Cobaloxime derivatives: synthesis and spectroscopic studies of alpha-furilglyoximate of cobalt (III), X-ray structure of bis(thiourea)bis(alpha-furilglyoximato)cobalt(III) nitrate

a-Furilglyoxime (H₂afdo) complexes of cobalt(III) were used to synthesize H₂afdo-cobaloximes with thiourea, triphenylphosphine, and aniline astrans-axial ligands. Encapsulation of the H-bonded species with BF₃:OEt₂ resulted in stable BF₂-capped macrocycles which mimic the central metal core of the biological molecules such as vitamin B₁₂ etc. Solution chemistry and spectroscopic measurements of the BF₂-macrocycles as well as H-bonded cobaloximes revealed six-coordinated cobalt(III) as the central atom and a short hydrogen bond in the case of latter. X-Ray structure of a representative complex [Co(Hafdo)₂(thiourea)₂]NO₃ (Haldo=a-furilglyoxime anion) confirmed a pseudo-octahedral geometry around cobait(III) with thiourea bonded to axial positions. The oxygen atoms of furyl groups are not involved in any kind of bonding and the overall structure of the complex differs from that of the H₂dmg-cobaloximes (H₂dmg=dimethylglyoxime).