Piperidine absorbs CO2 and H2O in air to form a molecular complex： piperidium-l-piperidinecarboxylate-H2O. The structure of the complex was characterized by X-ray single crystal diffraction. The crystal structure was...Piperidine absorbs CO2 and H2O in air to form a molecular complex： piperidium-l-piperidinecarboxylate-H2O. The structure of the complex was characterized by X-ray single crystal diffraction. The crystal structure was determined to be triclinic, space group P1^-with a=0.648 6（8） nm, b=0.809 200） nm, c= 1.357 1（16） nm, a=96.96706）°, β =102.506（15）°,γ=104.202 05）°, Z=2. The complex is stabilized via five hydrogen bonds between the three components, N-O electrostatic interaction and O-O interaction （electron transfer） betweenl-piperidinecarboxylate and H2O. Due to electron transference of carbamate ion, the oxygen atom in water molecule is strongly negatively charged and the O-H bond is considerably shorter than that of the free molecule of water. The formation of the molecular complex is a reversible process and will decompose upon heating. The mechanism of formation and stabilization is further investigated herein.展开更多
Piperidine absorbs CO2 and H2O contents in air to form a molecular complex： piperidium-1-piperidinecarboxylate-H2O. The structure of the complex was characterized by FT-IR and NMR. The complex is stabilized via five ...Piperidine absorbs CO2 and H2O contents in air to form a molecular complex： piperidium-1-piperidinecarboxylate-H2O. The structure of the complex was characterized by FT-IR and NMR. The complex is stabilized via five hydrogen bonds between the three components, N…O electrostatic interaction and O…O interaction （electron transfer） betweenl-piperidinecarboxylate and H2O. Through electron transfer from the carbamate ion, the oxygen atom in water molecule is strongly negatively charged and the O-H bond is considerably shorter than that of free water molecule. The formation of the molecular complex is a reversible process and will decompose upon heating. The mechanism of formation and stabilization is further investigated herein.展开更多
9,10-Anthraquinone forms a series of molecular complexes with NO and NO 2,which are stable in solid state or in organic solutions at room temperature and will decompose to original anthraquinone and NO/NO 2 upon heati...9,10-Anthraquinone forms a series of molecular complexes with NO and NO 2,which are stable in solid state or in organic solutions at room temperature and will decompose to original anthraquinone and NO/NO 2 upon heating.The molecular complexes are formed via charge transfer,which is confirmed by a high-resolution mass spectroscopy.By means of reduction,the complexes can be converted to anthrahydroquinone.The mechanism of formation is investigated herein.展开更多
Topological properties of charge distribution for the title complexes and their constituent are analyzed by using ab initio calculations at 3-21G basis set. The results obtained are compared with those originated from...Topological properties of charge distribution for the title complexes and their constituent are analyzed by using ab initio calculations at 3-21G basis set. The results obtained are compared with those originated from ab initio and energy decomposition method. It has been determined that the title molecular complexes are T-shaped. The characteristics of the bonds and the changes originated from the formation of the complexes are discussed.展开更多
The palladium complex of the molecular complex of poly(4 vinylpyridine) with acetic acid(PVP/ HAc Pd) was prepared. Its catalytic activity for the hydrogenation of nitrobenzene was found much higher than that of the c...The palladium complex of the molecular complex of poly(4 vinylpyridine) with acetic acid(PVP/ HAc Pd) was prepared. Its catalytic activity for the hydrogenation of nitrobenzene was found much higher than that of the corresponding palladium complex of poly(4 vinylpyridine). In the presence of a strong inorganic alkali, especially potassium hydroxide, the catalytic activity is greatly improved. The suitable hydrogenation condition for PVP/HAc Pd is to use 0 1 mol/L ethanol solution of potassium hydroxide as the hydrogenation medium and the hydrogenation is carried out at 45 ℃.展开更多
