Related Experiment Video
Updated: Apr 26, 2026
Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Single-molecule magnetism in a pentacoordinate cobalt(II) complex supported by an antenna ligand
Cyril Rajnák1, Ján Titiš, Olaf Fuhr
1Department of Chemistry, FPV, University of SS Cyril and Methodius , 917 01 Trnava, Slovakia.
Abstract:
Pentacoordinate complex [CoL(3)Cl2] with a tridentate antenna-like ligand L(3) forms a dimer held by short π-π stacking with head-to-head contacts at 3.4 Å. The direct-current (dc) magnetic susceptibility and magnetization data confirm weak ferromagnetic interaction and a large-magnetic anisotropy, D/hc = 150 cm(-1) and E/hc = 11.6 cm(-1). The system shows superparamagnetic behavior at low temperature that depends upon the applied magnetic field. At Bdc = 0.2 T, a low-frequency peak at the out-of-phase susceptibility is seen (ν ∼ 0.3 Hz), whereas the onset of the second peak appears at ν > 1500 Hz, indicating the existence of two slow relaxation processes.
Related Concept Videos
03:02Colors and Magnetism
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...
02:42Valence Bond Theory
02:51Metal-Ligand Bonds
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...
02:58Crystal Field Theory - Octahedral Complexes
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...
02:34Structural Isomerism
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,...
01:31Ferromagnetism