Oxidation of cobalt(ii) bispidine complexes with dioxygen*

• Verfasst von: Comba, Peter [VerfasserIn]
• Verfasst von: Pokrandt, Bianca [VerfasserIn]
• Verfasst von: Wadepohl, Hubert [VerfasserIn]
• Titel: Oxidation of cobalt(ii) bispidine complexes with dioxygen*
• Verf.angabe: Peter Comba, Bianca Pokrandt and Hubert Wadepohl
• Umfang: 5 S.
• Fussnoten: Gesehen am 28.08.2018
• Titel Quelle: Enthalten in: Australian journal of chemistry
• Jahr Quelle: 2017
• Band/Heft Quelle: 70(2017), 5, S. 576-580
• ISSN Quelle: 1445-0038
• DOI: doi:10.1071/CH16674
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1580437060

Abstract

Bispidine (3,7-diazabicyclo[3.3.1]nonane) ligands, derivatives of diazaadamantane, possess a very rigid backbone and have a high degree of pre-organization for cis-octahedral coordination geometries. Despite their rigidity, they exert a flexible coordination sphere, resulting in stable complexes with a variety of metal ions in various oxidation states. Due to the known high III/II redox potentials of their cobalt complexes, the CoII bispidine complexes are generally resistant to oxidation by dioxygen. Discussed in the present study are various CoII bispidine complexes with tetra- and pentadentate bispidines, with one of these complexes shown to be unstable under aerobic conditions. The decay process has been identified as an oxidative elimination of the 2-methylene pyridine substituent at one of the tertiary amine donors, resulting in picolinate, which is found coordinated to a CoIII product, where the dealkylated N-donor remains unprotonated. The mechanism of this interesting reaction has been studied, and details of the resulting structure of the product complex are discussed.