Hydrothermal synthesis, structural chemistry, and magnetic properties of materials of the MII/Triazolate/Anion family, where MII = Mn, Fe, and Ni

Hydrothermal chemistry has been exploited in the preparation of a series of manganese(II), iron(II), and nickel(II) triazolate frameworks, [Mn-7(trZ)(8)(CH3CO2)(4)(OH)(2)]center dot 2.5H(2)O (1 center dot 2.5H(2)O), [Mn-5(Htrz)(2)(SO4)(4)(OH)(2)] (2), [Fe-5(Htrz)(2)(SO4)(4)(OH)(2)[ (3), [Fe-3(Htrz)(3)(HSO4)(SO4)(2)(OH)]center dot H2O (4 center dot H2O), [Ni-3(trz)(3)(OH)(3)(H2O)(4)]center dot 5H(2)O (5 center dot 5H(2)O), and [Ni-3(trz)(5)(OH)]center dot 2.5H(2)O (6-2.5H(2)O). The materials all exhibit three-dimensional structures, reflecting the tendency of triazole/triazolate ligands to bridge multiple metal sites. A prominent characteristic of the structures is the presence of embedded metal clusters as building blocks: heptanuclear Mn-II units in 1, pentanuclear M-II sites in 2 and 3, and trinuclear M-II clusters in 4 and 5. The presence of the pentanuclear and trinuclear clusters of magnetic metal cations in 2-5 is reflected in the unusual magnetic characteristics of these materials, all of which exhibit spin frustration. The compound 5-5H(2)O reversibly clesorbs/sorbs solvent. However, the dehydrated phase does not adsorb methanol, N-2, O-2, or H-2, presumably as a consequence of the highly polar void volume and the narrow channels connecting the larger cavities of the, void structure.