The inclusion complexes of poorly water-soluble cephalosporin, cefuroxime axetil(CFA), were prepared with β-cyclodextrin(βCD) with or without addition of L-arginine(ARG) to improve its physicochemical properties. We...The inclusion complexes of poorly water-soluble cephalosporin, cefuroxime axetil(CFA), were prepared with β-cyclodextrin(βCD) with or without addition of L-arginine(ARG) to improve its physicochemical properties. We also investigated the effect of ARG on complexation efficiency(CE) of βCD towards CFA in an aqueous medium through phase solubility behaviour according to Higuchi and Connors. Although phase solubility studies showed AL(linear) type of solubility curve in presence and absence of ARG, the CE and association constant(Ks) of βCD towards CFA were significantly promoted in presence of ARG,justifying its use as a ternary component. The solid systems of CFA with βCD were obtained by spray drying technique with or without incorporation of ARG and characterized by differential scanning calorimetry(DSC), X-ray powder diffractometry(XRPD), scanning electron microscopy(SEM), and saturation solubility and dissolution studies. The molecular modeling studies provided a better insight into geometry and inclusion mode of CFA inside βCD cavity. The solubility and dissolution rate of CFA were significantly improved upon complexation with βCD as compared to CFA alone. However, ternary system incorporated with ARG performed better than binary system in physicochemical evaluation. In conclusion, ARG could be exploited as a ternary component to improve the physicochemical properties of CFA via βCD complexation.展开更多
Thiosemicarbazones of 2-amino-5-chlorobenzophenone and 3-aminobenzophenone （L1-La） have been synthesized and their Cu（II） complexes （1-4） were afforded via coordination with cupric chloride. All these compounds ...Thiosemicarbazones of 2-amino-5-chlorobenzophenone and 3-aminobenzophenone （L1-La） have been synthesized and their Cu（II） complexes （1-4） were afforded via coordination with cupric chloride. All these compounds were characterized by UV-vis and lR spectroscopy together with CHN elemental analysis. NMR spectroscopy was also applied to characterize the ligands. In vitro cholinesterase inhibitory assays for the complexes （1-4） showed ICso values less than 10 ~molJL, with complex 1 exhibiting the most activity, ICso = 2.15 ~molJL and 2.16 i^molJL for AChE and BuChE, respectively. Molecular modeling simulation revealed the binding interaction template for complex I with the AChE and BuChE receptors. In DPPH assay, the complexes also showed more in vitro antioxidant activities in comt）arison tn their narent li^ands.展开更多
This work studied the effect of copper ions concentration chelated by functional groups in chitosan on its molecular dynamic. Chitosan Copper complexes prepared having different copper concentrations by the electroche...This work studied the effect of copper ions concentration chelated by functional groups in chitosan on its molecular dynamic. Chitosan Copper complexes prepared having different copper concentrations by the electrochemical oxidation technique in aqueous-acetic acid medium. It was carried out at constant voltage (2 volt.) at room temperature at different electro-oxidation time. The result of partial elemental analysis and XRD studies of chitosan copper complexes compared with chitosan confirmed that the percentage composition of the complexes were found to be depend on the time of electrolysis which is in good agreement with our previous work. Interpretation of the effect of copper ions concentration on molecular motion of chitosan studied using dielectric spectroscopy, the results showed that dielectric constant of chitosan is higher than that of chitosan copper complexes. This may be attributed to the relatively fast segmental motion of chitosan chain slowed down by complexation with copper ions of all complex samples. Calculated activation energy from Arrhenius variation showed increase in value with increasing the copper concentration and all in the range that required for ionic conduction. Temperature dependence part of dielectric parameters gives very useful representation in the glass transition temperature determination.展开更多
