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1.
Sybout N. Poelsma Alastair H. Servante Francesco P. Fanizzi Peter M. Maitlis 《Liquid crystals》2013,40(4):675-685
Abstract Discotic β-diketonate liquid crystals containing palladium(II), and oxovanadium(IV), (V[tbnd]0), analogous to known copper complexes (which display discotic lamellar and columnar mesophases), have been prepared and characterized. These are the first enantiotropic discotics containing Pd(II) and among the earliest examples containing VO(IV). The best-behaved Pd(II) complex is [Pd(DK 10, 10)2], and it also is probable that the complexes [Pd(DKn,n)2] (n = 7–9) are mesomorphic, however their characterization is difficult due to decomposition in the isotropic phase. The mesophase of [Pd(DK 102,102)2], which appears below 100°C, is suggested to be an example of the rare Nd phase on the basis of optical microscopy. The complex [VO(DK8,8)2] is an enantiotropic discotic vanadyl complex; the monotropic behaviour of [VO(DK 10,10)2] was also confirmed. It is suggested that the discotic phase which occurs for [VO(DK 8,8)2] is more organized than that of [Cu(DK 8,8)2]. 相似文献
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Ildar Bikchantaev Yury G. Galyametdinov Olga Kharitonova Igor V. Ovchinnikov Duncan W. Bruce David A. Dunmur Daniel Guillon Benoî t Heinrich 《Liquid crystals》1996,20(4):489-492
Reaction of β-enaminoketones with lanthanide salts leads to mesomorphic complexes displaying an SA mesophase. The mesophase was characterized using X-ray scattering, EPR and magnetic susceptibility. A very high magnetic anisotropy was deduced for a complex containing dysprosium. 相似文献
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An overview of the Group 2 element β-diketonates is presented, including their synthesis, structural characteristics, physical properties, and some potential applications. 相似文献
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S. Stanimirov I. Petkov 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2009,72(5):1127-1133
In the present study, photophysical properties of fluorescent poly(oxyethylene phosphate) tris(β-diketonate) europium (III) complexes have been studied by means of stationary and time-resolved fluorescence spectroscopy (in ethanol at room temperature). The luminescent quantum yields and efficiency for the energy transfer from β-diketonate ligands to Eu(III) ion have been determined for the studied complexes by using diffusion-enhanced fluorescence resonance energy transfer. Obtained results show effect of the polymer ligands upon photophysical properties of the complexes and a relation has been established with length of the oxyethylene spacer between two phosphonate groups. The Förster radiuses of the synthesized compounds with SulfoRhodamine 101 as acceptor have been calculated. Measured distances between molecules of the donors and acceptor at identical acceptor/donor molar ratios have been illustrated the difference in structure of the ternary and polymer complexes in solution even at low concentration. 相似文献
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Li‐Ming Tang Yi‐Qun Duan Li Pan Yue‐Sheng Li 《Journal of polymer science. Part A, Polymer chemistry》2005,43(8):1681-1689
The copolymerizations of ethylene and cyclopentene with bis(β‐enaminoketonato) titanium complexes {[(Ph)NC(R2)CHC(R1)O]2TiCl2; R1 = CF3 and R2 = CH3 for 1a , R1 = Ph and R2 = CF3 for 1b ; and R1 = t‐Bu and R2 = CF3 for 1c } activated with modified methylaluminoxane (MMAO) as a cocatalyst were investigated. High‐molecular‐weight copolymers with cis‐1,2‐cyclopentene units were obtained. The catalyst activity, cyclopentene incorporation, polymer molecular weight, and polydispersity could be controlled over a wide range through the variation of the catalyst structure and reaction parameters, such as the Al/Ti molar ratio, cyclopentene feed concentration, and polymerization reaction temperature. The complex 1b /MMAO catalyst system exhibited the characteristics of a quasi‐living ethylene polymerization and an ethylene–cyclopentene copolymerization and allowed the synthesis of polyethylene‐block‐poly(ethylene‐co‐cyclopentene) diblock copolymer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1681–1689, 2005 相似文献
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The copper(II) complexes of acetylacetone, 1,1,1-trifluoroacetylacetone and 1,1,1,5,5,5-hexafluoroacetylacetone quench the triplet excited state benzophenone efficiently with about equal rate constants. However, the limiting quantum efficiency of the photoreduction increases with increasing number of CF3 groups in the complexes or with increasing hydrogen-atom-donating ability of the solvent. 相似文献
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Kadidal N. Mahendra Gyanendra K. Parashar Ram C. Mehrotra 《Transition Metal Chemistry》1978,3(1):130-133
Summary Equimolar quantities of CrCl3 · 3THF and-diketones, -dkH, react to yield CrCl2(-dk) · 2THF and CrCl2(-dk) · THF complexes in coordinating and noncoordinating solvents respectively. For 1 : 2 and 1 : 3 molar ratios of reactants, derivatives of general formulae CrCl(-dk)2 and Cr(-dk)3 (where-dkH = acerylacetrrnc, benzoylacetonc and dibenzoylmethane) have been isolated. All complexes have been characterized by elemental analysis, molecular weights and by i.r. spectra. 相似文献
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Activated dihydridocarbonyltris(triphenylphosphine)ruthenium catalyzes the cyclodimerization of both bis(2‐thienyl)acetylene and bis(3‐thienyl)acetylene to yield, respectively, 4,5,6‐tris(2′‐thienyl)‐benzo[b]thiophene and 5,6,7‐tris(3′‐thienyl)benzo[b]thiophene. These fluoresce in the blue. Both undergo irreversible one electron oxidation at & sim1.1 mV versus Ag/Ag+ electrode, consistent with oxidation of the benzo[b]thiophene nuclei rather than the substituent thiophene rings. 相似文献
