Showing papers by "Nankai University published in 2004"
TL;DR: Two 3d-4f heterometallic coordination polymers synthesized under hydrothermal conditions increased significantly upon addition of Zn2+, while the introduction of other metal ions caused the intensity to be either unchanged or weakened.
Abstract: Two 3d-4f heterometallic coordination polymers {[Ln(PDA)3Mn1.5(H2O)3].3.25H2O}infinity with 1D channels were synthesized under hydrothermal conditions (PDA = pyridine-2,6-dicarboxylic acid; Ln = Eu (1); Ln = Tb (2)). The emission intensities of 1 and 2 increased significantly upon addition of Zn2+, while the introduction of other metal ions caused the intensity to be either unchanged or weakened. The case implies that 1 and 2 may be used as luminescent probes of Zn2+.
818 citations
TL;DR: A nanotubular 3D heterometallic zeolitic polymer was designed and synthesized by simply tuning the amount of coordinated water on the Mn ion in the molecular ladder polymer.
Abstract: A nanotubular 3D heterometallic zeolitic polymer, {[Yb(PDA)3Mn1.5(H2O)3]·1.5H2O}n (2), was designed and synthesized by simply tuning the amount of coordinated water on the Mn ion in the molecular ladder polymer {[Yb(PDA)3Mn1.5(H2O)6]·6H2O}n (1). 1 and 2 were structurally and magnetically characterized. The water molecules capsulated within the nanotube were arrayed into an unprecedented “water” pipe. The robust 2 retained intact networks after the removal of guest water trapped in the nanotubes and even after methanol replaced guest water.
562 citations
TL;DR: This study reports herein a 3D twofold interpenetrating NbO-type network [Cu2(m2OMe)2(L)2·(H2O)0.69]n (2) with 1D channels, which is a bridging ligand to construct new framework materials with novel structures and special properties based on combining its bridging coordination ability with its steric bulk.
Abstract: The construction of coordination networks with novel topologies and porous structures that provide new sizes, shapes, and chemical environments is of great interest in recent years, due to their intriguing structural diversity and potential for many applications. 2] In recent years many porous metal– organic frameworks with unique structures have been obtained and their adsorption properties were widely investigated, however, those with specially shaped channels such as 1D helices are rare. Metal–ligand coordination has been well used in the directed assembly of extended porous metal–organic networks, and one of the key points for such studies is the design or choice of components that organize themselves into desired patterns with useful functions. In this regard, considerable attention has been devoted to the networking ability of isonicotinic acid (1) and its derivatives, which are multifunctional ligands potentially able to act as bridging ligands to produce open lattice species with various structural topologies and large pores. In this study, we choose an analogy of 1, 9-acridinecarboxylic acid (HL), whose coordination chemistry has not been previously investigated, as a bridging ligand to construct new framework materials with novel structures and special properties based on combining its bridging coordination ability with its steric bulk. Although the coordination sites of HL and 1 are very similar, their coordination chemistry are found to be quite different due to the bulk of HL. We report herein a 3D twofold interpenetrating NbO-type network [Cu2(m2OMe)2(L)2·(H2O)0.69]n (2) with 1D channels.
560 citations
TL;DR: This work reports on the first experimental observation of discrete vortex solitons in two-dimensional optically induced photonic lattices and demonstrates strong stabilization of an optical vortex by the lattice in a self-focusing nonlinear medium.
Abstract: We report on the first experimental observation of discrete vortex solitons in two-dimensional optically induced photonic lattices. We demonstrate strong stabilization of an optical vortex by the lattice in a self-focusing nonlinear medium and study the generation of the discrete vortices from a broad class of singular beams.
402 citations
TL;DR: The design and development of new high-performance catalysts for applications in asymmetric catalytic reactions is of ongoing interest in organic chemistry and the dual activation concept greatly broadens the range of artificial catalysts.
