Investigations into the engineering of inorganic/organic solids: Hydrothermal synthesis and structure characterization of one-dimensional molybdenum oxide polymers

Abstract

Two one-dimensional intercalating molybdenum oxide polymers have been synthesized using different structure-directing units under specific hydrothermal conditions. MoO-O (NaNH4Mo3O10) was synthesized using tetramethylammonium hydroxide, and MoO-1(C6H18N2-Mo4O13) was synthesized using 1,6-hexanediamine. The two crystal structures have been determined by the single-crystal X-ray diffraction method. Both consist of bundles of parallel molybdenum oxide chains interspersed with metals or organic cations which play the role of intercalating agent in the host structure. The Mo has a 6+ valence state and distorted octahedral coordination. Mo-0 has orthorhombic symmetry (Pnma, No. 62) with a = 8.407(2) Å, b = 7.603(2) Å, and c = 14.350(3) Å. MoO-1 has triclinic symmetry (P1̄, No. 2) with a = 8.267(2) Å, b = 8.986(2) Å, c = 12.714(3) Å, α = 87.58(3)°, β = 76.48(3)°, γ = 67.97(3)°. The study suggests that the structures and properties of intercalation-type molybdenum oxide polymers can be engineered by incorporating the structure-directing units, acidity, and the hydrothermal conditions.