Polymorph of {2-[(2-hydroxyethyl)iminiomethyl]phenolato-κO}dioxido{2-[(2-oxidoethyl)iminomethyl]-phenolato-κ3O,N,O′}molybdenum(VI)

A second polymorphic form (form I) of the previously reported compound {2-[(2-hydroxyethyl)iminiomethyl]phenolato-kappa O}dioxido{2-[(2-oxidoethyl) iminomethyl] phenolato-kappa O-3,N,O '}molybdenum(VI) (form II), [Mo(C9H9NO2)O-2(C9H11NO2)], is presented. The title structure differs from the previously reported polymorph [Glowiak, Jerzykiewicz, Sobczak & Zidlkowski (2003). Inorg. Chim. Acta, 356, 387392] by the fact that the asymmetric unit contains three molecules linked by O-H center dot center dot center dot O hydrogen bonds. These trimeric units are further linked through O-H center dot center dot center dot O hydrogen bonds to form a chain parallel to the [111] direction. As in the previous polymorph, each molecule is built up from an MoO22+ cation surrounded by an O,N,O'-tridentate ligand (O-C6H4-CH=NCH2CH2O-) and weakly coordinated by a second zwitterionic ligand (O-C6H4CH=N+HC2H4OH). All complexes are chiral with the absolute configuration at Mo being C or A. The main difference between the two polymorphs results from the alternation of the chirality at Mo within the chain.