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This work presents eight coordination assemblies based on divalent metal ions (M = CoII, CuII, ZnII, and CdII), dicyanamide anion (N(CN)2−, dca), and two isomeric bent dipyridyl coligands (L), namely, 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) and 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (4-bpo). In the resulting crystalline materials, both bpo and dca tectons generally display the bidentate bridging fashion (except in the mononuclear species 5), extending the metal centers to afford diverse one-, two-, and three-dimensional (1-D, 2-D, and 3-D) coordination networks that are not commonly observed in M−dca−L systems. Notably, the inclined polycatenated 2-D → 3-D framework and 3-D polyknotting network with the unique 6-connected (44.611) topology are formed for the CuIIand CdIIspecies with dca and 4-bpo. For the polymeric CoIIand CuIIcomplexes, very weak antiferromagnetic or ferromagnetic interactions are observed between the metal centers due to the μ1,5-bridging mode of dca, and their magneto-structural correlations have been discussed in detail. The ZnIIand CdIIcomplexes show solid-state fluorescent emissions at room temperature. [ABSTRACT FROM AUTHOR]

Seven Zn(II) and Cd(II) coordination polymers, formulated as {[Zn2(5-Br-ip)2(bpy)(H2O)]·2H2O}n(1), {[Zn(5-Br-ip)(bpa)(H2O)]}n(2), {[Cd(5-Br-ip)(bpp)(H2O)]}n(3), {[Zn(5-Br-ip)(bpe)]}n(4), {[Zn2(4-Br-ip)2(bpy)]·H2O}n(5), {[Zn(4-Br-ip)(bpa)(H2O)]}n(6), and {[Cd(4-Br-ip)(bpp)]}n(7), were prepared by hydrothermal reactions based on 4-bromo- or 5-bromoisophthalic acid (4-Br-H2ip or 5-Br-H2ip) and different dipyridyl-type coligands 4,4′-bipyridyl (bpy), 1,2-bi(4-pyridyl)ethane (bpa), 1,3-di(4-pyridyl)propane (bpp), and 1,2-di(4-pyridyl)ethene (bpe). All complexes 1−7were characterized by elemental analysis, IR spectra, and X-ray single-crystal diffraction. Complex 1is a 2D (6,3) coordination network and further assembled into a 3D framework via π−π stacking interactions. Complex 2shows a 1D coordination array and further forms a 2D supramolecular network via H-bonding interactions. Complex 3has a 2-fold interpenetrating 3D diamond framework. Complex 4is a 3-fold interpenetrating 3D network with CdSO4topology, constructed from alternately left- and right-handed helical arrays. Complex 5has a 3D (3,4)-connected network with (4·82)(4·82·103) topology. Complex 6features a 1D coordination chain and further forms a 2D helical supramolecular pattern by H-bonding. Complex 7exhibits a (3,5)-connected 2D layer with the Schläfli symbol of (42·6) (42·67·8). The results reveal that the diverse coordination networks of 1−7can be adjusted by the different dispositions of the -Br substituent of isophthalate building blocks, as well as the metal ions and the dipyridyl coligands. Moreover, the luminescent properties of the complexes have been investigated. [ABSTRACT FROM AUTHOR]

