Synthesis and Characterization of [Mn3(ppi)2(μ‐OAc)4(H2O)2] · 2MeOH — Unusual Structural Properties of a Trinuclear Oxygen‐Rich Manganese Complex

The trinuclear manganese(II) complex [Mn3(ppi)2(μ‐OAc)4(H2O)2]·2MeOH (1) (Hppi = 2‐pyridylmethyl‐2‐hydroxyphenylimine) is prepared by dissolving two equivalents of Hppi (from the Schiff Base reaction of aminophenol and pyridine‐2‐carboxaldehyde) in acetonitrile and three equivalents of Mn(OAc)2·4H2O in methanol and combining both solutions. The resulting red precipitate was recrystallized to yield red crystals suitable for single crystal X‐ray diffraction. Compound 1 crystallizes in the triclinic space group P1¯ (no. 2), with a = 9.691(2), b = 10.683(2), c = 11.541(2)Å, α = 63.19(3)°, β = 67.47(3)°, γ = 69.11(3)°, V = 960.2(3)Å3, and Z = 1. The binding mode of carboxylate in 1 represents a model for a transition state between symmetric syn, syn, anti‐μ2‐carboxolato‐O‐ and syn, anti‐μ2‐carboxylato‐O, O′‐coordination. Therefore a rare binding mode for the phenomenon of the carboxylate shift is realized. Furthermore the complex is stabilized by a distinctive hydrogen bonding pathway.