分类: 物理学 >> 普通物理:统计和量子力学,量子信息等 提交时间: 2017-05-02
摘要: We study type I clathrate Ba8Cu5.1Ge40.2Sn0.7 single crystals (space group Pm3"n, no. 223, a 1⁄4 10.7151(3)) grown using a Sn flux method. Microprobe analysis and single-crystal X-ray diffraction reveal a small amount of Sn embedded in the Cu/Ge framework, which increases disorder at the guest Ba sites. Ba8Cu5.1Ge40.2Sn0.7 is diamagnetic with a susceptibility of $2.8 10 7 emu g 1 and shows metal-like behavior (dr/dT > 0) with a low charge carrier concentration of 0.5 e per unit cell at 300 K. The single crystals show a relatively high carrier mobility (m (300 K) 1⁄4 11.9 cm2 V 1) and very low lattice thermal conductivity ($0.6 W m 1 K 1). The thermoelectric figure of merit ZT of Ba8Cu5.1Ge40.2Sn0.7 single crystals reaches a maximum value of 0.6 at 773 K, which can be further improved by adjusting the chemical composition.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: The title compound, ethyl (R)-2-(biphenyl-4-carbonyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4- b]indole-1-carboxylate (C27H24N2O3) has been synthesized, and its structure was characterized by 1H-NMR, 13C-NMR, ESI-MS and single-crystal X-ray diffraction. It crystallizes in the orthorhombic system, space group Pbca with a = 16.9950(8), b = 9.5445(4), c = 28.3188(3) Å, V = 4593.6(3) Å3, Z = 8, T = 294.64(10) K, μ(MoKα) = 0.08 mm-1, Dc = 1.228 g/cm3, F(000) = 1792.0 and GOOF = 1.036. 11836 reflections were measured (7.04≤2θ≤52.04°), and 4506 were unique (Rint = 0.0393, Rsigma = 0.0546) and used in all calculations. The final R = 0.0576 (I > 2σ(I)) and wR = 0.1563 (all data). The preliminary biological tests show that the title compound has a good antitumor activity against Hela in vitro with the IC50 value of 4.71 μmol/L.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: A novel coordination complex, {[Cd2(C20H10O5)2(H2O)4]·10H2O}n, has been synthesized based on fluorescein (2-(6-hydroxy-3-oxo-3H-xanthen-9-yl) benzoic acid) and systematically characterized by elemental analysis, infrared (IR) spectrum, thermo gravimetric analysis (TGA), powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Compound 1 crystallizes in monoclinic, space group P2/n with a = 20.428(5), b = 8.084(2), c = 21.689(5) Å, β = 96.360(5)º, Mr = 993.46, V = 3559.7(15) Å3, Z = 4, Dx = 1.845 g/cm3, μ = 1.276 mm-1, F(000) = 1974.0, GOOF = 1.044, λ(MoKα) = 0.71073 Å, the final R = 0.0553 and wR = 0.1720 for 7245 observed reflections with I > 2σ(I).
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Using 4΄-methoxy-5-hydroxyisoflavone and 4΄,5-dihydroxy-7-methoxyisoflavone as leding compounds, 6-methoxy-2H-phenanthro[9,10-c]pyrazol-11-ol (1a) and 9-methoxy-2H-phenanthro [9,10-c]pyrazol-6,11-diol (1b) were synthesized by two dehydration processes in the EtOH solution. They were characterized by IR, 1H NMR and 13C NMR. The black prism crystal of 1a was grown by the slow solvent evaporation technique from 40:1 (v/v) CHCl3/MeOH, and it was determined by single-crystal X-ray diffraction. In the crystal structure, 1a was stabilized by intramolecular (O–H···N) and intermolecular (N–H···O, O–H···O, π···π, C–H···π) interactions. In addition, the fluorescence properties of 1a and 1b in the base and neutral media revealed that they possessed excited state intramolecular proton transfer phenomena (ESIPT).
