First cyano-bridged coordination polymers based on N,N’-chelated Ag(I) ions and octahedral rhenium(III) chalcocyanide clusters exhibiting unusually long-lived photoluminescence

Abstract

First examples of Ag(I)-containing coordination polymers based on octahedral rhenium(III) chalcocyanide clusters, namely [{Ag(bpy)}{Ag4(bpy)4(μ-CN)}{Re6Q8(CN)6}] (Q = S in 1 or Se in 2; bpy = 2,2′-bipyridine), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, elemental and thermogravimetric analysis, EDS, IR and luminescence spectroscopy. The compounds are isostructural, crystallize in the orthorhombic system (space group Pccn, Z = 4) and possess a rigid 3D framework structure built up from {Re6Q8(CN)6}4– cluster anions and two distinct types of Ag(I)-containing cationic units, mononuclear {Ag(bpy)}+ and tetranuclear {Ag4(bpy)4(μ-CN)}3+, all of which are interconnected through cyanide bridging. The supramolecular structures of 1 and 2 are supported by argentophilic Ag⋯Ag interactions, but surprisingly show very limited π-π stacking of the pyridine rings. Both compounds are highly emissive in red region showing the longest lifetimes hitherto reported for the solid samples of hexarhenium cluster compounds.