Ordered Mesoporous Alumina with Tunable Morphologies and Pore Sizes for CO2 Capture and Dye Separation.

We describe a versatile and scalable strategy toward long-range and periodically ordered mesoporous alumina (Al2O3) structures by evaporation-induced self-assembly of a structure-directing ABA triblock copolymer (F127) mixed with aluminum tri-sec-butoxide-derived sol additive. We found that the separate preparation of the alkoxide sol-gel reaction before mixing with the block copolymer enabled access to a relatively unexplored parameter space of copolymer-to-additive composition, acid-to-metal molar ratio, and solvent, yielding ordered mesophases of two-dimensional (2D) lamellar, hexagonal cylinder, and 3D cage-like cubic lattices, as well as multiscale hierarchical ordered structures from spinodal decomposition-induced macro- and mesophase separation. Thermal annealing in air at 900 °C yielded well-ordered mesoporous crystalline γ-Al2O3 structures and hierarchically porous γ-Al2O3 with 3D interconnected macroscale and ordered mesoscale pore networks. The ordered Al2O3 structures exhibited tunable pore sizes in three different length scales, <2 nm (micropore), 2-11 nm (mesopore), and 1-5 µm (macropore), as well as high surface areas and pore volumes of up to 305 m2/g and 0.33 cm3/g, respectively. Moreover, the resultant mesoporous Al2O3 demonstrated enhanced adsorption capacities of carbon dioxide and Congo red dye. Such hierarchically ordered mesoporous Al2O3 are well-suited for green environmental solutions and urban sustainability applications, for example, high-temperature solid adsorbents and catalyst supports for carbon dioxide sequestration, fuel cells, and wastewater separation treatments.

Ethylene oligomerization using nickel dithiolene complexes Ni(S2C2R2)2 (R=Ph, CF3) and the crystal structure of Ni[S2C2(CF3)2]2.

Nickel bis(dithiolene) complexes have been known for over four decades, yet little is known regarding the chemistry of this important subclass of inorganic coordination complexes in olefin oligomerization or polymerization. We report here that Ni(S(2)C(2)R(2))(2) (R=Ph, CF(3)) are converted to active catalysts for ethylene oligomerization when activated with methylaluminoxane (MAO). The catalyst activity is comparable to some nickel coordination complexes with N-donor ligands under similar conditions. The products are mainly butenes and hexenes, with small amounts of higher oligomers. The product distribution pattern is consistent with a nickel hydride species being the active center, where fast beta-hydride elimination limits the products to mostly butenes and hexenes. The exact nature of the active center and the reaction mechanism remain to be investigated. In addition, we determined the crystal structure for Ni[S(2)C(2)(CF(3))(2)](2). The molecule crystallizes in the P2(1)/n space group and adopts a planar geometry with expected bond lengths and angles. Comparing this structure with that for the donor-acceptor complex with perylene reveals elongation of both the Ni-S and the S-C bonds in the latter, suggesting reduction of Ni[S(2)C(2)(CF(3))(2)](2) may have occurred in the latter.

Synthesis, Reactivity, and Structural Characterization of the Nonclassical [MTe(7)](n)()(-) Anions (M = Ag, Au, n = 3; M = Hg, n = 2).

Several tellurometalates of the general formula [MTe(7)](n)()(-) (n = 2, 3) have been isolated as salts of organic cations by reaction of suitable metal sources with polytelluride solutions in DMF. The [HgTe(7)](2)(-) anion has the same structure in both the NEt(4)(+) and the PPh(4)(+) salts except for a minor change in the ligand conformation. The [AgTe(7)](3)(-) and [HgTe(7)](2)(-) anions contain metal atoms coordinated in trigonal-planar fashion to eta(3)-Te(7)(4)(-) ligands. The central Te atom of an eta(3)-Te(7)(4)(-) ligand is coordinated to the metal atom and to two Te atoms in a "T"-shaped geometry consistent with a hypervalent 10 e(-) center. The planar [AuTe(7)](3)(-) anion may best be described as possessing a square-planar Au(III) atom coordinated to an eta(3)-Te(5)(4)(-) ligand and to an eta(1)-Te(2)(2)(-) ligand. The reaction of [NEt(4)](n)()[MTe(7)] (M = Hg, n = 2; M = Au, n = 3) with the activated acetylene dimethyl acetylenedicarboxylate (DMAD) has yielded the products [NEt(4)](n)()[M(Te(2)C(2)(COOCH(3))(2))(2)] (M = Hg, n = 2; M = Au, n = 1). The metal atoms are coordinated to two Te(COOCH(3))C=C(COOCH(3))Te(2)(-) ligands, for M = Hg in a distorted tetrahedral fashion and for M = Au in a square-planar fashion.