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: One new coordination polymer (CP) [Cd(bct)(bib)]·2(H2O) (1), based on 3,5-bis(4΄-carboxy- phenyl)-1,2,4-triazole (H2bct) and 1,4-bis(imidazol-1-ylmethyl)benzene(bib), has been synthesized by hydrothermal method, and its structure was determined and characterized by single-crystal X-ray diffraction analysis, elemental analysis, IR spectroscopy, and thermogravimetric analysis. The crystal structure of CP 1 is a three-dimensional framework with (3,5)-connected topology, where the bct ligands adopt a µ3-kO,kO,kO coordination mode connecting with three Cd centers and the bib ligands adopt a µ2-kN,kN coordination mode bridging two Cd ions. It crystallizes in monoclinic system, space group C2/c, with a = 2.6838(4), b = 1.24221(17), c = 1.8011(2) nm, β = 102.939(2)º, V = 5.8522(13) nm3, Z = 8, C30H27CdN7O6, Mr = 694.00, Dc = 1.566 g/cm3, F(000) = 2784, S = 1.055, R = 0.0294 and wR = 0.0731. Furthermore, solid-state photoluminescence measurements show that CP 1 produces strong emissions at room temperature.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Two new inorganic-organic hybrid vanadogermanates H[Cd(en)(phen)(H2O)][Cd(en)(phen)]{[Cd(phen)]2[Ge8V12O41(OH)7]}�H2O (1) and [Cd(dien)2][Cd(dien)]2{[Cd(phen)]2Ge8V12O42(H2O)(OH)6}�.5H2O (2) (en = ethylenediamine, dien = diethylenetriamine, phen = 1,10-phenanthroline) have been synthesized by hydrothermal method. Their structures were measured by single-crystal X-ray diffractions, thermogravimetric analysis, powder X-ray diffractions and infrared spectra. Structural analysis reveals that compound 1 is an infrequent dimeric structure based on di-Cd-substituted Ge-V-O cluster and transition-metal complex bridges, while compound 2 is an infinite 1-D chain constructed from di-Cd-substituted Ge-V-O clusters and dinuclear bridging complexes. Magnetic measurement indicated that both 1 and 2 exhibit antiferromagnetic behaviors.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Two new copper complexes based on pyrazole-3-carboxylic acid (H2pca) ligand, Cu(Hpca)2(H2O)2·2H2O (1) and Cu2(pca)2(H2O)4 (2) have been synthesized and fully characterized by single-crystal X-ray diffraction (SXRD), infrared spectroscopy (IR), thermal gravity analysis (TGA), powder X-ray diffraction (PXRD) and elemental analyses. Complex 1 is mononuclear while complex 2 shows a dinuclear structure. Complex 1 crystallizes in the monoclinic system, space group P21/c with Z = 2, a = 6.5591(5), b = 21.696(2), c = 4.9486(2) Å, V = 680.94(9) Å3, F(000) = 366, Dc = 1.745 g/cm3, μ = 1.650 mm-1, the final R = 0.0340 and wR = 0.0792. Complex 2 crystallizes in the monoclinic system, space group P21/n with Z = 2, a = 5.1935(4), b = 9.6052(7), c = 12.7347(9) Å, V = 634.44(8) Å3, F(000) = 420, Dc = 2.195 g/cm3, μ = 3.404 mm-1, the final R = 0.0305 and wR = 0.0653. The three-dimensional frameworks of two complexes are formed by the O−H···O and N−H···O hydrogen bonding interactions. Notably, two copper complexes are further used as catalysts in the oxidation of alkylbenzenes using t-butylhydroperoxide (TBHP) as the oxidant and they exhibit excellent catalytic performance (Conv. up to 98.9%, Sele. up to 98.7%).
