Synthesis and catalytic activity of novel heteronuclear Ln (III) -Cu(II) complexes with noncyclic polyether-amino acid Schiff base

A series of novel heteronuclear Ln(III)-CU(II) complexes with noncyclic polyether-amino acid Schiff base were synthesized. The general formula is (LnCu₂(H₂TALY) (NO₃)₅] (NO₃)₂·nH₂O (Ln= La, Nd, Sm, Gd,n = 4; Ln = Yb, Y,n = 3), where H₂TALY = tetraglycol aldehyde bis-lysine Schiff base. It is the first time to report the synthetic method for this new Cu(II) complexes and Ln(III)-Cu(II) heteronuclear complexes. The complexes were characterized by elemental analysis, IR spectra. TG-DTA, magnetic susceptibility, and especially by a 500 MHz NMR spectrometer for 2D-COSY NMR. Coordination mechanism and structures of complexes have been suggested as well. Of particular interest is the potential that the novel complexes obtained may be used as a catalyst. which prompted us to investigate them. It shows 100% conversion with the viscosity-average molecular weight 120 000 for the polymerization of methyl methacrylate (MMA) without addition of any cocatalyst. Furthermore, the complexes with such aliphatic Schiff bases can be used as a good catalyst, which has been confirmed and discussed here. They may be a new kind of catalyst system with the above speciality. Project supported by the National Natural Science Foundation of China (Grant No. 29671026) and Natural Science Foundation of Zhejiang Province (Grant No. 296062) and the Laboratory of MRAMP (Grant No. 971502).     

Properties of meso-tetrakis (4- n -alkanoyloxyphenyl) porphyrin liquid crystal Co and Ni complexes

Six series of meso-tetrakis (4-n-alkanoyloxyphenyl) porphyrin Co and Ni complexes (12 kinds) were reported. Nine of the compounds were found to exhibit liquid crystal properties and display a hexagonal columnar discotic columnar (Col_h) phase. Molecular structure of all synthesized compounds was confirmed by IR, UV, MS, ¹H NIVR, and elemental analysis. These liquid crystalline compounds have been studied by cyclic voltammetry, luminescence, and surface photovoltage spectroscopy. Supported by the National Natural Science Foundation of China (Grant No. 59783001), the Natural Science Foundation of Shandong Province (Grant No. Y2006B41), the Foundation of Shandong Provincial Education Department (Grant No. J06A53), the Natural Science Foundation of Shandong University of Technology (Grant No. 2004KJM15) and Doctor Foundation of Shandong University of Technology     

Crystal structures of the complexes of rare earth picrates with N, N, N′, N′-tetraphenyl-3, 6-dioxaoctanediamide

The complexes of rare earth picrate with N, N, N′, N′-tetraphenyl-3, 6-dioxaoctanediamide (TDD), [Eu(pic)₃(TDD)]-2CH₃CN and [Y(pic)₃(TDD)], have been synthesized. The crystal structures reveal that TDD acts as a tetradentate ligand, forming a ring-like coordination structure with its oxygen atoms together with one oxygen atom of the bidentate picrate. In the Eu (III) complex, the europium ion with a larger ionic radius lies out of the ring, while in the Y (III) complex, the yttrium ion with a smaller ionic radius enters the cavity of the ligand. The structures of the complexes are greatly affected by the ionic radii due to participation of the picrates in coordination. Project supported by the National Natural Science Foundation of China, the Doctoral Foundation of the State Education Commission of China, and the Climb Plan Foundation of the State Science and Technology Commission of China.     

