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ABSTRACT: Two polymorphs of the same Dy(III) complex show distinct slow magnetic relaxation behaviors due to the different local environments of Dy(III) in the crystal. This work represents the first example where the magnetic dynamic property of neutral rare earth complexes could be tuned by growing polymorphic crystals without changing the ligand.
Chemical Communications 06/2011; 47(24):6867-9. · 6.17 Impact Factor
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ABSTRACT: A series of mononuclear lanthanide complexes with chiral Schiff base ligands [Ln(FTA)(3)L] [Ln = Dy(1), Sm(2), Eu(3), Gd(4), and Tb(5), L = (S,S)-2,2'-Bis(4-benzyl-2-oxazoline)] were synthesized and characterized. Among these complexes, complex 1 represents the first example of mononuclear lanthanide complexes displaying single-ion magnet behavior and ferroelectricity.
Chemical Communications 05/2010; 46(17):2929-31. · 6.17 Impact Factor
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ABSTRACT: A series of new coordination polymers, {[Zn(1,2-bimb)(d-ca)]·2H2O}n (1), [Zn(1,3-bimb)(d-ca)]n (2), [Cd(1,3-bimb)(d-ca)]n (3), [Zn(1,4-bimb)(d-ca)]n (4), and {[Cd2(dpys)(d-ca)2(H2O)2]·H2O}n (5), (d-H2ca = d-camphoric acid, 1,2-bimb =1,2-bis(imidazol-1-ylmethyl)-benzene, 1,3-bimb = 1,3-bis(imidazol-1-ylmethyl) -benzene, 1,4-bimb = 1,4-bis(imidazol-1-ylmethyl)-benzene, dpys = 4,4′-dipyridylsulfide), have been prepared under hydrothermal conditions and characterized by elemental analyses, IR, vibrational circular dichroism, thermogravimetric and X-ray structural analyses. Their structures and properties can be tuned by variable coordination positions and conformations of the auxiliary ligands. Complex 1 features a three-dimensional (3D) supramolecular framework with a one-dimensional (1D)-nanosized channel. Complexes 2 and 3 show acentric 1D double-stranded chains. The chiral two-dimensional sheet with (4,4) topology is found in compound 4. Compound 5 displays a 1D ladderlike chain. Photoluminescent properties of 1 and 5 are studied. Compounds 2−5 display a second-order nonlinear optical effect and ferroelectric behaviors.
04/2010;
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ABSTRACT: Five novel d10 metal coordination polymers, {[Cd3(trz)5(Br)]·H2O}n (1), [Cd2(trz)3(NO3)(H2O)]n (2), [Cd(Htrz)(SO4)(H2O)]n (3), [Zn2(trz)2(NO3)2(H2O)]n (4), and [Zn2(Htrz)2(SO4)2]n (5) (Htrz = 1,2,4-triazole), have been synthesized through in situ solvothermal decarboxylation reactions using 1H-1,2,4-triazole-3-carboxylic acid and cadmium/zinc salts as starting materials. The X-ray crystallographic analyses demonstrate the two-dimensional structure of complex 4 and three-dimensional ones of complexes 1−3 and 5. The Htrz ligands adopt the μ1,2,4-bridging mode in complexes 1 and 2 and μ2,4-bridging mode in complex 3. Complex 5 represents the first example of metal/triazolate complexes, in which the neutral Htrz ligands act as both μ1,2 and μ2,4 bridges. The diversity of architectures of these complexes reveals that anions play important roles in the self-assembly process under in situ solvothermal conditions. The possible mechanism of decarboxylation is discussed, and the thermal stability and fluorescent properties of these complexes are reported briefly.
04/2010;
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ABSTRACT: Two novel homochiral enantiomers, trinuclear ionic clusters [(NiL(1))(2)Na](+)NCS(-).MeOH.Et(2)O (1) and [(NiL(2))(2)Na](+)NCS(-).MeOH.Et(2)O (2) [H(2)L(1) = N,N'-bis(3-methoxysalicylidene)-(1R,2R)-1,2-diphenylenediamine; H(2)L(2) = N,N'-bis(3-methoxysalicylidene)-(1S,2S)-1,2-diphenylenediamine], have been synthesized and structurally characterized. Both complexes have C(2) symmetry and crystallize in space group P2(1). Ferroelectric measurements reveal that complexes 1 and 2 represent a new type of ionic ferroelectric based on metal-organic coordination with a polarization value higher than that of KH(2)PO(4).
