2,2′-bi-1,6-naphthyridine metal complexes:: a new ligand and a novel 2x2 inclined interpenetration of (4,4) nets or formation of helicoidal chains

Cobalt(Ir), zinc(ri) and cadmium(II) salts react with the new spacer ligand 2,2'-bi-1,6-naphthyridine 1 to give 2D-planar (4,4) frameworks which interpenetrate such that each grid window of each sheet has two other sheets passing through it with all sheets being equivalent whereas copper(I) tetrafluoroborate and I form a 2(1)-helicoidal chain with neigboring chains interlocking through an aromatic pi-pi interaction.