A perfectly square-planar, D(4h)-symmetric, tetracoordinated oxygen has been observed in a tetracopper cluster-based coordination polymer that shows an unusual magnetic moment and ESR signal. The stabilization factor of the square-planar tetracoordinated oxygen has been revealed using DFT calculations.

Three novel tetrazole-based frustrated magnets, namely, Co3(OH)2(3-ptz)2(SO4)(H2O)4 (1), Co2(OH)(tzba)(H2O)4 (2) and [Co(OH)(tta)] (3) (3-ptz = 5-(3-pyridyl) tetrazole, H2tzba = 4-(1H-tetrazol-5-yl) benzoic acid, Htta = 1H-tetrazole) were hydrothermal synthesized and magnetically characterized. Compound 1 is a 2D (4,4) layered structure assembled by sulfate capped triangular [Co3(μ3-OH)(μ3-SO4)] clusters and in situ synthesized μ3-3-ptz ligands. Compound 2 features Co3(μ3-OH) triangle based magnetic Δ-chains linked with in situ generated μ5-tzba ligands to form a 2D layer. Compound 3 is a uninodal eight-connected body-centered-cubic (bcu) 3D network with square Co4O4 clusters as nodes and μ4-tta ligands as linkers. Interestingly, spin frustration was observed in these complexes due to inherent spin competition in triangle, Δ-chain and square. Magnetic studies show that 1 behaves as antiferromagnet, while 2 and 3 exhibits spin canting and long-range magnetic ordering.

Five tetrazolate-based coordination polymers with cationic copper(I) halide motifs, namely, Cu 4 (tta) 2 Cl 2 (1, tta = tetrazolate), Cu 4 (tta) 2 Br 2 (2), Cu 2 (tta)I (3), Cu 3 (mtta) 2 Cl (4, mtta = 5methyltetrazolate), and Cu 2 (tta)Br (5) were prepared by hydro(solvo)thermal reactions of CuX 2 or CuX with tetrazolato ligands in the presence of HX. Compounds 1, 2, and 3 show eight-connected square-planar layered structures constructed with butterfly-like [Cu 4 X 2 ] 2+ (X = Cl, Br, I) clusters and μ 4 -tta groups. Isomorphs 1 and 2 crystallize in the orthorhombic space group Pbca, but 3 crystallizes in the orthorhombic space group Pbam, because each μ 4 -tta group is co-According to a recent review by Li, [11] there are several routes towards copper(I) halide aggregates, for example direct introduction and in situ generation of a cuprous source. It seems that reduction of cupric salts is the most promising route for the in situ generation of a cuprous source. [12] An excess of halide ions and a higher pH value are favorable for the promotion of the formation of CuX aggregates. [13] Hereby, haloid acids are introduced into the reactions of tetrazole and CuX 2 (X = Cl, Br) with the hope of obtaining new copper(I) halide architectures, and five unusual cationic copper(I) halide based coordination polymers, Cu 4 (tta) 2 Cl 2 (1, tta = tetrazolate), Cu 4 (tta) 2 Br 2 (2), Cu 2 (tta)I (3), Cu 3 (mtta) 2 Cl (4, mtta = 5-methyltetrazolate), and Cu 2 (tta)Br (5) were synthesized (Scheme 2). Interestingly, our experiments reveal that the amount of hydrogen halide has a great influence on the structures of final products. Compounds 1, 2, and 3 show eight-connected squareplanar layered structures constructed from butterfly-like [Cu 4 X 2 ] 2+ clusters and μ 4 -tta groups, which represent the only 2D coordination polymers with eight-connected square-planar topology to date. Compound 4 is a [Cu 3 Cl] 2+ cluster based on a ten-connected ZrIn 2 topological framework, but 5 is a pillar layered structure constructed from [Cu 2 Br] n n+ cationic layers. The tetrazole groups of 4 come from in situ [2+3] cycloaddition reactions of acetonitrile with sodium azide. Compounds 1, 2, 4, and 5 exhibit strong green-blue emission in the solid state at room temperature, whereas cuprous iodide complex 3 shows red luminescence. Scheme 2. Self-assembly reactions of coordination polymers 1-6; R = H or CH 3 . Results and Discussion Synthesis ChemistryThe reaction of CuCl 2 or CuBr 2 and tetrazole under hydro(solvo)thermal conditions with HX (X = Cl, Br, F) as Eur.

Solvent-induced structural transformation was observed in two layered supramolecular isomers of [Zn 2 (H 2 O)(Hdtim) 2 ] (H 3 dtim＝4,5-ditetrazoyl-imidazole). Structural analyses revealed that the two isomers have the similar geometry of Zn, coordination mode of Hdtim 2-, and topology. Their structural differences only arise from different arrangement of the layers which seemingly corresponds to cooperative clockwise and counterclockwise 90° rotation of the adjacent layers. This is a quite unique solvent-dependent supramolecular isomerism in coordination polymers.

The effects of the draw ratio (DR) on the polymorphic nature of β-iPP were investigated by polarized light microscopy (PLM), wide angle X-ray diffraction (WAXD), small angle X-ray scattering (SAXS) and differential scanning calorimeter (DSC). The iPP sheet is extruded through a slit die, and then the extruded sheets were hot stretched with the different draw ratio (DR). DSC and WAXD results indicate that the β-iPP content increase with DR increasing from 4.8 to 10.8. β-spherulites can be observed by PLM in the stretched specimen even at a lower DR (4.8). With increasing draw ratio, the relative amount of the β-cylindrites crystals gradually increased.