Sulfonate-based fluorescent probes for imaging hydrogen peroxide in living cells

Based on the mechanism of H₂O₂-mediated hydrolysis of sulfonates, two fluorescein disulfonates compounds (FS-1 and FS-2) were designed and synthesized as the highly selective and sensitive fluorescent probes for imaging H₂O₂ in living cells. The probes were detected with elemental analysis, IR, ¹H NMR and ¹³C NMR. Upon reaction with H₂O₂, the probes exhibit strong fluorescence responses and high selectivity for H₂O₂ over other reactive oxygen species and some biological compounds. Furthermore, the sulfonate-based probes, as novel fluorescent reagents, are cell-permeable and can detect micromolar changes in H₂O₂ concentrations in living cells by using confocal microscopy. Supported by the National Basic Research Program of China (Grant No. 2007CB936000), the National Natural Science Funds for Distinguished Young Scholar (Grant No. 20725518), Major Program of the National Natural Science Foundation of China (Grant No. 90713019), the National Natural Science Foundation of China (Grant No. 20875057), the Natural Science Foundation of Shandong Province, China (Grant No. Y2007B02), and the Science and Technology Development Programs of Shandong Province, China (Grant No. 2008GG30003012)     

Preparation and characterization of a novel strong-fluorescent hydrotalcite-like compound (Al-HTLc)

A novel strong-fluorescent hydrotalcite-like compound (Al-HTLc) was synthesized by coprecipitation. In the sample, the content of aluminum(III) in the layers was decreased to a proper value. The Al3 ions coordinated with 8-hydroxyquinolines (8-HQ) which were dispersed into the anions in the interlayer region. The sample was characterized by XRD, XPS, FT-IR, TG-DSC, UV-Vis, and fluorescence spec- troscopy; its composition and structure were also determined. The results indicate that the sample can emit fluorescence (487 nm) with a strong fluorescence intensity (4.9×105 (a.u.)). The fluorescent lifetime and fluorescence quantum yield of Al-HTLc were measured to be 21.24 ns and 67%, respectively, higher than those of pure 8-hydroxyquinoline aluminum (Alq3). The result of TG-DSC measurement clearly shows the enhanced thermal stability of Al-HTLc compared with that of MgAl-LDH and pure Alq3. Al-HTLc may be used as a novel luminescent functional material.     

In-situ UV-Raman study on soot combustion over TiO2 or ZrO2-supported vanadium oxide catalysts

UV-Raman spectroscopy was used to study the molecular structures of TiO₂ or ZrO₂-supported vanadium oxide catalysts. The real time reaction status of soot combustion over these catalysts was detected by in-situ UV-Raman spectroscopy. The results indicate that TiO₂ undergoes a crystalline phase transformation from anatase to rutile phase with the increasing of reaction temperature. However, no obvious phase transformation process is observed for ZrO₂ support. The structures of supported vanadium oxides also depend on the V loading. The vanadium oxide species supported on TiO₂ or ZrO₂ attain monolayer saturation when V loading is equal to 4 (4 is the number of V atoms per 100 support metal ions). Interestingly, this loading ratio (V₄/TiO₂ and V₄/ZrO₂) gave the best catalytic activities for soot combustion reaction on both supports (TiO₂ and ZrO₂). The formation of surface oxygen complexes (SOC) is verified by in-situ UV Raman spectroscopy and the SOC mainly exist as carboxyl groups during soot combustion. The presence of NO in the reaction gas stream can promote the production of SOC. Supported by the National Natural Science Foundation of China (Grant Nos. 20473053, 20773163 and 20525621), the Beijing Natural Science Foundation (Grant No. 2062020), and the 863 Program of China (Grant No. 2006AA06Z346)     

Quantum dynamics of dissociative adsorption of H2 and D2: The time-dependent wave packet method

