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. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)