2D and 3D binuclear cobalt supramolecular complexes: synthesis and crystal structures

Three binuclear cobalt supramolecular complexes [(pda)2Co2(H2O)5](DMF)(H2O) (1) (H2 pda ¼ pyridine-2,6-dicarboxylic acid), [(dbto)Co2(CH3CN)(H2O)7](CH3CN)(NO3)3 (2) (dbto ¼ 4,6-di-1H-1,2,3-benzotriazol-1-yl-1,3,5-triazin-2-ol), and [(pyz)Co2(H2- O)10](SO4)2(H2O)2 (3) (pyz ¼ pyrazine) were synthesized through hydrothermal, solid-state and solution synthetic method, respectively. These supramolecular complexes have been structurally characterized by X-ray single crystal diffraction. The structure of (1) consists of binuclear neutral units, which show butterfly-like forms. In (2), the bent configuration of dbto has accommodated the formation of the horse-shoe-like unit. The two cobalt atoms in binuclear unit of (3) are equivalent since the unit has a symmetry center passing through the center of pyz. In each compound, all the units are held together by means of hydrogen bonds forming 3-D structure for (1) and (3) and 2-D structure for (2). q 2004 Elsevier B.V. All rights reserved.