Two new crystal structures of two-dimensional lead(II) coordination polymers with flexible alicyclic carboxylate ligands

Two new coordination polymers with flexible alicyclic carboxylate ligands, generally formulated as [Pb(chda)](n) (1, H(2)chda = 1,1'-cyclohexanediacetic acid) and [Pb(tmg)](n) (2, H(2)tmg = 3,3'-tetramethyleneglutate), have been successfully synthesized through the liquid-liquid diffusion method. They represent the first main group of metal-organic hybrid compounds assembled from H(2)chda and H(2)tmg. Compound 1 crystallized in the non-centrosymmetric space group Pca2(1), whereas 2 adopts the centrosymmetric P2(1)/c space group. Their structure features one-dimensional infinite chains extended into two-dimensional layer framework. Interestingly, the lead atoms exhibit hemi-as well as holo-directed coordination geometry with coordination number seven in both compounds.