Carbon dioxide fixation by zinc(II) complexes with macrocyclic ligand

Two novel zinc(II) coordination complexes [Zn2(L)(CO3)]Br2 · 7H2O (1) and [Zn2(L)(CO3)]Br2 · 0. 5CH3COCH3 · 5H2O (2) with new macrocyclic ligand 3, 6, 9, 12, 20, 23, 26, 29-octaazatricyclo[29.3.1.114,18] hexatriaconta-1(34), 14, 16, 18(36), 31(35), 32-hexaene (L) were synthesized at an initial pH of ca. 9.5 with evaporation and diffusion methods, respectively. The dinuclear units of [Zn2(L)]4+ in both complexes are linked together by carbonate anions to form 1D infinite chain structure. The results show that carbon dioxide from air was absorbed and converted to carbonate anion in the formation of complexes 1 and 2. To the best of our knowledge, this is the first example of absorption and hydration of atmosphere carbon dioxide to form the 1D chain structure in the zinc(II) macrocyclic complexes.