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: One novel phenoxyacetamide derivative (C22H28N2O3, Mr = 368.47) has been synthesized and determined by means of NMR spectroscopy, high resolution mass spectra and single-crystal X-ray diffraction. The single crystal belongs to the monoclinic system, space group Cc with a = 14.910(3), b = 14.592(3), c = 38.683(8) Å, β = 100.37(3)°, V = 8279(3) Å3, Z = 16, Dc = 1.183 g/cm3, F(000) = 3168, μ = 0.079 mm-1, MoKα radiation (λ = 0.71073 Å), the final R = 0.0508 and wR = 0.0666 for 4120 observed reflections with I > 2σ(I). There are four independent molecules in an asymmetric unit cell. The four symmetry-independent molecules have a variety of different conformations indicating considerable conformational freedom. The bioassay results indicated that the title compound displayed effective activities against glutamine-induced neurotoxicity in PC12 cells and significantly prolonged the survival time of mice subjected to acute cerebral ischemia.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Four new coordination compounds, [Zn(bppc)2(H2O)2]·3H2O (1), [Zn2(bppc)2(m-bdc)(H2O)4]·7H2O (2), [Zn(bppc)2(H2O)2]n·n(m-Hbdc)·n(H2O) (3), [Zn2(bppc)(btc)(H2O)3]n·5nH2O (4) (Hbppc = 2,6-bis(pyrazin-2-yl)pyridine-4-carboxylate, H2(m-bdc) = 1,3-benzenedicarboxylic acid, H3btc = 1,3,5-benzene-tricarboxylic acid), have been hydrothermally synthesized and structurally characterized. Compound 1 shows a mononuclear structure and 2 shows a dinuclear structure. Compound 3 is a one-dimensional chain structure, which is extended into a 3D supramolecular network by intermolecular hydrogen interactions. In 4, a 1D loop-like chain is connected by (btc)3- anions to generate a 2D layer structure. The structure differences of 1~4 show that the pH and aromatic acid as auxiliary ligand have important influence on the final structures.[1]Additionally, the luminescent properties of 1~4 have been investigated with fluorescent spectra in the solid state, and 1~4 display a strong fluorescent emission at room temperature and have potential applications as fluorescent-emitting materials.
提交时间: 2017-05-02
摘要: The title compound, C18H28O3, was prepared by the reaction of 2,6-di-tert-butylphenol with methyl acrylate under basic conditions using dimethyl sulfoxide as the promoter. The structure of this antioxidant indicates significant strain between the ortho te
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Two metal-organic frameworks [(Zn0.5L)·(H2O)]n (1) and [(Ni0.5L)·(H2O)]n (2) constructed by the 3-formyl-4-(pyridin-4-yl) benzoic acid ligand (HL) were synthesized and characterized by single-crystal X-ray diffraction. 1 crystallizes in orthorhombic space group Pnna with a = 16.6152(8), b = 12.6825(6), c = 15.3908(8) Å, V = 3243.2(3) Å3, Z = 4, Mr = 511.12, Dc = 1.047 g/cm3, F(000) = 1048, μ = 1.144 mm-1, GOOF = 1.061, the final R = 0.0471 and wR = 0.1262 for 12168 observed reflections with I > 2σ(I). 2 is isostructural to 1, which also crystallizes in orthorhombic space group Pnna with a = 16.6152(8), b = 12.6825(6), c = 15.3908(8) Å, V = 3243.2(3) Å3, Z = 4, Mr = 511.12, Dc = 1.047 g/cm3, F(000) = 1048, μ = 1.144 mm-1, GOOF = 1.061, the final R = 0.0471 and wR = 0.1262 for 12168 observed reflections with I > 2σ(I). Additionally, thermogravimetric analysis, FT-IR spectroscopy and powder X-ray diffraction were discussed.