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 pi-pi stacking interactions. In two dinuclear copper(II) nitrate complexes of 4, the ligand adopts very different bridging modes of coordination. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.