Extra large macrocycle: 40-membered macrocycle via 2:2 cyclization and its dimercury(II) complex

A large 40-membered N(4)O(4)S(4) macrocycle (L(2)) was obtained through a 2:2 cyclization of the corresponding dithiol and dichloride as a minor product during the preparation of a 20-membered N(2)O(2)S(2) macrocycle (L(1), 1:1 cyclization product). Each macrocycle was successfully separated from the mixed products and identified. The larger macrocycle L(2) allowed the preparation of its dimercury(II) complex, adopting a one-dimensional (1D) stairway-like polymeric chain linked with the anion. A monomercury(II) complex of the smaller macrocycle L(1) was also prepared. Both complexes and the larger macrocycle L(2) were structurally characterized by the single crystal X-ray analysis.