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Taking advantage of the conformational flexibility of the bpp ligand and aliphatic dicarboxylic acids, six interesting entangled coordination polymers, {[Cd(fum)(bpp)(H2O)]·(H2O)}n (1), {[Cd(fum)(bpp)2]·(H2O)5}n (2), {[Cd2(suc)1.5(bpp)2(NO3)(H2O)2]·6H2O}n (3), {[Cd(suc)(bpp)2]·(H2O)1.5}n (4), {[Cd2(glu)2(bpp)3]·10H2O}n (5), and {Cd(adp)(bpp)(H2O)}n (6) have been prepared and structurally characterized (bpp = 1,3-bi(4-pyridyl)propane, fum = fumaric, suc = succinate, glu = glutaric, adp = adipic). Compounds 1 and 2 are comprised of undulated 2D 44-sql networks. In the structure of compound 1, two identical undulated layers are parallelly interpenetrated with each other to give a 2D → 2D interpenetrating framework. For 2, the dangling arms projected from 2D layers are intercalated into the neighboring sheets, producing a 2D → 3D polythreading framework. Compound 3 shows a rare example of a 2D self-penetrating framework with a (3,4)-connected (42·63·8)(42·6) topology. Compound 4 presents an unusual 2D self-threading network with a novel 4-connected {42·63·8} topology. Compound 5 displays a 3D self-penetrating system based on a 2D → 3D parallel polycatenation array. Compound 6 exhibits an unprecedented 3D self-penetrating structure having both 1D + 1D → 1D polycatenation and 3D + 3D → 3D interpenetration characteristics. A comparison of these six compounds demonstrates that both the different spacer lengths of the aliphatic dicarboxylates and reactant ratios appear to play a significant role in the assembly of entangled frameworks. In addition, thermal stabilities and photoluminescence properties of 1–6 have been examined in the solid state at room temperature. [ABSTRACT FROM AUTHOR]

A series of Zn/Cd(ii) coordination polymers, namely, [Zn(IDPA)(H2O)]n·n(H2O) (1), [Cd(IDPA)(bpp)]n·n(H2O) (2), [Cd(IDPA)(4,4′-bpy)1/2]n (3), [Zn(IDPA)(4,4′-bpy)1/2]n (4), [Zn4(IDPA)4(phen)2·(H2O)2]n·2n(H2O) (5), [Zn(IDPA)(phen)·(H2O)]n·n(H2O) (6) and [Zn(IDPA)(2,2′-bpy)·(H2O)]n·n(H2O) (7), have been prepared on the basis of a bulky 1,3-benzenedicarboxylate derivative ligand, 5-(1-oxoisoindolin-2-yl)isophthalic acid (H2IDPA), with the help of 1,3-bis(4-pyridyl)propane (bpp), 4,4′-bipyridine (4,4′-bpy), 1,10-phenanthroline (phen) or 2,2′-bipyridine (2,2′-bpy) as a secondary ligand. H2IDPA is a luminous ligand with a large rigid π-conjugated system, and the solid-state luminescence properties of compounds 1–7 have been comparatively investigated. The results indicate that their luminescence properties have been enhanced compared to those of the free ligand, especially for compounds 2–7 which have been further regulated by N-donor ligands with a π-conjugated system. Compound 2 is a 2D layer structure, and its quantum yield (QY) is 39.80%, which is much higher than those of the H2IDPA ligand (QY = 4.41%) and compound 1 (QY = 6.32%). From the viewpoint of crystal structure diversity and comparison, our results further demonstrate that ligands with a large π-conjugated system have a promotional effect on luminescence properties of coordination polymers. [ABSTRACT FROM AUTHOR]