Inorganic Chemistry 02/2010; 49(4):1286-8. · 4.60 Impact Factor
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ABSTRACT: The assembly of chirality into magnetic nanowires enables the formation of two new cyano-bridged heterobimetallic 3,2-chain enantiomeric complexes, representing the first example of multiferroic compounds bearing both slow magnetization relaxation and ferroelectricity.
Chemical Communications 12/2009; · 6.17 Impact Factor
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ABSTRACT: Four isostructural inorganic-organic hybrid ferroelectric compounds, assembled from achiral 3-R-benzylidene-1-aminopyridiniums (R = NO(2), Br, Cl, or F for 1-4, respectively) and [PbI(3)](-) anions with the chiral Kagomé-shaped tubular aggregating architecture, show larger spontaneous polarizations.
Journal of the American Chemical Society 12/2009; 132(1):18-9. · 9.91 Impact Factor
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ABSTRACT: A new family of coordination polymers, [{Cd(d-ca)(bte)}·H2O]n (1, d-H2ca = d-camphor acid, bte = 1,2-bis(1,2,4-triazol-1-yl)ethane), [Cd4(d-ca)4(btp)2(H2O)4]n (2, btp = 1,3-bis(1,2,4-triazol-1-yl)propane), [{Cd(d-ca)(btb)1.5}·3H2O]n (3, btb = 1,4-bis(1,2,4-triazol-1-yl)butane), [{Cd4(d-ca)4(bth)4}·2H2O]n (4, bth = 1,6-bis(1,2,4-triazol-1-yl)hexane), and [{Cd(d-Hca)2(bth)(H2O)}·H2O]n (5), have been prepared under hydrothermal conditions and characterized by elemental analyses, IR, thermogravimetric and X-ray structural analyses. The bis(triazole) ligands with different spacer lengths exhibit conformational flexibility and lead to the generation of diversified architectures. Complex 1 shows a two-dimensional (2D) rectangular network with (4,4) topology. Complex 2 displays the chiral three-dimensional (3D) framework with (32·4) (3·84·12) (83) (4·8·10) topology. The 2D honeycomb motif with one-dimensional (1D) nanosized channels is found in compound 3. Compound 4 is a 2D parallelogram sheet with (4,4) topology. Compound 5 shows a chiral 1D fish-bone chain, and the chains are further connected through hydrogen-bonding interactions to form a 3D supramolecular framework. Their luminescent, second-order nonlinear optical and ferroelectric properties have been investigated in the solid state.
11/2009;
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Berichte der deutschen chemischen Gesellschaft 09/2009; 2009(32):4844 - 4849. · 2.94 Impact Factor
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ABSTRACT: Organocatalytic enantioselective synthesis of alpha-indolyl phosphonates has been successfully carried out via asymmetric Friedel-Crafts alkylation of substituted indoles with (E)-dialkyl 3-oxoprop-1-enylphosphonates in 48-82% yield and 73-96% ee.
Chirality 12/2008; 21(8):777-85. · 2.35 Impact Factor
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ABSTRACT: The use of an equimolar amount of pyrrolidine and HClO4 (30 mol%) was found to be effective in promoting the conjugate addition of indoles to (E)-alpha,beta-unsaturated ketones, affording the corresponding beta-indolyl ketones in excellent yields.
Chemical Communications 03/2006; · 6.17 Impact Factor
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ABSTRACT: By introducing two carrier-transporting moieties (oxadiazole and carbazole) into two diimine ligands (2-(2-pyridine)-benzimidazole and 2,2′-dipyridylamine), respectively, four novel ligands (L1–L4) and their corresponding rhenium(I) complexes (1–4) have been synthesized and characterized by elemental analysis, 1H NMR and IR spectra. Their photophysical properties, thermal analysis, along with the X-ray crystal structure analysis of L4 and corresponding complex 4 are also described. In absorption spectra, the 2-(2-pyridine)-benzimidazole containing complexes 1, 2 show the intraligand charge-transfer (π → π* (L)) bands and metal-to-ligand charge-transfer dπ(Re) → π* MLCT bands, while the 2,2′-dipyridylamine containing complexes 3, 4 only show the π → π* bands. In the excitation spectra, all the complexes show strong MLCT bands. After excitation of π → π* or MLCT bands, all the four Re(I) complexes exhibit broad bands around 550–560 nm due to the Re(I)-based 3MLCT emission. The two complexes 1 (with oxadiazole moiety) and 2 (with carbazole moiety) show the photoluminescence quantum efficiency of 2.0% and 7.5% in solid state, respectively, indicating that the carbazole unit is the better chromophore to enhance the luminescence efficiency of diimine Re(I) complexes than the oxadiazole moiety.
Journal of Photochemistry and Photobiology A: Chemistry.