A time-dependent quantum wave packet method was used to study the dynamics of dissociative adsorption of H₂ and D₂ on a flat and static surface. The molecule-surface interaction is described using a modified London-Eyring-Polanyi-Sato (LEPS) type potential for the H₂/Ni(100) system. The three-dimensional (3-D) dissociation probabilities were calculated for different initial rovibrational states as a function of initial incident energies. Our results show that the dissociation of the diatomic rotational states whose quantum numbers satisfyj+m = odd is forbidden at low energies for the homonuclear H_z and D₂ due to the selection rule. The effect of the rotational orientation of diatoms on adsorption predicts that the in-plane rotation (m = j) is more favorable for dissociation than the out-of-plane rotation (m = 0). Enhanced dissociation for vibrationally excited molecules and the significant enhancement of the dissociation probability of H2 when compared to D₂ were explained reasonably in terms of quantum mechanical zero-point energies, the tunneling effect and the reflection from an activation barrier. Project supported by the National Natural Science Foundation of China (Grant No. 19694033) and partially by the Science Foundation for Overseas Chinese Scholars and Students, administered by the State Education Commission of China (Grant No. 1992), by the State Key Laboratory of Theoretical and Computational Chemistry of Jilin University at Changchun (Grant No. 98011, and by the Natural Science Foundation of Shandong Province (Grant No. Y96B03022)     

Syntheses, structures and magnetic properties of a family of one-dimensional M(Ⅱ)-lanthanide(Ⅲ) (M =Ni(Ⅱ) and Zn(Ⅱ)) coordination polymers

A series of 1D nickel(Ⅱ)/zinc(Ⅱ)-lanthanide(Ⅲ) coordination polymers, [M(μ-L)2Ln(NO3)3]n· solvents (HL =bis(2-pyridylcarbonyl)amine; M = Ni, Ln = Gd (1 · NiGd), Tb (2· NiTb), Dy (3· NiDy), Ho (4· NiHo), Y (5· NiY);M = Zn, Ln =Gd (6· ZnGd), Tb (7· ZnTb), Dy (8· ZnDy), Ho (9· ZnHo); solvents = H2O or H2O-ethanol), was synthesized and characterized. All of the complexes are isostructural at 293 K and crystallize in the orthorhombic space group Fddd. Magnetic measurements were performed on 1-9, where weak ferromagnetic interaction is found in 1 · NiGd, ferromagnetic interaction in 2·NiTb and 3·NiDy, and antiferromagnetic interaction in 4· NiHo. A remarkable dc magnetic field dependence of ac susceptibilities was found in this series of complexes.     

Synthesis and magnetic resonance of new heteropolynuclear Ln(III)-Cu(II) complexes with noncyclic polyether Schiff base

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Preparation and properties of wheat gluten/silica composites

Wheat gluten (WG)/silica (SiO₂) hybrids were prepared through in-situ synthesis of SiO₂ in WG dispersion of aqueous ammonia. The hybrids with different SiO₂ contents were mixed with glycerol plasticizer to form cohesive dough and the dough was compressively molded to form cross-linked sheets. Morphology, moisture absorption, protein solubility in water, tensile mechanical properties and dynamic rheological behavior of the WG/SiO₂ composites were investigated in relation to SiO₂ contents. Supported by the National Natural Science Foundation of China (Grant No. 50773068) and Natural Science Foundation of Zhejiang Province (Grant No. Y407011)     

PdCl2-catalyzed heterocyclotrimerization in MeOH/scCO2: A versatile approach to dimethyl pyridine-3,5-dicarboxylate from methyl acrylate and urea

A novel and green method for the synthesis of dimethyl pyridine-3,5-dicarboxylate has been developed. It is PdCl₂-catalyzed heterocyclotrimerization of methyl acrylate with urea in methanol/supercritical carbon dioxide. The target compound was obtained with a 75% isolated yield under the optimized conditions. Supported by the National Natural Science Foundation of China (Grant Nos. 20332030, 20572027, 20625205 and 20772034) and Guangdong Natural Science Foundation (Grant No. 07118070)     

DFT and TDDFT investigations on the ground and excited states for polynuclear platinum(II) complexes containing the rigid phenylacetylide ligand

