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Isolation of a trigonal bipyramidal Mn(II) diradical complex with an intermediate spin state (S = 3/2)
Sujit Das1, Björn Schwarz2, Kartik Chandra Mondal1
1Department of Chemistry, Indian Institute of Technology Madras, Chennai, 600036, Tamil Nadu, India. csdkartik@iitm.ac.in.
Dalton Transactions (Cambridge, England : 2003)
|July 2, 2026
Summary
Researchers isolated a rare manganese(II) complex with an intermediate spin state (SMn2+ = 3/2). This unprecedented Mn(II)-bis(dithiolene-radical) complex exhibits unique magnetic properties and structural characteristics.
Area of Science:
- Inorganic Chemistry
- Coordination Chemistry
- Magnetochemistry
Background:
- Isolation of manganese(II) complexes with intermediate spin states (SMn2+ = 3/2) is rare.
- Previous studies only speculated on such species, proposing mixed spin states in related manganese anions.
Purpose of the Study:
- To report the isolation and structural characterization of a novel Mn(II)-bis(dithiolene-radical) complex.
- To investigate the spin state and magnetic properties of the synthesized complex.
Main Methods:
- X-ray crystallography for structural characterization.
- Magnetic susceptibility and Electron Paramagnetic Resonance (EPR) spectroscopy for spin state determination.
- XPS, IR, UV-Vis, and Raman spectroscopy for further characterization.
- Cyclic voltammetry for redox property investigation.
Main Results:
- An unprecedented Mn(II)-bis(dithiolene-radical) complex (1) was successfully isolated.
- The complex features a Mn(II) center with an intermediate spin state (SMn2+ = 3/2) in a distorted trigonal bipyramidal geometry.
- Antiferromagnetic coupling was observed between the Mn(II) center and the dithiolene ligands.
Conclusions:
- The study reports the first isolation of a Mn(II) complex with an intermediate spin state (SMn2+ = 3/2).
- The complex exhibits unique structural and magnetic properties due to antiferromagnetic coupling.
- Further investigations into its redox behavior were conducted.
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