Related Experiment Video
Updated: Jun 1, 2026

Preparation of SNS Cobalt(II) Pincer Model Complexes of Liver Alcohol Dehydrogenase
Published on: March 19, 2020
Bis[bis-(1-ethyl-benzimidazol-2-ylmeth-yl) ether]cobalt(II) dipicrate dimethyl-formamide disolvate
Huilu Wu1, Ruirui Yun, Tao Sun
1School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou 730070, People's Republic of China.
Abstract:
In the title complex, [Co(C(20)H(22)N(4)O)(2)](C(6)H(2)N(3)O(7))(2)·2C(3)H(7)NO, the Co(II) ion is coordinated by two sets of two N atoms and an O atom from two independent tridendate ligands in a distorted octa-hedral coordination environment. There are significant differences between chemically equivalent coordination bond lengths. The crystal structure is stabilized by weak inter-molecular C-H⋯O hydrogen bonds and weak π-π stacking inter-actions [centroid-centroid distance 3.495 (1) Å]. In one of the anions one nitro group is rotationally disordered about the C-N bond with refined occupancies of 0.524 (8) and 0.476 (8).
Related Concept Videos
Colors 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 eye.
Valence Bond Theory
Formation of Complex Ions
Structural 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, SCN− can be...
Crystal 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...

