Related Experiment Video
Updated: May 15, 2025
![Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F59399.jpg&w=3840&q=50)
11:57
Measuring the Spin-Lattice Relaxation Magnetic Field Dependence of Hyperpolarized [1-13C]pyruvate
Published on: September 13, 2019
6.5K
Spin-Crossover in a Dinuclear Iron(II) Complex on Highly Oriented Pyrolytic Graphite: An X-Ray Absorption
Marcel Walter1, Sebastien Elie Hadjadj1, Clara Trommer2
1Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
Summary
Spin-crossover (SCO) properties were investigated for thin films and dropcast samples. Substrate interactions limit SCO switching in thin films compared to dropcast samples.
Area of Science:
- Materials Science
- Chemistry
- Physics
Background:
- Spin-crossover (SCO) complexes exhibit distinct magnetic states.
- Understanding SCO behavior in thin films is crucial for device applications.
Purpose of the Study:
- To investigate the SCO properties of a dinuclear complex in (sub)-monolayer and thin film forms.
- To compare SCO behavior in thin films deposited on highly oriented pyrolytic graphite (HOPG) versus dropcast samples.
Main Methods:
- Ultrahigh vacuum liquid-jet deposition technique for thin film preparation.
- X-ray absorption spectroscopy (XAS) for SCO property analysis.
- Comparison with dropcast and bulk powder samples.
Main Results:
- Thin films show limited spin-switching probability (≈43% low-spin state at 80 K) compared to dropcast samples (≈66% low-spin state).
- Substrate-molecule interactions on HOPG restrict SCO properties in thin films.
- The soft-X-ray-induced excited spin-state trapping (SOXIESST) effect is observed, with light-induced high-spin fractions higher than SOXIESST-induced fractions.
Conclusions:
- Substrate interactions significantly influence SCO behavior in thin films.
- Dropcast samples retain SCO properties similar to bulk materials, unaffected by deposition solvent.
- The complex exhibits sensitivity to light, impacting its spin state.
Related Concept Videos
01:17Spin–Spin Coupling: One-Bond Coupling
912
Coupling interactions are strongest between NMR-active nuclei bonded to each other, where spin information can be transmitted directly through the pair of bonding electrons. While nuclei polarize their electrons to the opposite spins, the bonding electron pair has opposite spins. Configurations with antiparallel nuclear spins are expected to be lower in energy. When coupling makes antiparallel states more favorable, J is considered to have a positive value. The one-bond coupling constant, 1J,...
912
01:08NMR Spectroscopy: Spin–Spin Coupling
1.1K
The spin state of an NMR-active nucleus can have a slight effect on its immediate electronic environment. This effect propagates through the intervening bonds and affects the electronic environments of NMR-active nuclei up to three bonds away; occasionally, even farther. This phenomenon is called spin–spin coupling or J-coupling. Coupling interactions are mutual and result in small changes in the absorption frequencies of both nuclei involved. While nuclei of the same element are involved...
1.1K
01:20Spin–Spin Coupling: Two-Bond Coupling (Geminal Coupling)
914
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...
914
03:02Colors and Magnetism
11.4K
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...
11.4K
02:42Valence Bond Theory
8.4K
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...
8.4K
01:22Spin–Spin Coupling: Three-Bond Coupling (Vicinal Coupling)
1.0K
Vicinal or three-bond coupling is commonly observed between protons attached to adjacent carbons. Here, nuclear spin information is primarily transferred via electron spin interactions between adjacent C‑H bond orbitals. This generally favors the antiparallel arrangement of spins, so 3J values are usually positive.
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
The extent of coupling depends on the C‑C bond length, the two H‑C‑C angles, any electron-withdrawing substituents, and the dihedral angle between the...
1.0K