Silver(I) complexes with quinoline based linear multidentate ligands: self-assembly of sulfur-bridged tetrametallotricyclic boxes

The flexible linear multidentate ligands 1,5-bis(8-quinolylsulfanyl)-3-oxapentane (OESQ) and 1,8-bis(8-quinolylsulfanyl)-3,6-dioxaoctane (ODSQ) reacted with silver(I) perchlorate affording the simple mononuclear complexes [Ag(OESQ)]ClO4 1 and [Ag(ODSQ)]ClO4 2, respectively. However, with silver(I) nitrate, novel metallosupramolecular complexes [Ag-4(ODSQ)(2)(eta(1)-NO3)(2)(eta(2)-NO3)(2)] 3 and [Ag-4(OESQ)(ODSQ)(eta(1)-NO3)(2)(eta(2)-NO3)(2)]. H2O 4 were obtained, in which the co-ordination motifs [Ag(OESQ)](+) and [Ag(ODSQ)](+) are spontaneously self-assembled by sulfur-bridged silver(I) ions into tetrametallotricyclic molecules containing the same or mixed building blocks. All four complexes have been characterized by elemental analyses, IR and H-1 NMR spectroscopy, and single crystal X-ray diffraction methods. The possible self-assembly process has been discussed with the aid of electrospray mass spectrometry.