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: A homochrial manganese(III) complex (1) derived from chiral salen ligand (1R,2R)-(-)-1,2-diphenylethane-1,2-diamine-N,N΄-bicarboxyl-salicylidene) has been synthesized through solvothermal procedure and characterized by IR, elemental analysis, TGA, circular dichroism (CD), powder and single-crystal X-ray crystallography. It crystallizes in orthorhombic, space group P212121 with a = 9.108(3), b = 16.431(5), c = 26.531(6) Å, V = 3970.4(19) Å3, Z = 4, Dc = 1.248 g/cm3, F(000) = 1568, Mr = 745.73, μ = 0.383 mm-1, the final GOOF = 0.957, R = 0.0631 and wR = 0.1079 for 13250 observed reflections with I > 2σ(I). The coordination polymer 1 possesses a 1D infinite zigzag chain architecture constructed by the dicarboxyl-functionalized metallosalen ligand (Mn-salen), and the polymeric chains are further assembled into a 3D supramolecular network structure via strong intermolecular hydrogen bonding interactions between adjacent zigzag chains. As a heterogeneous catalyst, 1 was used as an efficient heterogeneous catalyst for the asymmetric olefin epoxidation.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Two new zinc(II) coordination polymers, [Zn(ph)(H2L)·H2O]2n (1) and [Zn(ip)(H2L)(H2O)]n (2) (H2ph = phthalic acid, H2ip = isophthalic acid, H2L = 3-(1H-pyrazol-4-yl)-5-(pyridin-2-yl)-1,2,4-triazole), have been successfully synthesized via hydrothermal reaction. It has been structurally characterized by X-ray single-crystal analysis, IR spectra, fluorescence spectroscopy and thermogravimetry analysis. The single-crystal X-ray diffraction studies reveal that compounds 1 and 2 both exhibit 1D chain structures, and assemble into 2D and 3D supermolecules through hydrogen bonds or π-π interactions. Moreover, the thermal stability and luminescent properties of compounds 1 and 2 were also studied.
分类: 生物学 >> 生物物理学 提交时间: 2016-05-12
摘要: O-linked N-acetylglucosaminylation (O-GlcNAcylation) is a reversible post-translational modification that plays essential roles in many cellular pathways. Research in this field, however, is hampered by the lack of suitable probes to identify, accumulate, and purify the O-GlcNAcylated proteins. We have previously reported the identification of a lectin from the mushroom Agrocybe aegerita, i.e., Agrocybe aegerita lectin 2, or AAL2, that could bind terminal N-acetylglucosamine with higher affinities and specificity than other currently used probes. In this paper, we report the crystal structures of AAL2 and its complexes with GlcNAc and GlcNAc beta 1-3Gal beta 1-4GlcNAc and reveal the structural basis of GlcNAc recognition by AAL2 and residues essential for the binding of terminal N-acetylglucosamine. Study on AAL2 may enable us to design a protein probe that can be used to identify and purify O-GlcNAcylated proteins more efficiently.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Two new coordination polymers, namely, {[Cd1.5(bc)2(HL)].H2O}2n (1) and [Mn(ip)(H2L)(H2O)]n (2) (H2L = 3-(1H-pyrazol-4-yl)-5-(pyridin-2-yl)-1,2,4-triazole, Hbc = benzoic acid, H2ip = isophthalic acid) were constructed by solvothermal reaction. The compounds were characterized by elemental analysis, FT-IR spectroscopy, and single-crystal X-ray diffraction. Compound 1 displays a two-dimensional plane structure consisting of [Cd3(bc)2(HL)] subunits. Compound 2 possesses a one-dimensional chain structure and is further extended into a 3-D supramolecular architecture via hydrogen bonds. Moreover, photoluminescence studies showed compound 1 exhibits luminescent emissions with emission maxima at 375 nm. Magnetic susceptibility measurements of 2 indicate that domain antiferromagnetic interactions exist between Mn(II) ions. In addition, thermogravimetric properties of 1 and 2 were also measured.