New heterotopic, linked macrocyclic systems derived from selectively protected macrocycles

The use of orthogonally protected cyclam and 1,9-dithia-5,13-diazacyclohexadecane macrocycles, in combination with aza-18-crown-6, has enabled the efficient synthesis of a new heterotritopic macrocyclic ligand incorporating N4-, N2S2- and NO5-donor sites. A similar strategy has allowed the incorporation of cyclam and 1,9-dithia-5,13-diazacyclohexadecane into a cofacial ligand. Further, the synthesis of novel tetramacrocyclic ligands has been achieved in which the macrocycles are linked in a cyclic arrangement. The availability of different binding sites in the respective products makes the latter suitable candidates for the synthesis of a range of mixed-metal multinuclear complexes