Tuning Photoluminescent Properties of Silver(I)-Based Coordination Networks through their Supramolecular Interactions

Eight novel luminescent silver(I)-based coordination networks have been self-assembled from two flexible dicyanomethylene ligands bearing diethylene (L1) and triethylene glycol (L2) spacers and silver salts (AgClO₄ or AgBF₄) in dichloromethane/toluene or dichloromethane/benzene solvents. Single-crystal X-ray diffraction reveals a variety of geometries around the silver(I) ion, resulting in mono-, bi-, and tetranuclear networks with rare topologies. The coordination networks show two-dimensional architectures through coordination of the cyano and glycolic groups to the silver(I) ions. The three-dimensional supramolecular arrangement is formed through weak π···π and Ag···π interactions as well as hydrogen bonds between water molecules and ClO₄^- and BF₄^- counterions. The silver(I)-based coordination networks display green to yellow emissions in the solid state, with quantum yields (φ_em) varying from 1.1 to 8.5%. The emission properties are attributed to intraligand charge transfer and metal-perturbed intraligand transitions. Supramolecular interactions, such as Ag···π and π···π interactions, play an important role in the photophysical properties of these compounds.