The potentially penta-coordinating ligands L2 and L3 have been synthesized by reaction of the 10-membered macrocycle 1, 5-diaza-8-oxacyclodecane with either 1, 9-dichloro-3, 7- diazanonane-2, 8-dione, and subsequent reduction of the diamide (3), or with 1, 9-dichloro- 3, 7-(dimethyl) diazanonane-2, 8-dione and reduction (L3). A similar procedure is outlined for the dimethylated macrobicycle (L4), based on the corresponding nine-membered 1, 4- ...