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 inter penetrate such that each grid window of each sheet has two other sheets pas sing through it with all sheets being equivalent whereas copper(I) tetraflu oroborate and I form a 2(1)-helicoidal chain with neigboring chains interlo cking through an aromatic pi-pi interaction.