We have studied the ground and excited states of the three dendritic polynuclear Pt(II) complexes 1-[Cl(PH3)2PtC≡≡ C]-3,5-[HC≡≡ C]C6H3 (1), 1,3-[Cl(PH3)2PtC≡≡ C]2-5-[HC≡≡ C]C6H3 (2), and 1,3,5-[Cl(PH3)2- PtC≡≡ C]3C6H3 (3), by using the B3LYP and UB3LYP methods, respectively. TDDFT approach with the PCM model was performed to predict the emission spectra properties of 1―3 in CH2Cl2 solution. We first predicted the excited-state geometries for the three complexes. With the change of the number of Pt(II) atom, 1―3 show the different geometry structures in both the ground and excited states; fur- thermore, the increase of the metal density from 1 to 3 results in the red shift of the lowest-energy emissions along the series. The luminescent properties of 1 are somewhat different from those of 2 and 3. The emission properties of 2 and 3 are richer than 1. Our conclusion can give a good support for designing the high efficient luminescent materials.     

Resonance-enhanced photon excitation spectroscopy of the even-parity autoionizing Rydberg states of Kr

Kr atoms were produced in their metastable states 4p⁵5s [3/2]₂ and 4p⁵5s’ [1/2]₀ in a pulsed DC discharge in a beam, and subsequently excited to the even-parity autoionizing Rydberg states 4p⁵ np′ [3/2]_1,2, [1/2]₁ and 4p⁵ nf′ [5/2]₃ using single photon excitation. The excitation spectra of the even-parity autoionizing resonance series from the metastable Kr were obtained by recording the autoionized Kr⁺ ions with time-of-flight ion detection in the photon energy range of 29000–40000 cm⁻¹. A wealth of autoionizing resonances were newly observed, from which more precise and more systematic spectroscopic data of the level energy and quantum defects were derived. Supported by the National Natural Science Foundation of China (Grant No. 20673107), the National Key Basic Research Special Foundation of China (Grant No. 2007CB815203), and Chinese Academy of Sciences (Grant No. KJCX2-SW-H08)     

Two novel interpenetrated zinc(II) and cadmium(II) coordination polymers based on 4-imidazole-benzoate: Syntheses,crystal structures and properties

Two novel interpenetrated coordination polymers, [Zn(IBA)₂] _n (1) and {[Cd(IBA)₂(H₂O)]·4H₂O} _n (2), have been synthesized by using 4-imidazole-benzoic acid (HIBA) as ligand under hydrothermal conditions. Complex 1 crystallizes in a chiral space group and has a two-fold interpenetrated 2D network structure with (4,4) topology, while complex 2 is a 3D porous dia network with four nets interpenetrating each other. The SHG activity of 1 and the photoluminescent property of 2 have been investigated. Supported by the National Natural Science Foundation of China (Grant Nos. 20731004 & 20721002) and the National Basic Research Program of China (Grant No. 2007CB925103)     

Eu<Superscript>3+</Superscript>-doped LaPO<Subscript>4</Subscript> and LaAlO<Subscript>3</Subscript> nanosystems and their luminescence properties

Eu³⁺ ion-doped LaPO₄ nanowires or nanorods have been successfully synthesized by a simple hydrothermal method. The influence of varying the hydrothermal and subsequent sintering conditions on the morphology and structure of the LaPO₄ host has been investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). For comparison, the Eu³⁺ ions were also doped into monoclinic monazite LaPO₄ nanoparticles and perovskite LaAlO₃ nanoparticles. The relative intensities of the emission lines of the LaPO₄:Eu³⁺ nanosystems were essentially independent of their shape. The optimal doping concentrations in the monoclinic LaPO₄ and perovskite LaAlO₃ nanosystems were determined to be about 5.0 and 3.5 mol%, respectively. Under appropriate UV-radiation, the red light emitted from LaAlO₃:Eu³⁺ (3.5 mol%) was brighter than that from LaPO₄:Eu³⁺ (5.0 mol%) nanomaterial, resulting from differences in their spin-orbit couplings and covalence, which indicates that the nanoscale LaAlO₃ is a promising host material for rare earth ions. Electronic Supplementary Material  Supplementary material is available for this article at and is accessible for authorized users. Supported by the National Natural Science Foundation of China (Grant Nos. 20873039 & 90606001), Hunan Provincial Natural Science Foundation (No. 07jj4002), and the Students Innovation Training Fund of Hunan University     

