symmetry exhibit positive magnetic anisotropy (D). Lowering symmetry to C3v causes orbital mixing, making D negative, with the Co(II) center
Area of Science:
- Inorganic Chemistry
- Magnetochemistry
- Computational Chemistry
Background:
- Understanding magnetic anisotropy is crucial for developing molecular magnets and quantum computing technologies.
- High spin cobalt(II) complexes are promising candidates due to their rich electronic structures and tunable magnetic properties.
- The sign and magnitude of magnetic anisotropy (D) are highly sensitive to the complex's geometry and electronic configuration.
Purpose of the Study:
- To investigate the magnetic properties of two novel high spin cobalt(II) complexes, Co(BDPRP).
- To elucidate the relationship between molecular symmetry, electronic structure, and magnetic anisotropy (D) in cobalt(II) complexes.
- To determine the influence of the cobalt(II) center's position relative to the equatorial plane on magnetic properties.
Main Methods:
- Magnetometry and multi-frequency electronic paramagnetic resonance (EPR) spectroscopy were employed to experimentally determine magnetic properties.
- Wave function-based ab initio calculations were utilized to complement experimental data and provide theoretical insights.
- Ligand field analyses were performed to understand the contributions of electronic states to magnetic anisotropy.
Main Results:
- Complexes 8 and 9, with effective D3h symmetry, displayed positive magnetic anisotropy values (D=24.0 and 32.0 cm-1, respectively) in their S=3/2 ground states.
- Low-lying d-d excited states were found to contribute positively or negligibly to the total magnetic anisotropy (D).
- A decrease in symmetry from D3h to C3v resulted in negative D values, attributed to orbital mixing and excited state admixture.
Conclusions:
- The symmetry of high spin cobalt(II) complexes significantly dictates the sign and magnitude of their magnetic anisotropy.
- The deviation of the cobalt(II) center from the equatorial plane (δ) is a critical factor determining the magnetic anisotropy in five-coordinate trigonal bipyramidal complexes.
- These findings provide a deeper understanding of magnetic anisotropy in cobalt(II) complexes, guiding the design of future molecular magnetic materials.
Keywords:
High Spin Cobalt(II) ComplexesMagneto-Structural CorrelationTrigonal BipyramidalZero-field splittingMore Related Videos
08:55Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
8.5K
11:04Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
Published on: September 7, 2019
9.2K
Related Concept Videos
03:02Colors and Magnetism
11.7K
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...
11.7K
02:42Valence Bond Theory
8.5K
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...
8.5K
02:34Structural Isomerism
19.2K
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...
19.2K
02:58Crystal Field Theory - Octahedral Complexes
26.5K
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
26.5K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
42.5K
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
42.5K