Systematic study of synthesis and crystal structures of Ag(DPK)nX complexes (DPK=di-2-pyridyl ketone; X=NO2 −, ClO4 −, ClO3 −, PF6 −, n=1; X=ClO4 −, ClO3 −, n=2): role of anion and π–π stacking interaction

Six complexes formulated as Ag(DPK)X (DPK=di-2-pyridyl ketone; X=NO2 −, ClO3 −, ClO4 −, PF6 −) and Ag(DPK)2X (X=ClO3 −, ClO4 −) have been prepared and their structures have been determined by X-ray diffraction, showing that both the anion coordination and π–π stacking interaction play important roles in the solid structures of these complexes. The Ag(DPK)X complexes exhibit three kinds of helical structures and interesting structural variations within the series resulted from the different coordination modes of the anions. In Ag(DPK)2X, each DPK ligand coordinates to an Ag(I) atom through one of its pyridyl group in an unprecedented monodentate mode. The mononuclear complexes are stabilized by the intramolecular π–π stacking interactions and aligned into chains through the intermolecular π–π stacking interactions in a zipper-like fashion.