Cu(ii) and Ni(ii) complexes with dipyridine-containing macrocyclic polyamines with different binding unitsElectronic supplementary information (ESI) available: selected bond lengths [Å] and angles [°] for [CuL1](ClO4)2 (Table S1) and for [NiL1](ClO4)2 (Table S2); absorption spectra of L2 in the presence of Cu(ii) (1 ∶ 1 molar ratio) at different pH values (Fig. S1). See http://www.rsc.org/suppdata/dt/b2/b211904h