Assembly of carbohydrates on nickel (Ⅱ) center by utilizing N-glycosidicbond formation with a branched amine: tris(2-aminoethyl)amine (tren), an unprecedentedchiral inversion around the metal center (Co or Mn) induce...Assembly of carbohydrates on nickel (Ⅱ) center by utilizing N-glycosidicbond formation with a branched amine: tris(2-aminoethyl)amine (tren), an unprecedentedchiral inversion around the metal center (Co or Mn) induced by an interaction betweensugars and sulfate anions, peroxo-bridged dinuclear cobalt (Ⅲ) complex containing N-glycoside ligands from tren and D-glucose and its reversible dioxygen binding property,and novel trimanganese complexes with a linear Mn_3 (Ⅱ, Ⅲ, Ⅱ) assemblage bridged bycarbohydrates are described.展开更多
Six water-soluble polysaccharide-protein complexes coded as GM1, GM2, GM3, GM4, GM5 and GM6 wereisolated from the mycelium of Ganoderma tsugae by extracting with 0.2 mol/L phosphate buffer solution at 25, 40 and80℃, ...Six water-soluble polysaccharide-protein complexes coded as GM1, GM2, GM3, GM4, GM5 and GM6 wereisolated from the mycelium of Ganoderma tsugae by extracting with 0.2 mol/L phosphate buffer solution at 25, 40 and80℃, water at 120℃, 0.5 mol/L aqueous NaOH solution at 25 and 65℃, consecutively. Their chemical components wereanalyzed by using IR, GC, HPLC and ^(13)C-NMR, and some new results were obtained. The four samples GM1, GM2, GM3and GM4 are heteropolysaccharide-prote in complexes, in which, α- (1→3) linked D-glucose is the major monosaccharidewhile galactose, mannose and ribose are the secondary ones. GM5 and GM6 are β-(1→3)-D-glucan-protein complexes. Theprotein content increased from 32% to 69% with the progress of isolation. Weight-average molecu1ar mass M_w and theintrinsic viscosity [η] of the GM samples in 0.5 mol/L aqueous NaCl solution at 25℃ were measured systematically by laserlight scartering (LLS), size exclusion chromatography (SEC) combined with LLS, and viscometry. The M_w of GM1 to GM6are 35.5, 46.8, 58.9, 41.6, 3.3 and 22.0×10~4, respectively. The conformation and molecular mass of the two fractions of sample GM5 were characterized satisfactorily by SEC-LLS without further fractionation.展开更多
In view of the growing interest in molecular orbitals (MOs) encountered in certain complex oxides, we review some of their properties from the band theory perspective and provide detailed examples based on real materi...In view of the growing interest in molecular orbitals (MOs) encountered in certain complex oxides, we review some of their properties from the band theory perspective and provide detailed examples based on real materials. Our discussion includes some technical aspects of identifying MOs in electronic structure calculations and considers cases when MOs can be both orthogonal and non-orthogonal. We also describe orthonormalization of MOs, a procedure converting them into Wannier functions, and discuss the problem of Wannier functions possibly being rather spatially extended and how using MO, rather than atomic orbital, based effective Hamiltonians might be a better choice in describing certain strongly correlated systems as well as systems with strong electron-phonon coupling. Furthermore, we address the problem of strongly correlated MOs and how it can be treated in band theory calculations.展开更多
The crystal and molecular structure of copper(Ⅱ) dimeric complex of S-methyl-B-N-(pyridine N-oxide-2-ylmethylidene) dithiocarbazate with acetonitrile, [CuL (CH3CN)]2 (ClO4)2, was determined by X-ray diffraction. The ...The crystal and molecular structure of copper(Ⅱ) dimeric complex of S-methyl-B-N-(pyridine N-oxide-2-ylmethylidene) dithiocarbazate with acetonitrile, [CuL (CH3CN)]2 (ClO4)2, was determined by X-ray diffraction. The complex crystalizes in monoclinic system with space group P21/n, a= 7. 685(2), 6=20.160(6), c= 10. 847(5) A ,B = 107.89(3), Z=2,Dc=1.788 g/cm3, F(000) = 835. 8, u= 18. 17 cm-1(Moka,R= 0. 057.Each Cu(Ⅱ) ion in the complex is surrounded by a distorted square pyramidal. The basal plane is comprised of S, N and O atoms of one ligand together with a N atom of the solvent--acetonitrile, while the axial position is occupied by the S atom of the other ligand. The bond length of Cu-S(bridging) is 3. 038A . and Cu-Cu distance is 3. 700A.展开更多
