Dinuclear based polymeric copper(II) complexes derived from a Schiff base ligand: effect of secondary bridging moieties on geometrical orientations and magnetic properties

[1 + 1] condensation of salicylaldehyde and 2-aminobenzenesulfonic acid led to the formation of the acyclic Schiff base o-[(o-hydroxyphenyl)methylideneamino]benzenesulfonic acid (H2L) which, upon reaction with Cu(II) salts in the presence of triethylamine or 4,4′-bipyridine, formed a 2D polymeric species [Cu2L2]n (1) via sulfonate bridge and a 1D polymeric complex [{Cu2L2(4,4′-bipy)}·DMF]n (2) via 4,4′-bipyridine bridge, respectively. The copper cations sit on O4N basal- or O3N2 facial-edge-sharing inverted square pyramidal environments in 1 or 2, respectively. In spite of their comparable compositions, the relative orientations of the metal polyhedra affect the magnetic properties of these polymers since 1, in contrast to 2, presents a strong exchange interaction of an antiferromagnetic nature.