A trinuclear silver coordination polymer from a bipyridine bis-urea macrocyclic ligand and silver triflate

We report herein the construction of a metal organic polymeric framework from a bipyridine macrocyclic ligand and silver triflate. The ligand consists of two triazinanone protected urea groups and two bipyridine units that coordinate with the Ag atoms in crystallographically different manners. In a unit cell of the crystal there are three independent Ag atoms and two ligands that form a basket shape enclosing two of the silver atoms. Two silver atoms are 3.13 Å apart, suggesting an Ag–Ag bond interaction. We probe the characteristics of the complex by solid-state spectroscopic techniques including UV–vis, Fluorescence, IR, NMR and Raman spectroscopy. The Raman spectra suggest that a bonding interaction indeed exists between two Ag atoms and that this proximity is not merely a packing artifact. A third silver atom helps organize these boxes into an elongated polymeric chain, and ultimately these chains stack into layers with the adjacent chains to give an intriguing supramolecular structure.

Graphical abstractA trinuclear complex Ag3(C38H46N10O2)2(CF3SO3)3(CH2Cl2)3(CH3OH)0.5 was generated from the reaction of Ag(CF3SO3) and a bipyridine containing macrocyclic bis-urea (1). The structure features a basket enclosing two silver atoms at 3.13 Å distance. This argentophilic interaction is supported by Raman spectroscopy. A third silver atom organizes these baskets into a polymeric chain.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A trinuclear complex was generated from silver triflate and a bipyridine macrocyclic bis-urea. ► The structure features two ligands that form a basket enclosing two of the silver atoms at 3.13 Å distance. ► An argentophilic interaction is supported by Raman spectroscopy.