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

A decanuclear gold­(I)–sulfido complex, [(L^H)₄Au₁₀S₄]­Cl₂ (L^H-Au₁₀S₄-Cl, where L^H = 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 L^H-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 L^H-Au₁₀S₄-Cl exhibit remarkable solvatochromic luminescence in the presence of benzene and cyclohexane. Notably, due to the size confinement of the lattice cavities, the L^H-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.