Combining oximes with azides to create a novel 1-D [NaCoIII2] system: synthesis, structure and solid-state NMR

Abstract

The synthesis and structure of a novel complex with the formula [NaCo^III₂(dmo)₂(μ-N₃)₃(N₃)₂]_∞, 1, are reported. Complex 1 was synthesized from the reaction of 1-(dimethylamino)propan-2-one oxime (Hdmo), CoCl₂·6H₂O, and NaN₃ in MeOH. It crystallizes in the monoclinic space group C2/c. The molecular structure consists of one Na^I and two Co^III ions bridged by two oxime ligands, two end-to-end azide and three end-on azide anions. The units are linked, forming a 1-D chain. This complex was characterized by UV-Vis spectroscopy where the data confirm the presence of low-spin Co^III ions. Solid-state ²³Na NMR experiments indicate the presence of one magnetically unique site in the repeating unit, that sample purity in the bulk powdered form is high, and that it possesses microcrystalline order. Solid-state ⁵⁹Co NMR experiments at ultra-high field (B₀ = 21.1 T) are in agreement with the structure obtained through X-ray crystallography where the Co^III ions are coordinated to five nitrogen atoms as well as an oxygen atom.