Dual Emissive Gold(I)–Sulfido Cluster Framework Capable of Benzene–Cyclohexane Separation in the Solid State Accompanied by Luminescence Color Changes

Abstract

A decanuclear gold(I)–sulfido complex, [(LH)4Au10S4]Cl2 (LH-Au10S4-Cl, where LH = 4,5-bis(diphenylphosphanyl)-2H-1,2,3-triazole), assembled from the reaction of H2S with the chlorogold(I) precursor obtained from the click reaction of [dppa(AuCl)2] (where dppa = 1,2-bis(diphenylphosphino)acetylene) with NaN3, is shown to display a bright dual green and red emission in the solid state. Single crystal X-ray diffraction (SCXRD) studies indicate a gold(I) cluster-based framework assembled through intermolecular halogen···hydrogen bonds as well as other weak interactions. The framework of LH-Au10S4-Cl is found to display high stability toward solvent molecules, with capability to encapsulate solvent molecules, such as benzene and cyclohexane, inside the crystal lattice voids via a single-crystal-to-single-crystal (SCSC) transformation. With different degrees of influence on the dual green and red emission, crystalline solids of LH-Au10S4-Cl exhibit remarkable solvatochromic luminescence in the presence of benzene and cyclohexane. Notably, due to the size confinement of the lattice cavities, the LH-Au10S4-Cl solids exhibit a high selectivity (>95%) toward benzene in a mixture of equimolar concentration of benzene and cyclohexane. This work has demonstrated the promising capability of gold(I)–sulfido cluster frameworks to serve as luminescent functional materials for the separation of benzene and cyclohexane.