aCoordination Chemistry Institute, State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China
bDepartment of Chemical Technology, Huaihai Institute of Technology, Lianyungang 222005, China
Available online 8 May 2008.
Abstract
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.
Graphical abstract
Two novel zinc(II) coordination complexes [Zn2(L)(CO3)]Br2 · 7H2O (1) and [Zn2(L)(CO3)]Br2 · 0.5CH3COCH3 · 5H2O (2) with 1D chain structure linked by carbonate anions were obtained by reactions of 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) with zinc salt at an initial pH of ca. 9.5. The results show that carbon dioxide from air was absorbed and converted to carbonate anion during the formation of 1 and 2.
Keywords: Carbon dioxide; Zinc(II) complex; 1D chain
Scheme 1. Schematic drawing for the macrocyclic ligand L.
Fig. 1. (a) ORTEP drawing of 1 showing the coordination environment around Zn(II) at 30% probability, the hydrogen atoms and uncoordinated water molecules were omitted for clarity. (b) Infinite 1D chain structure of 1, the hydrogen atoms and water molecules were omitted for clarity. (c) 2D network of 1 linked by N–H 
Br2 hydrogen bonds indicated by dashed lines. (d) The 3D structure of 1 through π–π stacking of the 2D network.
Fig. 2. (a) ORTEP drawing of 2 showing the coordination environments around Zn1 and Zn2 centers at 30% probability level, the hydrogen atoms and uncoordinated solvent molecules were omitted for clarity. (b) 1D chains formed by π–π stacking of the benzene ring planes and the hydrogen bonds indicated by dashed lines. (c) 2D network of 2 linked by N–H Br4 hydrogen bonds. (d) 3D structure of 2.
