Heteroleptic complexes of silver(I) featuring 4′-hydroxy- and 4′-(2-furyl)-2, 2′:6′, 2″-terpyridine: An easy route for synthesis of silver nanoparticles

Abstract

New coordination complexes of silver(I) containing triphenylphosphine and 4′-hydroxy-2,2′:6′,2″-terpyridine (tpyOH) or 4′-(2-furyl)-2,2′:6′,2″-terpyridine (ftpy) have been synthesized to afford the new compounds [Ag(tpyOH)(PPh3)](NO3) (1) and [Ag(ftpy)(PPh3)](NO3) (2). In addition, the reaction of silver(I) nitrate with ftpy in the presence of excess of 4,4′-bipyridine (bpy) and NH4PF6 led to the formation of binuclear complex [Ag2(ftpy)2(μ-bpy)](PF6)2 (3). The products have been characterized by elemental analysis, IR, UV–Vis, NMR (1H, 31P) spectroscopy and single crystal X-ray diffraction in the case of 3. The 31P NMR data reveal that the interaction of PPh3 with silver(I) is maintained in solution in 1–2. The crystal structure of 3 shows that each Ag+ ion is coordinated by three N-atoms of ftpy and a nitrogen from the bridging ligand of bpy in a slightly distorted square planar geometry. There are some strong noncovalent interactions of hydrogen bonding and Ag-η2-furyl in the crystal structure, connecting molecules to form a supramolecular network. The thermal decomposition of 1–3 has also been investigated. The thermal stabilities of all complexes, as determined by thermogravimetric analysis (TGA), are almost the same and they are thermally stable up to 220 °C. The complex 3 was used for the preparation of Ag nanoparticles by simple calcination method at two different temperatures of 400 and 600 °C resulting in the formation of silver nanoparticles, crystalline in nature with the size of 66 and 52 nm, respectively, using Scherrer’s equation. The nano-sized silver particles have also been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDX).