A Missing Structural Link in the Werner Series of Cobalt(III) Complexes: The Crystal Structure of Δ‐(–)589‐Tris(ethylenediamine)cobalt(III) Iodide Monohydrate

Alfred Werner's historic resolution of Δ/Λ‐[Co(en)3]3+ (where en = ethylenediamine) provided conclusive evidence for octahedral geometry coordination compounds and the first example of chirality in an inorganic molecule. Herein, we report the historically significant structure and absolute configuration of Δ‐(–)589‐tris(ethylenediamine) cobalt(III) iodide monohydrate, Δ‐[Co(en)3]I3 (1), the missing crystallographic piece in the series of [Co(en)3]3+ complexes. Complex 1 crystallizes in an orthorhombic space group P212121 with unit cell dimensions of a = 8.4016(10), b = 11.2573(13), c = 18.825(2) Å, V = 1780.4(4) Å3, and Z = 4. The absolute configuration of the complex cation [Co(en)3]3+ is Δ and the en ligands adopt a λλδ configuration.