Synthesis and characterization of [Mn-3(ppi)(2)(mu-OAc)(4)(H2O)(2)]center dot 2MeOH unusual structural properties of a trinuclear oxygen-rich manganese complex

摘要

The trinuclear manganese(II) complex [Mn-3(ppi)(2)(mu-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).4H(2)O 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 P (1) over bar (no. 2), with a = 9.691(2), b = 10.683(2), c = 11.541(2) Angstrom, alpha = 63.19(3)degrees, beta = 67.47(3)degrees, gamma = 69.11(3)degrees, V = 960.2(3) Angstrom(3), and Z = 1. The binding mode of carboxylate in 1 represents a model for a transition state between symmetric syn,syn,anti-mu(2)-carboxolato-O- and syn,anti-mu(2)-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. [References: 34]