Solvothermal synthesis and characterization of intercalated iron-sulfides
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Recent interest in the intercalation chemistry of layered iron chalcogenides has led to the discovery of many new compounds with magnetic properties ranging from simple paramagnetism to antiferromagnetism and superconductivity. The parent superconducting compounds, mackinawite-FeS and β-FeSe, are composed of iron-chalcogen layers stacked via van der Waals forces. These relatively weak interlayer forces make iron chalcogenides suitable candidates for intercalation studies. Numerous reports have shown that drastic changes to magnetic behavior can arise from intercalation by a variety of species, such as, metal hydroxides, metal-amine complexes, and neutral organic molecules. Although a wide variety of intercalates are possible, their diversity can pose a challenge when trying to assess direct relationships between the intercalated species and bulk properties. One approach towards a more systematic study is to intercalate iron-chalcogenides with transition metal complexes and subsequently tune the complex while assessing structural and property variations. This report follows the solvothermal synthesis and characterization of intercalated iron sulfides. The compound [Fe8S10]Fe(en)3·en0.5 (en = ethylenediamine) is explored to show that coordination complexes and free ligand can intercalate in tandem. A pseudo-polymorph, [Fe9.4S10][Fe(en)3]0.6·en¬1.2 is discovered, and its structure is determined through systematic comparison to [Fe8S10]Fe(en)3·en0.5. The Fe-S-en system is used as a model to guide characterization of related Fe-S-L phases (L = ethylenediamine, 1,2-diaminopropane, 2,2’-bipyridine, dimethylformamide).