Search

A series of mixed-ligand coordination complexes have been prepared using diffusion method, by reacting the CoII, NiII, ZnII, AgI, CdII, CuII, or PbIInitrate with tetrabromoterephthalic acid (H2tbta) and 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (4-bpo). These complexes show various 0D, 1D, 2D, and 3D coordination motifs with different geometries of the metal centers, indicating a metal-directed assembly. The synthetic condition will also affect the resulting crystalline products for ZnIIspecies. Crystal structure analysis reveals that secondary interactions such as hydrogen bonding and aromatic stacking will further extend the coordination arrays to diverse supramolecular architectures. All complexes have been characterized by IR, elemental analysis, and powder X-ray diffraction techniques. In addition, the polymeric coordination systems with d10metal centers show solid-state fluorescent emissions at room temperature, which thus may be applied as potential hybrid luminescent materials. [ABSTRACT FROM AUTHOR]

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]

To systematically explore the influence of the pyridyl N-donor spatial positions of benzotriazol-1-yl-based pyridyl tectons on structural assemblies of coordination polymers, three closely related ligands, 1-(2-pyridylmethyl)-1H-benzotriazole (2-pbt), 1-(4-pyridylmethyl)-1H-benzotriazole (4-pbt), and 1-(3-pyridylmethyl)-1H-benzotriazole (3-pbt), were designed and prepared. Their reactions with CuI under hydrothermal conditions afforded three new copper(i)-iodide coordination polymers, namely, [CuI(2-pbt)]∞(1), [Cu2I2(4-pbt)]∞(2), and [Cu3I3(3-pbt)]∞(3). Single-crystal X-ray diffraction analysis shows that 1has a two-dimensional (2D) (4,4) sheet structure containing rhomboid [Cu2I2] dimeric units, which are further extended to form a three-dimensional (3D) framework by interlayer C–Hπ supramolecular interactions. Complexes 2and 3, with one-dimensional (1D) looped-chain [Cu2I2]nand 1D staircase double-chain [Cu3I3]ncopper(i)-iodide arrays, show an unusual 3D six-connected self-penetrating robnet with the Schläfli symbol of (48.66.8) and a 3D four-connected homochiral diamond net, respectively. The results reveal that the different spatial positions of pyridyl N-donors in this series of ligands play an important role in constructing coordination polymers 1–3. Moreover, the photoluminescent properties and thermal stability of 1–3in the solid state have also been investigated. [ABSTRACT FROM AUTHOR]

The mol­ecular structure of the neutral mononuclear complex [Fe(NCS)2(3-bpo)2(H2O)2], in which 3-bpo denotes 2,5-di-3-pyrid­yl-1,3,4-oxadiazole (C12H8N4O), is centrosymmetric, with FeII located on an inversion center. This complex is octa­hedral, and the FeII atom is trans coordinated by two monodentate NSC− ligands, two monodentate 3-bpo ligands and two water mol­ecules. Each complex is linked to four others, forming a (011) sheet, by O—H⋯N hydrogen bonding. Weak C—H⋯S inter­actions link each (011) sheet to the two adjacent sheets, hence forming a three-dimensional array. There is also some slipped π stacking within each sheet. [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]