Synthesis and structures of two new metal–organic polymers containing imidazoldicarboxylate ligands for hydrogen bonding networks, one with a covalent pleated sheet conformation

The reactions of Cd(NO3)2 · 4H2O with imidazol-4,5-dicarboxylic acid and 4,4′-bipyridine under hydrothermal reaction conditions resulted in two metal–organic polymers [(H2O)2Cd(H2IDC)2] · BPY (1) and [(H2O)2Cd2(HIDC)2BPY] (2). The compound 1 has a three-dimensional (3D) hydrogen-bonding network. The hydrogen-bonding linked 3D structure of complex 2 composed of covalent pleated sheets.