(C6H15N3)1.3(NH4)1.5H1.5In3SnS8: a layered metal sulfide based on supertetrahedral T2 clusters with photoelectric response and ion exchange properties

Abstract

A new layered metal sulfide, namely (C₆H₁₅N₃)_1.3(NH₄)_1.5H_1.5In₃SnS₈ (1, C₆H₁₅N₃ = N-(2-aminoethyl) piperazine), has been solvothermally synthesized and characterized. Compound 1 crystallizes in the monoclinic space group C2/c. Its structure features a two-dimensional layer of {In₃SnS₈}_n³ⁿ⁻ with the (4,4) topology net, which is formed by interlinking supertetrahedral T2 clusters as secondary building units. Band structure calculations revealed that 1 had a band gap of 2.7 eV. The photoelectric response of 1 showed steady and reversible on/off cycles with an “on” state of 121.13 nA cm⁻². Moreover, the activation of 1 by replacing the sluggish organic cations with harder K⁺ ions endowed the material with improved adsorption performances for Sr²⁺ ions from aqueous solutions.