Synthesis and crystal structures of mono- and dinuclear silver(I) complexes bearing 1,8-naphthyridine ligand

Mononuclear and dinuclear silver(I) complexes bearing 1,8-naphthyridine (napy) were prepared. The crystal structures of [Ag(napy-kappaN)(2)](PF6) (1) and [Ag-2(mu-napy)(2)](PF6)(2).3CH(3)CN (2.3CH(3)CN) were determined by X-ray diffraction studies. In complex 1, intermolecular pi-pi interaction of napy ligands between neighboring molecules forms left-handed hexagonal columns in the solid state. On the other hand, two napy ligands bridging two Ag ions in the dinuclear complex 2 shape a face-to-face pi-pi stacking with those of the neighboring molecule to form the dimeric unit. Besides, two of four napy ligands, which are located in a diagonal position in the dimeric unit, build intermolecular back-to-back pi-pi stackings with those of the adjacent dimeric unit, and a ladder-like stairway structure is generated in the solid state. Irrespective of such characteristic structures of 1 and 2 in the solid state, both complexes show very rapid dynamic behavior in solutions. No conversion between 1 and 2 took place even in the presence of excess amounts of Ag+ or napy in solutions. (C) 2004 Elsevier B.V. All rights reserved.