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.

A 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 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.