The first‐row transition‐metal series of tris(ethylenediamine) diacetate complexes [M(en)3](OAc)2 (M is Mn,Fe, Co,Ni, Cu,and Zn)

The crystal structures of the first‐row transition‐metal series of tris(ethylenediamine‐κ²N ,N ′)metal(II) diacetate, [M (C₂H₈N₂)₃](CH₃CO₂)₂, with M = Mn, Fe, Co, Ni, Cu, and Zn, are reported. The complexes are all isostructural, crystallizing in a centrosymmetric triclinic cell and possessing an asymmetric unit composed of one [M (en)₃]²⁺ cation and two symmetrically independent acetate anions. In the unit cell, the two complex cations are inversion‐generated enantiomers, possessing the energetically favoured Δ(λλλ) and Λ(δδδ) configurations. The complex cations and acetate anions combine through a series of N—H…O hydrogen bonds to generate a three‐dimensional network in the crystals. The other notable feature of the series is a significant Jahn–Teller distortion for the d ⁹ Cu²⁺ complex.