Abstract: The design and development of new high-performance catalysts for applications in asymmetric catalytic reactions is of ongoing interest in organic chemistry. The combination of a Lewis acid and a Lewis base working in concert is now considered state of the art in stereoselective syntheses. The synergistic activation by two or more reactive centers allows high reaction rates and excellent transfer of stereochemical information. Despite the self-quenching reaction between Lewis acids and Lewis bases that might lead to an inactive catalyst, considerable effort has been directed towards the development of the dual-activation concept. The ultimate goal is to mimic nature by the discovery of catalytic systems analogous to enzymatic processes that involve metal-ion cocatalysts. With this aim, the dual activation concept greatly broadens the range of artificial catalysts. The most efficient catalytic systems are reviewed, and the mechanisms of action are discussed.
368 citations
TL;DR: In this article, a modified version of the CQ algorithm, called the relaxed CQ, is given, in which we replace PC and PQ by and, respectively, and the latter is easy to implement.
Abstract: Let C and Q be nonempty closed convex sets in RN and RM, respectively, and A is an M by N real matrix. The split feasibility problem (SFP) is to find x C with Ax Q, if such x exists. Byrne proposed an iterative method called the CQ algorithm that involves only the orthogonal projections onto C and Q and does not need to compute the matrix inverse, which may be the main advantage compared with other algorithms. The CQ algorithm is as follows: where γ (0, 2/L), with L being the largest eigenvalue of the matrix ATA and PC and PQ denote the orthogonal projections onto C and Q, respectively. Byrne (2002 Inverse Problems 18 441–53, 2004 Inverse Problems 20 103–20) proved the convergence of the CQ algorithm for arbitrary nonzero matrix A. In his algorithm, Byrne assumed that the projections PC and PQ are easily calculated. In this paper, a modification of the CQ algorithm, called the relaxed CQ algorithm, is given, in which we replace PC and PQ by and , respectively, and the latter are easy to implement. Under mild assumptions, the convergence of the proposed algorithm is established. Then another algorithm for SFP is given; with the help of the CQ algorithm and its relaxed version, it is easy to obtain the convergence of this algorithm and corresponding relaxed scheme.
366 citations
TL;DR: In this article, high-linked narrow or monodisperse poly(divinylbenzene) (PDVB) microspheres were prepared by distillation−precipitation polymerization as a novel polymerization technique in acetonitrile with 2,2'-azobis(2-methylpropionitrile) (AIBN) as initiator.
Abstract: Highly cross-linked narrow or monodisperse poly(divinylbenzene) (PDVB) microspheres were prepared by distillation−precipitation polymerization as a novel polymerization technique in acetonitrile with 2,2‘-azobis(2-methylpropionitrile) (AIBN) as initiator. The polymeric microspheres were formed simultaneously through a precipitation polymerization manner during the distillation of acetonitrile off the reaction system. Narrow or monodisperse particles with spherical shape and smooth surface were prepared with diameters between 1.10 and 3.41 μm without any stabilizers. The particle size and size distribution depended on the reaction conditions. The maximum particle size of 2.14 μm with size distribution index of 1.058 was attained at cross-linking degree of 64%, and the size distribution became narrower with increasing cross-linking degree. The particle sizes increased with increasing monomer and initiator concentration. A series of polymer particles with diameter between 1.99 and 3.41 μm were obtained by mu...
272 citations
TL;DR: It is reported that Apollon binds to, ubiquitinates and facilitates proteasomal degradation of SMAC and caspase-9, which both contain IAP-binding motifs, and suggests thatApollon has an essential function in preventing SMAC-induced apoptosis.