Eight ZnIIand CdIIcoordination complexes, {[Zn3(nbta)2(bpy)2(H2O)2](H2O)2}n(1), [Zn4(nbta)2(bpe)2(OH)2]n(2), {[Cd3(nbta)2(bpy)5(H2O)2](H2O)6}n(3), {[Cd3(nbta)2(bpe)2(H2O)2](H2O)2}n(4), [Zn2(Hbta)2(bpy)2(H2O)2](H2O) (5), [Zn(bta)(Hbpe)]n(6), [Cd5(bta)2(Hbta)2(bpy)3(H2O)2]n(7), and {[Cd4(bta)2(bpe)2(H2O)4(OH)2](H2O)2}n(8), were prepared via hydrothermal reactions based on H3nbta or H3bta (H3nbta = 5-nitro-1,2,3-benzenetricarboxylic acid and H3bta = 1,2,3-benzenetricarboxylic acid) and the dipyridyl-type coligand 4,4′-bipyridyl (bpy) or 1,2-di(4-pyridyl)ethene (bpe). All complexes were characterized by elemental analysis, IR spectra, and X-ray powder diffraction techniques. Complexes 1−4all display unusual three-dimensional (3-D) self-penetrating coordination networks. From the topology point of view, complexes 1and 2display the 4-connected frameworks with the Schläfli symbols of (4.104.12)2(43.62.8)2(44.62) and (4.62.72.8)2(42.62.7.8), respectively. Complex 3features an unprecedented 3-nodal network with (3,5,6)-connectivity and the Schläfli symbol of (52.64.72.86.10)(52.65.72.8)2(52.6)2, also exhibiting an intriguing polyrotaxane entangled motif. Complex 4shows a new 4-connected (42.63.8)4(64.8.10) topology. Different from 1−4, complexes 5−8based on H3bta all present the non-self-penetrating structural type. Complex 5possesses binuclear units which are further extended to a two-dimensional (2-D) supramolecular network via extensive H-bonding interactions, showing alternate left- and right-handed helical chains. Complex 6has a 2-D layered motif generated via H-bonding interactions between the one-dimensional (1-D) coordination chains. Complex 7shows a 3-D coordination framework, which is constructed from the 2-D metal-carboxylate layers pillared by the rod-like bipy spacers. Complex 8presents a 2-D net with the [Cd4(μ3-OH)2]6+clusters as the linking nodes. These results reveal that the existence of the electron-withdrawing -NO2group in such a tricarboxyl building block plays a critical role in structural direction of the self-penetrating coordination frameworks. [ABSTRACT FROM AUTHOR]

Five novel zinc(II) and cadmium(II) metal−organic coordination polymers with a tricarboxyl tecton and N-donor ancillary ligands, {[Zn(Hnbta)(2,2′-bipy)]·H2O}n(1), {[Cd3(nbta)2(2,2′-bipy)2(H2O)2]}n(2), {[Cd3(nbta)2(bpa)2]}n(3), {[Zn2(nbta)(OH)(bpa)1.5]·2H2O}n(4), and {[Zn3(nbta)2(bpp)2(H2O)2]}n(5) (H3nbta = 5-nitro-1,2,3-benzenetricarboxylic acid, 2,2′-bipy = 2,2′-bipyridine, bpa = 1,2-bi(4- pyridyl)ethane, and bpp = 1,3-bi(4-pyridyl)propane), have been prepared and characterized by elemental analysis, IR spectra, and X-ray diffraction. Complex 1has a two-dimensional (2D) bilayer supramolecular network constructed from one-dimensional (1D) zigzag coordination chains via π···π interactions, whereas 2exhibits a three-dimensional (3D) supramolecular network assembled from 1D coordination arrays through π···π interactions and weak C−H···O interactions. Complex 3features a (4,5)-connected self-penetrating 3D coordination net with a (43·65·82)(43·62·8)(44·64·82)(45·65) topology. The 3D framework of 4can be described as a trinodal (4,5)-connected (3·4·53·6)(3·52·62·84·9)(3·4·5·83) topology, which consists of 2D [Zn(nbta)] helical arrays and bpa pillars. Complex 5has a 3D trinodal 4-connected (4·64·8)(44·62)(43·63) topology. Moreover, thermal stabilities and luminescent properties of complexes 1−5have also been investigated. [ABSTRACT FROM AUTHOR]

A series of CdII, CoII, NiII, and PbIImixed-ligand coordination complexes 1−8based on 5-sulfoisophthalic acid (H3sip) and the bent dipyridyl ligand 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) or its 4-pyridyl N-donor analogue (4-bpo) have been synthesized and fully characterized by IR spectra, microanalyses, and single crystal and powder X-ray diffraction techniques. The significant pH effect on assembly of the CdIIcomplexes 1−4has been demonstrated, which leads to the formation of distinct crystalline products, whereas the CoII, NiII, and PbIIsystems 5−8are independent to pH condition of the synthetic reaction. Complexes 1−8display various coordination motifs with different existing forms, conformations, and coordination modes of the organic ligands. Further, extended supramolecular networks are constructed via secondary interactions such as hydrogen-bonding and aromatic stacking. Solid-state properties of thermal stability and fluorescence for these crystalline materials are also presented. [ABSTRACT FROM AUTHOR]