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The aqueous medium reactions of lead(II) nitrate with H 2 ATIBDC as a main ligand and bipy or biim as an auxiliary ligand lead to the two fascinating coordination polymers:and H 2 ATIBDC ¼ 5-amino-2,4,6-triiodoisophthalic acid]. The interesting chiral three-dimensional (3D) network [Pb(ATIBDC)] (3) is obtained in the absence of any auxiliary ligands.Complex 1 is a one-dimensional (1D) helical chain, which further arrays into a 3D supramolecular metal-organic framework (MOF) with a 1D channel through the hydrogen-bonding and strong offset p/p stacking interactions. Furthermore, a 1D hydrogen-bonded helical water chain was found in 1. Interestingly, complex 1 exhibits reversible adsorption/desorption to water molecules. Framework 1 falls within the category of ''recoverable collapsing'' and ''guest-induced re-formation'' frameworks. Complex 2 features a fascinating 3D MOF. It displays a novel four-connected 4 6 6 8 -SOD (sodalite) zeotype network structure with 1D nanotubular channels. Complex 3 crystallizes in the chiral space group P3 1 and possesses a 3D honeycomb-like structure built up from a 1D Pb(II)-carboxylate-bridged helical chain with a 3 1 helix and ATIBDC 2À ligand. The coordination modes of the ATIBDC 2À ligand and crystalline architectures of the complexes are greatly dependent on the auxiliary ligands. The thermal stability and solid state fluorescent properties have been studied. Adsorption/desorption properties reveal that 2 may be used as an adsorbent material for some guest molecules. The study broadens the still very limited use of H 2 ATIBDC as a spacer and lead(II) ion for crystal engineering of MOFs with channels and cavities. These compounds represent the first examples of lead(II) complexes with H 2 ATIBDC.

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In the title compound, [Co(C2O4)(C10H8N2)]n, the oxalate group chelates two adjacent metal atoms, resulting in a zigzag chain running along the a axis. The CoII centre exists in an all cis-octa­hedral coordination geometry.

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