A series of Cu(II) complexes based on different bis(imidazole) ligands and organic acids: formation of water clusters and fixation of atmospheric carbon dioxide

Two structurally related flexible bis(imidazole) ligands, 1,2-bis(imidazole-1-ylmethyl)-benzene (1,2-bix) and 1,4-bis(imidazole-1- ylmethyl)-benzene (1,4-bix), reacted with Cu(II) salts and various organic acids at room temperature, leading to the formation of nine novel metal-organic coordination architectures, from dinuclear structures to two-dimensional networks: [Cu2(CO3)2(1,2-bix) 4]·8H2O (1), [Cu(L1)(1,2-bix) 2]·2H2O (2), [Cu2(L2)(1,2-bix) 2(H2O)4]·8H2O (3), [Cu(1,2-bix)2(H2O)2]·L 3·4H2O (4), [Cu(L4)2][Cu(1,2- Wx)2(H2O)2]·3H2O (5), [Cu(L5)(1,2-bix)]-H2O (6), [Cu2(L 6)2(1,2-bix)2]·H2O (7), [Cu2(CO3)2(1,4-bix)3]·(1,4-bix)· 10H2O (8), and [Cu(L6)2(1,4-bix)][Cu(1,4-bix) 2(H2O)2]·4H2O (9) (H 2L1 - 1,4-naphthalenedicarboxylic acid, H 4L2 = 1,2,3,4-benzenetetricarboxylic acid, H 2L3 = sebacylic acid, H2L4 = maleic acid, H2L5 = fumaric acid, and H2L6 = 1,3-benzenedicarboxylic acid). All complexes were structurally characterized by X-ray diffraction analysis. The formation of water clusters and the fixation of atmospheric carbon dioxide in these complexes were observed. The organic anion effects on the structures of the complexes are also discussed.