A High‐Valent Manganese(IV)–Oxo–Cerium(IV) Complex and Its Enhanced Oxidizing Reactivity

• Published in: Angewandte Chemie International Edition 2019-11, Vol.58 (45), p.16124-16129
• Main Authors: Karmalkar, Deepika G., Sankaralingam, Muniyandi, Seo, Mi Sook, Ezhov, Roman, Lee, Yong‐Min, Pushkar, Yulia N., Kim, Won‐Suk, Fukuzumi, Shunichi, Nam, Wonwoo
• Format: Article
• Language: English
• Subjects: Ammonium; Ammonium nitrate; Binding; biomimetic chemistry; Cerium; Cerium ammonium nitrate; Chemical properties; electron transfer; high-valent manganese–oxo; Intermediates; Manganese; Metal ions; Organic chemistry; Oxidation; oxygen atom transfer; redox-active metal ions; Resonance; Spectroscopy
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201910032

A mononuclear nonheme manganese(IV)–oxo complex binding the Ce4+ ion, [(dpaq)MnIV(O)]+–Ce4+ (1‐Ce4+), was synthesized by reacting [(dpaq)MnIII(OH)]+ (2) with cerium ammonium nitrate (CAN). 1‐Ce4+ was characterized using various spectroscopic techniques, such as UV/Vis, EPR, CSI‐MS, resonance Raman, XANES, and EXAFS, showing an Mn−O bond distance of 1.69 Å with a resonance Raman band at 675 cm−1. Electron‐transfer and oxygen atom transfer reactivities of 1‐Ce4+ were found to be greater than those of MnIV(O) intermediates binding redox‐inactive metal ions (1‐Mn+). This study reports the first example of a redox‐active Ce4+ ion‐bound MnIV‐oxo complex and its spectroscopic characterization and chemical properties. A mononuclear nonheme manganese(IV)–oxo complex binding the Ce4+ ion, [(dpaq)MnIV(O)]+–Ce4+, was synthesized and characterized. It has a Mn−O bond distance of 1.69 Å with a Raman band at 675 cm−1. Electron transfer (ET) and oxygen atom transfer (OAT) reactivities of the [(dpaq)MnIV(O)]+‐Ce4+ complex were found to be greater than those of MnIV(O) complexes binding redox‐inactive metal ions, such as Ca2+ and Sc3+.