Preparation and characterization of two new metal–organic coordination polymers with 3,3′-azodibenzoic acid under N-donor auxiliary chelating ligand intervention

Abstract

Reactions of 3,3′-azodibenzoic acid (H2azdc) with Mn(II) and Cd(II) in the presence of 1,10-phenanthroline (phen) yield two new metal–organic coordination polymers, {[Mn(azdc)(phen)(DMF)(H2O)]}n (1) and {[Cd(azdc)(phen)]}n (2), which display 1-D azdc-bridged coordination arrays with different topology. 1 was synthesized under ambient conditions and exhibits a zigzag chain structure, further extending into a 2-D supramolecular double layer through C–Hπ and C–HO hydrogen bonds. Solvothermally 2 was obtained and shows a double-chain structure. Adjacent double chains are linked by C–HN hydrogen bonds to give a 2-D supramolecular wavy double layer. Distinct extended 3-D supramolecular network architectures are further constructed with weak secondary interactions, especially aromatic stacking and hydrogen bonding as supramolecular driving forces. The coordination modes of azdc2− and crystalline architectures of the complexes depend on the central metal ions. The desolvation–resolvation behavior of 1 has been explored. Thermal stabilities of 1 and 2 have been studied. Solid-state fluorescence of 2 has been investigated.