Axial Mn-CCN Bonds of Cyano Manganese(II) Porphyrin Complexes: Flexible and Weak?
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Updated: Mar 20, 2026

Preparation of SNS CobaltII Pincer Model Complexes of Liver Alcohol Dehydrogenase
Published on: March 19, 2020
Mingrui He1, Xiangjun Li1, Yanhong Liu2
1College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences , Yanqi Lake, Huairou District, Beijing 101408, China.
Abstract:
Three five-coordinate high-spin (cyano)manganese(II) complexes, utilized tetraphenylporphyrin (TPP), tetratolylporphyrin (TTP), and tetramesitylporphyrin (TMP) as ligands, are prepared and studied by single-crystal X-ray, FT-IR, UV-vis, and EPR spectroscopies. The crystal structure studies revealed noteworthy structural features including unexpectedly wide tilting angles of the axial Mn-CCN bonds, which is contrasted to the isoelectronic Fe(III)-CCN bonds. Solid-state EPR measurements (90 K) and simulations are applied to obtain the ZFS parameters (D, E, and E/D (λ)), which are compared to Mn(II) porphyrin analogues of hemes to understand the ligand field of the cyanide. The solution EPR studies gave new insights into the chemical equilibrium of four- and five-coordinate species, which has been monitored by UV-vis spectroscopy.
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