Coordination polymers constructed by linking metal ions with azodibenzoate anions

Twelve new coordination polymers have been obtained using three different azodibenzoate ligands, 3,3'-azodibenzoic acid (3,3'-ADB), 3,3'-azoxydibenzoic acid (3,3'-AODB) and 4,4'-azodibenzoic acid (4,4'-ADB) in combination with a variety of metal ions and co-ligands. Their crystal structures have been elucidated using single crystal X-ray diffraction analysis and the thermal stabilities of some of the products have been investigated using thermogravimetric analysis. The compounds, [Pb(3,3'-ADB)(phen)](n) (1), [Cu-2(3,3'-AODB)(PPh3)(2)](n) (2), [Zn(4,4'-ADB)(Py)(2)](n) (3), [Cd(4,4'-ADB)(H2O)(2)](n) (4), and [Co(4,4'-ADB)(Py)(2)(H2O)(2)](n) (5), form 1-D chains. Compounds Zn(3,3'-ADB)(CH3CH2OH) (6) and Co-3(3,3'-ADB)(2)(phen)(2)(CH3COO)(2) (7) form 2D sheets which have the (4,4) topology. Two-dimensional sheets are also formed in the case of Cd(4,4'-ADB)(phen)(H2O) (8), Y-2(3,3'-ADB)(3)(phen)(2) (9), Sm-2(3,3'-ADB)(3)(phen)(2) (10) and Er-2(3,3'-ADB)(3)(phen)(2) (11) with 9, 10 and 11 being isomorphous. In the structure of Ba(4,4'-ADB) (12), Ba(II) carboxylate units form 2D sheets which are linked by organic links to form a 3D pillared structure.