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, [(L^H)₄Au₁₀S₄]Cl₂ (<b>L^H-Au₁₀S₄-Cl</b>, where L^H = 4,5-bis(diphenylphosphanyl)-2<i>H</i>-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 <b>L^H-Au₁₀S₄-Cl</b> 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 <b>L^H-Au₁₀S₄-Cl</b> exhibit remarkable solvatochromic luminescence in the presence of benzene and cyclohexane. Notably, due to the size confinement of the lattice cavities, the <b>L^H-Au₁₀S₄-Cl</b> 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.