Related Experiment Video
Updated: Jul 1, 2026
09:01
High-resolution Thermal Micro-imaging Using Europium Chelate Luminescent Coatings
Published on: April 16, 2017
59Co Thermal Sensitivity in Co(III) Trisdithiocarbamate Complexes
Ökten Üngör1, Sara Termos2,3, Robert W Schurko2,3
1Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210, United States.
Inorganic Chemistry
|March 27, 2025
Summary
Researchers studied cobalt complexes with dithiocarbamate ligands to understand temperature sensitivity for magnetic resonance imaging. Ligand structure influences thermal sensitivity, but quadrupolar relaxation in solution limits temperature-sensing resolution.
Area of Science:
- Coordination Chemistry
- Nuclear Magnetic Resonance (NMR) Spectroscopy
- Materials Science
Background:
- Accurate noninvasive temperature mapping is crucial for molecular imaging.
- Cobalt(III) complexes with dithiocarbamate ligands are potential candidates for temperature-sensitive probes.
- Understanding the relationship between ligand structure and temperature sensitivity is essential for developing novel probes.
Purpose of the Study:
- To investigate the effect of heavy-donor-atom dithiocarbamate ligands on the variable-temperature 59Co NMR properties of Cobalt(III) complexes.
- To correlate solid-state vibrational modes with observed thermal sensitivities.
- To elucidate the factors contributing to line broadening in solution-phase 59Co NMR spectra.
Main Methods:
- Synthesis and characterization of six Cobalt(III) complexes with varying dithiocarbamate ligands.
- Variable-temperature 59Co NMR spectroscopy to determine chemical shift temperature dependences.
- Solid-state Raman spectroscopy to analyze vibrational modes.
- Solution-state NMR relaxation measurements (T1 and T2*) to study line width contributions.
Main Results:
- The 59Co chemical shift exhibited temperature dependences ranging from 1.17(3) to 1.73(4) ppm/°C, influenced by ligand substituents.
- A positive correlation was observed between the number of Raman-active Co-S6 vibrational modes and higher thermal sensitivities.
- Short spin-lattice relaxation times (T1 ≈ 200 μs) in solution were measured.
- Solution-phase line widths were primarily attributed to quadrupolar relaxation processes.
Conclusions:
- Dithiocarbamate ligand structure significantly impacts the temperature sensitivity of Cobalt(III) complexes.
- Solid-state vibrational modes provide insights into the thermal sensitivity mechanism.
- Quadrupolar relaxation in solution limits the resolution of temperature-sensing applications, necessitating further investigation for improved probe design.
More Related Videos
Related Concept Videos
02:42Valence Bond Theory
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...
02:58Crystal Field Theory - Octahedral Complexes
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...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
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,...
03:02Colors and Magnetism
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 eye.
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 eye.
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
01:16Thermal Sigmatropic Reactions: Overview
Sigmatropic rearrangements are a class of pericyclic reactions in which a σ bond migrates from one part of a π system to another. These are intramolecular rearrangements where the total number of σ and π bonds remain unchanged.
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred to as...
Sigmatropic shifts are classified based on an order term [i, j ], where i and j indicate the number of atoms across which each end of the σ bond migrates. Below are examples of a [3,3] sigmatropic shift in 1,5-hexadiene, referred to as...