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ABSTRACT: Two new 3-dimensional Bi contg. coordination polymers are reported along with their single crystal structures and SHG properties. Compd. 1: Bi2O2(pydc) (pydc = pyridine-2,5-dicarboxylate), crystallizes in the monoclinic, polar space group, P21 (a 9.6479(9), b 4.2349(4), c 11.9615(11) Å, β 109.587(1)°), which contains Bi2O2 chains that are connected into a 3-dimensional structure via the pydc ligands. Compd. 2: Bi4Na4(1R3S-cam)8(EtOH)3.1(H2O)3.4 (1R3S cam = 1R3S-camphoric acid) crystallizes in the monoclinic, polar space group, P21 (a 19.0855(7), b 13.7706(5), c 19.2429(7) Å, β 90.701(1)°) and is a true 3-dimensional coordination polymer. These are two example of SHG compds. prepd. using unsym. ligands (compd. 1) or chiral ligands (compd. 2), together with metals that often exhibit stereochem.-active lone pairs, such as Bi3+, a synthetic approach that resulted in polar, noncentrosym., 3-dimensional metal-org. coordination polymer. [on SciFinder(R)]
J. Solid State Chem. 01/2012; 195:94-100.
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ABSTRACT: A new Kagomé lattice topology assembled from ML(4) metal-organic polyhedra prepared using bismuth nitrate and pyridine-2,5-dicarboxylate has been obtained via a solvo-thermal reaction. Bi(pydc)(2)·(H(3)O(+))(H(2)O)(0.83) is, to the best of our knowledge, the first example of a bismuth-based coordination polymer to form with a Kagomé topology. Its structure and photoluminescence properties are reported.
Chemical Communications 07/2011; 47(26):7371-3. · 6.17 Impact Factor
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ABSTRACT: There is much interest in designing molecular sized containers that influence and facilitate chemical reactions within their nanocavities. On top of the advantages of improved yield and selectivity, the studies of reactions in confinement also give important clues that extend our basic understanding of chemical processes. We report here, the synthesis and self-assembly of an expanded bis-urea macrocycle to give crystals with columnar channels. Constructed from two C-shaped phenylethynylene units and two urea groups, the macrocycle affords a large pore with a diameter of ∼9 Å. Despite its increased size, the macrocycles assemble into columns with high fidelity to afford porous crystals. The porosity and accessibility of these channels have been demonstrated by gas adsorption studies and by the uptake of coumarin to afford solid inclusion complexes. Upon UV-irradiation, these inclusion complexes facilitate the conversion of coumarin to its anti-head-to-head (HH) photodimer with high selectivity. This is contrary to what is observed upon the solid-state irradiation of coumarin, which affords photodimers with low selectivity and conversion.
Journal of the American Chemical Society 05/2011; 133(18):7025-32. · 9.91 Impact Factor
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ABSTRACT: The ordered double-perovskites Sr(2)MOsO(6) (M = Cu, Ni) consisting of 3d and 5d transition-metal magnetic ions (M(2+) and Os(6+), respectively) are magnetic insulators; the magnetic susceptibilities of Sr(2)CuOsO(6) and Sr(2)NiOsO(6) obey the Curie-Weiss law with dominant antiferromagnetic and ferromagnetic interactions, respectively, and the zero-field-cooled and field-cooled susceptibility curves of both compounds diverge below ∼20 K. In contrast, the available density functional studies predicted both Sr(2)CuOsO(6) and Sr(2)NiOsO(6) to be metals. We resolved this discrepancy on the basis of systematic density functional calculations. The magnetic insulating states of Sr(2)MOsO(6) are found only when a substantially large on-site repulsion is employed for the Os atom, although it is a 5d element. The cause for the divergence between the zero-field-cooled and field-cooled susceptibility curves in both compounds and the reason for the difference in their dominant magnetic interactions were investigated by examining their spin exchange interactions.
Inorganic Chemistry 03/2011; 50(9):4142-8. · 4.60 Impact Factor
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ABSTRACT: Pyridine macrocycles with no cavities assembled into close packed columns yet absorbed guests including hydrogen, carbon dioxide, and iodine.
Chemical Communications 01/2011; 47(1):277-9. · 6.17 Impact Factor
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ABSTRACT: New two-dimensional (2D) bismuth and three-dimensional (3D) lead based coordination polymers containing pyridine-2,5-dicarboxylate ligands (H(2)pydc) have been synthesized hydrothermally and characterized by single crystal X-ray diffraction. Bi(3)(μ(3)-O)(2)(pydc)(2)(Hpydc)(H(2)O)(2) (1), which crystallizes in the space group P1̅ (a = 8.7256(5) Å, b = 11.1217(7) Å, c = 14.0933(9) Å, α = 85.239(1)°, β = 98.582(1)°, γ = 71.106(1)°), has a 3D structure that contains Bi(6)O(4) clusters that connect into 2D sheets via linking ligands. The sheets form a 3D supramolecular structure via hydrogen bonding along the z-axis. Pb(pydc)(H(2)O) (2), which crystallizes in the space group P2(1)/c (a = 10.8343(14) Å, b = 11.2099(15) Å, c = 6.6573(9) Å, β = 90.697(2)°), contains 1D chains of corner-sharing distorted face capped trigonal prisms that are connected into a 3D framework via the pydc ligand. In addition, the ligands are hydrogen bonded to each other. Both 1 and 2 are single component "white" light emitting phosphors and are shown to exhibit "white" luminescence that covers a much wider spectral range than is observed for the as received H(2)pydc ligand.
Inorganic Chemistry 11/2010; 49(23):11001-8. · 4.60 Impact Factor
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ABSTRACT: Reported is a macrocyclic diacetylene that assembled into columns to afford porous crystals. Heating this assembly initiated a topochemical polymerization of the preorganized diacetylene units to give covalent conjugated polydiacetylenes. These stable conjugated materials maintained permanent porosity as evidenced by their type I gas adsorption isotherms with CO(2) (g). Such conjugated polymeric nanotubes could possess unusual properties for sensing and electronics.
Journal of the American Chemical Society 03/2010; 132(15):5334-5. · 9.91 Impact Factor