Abstract: Apollon (also known as BRUCE or BIRC6) is a large protein containing baculoviral-IAP-repeat (BIR) and ubiquitin-conjugating enzyme (UBC) domains at the amino- and carboxy termini, respectively. Apollon inhibits apoptosis, but its molecular and physiological function remains unclear. Here we report that Apollon binds to, ubiquitinates and facilitates proteasomal degradation of SMAC and caspase-9, which both contain IAP-binding motifs. Targeted disruption of Apollon in mice caused embryonic and neonatal lethality. Notably, SMAC induced apoptosis in Apollon-deficient cells, but not in Apollon-expressing cells. Furthermore, the IAP-binding motif of SMAC was required to induce apoptosis in Apollon-deficient cells. These results suggest that Apollon has an essential function in preventing SMAC-induced apoptosis.
249 citations
TL;DR: In this paper, a method of grafting ring-opening polymerization of L-lactide onto the surface of hydroxyapatite nano-particles (n-HAP) was developed.
229 citations
TL;DR: Titanium disulfide nanotubes were used as the cathode materials of rechargeable magnesium-ion batteries, showing potential low-cost, high-capacity, and good-reversibility properties.
224 citations
TL;DR: In this paper, the molar ratio of lauric acid to iron nitrate is set 2:1 and the appropriate temperature lies in the range 573-673 K. The experimental results indicate that the particle sizes, thermal stability and magnetic properties of the iron oxide strongly depend on the conditions in the preparation.
TL;DR: Six complexes exhibit six types of bridging modes of N1,N2-triazole in combination with single-atom bridges, whereas 3 is the first example of the micro(3)-Cl bridging mode in triazole-metal complexes.
Abstract: Cadmium salts with different triazole ligands have led to a series of novel triazole−cadmium compounds varying from zero- to three-dimensionality. [Cd2(deatrz)2(H2O)Br4] (1) (deatrz = 3,5-diethyl-4-amino-1,2,4-triazole) is a zero-dimensional complex which uses a triazole ligand together with μ-OH2 as bridges to form a 1D chain via hydrogen-bonding contacts. {[Cd3(deatrz)2Cl6(H2O)2]·2H2O}n (2), {[Cd(dmtrz)Cl2]·1.5H2O}n (3) (dmtrz = 3,5-dimethyl-1,2,4-triazole), and {[Cd3(deatrz)4Cl2(SCN)4]·2H2O}n (4) are polymeric 1D chains. 2 and 4 were constructed via trinuclear cadmium units bridged by triazole ligands and chloride atoms, while 3 consists of μ2-Cl, μ3-Cl, and triazole bridges, cross-linked by hydrogen bonding to give a 3D framework. {[Cd3(dmatrz)4(SCN)6]}n (5) (dmatrz = 3,5-dimethyl-4-amino-1,2,4-triazole) shows a two-dimensional structure whose fundamental units are trinuclear metal cations bridged via triazole ligands. The complex {[Cd(dmtrz)(SCN)2]}n (6) is the first three-dimensional example in N1,N...
TL;DR: The MIP has much higher adsorption capacity for Hb than the non-imprinted polymer with the same chemical composition, and the MIP also has a higher selectivity for the imprinted molecule.
TL;DR: The sorbent possesses a fast kinetics for the removal of Cd(II) from aqueous solution and the uptake capacity and selectivity coefficient are much higher than those of the sorbent prepared in the absence of CTAB-template.
Abstract: A hierarchical double-imprinting concept was applied to the preparation of a new organic−inorganic hybrid sorbent for selective separation of Cd(II) from aqueous solution. In the prepared hierarchically imprinted sorbent, both Cd(II) and surfactant micelles (cetyltrimethylammonium bromide) were used as templates. The sorbent was prepared through self-hydrolysis, self-condensation, and co-condensation of the cross-linking agent (tetraethoxysilicate) and the functional precursor (3-(2-aminoethylamino)-propyltrimethoxysilane) in an alkaline media followed by gelation. The selectivity of the sorbent was investigated by a batch competitive ion-binding experiment using an aqueous Cd(II) and Zn(II) mixture. The largest selectivity coefficient for Cd(II) in the presence of Zn(II) was found to be over 100; the largest relative selectivity coefficient between Cd(II) and Zn(II), over 200. The uptake capacity of the prepared hierarchically imprinted sol−gel sorbent and the selectivity coefficient are much higher than...
