Amine-templated one-dimensional metal sulfates including a mixed-Valent Fe compound with a half-kagome structure

Abstract

Organically templated metal sulfates are relatively new. Six amine-templated transition-metal sulfates with different types of chain structures, including a novel iron sulfate with a chain structure corresponding to one half of the kagome structure, were synthesized by hydro/solvothermal methods. Amongst the one-dimensional metal sulfates, [C₁₀N₂H₁₀][Zn(SO₄)Cl₂] (1) is the simplest, being formed by corner-linked ZnO₂Cl₂ and SO₄ tetrahedra. [C₆N₂H₁₈][Mn(SO₄)₂(H₂O)₂] (2) and [C₂N₂H₁₀][Ni(SO₄)₂(H₂O)₂] (3) have ladder structures comprising four-membered rings formed by SO₄ tetrahedra and metal-oxygen octahedra, just as in the mineral kröhnkite. [C₄N₂H₁₂][V^III(OH)(SO₄)₂]·H₂O (4) and [C₄N₂H₁₂][VF₃(SO₄)] (5) exhibit chain topologies of the minerals tancoite and butlerite, respectively. The structure of [C₄N₂H₁₂][H₃O][Fe^IIIFe^II F₆(SO₄)] (6) is noteworthy in that it corresponds to half of the hexagonal kagome structure. It exhibits ferrimagnetic properties at low temperatures and the absence of frustration, unlike the mixed-valent iron sulfate with the full kagome structure.