[NH3CH3]4[In4SbS9SH]: a novel methylamine-directed indium thioantimonate with Rb+ ion-exchange property

Abstract

The protonated methylamine was successfully used to direct the formation of one novel indium thioantimonate compound, namely, [NH₃CH₃]₄[In₄SbS₉SH] (1), whose structure features a three-dimensionally microporous framework based on the linkage of a T2 {In₄S₉SH} cluster and a {SbS₃} pyramid. Detailed ion-exchange reactions performed on the sample of 1 demonstrated its high selectivity for Rb⁺ ion adsorption, as well as the significant role of the pore size directed by the organic amine cation on ion-exchange selectivity. Under the time-dependent Rb⁺-exchange treatments, compound 1 exhibited framework flexibility, in which the increasing exchange yields accompanied the gradual contraction of its unit cell.