Ho-Chol Chang

A novel three-dimensional coordination polymer constructed with mixed-valence dimeric copper(i,ii) unitsElectronic supplementary information (ESI) available: synthesis and data for 1. See http://www.rsc.org/suppdata/cc/b2/b210914j/

A novel three-dimensional coordination polymer with a mixed-valence localized copper(I,II) dimeric unit, [Cu2(4-pya)3]n (4-pya = 4-pyridinecarboxylate), was hydrothermally synthesized via a simultaneous in-situa redox and hydrolysis reaction of Cu(II) and 4-cyanopyridine and crystallographically characterized to be a twofold interpenetrated three-dimensional coordination network with a cubic [Cu16(4-pya)12] building unit.

Molecule-based valence tautomeric bistability synchronized with a macroscopic crystal-melt phase transition

Here, we show a synchronic bistability of valence tautomeric (VT) molecular interconversion and a macroscopic crystal-melt phase transition in long alkoxy-functionalized cobalt-dioxolene complexes. Studies have been carried out for a novel series of complexes, [Co(CnOpy) 2(3,6-DTBQ)2] (3,5-dialkoxy(C(n)H2(n+1)O-; n = 9, 12, and 17)pyridine (CnOpy) and 3,6-di-tert-butyl semiquinonate or catecholate ligands (3,6-DTBQ)). All complexes show the molecular VT interconversion with thermal hysteresis attributed to the synchronous crystal-melt phase transition. Thermodynamic analysis has revealed that the molecular VT interconversion is restricted over 50 K and crystal-melt phase transition is accelerated about 50 K by the synchronicity. The synchronicity is attributed to enthalpic and entropic effects of the alkoxy chains in the crystalline phase of the one tautomer and the melt phase of the other, respectively. Our results show efficient chemical and thermodynamic strategies to combine molecule-based and macroscopic bistabilities.

A New Class of Cyclic Hexamer: [Co6L6]24− (H6L=hexaazatriphenylene hexacarboxylic acid)

The construction of nanostructured polynuclear metal complexes with cyclic topologies, particularly those containing multifunctional ligands containing π-electronic structures, is of great interest since they can potentially lead to compounds with unusual electrochemical properties. A novel cyclic module with a hexacarboxylate derivative is described. The results show that the peripheral substituents not only control the electronic structure, but also influence its mode of coordination.

Syntheses and crystal structures of three one-dimensional copper(II) complexes constructed by salicylate and 4,4 '-bipyridine: ladder, zig-zag, and linear polymeric assembly

Syntheses and crystal structures of three new compounds { trans -[Cu(Hsal) 2 (4,4′-bipy)](DMF)} n ( 1 ), { cis -[Cu(Hsal) 2 (4,4′-bipy)](2H 2 O)} n ( 2 ), and [Cu 2 (Hsal) 4 (4,4′-bipy)] n ( 3 ) are reported. These three compounds have trans -, cis -, and dimer geometries bearing a common motif [Cu(Hsal) 2 (4,4-bipy) n ] leading to ladder, zig-zag, and linear one-dimensional (1-D) networks, respectively. The Cu⋯Cu distances separated by 4,4′-bipy are different in these three compounds, which leads to an extension structure in compound 3 and a compact structure in compound 2 . Conformations of 4,4′-bipy ligands in these three compounds are also different. In compound 1 there is stacking of the bidentate salicylate and the bridging salicylate from another molecule. There is also stacking of salicylate and 4,4′-bipy from another molecule in compound 2 .

Porous lanthanide–organic framework with zeolite-like topology

Two novel isomorphous porous frameworks of Ln(III), {[Ln2(imidc)2(H2O)3](H2O)}n, [Ln = Gd(III) (1) and Er(III) (2)] have been synthesized hydrothermally using multifunctional 4,5-imidazoledicarboxylic acid (imidc) as a connector; they have a zeolite-like network topology which can provide another form upon dehydration, and exhibit selective adsorption properties for H2O over N2, CO2 and MeOH.