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Federica Benvenuti Carlo Carlini Anna Maria Raspolli Galletti Glauco Sbrana Mario Marchionna Paolo Ferrarini 《先进技术聚合物》1998,9(2):113-120
Styrene–divinylbenzene resins were used for the synthesis of different polymer-bound β-diketones, obtained by anchoring the chelating group through either the central or the lateral position. The heterogenized diketone ligand was subsequently reacted with Ni(COD)2 analogously to the corresponding homogeneous catalysts active in α-olefin oligomerization. The heterogenized catalysts showed a good activity only when the central position of the chelate moiety was free. Heterogenization caused a significant change of selectivity: olefin oligomerization was accompanied by the formation of a large amount of polymeric products. This behavior is discussed in terms of steric effects caused by the bulky polymeric ligand. © 1998 John Wiley & Sons, Ltd. 相似文献
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Li‐Ming Tang Tao Hu Li Pan Yue‐Sheng Li 《Journal of polymer science. Part A, Polymer chemistry》2005,43(24):6323-6330
Copolymerizations of ethylene with α‐olefins (i.e., 1‐hexene, 1‐octene, allylbenzene, and 4‐phenyl‐1‐butene) using the bis(β‐enaminoketonato) titanium complexes [(Ph)NC(R2)CHC(R1)O]2TiCl2 ( 1a : R1 = CF3, R2 = CH3; 1b : R1 = Ph, R2 = CF3; and 1c : R1 = t‐Bu, R2 = CF3), activated with modified methylaluminoxane as a cocatalyst, have been investigated. The catalyst activity, comonomer incorporation, and molecular weight, and molecular weight distribution of the polymers produced can be controlled over a wide range by the variation of the catalyst structure, α‐olefin, and reaction parameters such as the comonomer feed concentration. The substituents R1 and R2 of the ligands affect considerably both the catalyst activity and comonomer incorporation. Precatalyst 1a exhibits high catalytic activity and produces high‐molecular‐weight copolymers with high α‐olefin insertion. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6323–6330, 2005 相似文献
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Fritz Marktscheffel A. F. Turbak Z. W. Wilchinsky 《Journal of polymer science. Part A, Polymer chemistry》1966,4(10):2423-2427
The polymerization of bis(β-chloroethyl) vinylphosphonate to a crystalline solid was carried out with a Ziegler-Natta catalyst. A confirmation of the crystalline nature of the polymers was carried out by x-ray diffraction. The polymers would not melt even at temperatures up to 620°C., but instead began to char. However, they were soluble in dimethylformamide and acrylonitrile. 相似文献
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A novel ligand: 4,4′-bis(8-hydroxyquinoline-5-propenyl)-biphenyl (B8QPB) (1), has been synthesized by Witting-Horner reaction, and the corresponding two polymeric metal complexes were also prepared by polynuclear of the ligand with aluminium (III) (2) and zinc (II) (3) halides, respectively. The structure of the ligand was characterized by 1H NMR, FT-IR and elemental analysis techniques; polymeric metal complexes were characterized by FT-IR, UV-vis, elemental analysis techniques, conductivity measurements and gel permeation chromatography (GPC). The results indicate that the stoichiometry of polymeric metal complexes is [(C34H24O2N2)11Al12Cl28] and [(C34H24O2N2)32(ZnCl2)33]. B8QPB coordinated with metal ions to form polymers. The luminescence properties of the complexes 1-3 were investigated by UV-vis and fluorescence spectra at room temperature. The experimental results show that polymeric metal complexes 2 and 3 emit blue/green luminescence at 514 and 504 nm in the solid state and at 470 and 507 nm in DMSO solution. Thermal properties measurement and analysis show that they have good thermal stabilities. 相似文献
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Anders Hammershi Magnus Schau‐Magnussen Jesper Bendix Anne Mlgaard 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(11):m319-m322
The structures of the diastereoisomers Λ(+)578‐, (I), and Δ(−)578‐bis(ethane‐1,2‐diamine)[β‐ethyl (S)‐aspartato‐κ2N,O1]cobalt(III) bis(perchlorate) monohydrate, (II), both [Co(C6H10N2O4)(C2H8N2)2](ClO4)2·H2O, are compared. In both structures, the ester group of the amino acid side chain is engaged only in intramolecular hydrogen bonding to coordinated amine groups. This interaction is stronger in (I) and correlates with previously observed diastereoisomeric equilibrium ratios for related metal complex systems in aqueous media. The two perchlorate anions of (II) are located on twofold axes. Both perchlorates in (I) and one of the perchlorates in (II) are affected by disorder. Both structures exhibit extensive three‐dimensional hydrogen‐bonding networks. 相似文献
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Kenneth E. Rohly John S. Heffren Bodie E. Douglas 《Journal of mass spectrometry : JMS》1984,19(8):398-402
Complexes of 2,4-pentanedione (acetylacetone, acac), [Cu(acac)2], [VO(acac)2] and [CO(acac)3], and the chromium(III) derivative of 3-methyl-2,4-pentanedione (methylacetylacetone, meac), [Cr(meac)3], the ligands bis(benzoylacetone)ethylenediimine and bis(salicylidene)ethylenediimine, and their cobalt(II), nickel(II) and copper(II) chelates were analysed by laser desorption mass spectrometry (LAMMA) and compared to electron impact (EI) results. The positive ion LAMMA spectra generally reveal mostly small fragments, although metal cationization peaks are seen for most complexes. Negative ion LAMMA produce carbon clusters and some structurally important fragments. 相似文献