Related Experiment Video
Updated: Nov 1, 2025
07:56
Preparation of 6-aminocyclohepta-2,4-dien-1-one Derivatives via Tricarbonyltroponeiron
Published on: August 12, 2019
8.1K
Chiral Resolution of Spin-Crossover Active Iron(II) [2x2] Grid Complexes
Nithin Suryadevara1, Ansgar Pausch2, Eufemio Moreno-Pineda3
1Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|June 24, 2021
Summary
Researchers developed a new method to create enantiomerically pure iron(II) grid complexes using chiral ligands. This breakthrough enables precise control over chiral magnetic materials for advanced molecular devices.
Area of Science:
- Coordination Chemistry
- Materials Science
- Magnetochemistry
Background:
- Chiral magnetic materials are crucial for advanced applications like non-linear optics and magneto-chiral dichroism.
- Tetra-nuclear Fe(II) grid complexes (C/S-[Fe4L4]8+) exhibit chirality due to ligand isomerism and non-centrosymmetric spatial arrangements.
- Achieving enantiomerically pure grid complexes via spontaneous self-assembly is challenging.
Purpose of the Study:
- To design and synthesize novel intrinsically chiral ligands for pre-synthesis programmable resolution of Fe(II) grid complexes.
- To obtain enantiomerically pure Fe(II) grid complexes in a controlled manner.
- To investigate the spin crossover (SCO) properties of the resulting chiral complexes.
Main Methods:
- Synthesis of two novel intrinsically chiral ligands by appending chiral moieties to a parent ligand.
- Complexation of these chiral ligands with Fe(II) salts.
- Characterization of enantiomeric purity using Circular Dichroism (CD) and X-ray Diffraction (XRD) studies.
- Analysis of thermal and photo-induced spin crossover (SCO) characteristics.
Main Results:
- Successful synthesis of enantiomerically pure Fe(II) grid complexes using the designed chiral ligands.
- Unambiguous confirmation of enantiomeric purity and structural elucidation via CD and XRD.
- Similar gradual and half-complete thermal and photo-induced SCO behaviors observed in enantiomeric complexes.
- Strong agreement between experimental and calculated CD spectra, validating enantiomeric purity and magnetic studies.
Conclusions:
- The study presents a novel strategy for the controlled synthesis of enantiomerically pure Fe(II) grid complexes.
- This method overcomes the limitations of spontaneous self-assembly in achieving chiral resolution.
- The findings pave the way for the fabrication of magneto-chiral molecular devices and advanced functional materials.
More Related Videos
Related Concept Videos
02:42Valence Bond Theory
9.9K
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...
9.9K
03:02Colors and Magnetism
12.6K
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...
12.6K
02:52Stereoisomerism
12.8K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
12.8K
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
45.6K
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,...
45.6K
02:58Crystal Field Theory - Octahedral Complexes
28.6K
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...
28.6K
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
6.4K
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
6.4K