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Three new coordination polymers, namely [Zn(FDA)(phen)(H2O)·H2O]n (1), [Cd(HFDA)(phen)2(NO3)] (2) and [Cd(FDA)(phen)]n (3) (H2FDA = 2,5-furandicarboxylic acid, phen = 1,10-phenanthroline) have been synthesized by the solvothermal method and characterized by elemental analysis, IR, powder X-ray diffraction, thermogravimetric analysis and X-ray single-crystal diffraction analysis. For 1, the neighboring Zn2+ ions are bridged by FDA2- as linkers to form one-dimensional (1D) chains, and phen ligands are as the terminal ligands. Furthermore, the 1D chains are packed into a three-dimensional (3D) supramolecular structure through hydrogen bonds and π-π interactions. For 2, the H2FDA ligand is partial deprotonation, which is a rare phenomenon among other coordination polymers based on H2FDA. Under the synergetic effect of phen ligands and the partial deprotonation of H2FDA, the structure of 2 is discrete. For 3, the Cd2+ ions are linked by two carboxylates of FDA2- ligand to give rise to 1D zig-zag chains, and phen ligands chelate the Cd2+ ions like 1. In addition, solid-state luminescent spectra of three coordination polymers were also studied at room temperature.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: A copper coordination polymer, namely [CuL2(H2O)2]·H2O 1 (HL = 3-(1,2,4-triazol-1-yl)benzoic acid) has been synthesized by the hydrothermal reaction under 140 ºC. The structure of 1 was characterized by single-crystal X-ray diffraction analysis, elemental analyses, powder X-ray diffraction, IR spectroscopy, and thermogravimetric analysis. Single-crystal X-ray diffraction analysis reveals that 1 crystallizes in P21/n space group with a = 12.374(5), b = 12.730(5), c = 12.561(5) Å, β = 91.105(9)º, V = 1978.2(14) Å3, Z = 4, Dc = 1.618 g/cm3, μ = 1.160 mm-1, F(000) = 964, the final R = 0.0449 and wR = 0.1443 with I > 2σ(I). Magnetic measurements show that 1 exhibits antiferromagnetic interactions by the analysis of magnetic test data.
分类: 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间: 2016-05-12
摘要: The oxygen-evolving center (OEC) in photosystem II catalyzes a water splitting reaction. Great efforts have already been made to artificially synthesize the OEC, in order to elucidate the structure-function relationship and the mechanism of the reaction. Now, a new synthetic model makes the best mimic yet of the OEC. This recent study opens up the possibility to study the mechanism of photosystem II and photosynthesis in general for applications in renewable energy and synthetic biology.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: Two new complexes [Ag(bix)]n·nNAA·nH2O (1) and [Cd(NAA)(phen)2(H2O)]2·2CH3COO-·H2O (2) (bix = 1,4-bis(imidazol-1-ylmethyl)benzene, HNAA = α-naphthylacetic acid, phen = 1,10-phenanthroline) have been successfully synthesized under hydrothermal conditions. Their structures have been determined by elemental analyses, IR spectroscopy, TG and single-crystal X-ray diffraction analysis. The intermolecular hydrogen bonding or π-π stacking interactions extend the complexes into a 3D supramolecular structure. Moreover, the luminescent properties of complex 2 have been investigated in the solid state.
分类: 化学 >> 物理化学 提交时间: 2017-11-05 合作期刊: 《结构化学》
摘要: A new metal-organic cadmium coordination polymer [Cd(pzdc)0.5(L)]n·nH2O (1, H2pzdc = pyrazine-2,3-dicarboxylic acid, HL = 3-(2-pyridyl)pyrazole) has been successfully synthesized under hydrothermal conditions. The structure has been determined by single-crystal X-ray diffraction analysis, elemental analyses, IR and fluorescence spectrum. Brown crystals crystallize in the orthorhombic system, space group Fdd2 with a = 11.2636(9), b = 38.296(3), c = 10.5795(8) Å, V = 4563.5(6) Å3, C11H9CdN4O3, Mr = 357.62, Dc = 2.082 g/cm3, μ(MoKα) = 1.924 mm-1, F(000) = 2800, Z = 16, the final R = 0.0169 and wR = 0.0443 for 2106 observed reflections (I > 2s(I)). It shows a two-dimensional network structure and extends into a three-dimensional supramolecular framework through π-π stacking interactions. Moreover, we analyzed Natural Bond Orbital (NBO) by using the PBE0/LANL2DZ method built in Gaussian 03 Program. The calculation results showed obvious covalent interaction between the coordinated atoms and Cd(II) ion.