Extra Large Macrocycle: 40-Membered Macrocycle via 2:2 Cyclization and Its Dimercury(II) Complex

A large 40-membered N4O4S4 macrocycle (L2) was obtained through a 2:2 cyclization of the corresponding dithiol and dichloride as a minor product during the preparation of a 20-membered N2O2S2 macrocycle (L1, 1:1 cyclization product). Each macrocycle was successfully separated from the mixed products and identified. The larger macrocycle L2 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 L1 was also prepared. Both complexes and the larger macrocycle L2 were structurally characterized by the single crystal X-ray analysis.