Catalytic activity correlation of Ni(II), Co(II) and Pd(II) complexes to metal atom net charge

The metal atom net charge correlation (MANCC) method was developed in prediction of catalyst activity of asymmetric late-transition metal complexes, 2-quinoxalinyl-6-iminopyridine Ni (II), 2-imino-1, 10-phenanthroline Co(II) and 2-methoxycarbonyl-6-iminopyridine Pd(II) complexes, from the net charge of the metal atom for ethylene polymerization. Dreiding force field was modified according to the X-ray diffraction data. We found that the asymmetric structure of the complexes resulted in a charge difference between two halogen atoms coordinated to the metal atom. In order to remove such contribution we introduced the effective charge Q _eff, which was obtained by the charge equilibration (QEq) approach. The results verified the successful introduction of Q _eff and showed that the catalytic activities of different complexes are related to central metal atom effective charge. Supported by the National Natural Science Foundation of China (Grant Nos. 90612015, 20674090, and 20474073), and 973 Project (Grant No. 2004CB720606)     

The enzyme-amplified amperometric DNA sensor using an electrodeposited polymer redox mediator

A highly sensitive method for the detection of a breast cancer-associated BRCA-1 gene is reported. The detection is based on a classical sandwich-type assay using horseradish peroxidase (HRP) as a catalytic label and electrodeposited Os^2+/3+ conducting polymer (PAA-PVI-Os) as a redox mediator. Target DNA could be detected by the HRP-catalyzed reduction of H₂O₂, leading to a limit of detection as low as 10 fM. Supported by the National Natural Science Foundation of China (Grant Nos. 20725516, 20704043, 20873175 & 20805055), Shanghai Municipal Commission for Science and Technology (Grant Nos. 0752nm021 & 07ZR14136), Ministry of Science and Technology (Grant Nos. 2006CB933000, 2007CB936000 & 2007AA06A406), Ministry of Health (Grant No. 2009ZX10603), and China Postdoctoral Science Foundation and Shanghai Postdoctoral Scientific Program (Grant No. 07R214160).     

Synthesis and structures of two supramolecular complexes constructed via hydrogen bond linking

Two supramolecular complexes,[Ni(rac-L)]3[CrO4]2[ClO4]2-4H2O (1) and [meso-H2L]0.5[VO3]-0.16H2O (2) (L= 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetra-decane),have been prepared in an aqueous solu-tion,and detected by elemental analysis,IR,TG,and single crystal X-ray diffraction analyses. Com-pound 1 shows a one-dimensional hexagonal prism formed by the hydrogen bonding interactions between the secondary amines of rac-L and CrO42-anion/water molecules. Compound 2 displays a three-dimensional structur...     

An accurate three-dimensional potential energy surface for the He-Na<Subscript>2</Subscript> complex

An accurate three-dimensional potential energy surface (PES) for the He-Na₂ van der Waals complex was calculated at the coupled cluster singles-and-doubles with noniterative inclusion of connected triple (CCSD(T)) level of theory. A mixed basis set, aug-cc-pVQZ for the He atom and cc-pCVQZ for the sodium atom, and an additional (3s3p2d1f) set of midbond functions were used. The computed interaction energies in 819 configurations were fitted to a 96-parameter analytic potential model by least squares fitting. The PES has two shallow wells corresponding to the T-shaped structure and the linear configuration, which are located at 12.5a ₀ and 14 a ₀ with depths of 1.769 and 1.684 cm⁻¹, respectively. The who potential energy surface exhibits weak anisotropy. Based on the fitted PES, state-to-state differential cross sections were calculated. Supported by the Natural Science Foundation of Anhui Educational Committee (Grant No. 2006kj072A) and the Natural Science Foundation of Anhui Province (Grant No. 070416236)