Different supramolecular hydrogen bond structures and significant changes in magnetic properties in dinuclear �2-1,1-N3 copper(ii) complexes with very similar tridentate Schiff base blocking ligandsElectronic supplementary information (ESI) available: Figs. S1 and S2: ORTEP-3 views of complexes 2 and 3. Fig. S3: Representation of J values vs. Cu?N?Cu angles in asymmetric (basal?apical) geometries. Fig. S4: Simulation of ?MT�vs. T (for a ring of 12 copper(ii) ions, representing an infinite chain). See http://www.rsc.org/suppdata/dt/b3/b311499f/