X-ray Crystallographic Study of Copper(II), Cobalt(II) and Silver(I) Complexes of Ligands Containing Two Oxine Subunits Linked by Xylylene Spacer Groups

X-ray crystal structures are reported for six transition-metal complexes of the ligands 1,2-bis(8-quinolyloxymethyl)benzene (3) and 1,3-bis(8-quinolyloxymethyl)benzene (4). In three mononuclear copper(II) and cobalt(II) complexes, 3 acts as a chelating ligand with either N, O, N′-tridentate or N,O,O′,N′-tetradentate coordination. A novel dinuclear silver(I) complex of 3 is shown to be stabilised by a number of weak metal-ligand contacts and multiple intramolecular π-π stacking interactions. In two dinuclear copper(II) nitrate complexes of 4, the ligand adopts very different bridging modes of coordination.