Synthesis and characterization of a formal 21-electron cobaltocene derivative

• Published in: Nature communications 2023-09, Vol.14 (1), p.4979-4979, Article 4979
• Main Authors: Takebayashi, Satoshi, Ariai, Jama, Gellrich, Urs, Kartashov, Sergey V., Fayzullin, Robert R., Kang, Hyung-Been, Yamane, Takeshi, Sugisaki, Kenji, Sato, Kazunobu
• Format: Article
• Language: English
• Subjects: 119/118; 140/131; 140/58; 639/638/263/406/910; 639/638/263/406/939; 639/638/911/406/910; Bonding strength; Carbon; Catalysis; Chemical bonds; Chemical synthesis; Chemistry; Cobalt; Configurations; Coordination; Deviation; Electron spin; Humanities and Social Sciences; Metallocenes; multidisciplinary; Organometallic compounds; Science; Science (multidisciplinary); Transition metals
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-40557-7

Metallocenes are highly versatile organometallic compounds. The versatility of the metallocenes stems from their ability to stabilize a wide range of formal electron counts. To date, d -block metallocenes with an electron count of up to 20 have been synthesized and utilized in catalysis, sensing, and other fields. However, d -block metallocenes with more than formal 20-electron counts have remained elusive. The synthesis and isolation of such complexes are challenging because the metal–carbon bonds in d -block metallocenes become weaker with increasing deviation from the stable 18-electron configuration. Here, we report the synthesis, isolation, and characterization of a 21-electron cobaltocene derivative. This discovery is based on the ligand design that allows the coordination of an electron pair donor to a 19-electron cobaltocene derivative while maintaining the cobalt–carbon bonds, a previously unexplored synthetic approach. Furthermore, we elucidate the origin of the stability, redox chemistry, and spin state of the 21-electron complex. This study reveals a synthetic method, structure, chemical bonding, and properties of the 21-electron metallocene derivative that expands our conceptual understanding of d -block metallocene chemistry. We expect that this report will open up previously unexplored synthetic possibilities in d -block transition metal chemistry, including the fields of catalysis and materials chemistry. The synthesis and isolation of d-block metallocenes with more than 18-electron is challenging since metal–carbon bonds become weaker with increasing deviation from the 18-electron configuration. Here the authors report a formal 21-electron cobaltocene derivative by coordination of a two-electron donor to a 19-electron cobaltocene derivative while maintaining the cobalt-carbon bonds.