Microporous layered tin sulfide, SnS-1: molecular sieve or intercalant?

Abstract

The results of a detailed study of the structure, thermal/pressure stability, ion-exchange, amine intercalation and adsorption property relations, of microporous layered tin(iv) sulfides A₂Sn₃S₇ , denoted SnS-1, where A=tetramethylammonium (TMA), quinuclidinium (QUIN), or tert-butylammonium (TBA), are reported and comparisons are made to zeolites and layered metal sulfides. The thermal stability of the materials indicates potential for the removal of void filling organic template without affecting the integrity of the lattice. The sensitivity of the materials to applied pressure is found to depend on the nature of the occluded template. Aqueous ion-exchange and gas-phase exchange by amines are observed in SnS-1 templated with the tertiary ammonium cation. This allows for an intercalation-like process similar to the layered chalcogenides. Adsorption isotherms for SnS-1 show it to exclude gaseous species of kinetic diameter >3.4 Å, thus acting as a molecular sieve like zeolites and showing potential for catalysis, separation and chemical sensing applications.