A novel ligand N-4-hydroxyacetophenone isonicotinoyl hydrazone and its manganese(II) and nickel(II) metal complexes have been synthesized. The synthesized Schiff base and its metal complexes have been characterized by...A novel ligand N-4-hydroxyacetophenone isonicotinoyl hydrazone and its manganese(II) and nickel(II) metal complexes have been synthesized. The synthesized Schiff base and its metal complexes have been characterized by physical state determination, melting point and solubility measurements in different solvents, infrared, proton nuclear magnetic resonance, mass spectrometric and powder X-ray spectroscopic techniques. The thermal properties of the prepared compounds were obtained from TG/DTG measurements. On the basis of the analytical techniques, the ligand was found to be bidentate in nature coordinating to the metal ions through the azomethine nitrogen and carbonyl oxygen atoms leading to distorted octahedral geometries of the metal complexes which were modeled using MM2 force field. The ligand and its metal(II) complexes were evaluated for antifungal activity against <i>Aspergillus fumigatus, Aspergillus niger, Candida albicans and Rhizopus stolonifera.</i> The antifungal evaluation results revealed an enhanced activity upon coordination of the ligand with the metal(II) ions. The activity of the metal complex to the tested fungal strains was in the order Ni(II) > Mn(II).展开更多
Theoretical investigation on the structures of the octacoordinated [Nd(CO3)4]5-and the nonacoordinated [Nd(CO3)4.OH2]5-complexes, using the SPARKLE parameters of the lanthanides within MOPAC, revealed that they posses...Theoretical investigation on the structures of the octacoordinated [Nd(CO3)4]5-and the nonacoordinated [Nd(CO3)4.OH2]5-complexes, using the SPARKLE parameters of the lanthanides within MOPAC, revealed that they possessed dodecahedral and square antiprismatic structures respectively with an average Nd-O distance of 0.249 nm. These structures and the Nd-O distances agreed well with those experimentally found in the crystal structures. Replacing the water molecule with a fluoride ion or a mondentatecarbonato ligand resulted in a nonacoordinated distorted square antiprismatic structures where the trans-carbonato groups were twisted. The corresponding decacoordinated structures with two fluoride ions or a bidentatecarbonato group, [Nd(CO3)4·F2]7-and [Nd(CO3)5]7-, were also investigated. In both cases considerable twisting of the transcarbonato groups was observed.展开更多
The synthesis and structural characterization of cobalt(II) complexes of amino acid Schiff bases was prepared from Salicylaldehyde and three amino acid (Valine, Leucine, and Isoleucine)?in basic medium. The metal comp...The synthesis and structural characterization of cobalt(II) complexes of amino acid Schiff bases was prepared from Salicylaldehyde and three amino acid (Valine, Leucine, and Isoleucine)?in basic medium. The metal complexes was synthesized by treating an ethanolic solution of the ligand with appropriate amount of metal salts [1:2] [M:L] ratio. The synthesized Schiff bases and their metal complexes have been investigated on the bases of elemental chemical analysis, FTIR, electronic spectral,?1HNMR,?13CNMR, MS, molar conductance and magnetic susceptibility measurements. The electronic spectra of the metal complexes and their magnetic susceptibility measurements suggest octahedral structures are the probable coordination geometries for the isolated complexes. The Schiff bases and their metal complexes were preliminary scanned against various strains of microbes to study their biological effect.展开更多