TL;DR: In this paper, an efficient catalytic system for the reactions of indole with aldehydes/ketones or imines was presented, where the use of ionic liquids as the reaction media allows facile separation and recycling of the catalyst.
TL;DR: The estrogenic pollutants 4-tert-octylphenol, 4-nonylphenol and BPA were determined in surface water samples from the Haihe River, Tianjin, China by gas chromatography-mass spectrometry (GC-MS) with selected ion monitoring (SIM).
TL;DR: In this article, the authors focus on the decomposition of impacts of core competencies on firm performance and the moderating effects of environmental turbulence on the basis of developing structural equation models using the partial least square (PLS) method.
TL;DR: The formation, crystal structures, and properties of a series of three-dimensional (3-D) Cu(II) coordination polymers, [[Cu(L)2(H2O)2](PF6)2 (H2 O)(1.25)]n, with an angular bridging ligand 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (L)n are reported.
Abstract: The formation, crystal structures, and properties of a series of three-dimensional (3-D) CuII coordination polymers, {[Cu(L)2(H2O)2](PF6)2(H2O)1.25}n (1), {[CuL(N3)2](H2O)1.5}n (2), and {[CuL(H2O)(SO4)](H2O)2}n (3), with an angular bridging ligand 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (L) are reported. Complex 1 crystallizes in the tetragonal I41/a space group (a = b = 13.462(2) A, c = 46.47(1) A, Z = 8), complex 2 in the orthorhombic Pna21 space group (a = 6.379(2) A, b = 10.060(3) A, c = 27.232(9) A, Z = 4), and complex 3 in the orthorhombic P212121 space group (a = 5.510(2) A, b = 10.576(4) A, c = 28.34(1) A, Z = 4). Different polymeric frameworks are obtained by only varying the counterions. These include the 2-fold interpenetrated diamondoid structure of 1, the acentric α-Po network of 2, and the chiral open framework of 3 with (63).(69.8) topology. The interesting anion-exchange, porous, and magnetic properties of these coordination supramolecules have been investigated in detail.
TL;DR: Results showed that the adsorption rates of dye K-GN, K-2BP, KN-R, AAB and 2G are all controlled by liquid film diffusion and particle diffusion.
TL;DR: In this paper, the modified Friedmann equation was derived in the Palatini formulation of modified gravity models of the L(R) type and various cosmological predictions were discussed.
Abstract: Recently, corrections of the L(R) type to Einstein–Hilbert action that become important at small curvature have been proposed. These type of models are intended to explain the observed cosmic acceleration without dark energy. We derive the full modified Friedmann equation in the Palatini formulation of these modified gravity models of the L(R) type. Then, we discuss various cosmological predictions of the modified Friedmann equation.
TL;DR: In this article, the decay of J / ψ → ω π + π − is studied using a sample of 58 million J/ ψ events recorded in the BESII detector.
TL;DR: In this paper, the properties of monodisperse rhombohedral α-Fe 2 O 3 nanoparticles modified by four different surfactants, namely, sodium dodecylsulfonate (SDS), DBS, cetyltrimethyl ammonium bromide (CTAB) and hexadecyipyridinium chloride (HPC), were characterized by means of Fourier transform infrared spectroscopy, X-ray diffraction (XRD), transmission electron micrograph (TEM) and magnetization measurements.
TL;DR: In this article, the Palatini formulation of the modified gravity with a ln R term suggested by Nojiri and Odintsov is discussed and it reduces to the standard Friedmann evolution for high redshift region.
TL;DR: Six new metal-organic coordination networks based on linking unit 2,5-bis(4-pyridyl)-1,3,4-thiadiazole and inorganic Cu(II), Cd(II, and Co(II) salts have been prepared and structurally characterized by single-crystal X-ray analysis.
