Template synthesis of azacyclam metal complexes using primary amides as locking fragments

Nickel(II) and copper(II) azacyclam complexes can be obtained through a metal template procedure involving the pertinent open-chain tetramine, formaldehyde and a primary amide (either carboxy- or sulfonamide) as a locking fragment. Azacyclam complexes, which display the same properties and solution behavior of the corresponding cyclam analogues, can be obtained with any desired side-chain appended to the ligand's framework, by choosing the appropriate amide derivative, through a convenient one-pot synthesis. This opens the way to the design of multi centered redox systems, redox switches of fluorescence, and anion receptors of unusually high Brønsted acidity.