Primary Amine-Functionalized Ligand Substitution and Biotinylation of Co(III) for Ligand-Anchored Artificial Metalloenzymes

Abstract

Group IX metals in the +3-oxidation state can be incorporated into [Cp*MCl₂]₂ complexes for the design and synthesis of new artificial metalloenzymes for biological functions. While previous studies have applied the more costly and less abundant rhodium- or iridium-(III) metals, use of a cobalt(III) metal center provides a low-cost route to preparing artificial metalloenzymes. Herein, a new metal cofactor is acquired through synthesis of a primary amine-functionalized Cp* ligand and subsequent complexation with a Co(III) metal center. Key signals corresponding to the Cp* and NH₂ groups are visible by Fourier Transform Infrared spectroscopy where the aromatic signal of the Cp* and the stretching mode of the primary amine are present in their characteristic regions, supporting the formation of a tentatively assigned bis[dichloro-ⴄ⁵(1-ethylamine-2,3,4,5-tetramethylcylopentadienyl)cobalt-(III)]. Biotinylation of this complex would allow for pairing with engineered proteins to foster catalytic C–H activation, improving enzymatic processes in biological and biochemical applications.