Abstract: Six new metal-organic coordination networks based on linking unit 2,5-bis(4-pyridyl)-1,3,4-thiadiazole (L(1)) or 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (L(3)) and inorganic Cu(II), Cd(II), and Co(II) salts have been prepared and structurally characterized by single-crystal X-ray analysis. Using L(1) to react with three different Cu(II) salts, Cu(OAc)(2).H(2)O, Cu(NO(3))(2).3H(2)O, and CuSO(4).5H(2)O, respectively, two different one-dimensional (1-D) coordination polymers, [[Cu(2)L(1)(mu-OAc)(4)](CHCl(3))(2)](n) (1) [triclinic, space group P1, a = 7.416(3) A, b = 8.207(3) A, c = 14.137(5) A, alpha = 100.333(7) degrees, beta = 105.013(6) degrees, gamma = 94.547(6) degrees, Z = 1] and [[CuL(1)(NO(3))(2)](CHCl(3))(0.5)](n) (2) [monoclinic, space group C2/c, a = 28.070(8) A, b = 9.289(3) A, c = 15.235(4) A, beta = 113.537(5) degrees, Z = 8], and a chiral 3-D open framework, [[CuL(1)(H(2)O)(SO(4))](H(2)O)(2)](n) (3) [orthorhombic, space group P2(1)2(1)2(1), a = 5.509(2) A, b = 10.545(4) A, c = 29.399(11) A, Z = 4], were obtained. Reaction of L(1) and Cd(ClO(4))(2).6H(2)O or Co(ClO(4))(2).6H(2)O, in the presence of NH(4)SCN, yielded another 3-D open framework, [[CdL(1)(NCS)(2)](CH(3)OH)(1.5)](n) (4) [monoclinic, space group C2/c, a = 28.408(10) A, b = 9.997(5) A, c = 7.358(4) A, beta = 99.013(8) degrees, Z = 4], or a 2-D network, [[Co(L(1)())(2)(NCS)(2)](H(2)O)(2.5)](n) (5) [orthorhombic, space group Pnna, a = 22.210(5) A, b = 12.899(3) A, c = 20.232(4) A, Z = 4]. When L(1) was replaced by L(3) to react with Co(ClO(4))(2).6H(2)O and NH(4)SCN, another 2-D coordination polymer, [Co(L(3))(2)(NCS)(2)](n) (6) [monoclinic, space group P2(1)/c, a = 8.120(3) A, b = 9.829(4) A, c = 17.453(6) A, beta = 103.307(6) degrees, Z = 2], was constructed. These results indicate that the nature of the ligands, metal centers, or counteranions plays the critical role in construction of these novel coordination polymers. The interesting porous natures of two 3-D open frameworks 3 and 4 were investigated by TGA and XPRD techniques, and the magnetic properties of the Cu(II) and Co(II) complexes were studied by variable-temperature magnetic susceptibility and magnetization measurements.
TL;DR: Methylene blue is a phenothiazinium photosensitizer with promising applications in the photodynamic therapy (PDT) for anticancer treatment and the photobleaching processes indicate that the reactive oxygen species are responsible for the self-sensitized photooxidation of MB.
Abstract: Methylene blue (MB) is a phenothiazinium photosensitizer with promising applications in the photodynamic therapy (PDT) for anticancer treatment. The binding properties of MB to herring sperm DNA have been investigated by the measurements of absorption spectra, quenching experiments and the elucidation of the photobleaching processes. Remarkable hypochromic and bathochromic effects of MB in the presence of increasing amounts of DNA have been observed in the absorption spectra. The quenching of MB by the DNA bases obeys the Stern–Volmer equation and ferrocyanide quenching of MB in the absence and presence of DNA is also measured as extended experiments. Results from the above spectral measurements are all consistent with the intercalative binding mode of MB to DNA with the Kb value of 1.89 × 104 M−1. The photobleaching processes of MB and its DNA complex have also been studies, which indicate that the photobleaching of MB and its DNA complex proceeds with different mechanisms and the reactive oxygen species are responsible for the self-sensitized photooxidation of MB.