Photo- and Vapor-Controlled Luminescence of Rhombic Dicopper(I) Complexes Containing Dimethyl Sulfoxide

Halide-bridged rhombic dicopper(I) complexes, [Cu2(μ-X)2(DMSO)2(PPh3)2] (X = I(-), Br(-); DMSO = dimethyl sulfoxide; PPh3 = triphenylphosphine), were synthesized, the iodide complex of which exhibited interesting photochromic luminescence driven by photoirradiation and by exposure to DMSO vapor in the solid state. Single-crystal X-ray diffraction measurements revealed that the iodo and bromo complexes (abbreviated Cu2I2-[O,O] and Cu2Br2-[O,O]) were isomorphous, and that the two DMSO ligands were coordinated to the Cu(I) ion via the O atom in both complexes. Both complexes exhibited bright blue phosphorescence at room temperature (λ(em) = 435 nm, Φ(em) = 0.19 and 0.14 for Cu2I2-[O,O] and Cu2Br2-[O,O], respectively) with a relatively long emission lifetime (τ(em) ~ 200 μs at 77 K) derived from the mixed halide-to-ligand and metal-to-ligand charge transfer ((3)XLCT and (3)MLCT) excited state. Under UV irradiation, the blue phosphorescence of Cu2Br2-[O,O] disappeared uneventfully and no new emission band appeared, whereas the blue phosphorescence of Cu2I2-[O,O] rapidly disappeared with simultaneous appearance of a new green emission band (λ(em) = 500 nm). On further irradiation, the green emission of the iodide complex gradually changed to bright yellowish-green (λ(em) = 540 nm); however, this change could be completely suppressed by lowering the temperature to 263 K or in the presence of saturated DMSO vapor. The initial blue phosphorescence of Cu2I2-[O,O] was recovered by exposure to DMSO vapor at 90 °C for a few hours. IR spectroscopy and theoretical calculations suggest that the DMSO ligand underwent linkage isomerization from O-coordination to S-coordination, and both the occurrence of linkage isomerization and the removal of DMSO result in contraction of the rhombic Cu2(μ-I)2 core to make the Cu···Cu interaction more effective. In the contracted core, the triplet cluster-centered ((3)CC) emissive state is easily generated by thermal excitation of the (3)XLCT and (3)MLCT mixed transition state, resulting in the green to yellowish-green emission. In contrast, the Cu···Cu distance in Cu2Br2-[O,O] is considerably longer than that of Cu2I2-[O,O], which destabilizes the (3)CC emissive state, resulting in the nonemissive character.

Temperature-controlled hydrothermal synthesis of a 2D ferromagnetic coordination bilayered polymer and a novel 3D network with inorganic Co3(OH)2 ferrimagnetic chainsElectronic supplementary information (ESI) available: three figures, plots of eff versus T and field dependence of 2, and the simulated and experimental powder diffraction patterns for 1 and 2. See http://www.rsc.org/suppdata/cc/b3/b312058a/

A 2D bilayered ferromagnetic coordination polymer, generated by lower-temperature hydrothermal reactions of cobalt(II) salt with the 3,4-pyridinedicarboxylate dianion, was controlled to transform into a 3D magnetic coordination network with Co3(OH)2 ferrimagnetic chains at a higher temperature.

Cation-templated construction of three-dimensional α-Po cubic-type [M(dca)3]− networks. Syntheses, structures and magnetic properties of A[M(dca)3](dca = dicyanamide; for A = benzyltributylammonium, M = Mn2+, Co2+; for A = benzyltriethylammonium, M = Mn2+, Fe2+)

A new family of three-dimensional cubic-like [M(dca)3]− networks (dca = dicyanamide) templated by appropriate cations has been constructed and structurally characterized by X-ray crystallography.

A redox-active columnar metallomesogen and its cyclic voltammetric responses

We demonstrate a strategy that appears particularly well suited for the design of redox-active liquid crystals and also constitutes the first demonstration of cyclic voltammetric responses of a metallomesogen in the columnar liquid crystalline phase.

Nonprecious-Metal-Assisted Photochemical Hydrogen Production from ortho-Phenylenediamine

The combination of o-phenylenediamine (opda), which possesses two proton- and electron-pooling capability, with Fe(II) leads to the photochemical hydrogen-evolution reaction (HER) in THF at room temperature without addition of photosensitizers. From the THF solution, the tris(o-phenylenediamine) iron(II) complex, [Fe(II)(opda)3](ClO4)2 (1), was isolated as a photoactive species, while the deprotonated oxidized species was characterized by X-ray crystallographic analysis, electrospray ionization mass spectrometry, and UV-vis NIR spectra. Furthermore, the HER is photocatalyzed by hydroquinone, which serves as a H(+)/e(-) donor. The present work demonstrates that the use of a metal-bound aromatic amine as a H(+)/e(-) pooler opens an alternative strategy for designing nonprecious-metal-based molecular photochemical H2 production/storage materials.