Influences of secondary metal-ligand subunits on molybdenum oxide structures: The hydrothermal syntheses and structures of [M(tpytrz)₂Mo₄O₁₃] (M = Fe, Co, Ni, Zn; tpytrz = tripyridyltriazine), [Ni(tpytrz)Mo₂O₇] and [Zn₂(tpytrz)Mo₂O₈]

The hydrothermal reactions of the appropriate salts of the first row transition metal dipositive cations M′(II), MoO₃ and 2,4,6-tri(4-pyridyl)-1,3,5-triazine (tpytrz) yielded the bimetallic oxide hybrid solids [M′(tpytrz)₂Mo₄O₁₃] [M′ = Fe (1), Co (2), Ni (3), Zn (4)], [Ni(tpytrz)Mo₂O₇] (6) and [Zn₂(tpytrz)Mo₂O₈] (7) and the molecular compound [Ni(H₂O)₄-(Htpytrz)₂][Mo₈O ₂₆]·1.2H₂O (5·1.2H₂O). The isomorphous series 1-4 exhibits a two-dimensional bimetallic oxide network constructed from chains of corner-sharing Mo(VI) octahedra and tetrahedra, linked by {M′O₄N₂} octahedra. The inorganic layers are tethered by bidentate tpytrz ligands, each of which bonds to an M′ site of one layer and an octahedral {MoO₅N} site of an adjacent layer, with one pyridyl group adopting a pendant mode in the interlamellar region. In contrast, the structure of [Ni(tpytrz)Mo₂O₇] (6), while adopting the prototypical motif of alternating bimetallic oxide networks and bridging ligand domains, is characterized by an oxide layer constructed from bimolybdate units {Mo₂O₇}^2- linked through {NiO₄N₂} octahedra. Curiously, the {Zn₂Mo₂O₈} network of [Zn₂(tpytrz)Mo₂O₈] (7) is constructed from {MoO₄} tetrahedra linked through binuclear units of edge-sharing {ZnO₄N} square pyramids.