TL;DR: A simple way to prepare a water-soluble fullerene assembly with a coordinated metal center through end-to-end intermolecular inclusion complexation of a dimeric cyclodextrin with a fullerenes is reported.
Abstract: Fullerene (C60), which has a spherical p-electron system, shows interesting magnetic, superconductivity, electrical, and biochemical properties. It is not surprising then that fullerenes and their derivatives have attracted a lot of attention in recent years and have been successfully applied to materials science and biological technology. However, the application of fullerenes and their derivatives has been limited, owing to their low solubility in water and other frequently used solvents. Several approaches have been explored for preparing water-soluble fullerenes, such as carboxylic acid fullerene derivatives, amino acid fullerene derivatives, fullereneol, peptide and oligonucleotide functionalized fullerene derivatives, protein–fullerene conjugates, pendant fullerene polymers, main-chain fullerene polymers, and dendrimeric fullerenes. In addition, cyclodextrins and bridged bis-cyclodextrins as multifunctional molecular receptors can selectively bind a wide variety of organic, inorganic, [15] and dye guest molecules through hydrophobic interactions, forming host–guest inclusion complexes or nanometer supramolecular assemblies. Therefore, investigations on the molecular recognition and assembly or self-assembly of cyclodextrins and their derivatives are of current interest in chemical and biological systems. Besides, noncovalent supramolecular complexes based on cyclodextrins and fullerenes have been well documented, and the obtained results indicate that watersoluble cyclodextrin–fullerene complexes show unique photophysical and biological properties. Recently, our studies indicated that the resultant complexes of bis-cyclodextrins and pharmacy molecules significantly enhance both water solubility and biological activity of fullerene derivatives. Herein, we report a simple way to prepare a water-soluble fullerene assembly with a coordinated metal center through end-to-end intermolecular inclusion complexation of a dimeric cyclodextrin with a fullerene. Furthermore, the assembly behavior of this complex has been comprehensively
TL;DR: The results suggest that 5,7,4'-trihydroxy-3',5'-dimethoxyflavone and 3-isopropyl- 5-acetoxycyclohexene-2-one-1 may act as allelochemicals participating in the defense of rice against weeds and pathogens.
TL;DR: Five new eclipsed two-dimensional (2D) coordination polymers have been synthesized and characterized by X-ray diffraction and it is indicated that the eclipsed open-channel frameworks are thermally stable up to 300 degrees C.
Abstract: Five new eclipsed two-dimensional (2D) coordination polymers, {[Cd2(TPT)2L2](GM1)3/2(H2O)}∞ (1) (TPT = terephthalate, L = 3-(2-pyridyl)pyrazole, GM1 = terephthalic acid), {[Cd(TPT)L](GM2)(H2O)2}∞ (2) (GM2 = L = 3-(2-pyridyl)pyrazole), {[Cd(TPT)L](GM3)1/2(H2O)}∞ (3) (GM3 = mesitylene), {[Cd4(TPT)4L4](GM4)7/2}∞ (4) (GM4 = tetramethylbenzene), and {[Cd(TPT)L](GM5)1/2}∞ (5) (GM5 = naphthalene), have been synthesized and characterized by X-ray diffraction. All the five complexes take the similar eclipsed 2D open-channel framework with different guest molecules included in the cavities of their channels. TGA analysis indicates that the eclipsed open-channel frameworks are thermally stable up to 300 °C. The porous property of the 2D framework of 5 was also investigated by the XRPD technique, which indicated that the guest molecules included in the open-channel frameworks are removable and the framework is maintained after the removal of the guest molecules. Moreover, complexes 1−5 also display strong blue emissi...