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.