Silver(I)–Organic Frameworks Showing Remarkable Thermo‑, Solvato- And Vapochromic Phosphorescence As Well As Reversible Solvent-Driven 3D-to-0D Transformations

A series of isoreticular Ag­(I) luminescent metal–organic frameworks (LMOFs), {[Ag2L2(CH3CN)2]­(X)2} n (X = ClO4, OTf, and BF4), has been designed, exploiting diphenyl­(2-pyrazyl)­phosphine (L) as a multidentate linker. At ambient temperature, these compounds emit a bright long-lived phosphorescence (λem = 545–555 nm) with a quantum efficiency as high as 22%, which is the highest value for phosphorescent Ag-LMOFs. The prepared LMOFs also exhibit pronounced thermochromic luminescence, reversibly changing their emission color in the 300–77 K range. These LMOFs also demonstrate prominent solvato- and vapochromic luminescence, which manifest as a reversible change in the emission properties during the removal and recovery of the coordinated and guest MeCN molecules, respectively. Moreover, we have discovered a reversible solvent-driven 3D-to-0D transformation of the framework {[Ag2L2(CH3CN)2]­(ClO4)2} n into a brightly emissive complex [Ag4L4(ClO4)4]. To the best of our knowledge, the compounds obtained are the first Ag-LMOFs that exhibit thermo-, solvato-, and vapochromic luminescence.