Axial Mn–CCN Bonds of Cyano Manganese(II) Porphyrin Complexes: Flexible and Weak?

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• 作者：Mingrui He ; Xiangjun Li ; Yanhong Liu ; Jianfeng Li
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：June 20, 2016
• 年：2016
• 卷：55
• 期：12
• 页码：5871-5879
• 全文大小：453K
• 年卷期：0
• ISSN：1520-510X

文摘

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–C_CN bonds, which is contrasted to the isoelectronic Fe(III)–C_CN 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.