The crystal structure of the title complex salt has been determined by single-crystal X-ray structure analysis. The crystal data are as follows; Monoclinic, P21/c, a=15.6480(10)A,b=16.7870(10)A, c=10.347(2)A, β=90.79...The crystal structure of the title complex salt has been determined by single-crystal X-ray structure analysis. The crystal data are as follows; Monoclinic, P21/c, a=15.6480(10)A,b=16.7870(10)A, c=10.347(2)A, β=90.790(10), V=2717.7(6)A3, Z=3, and R=0.0333 for 4789 unique reflections. The complex anion has a pseudo-octahedral structure distorted more than the CrⅢand CoⅢ analogs, in which cach iminodiacetato ligand (ida2-) is coordinated in a facial fashion with the two N atoms in a cis configuration, resulting in an unsyin-fac structure.展开更多
Studies on the electronic structure,molecular design,syntheses of some novel series of tetranuclear rare earth complexes in our laboratory have been reviewed.Spin-unrestricted localized INDO method was used to calcula...Studies on the electronic structure,molecular design,syntheses of some novel series of tetranuclear rare earth complexes in our laboratory have been reviewed.Spin-unrestricted localized INDO method was used to calculate the electronic structure and the chemical bonding in the typical rare earth cluster Sc[Sc_6Cl_(12)Co]was discussed.展开更多
The reaction of the cobalt(II) meso-tetraphenylporphyrin (TPP) starting material with an excess of 2-aminophenol (Hon) in organic solvents, yields the cobalt(II) porphyrin species [CoII(TPP)(Hon)2] (1). This compound ...The reaction of the cobalt(II) meso-tetraphenylporphyrin (TPP) starting material with an excess of 2-aminophenol (Hon) in organic solvents, yields the cobalt(II) porphyrin species [CoII(TPP)(Hon)2] (1). This compound has been characterized by UV-vis., IR, MSI MS and 1H NMR spectroscopy. The UV-vis data and especially the proton NMR results, for the isolated product, indicated that complex 1 is a Co(II) mesoporphyrin derivative.The X-ray molecular structure of the title compound bis(2-aminophenol) (tetraphenylporphyrinato) cobalt(II) has been determined. This structure is the first one reported of a metalloporphyrin with a 2-aminophenol axial ligand species. The central metal is hexacoordinated by the four nitrogen atoms of the pyrrole rings and the nitrogen atoms of the two Hon trans axial ligands.展开更多
I. THE COMPLEXITY OFBIOLOGICAL RESPONSESFor an organism, to be living or notdepends on its response to foreign matters.Facing the increasing amount and diversi-ty of chemicals, natural and synthetic, tounderstand the ...I. THE COMPLEXITY OFBIOLOGICAL RESPONSESFor an organism, to be living or notdepends on its response to foreign matters.Facing the increasing amount and diversi-ty of chemicals, natural and synthetic, tounderstand the principles of the biologicalresponses becomes extremely importantin pursuing the way of rational utiliza-tion and governing the foreign matters.However, most biological responses aretoo complex to explore their nature. Forinstance, the risk to human beings andorganisms related to the application ofrare earths in agriculture, forestation, fish-ery and husbandry has been argued展开更多
基金Supported by Project of Education Department of Liaoning Province(20040084)
文摘Piperidine absorbs CO2 and H2O in air to form a molecular complex： piperidium-l-piperidinecarboxylate-H2O. The structure of the complex was characterized by X-ray single crystal diffraction. The crystal structure was determined to be triclinic, space group P1^-with a=0.648 6（8） nm, b=0.809 200） nm, c= 1.357 1（16） nm, a=96.96706）°, β =102.506（15）°,γ=104.202 05）°, Z=2. The complex is stabilized via five hydrogen bonds between the three components, N-O electrostatic interaction and O-O interaction （electron transfer） betweenl-piperidinecarboxylate and H2O. Due to electron transference of carbamate ion, the oxygen atom in water molecule is strongly negatively charged and the O-H bond is considerably shorter than that of the free molecule of water. The formation of the molecular complex is a reversible process and will decompose upon heating. The mechanism of formation and stabilization is further investigated herein.
基金Supported by Project of Education Department of Liaoning Province (20040084)
文摘Piperidine absorbs CO2 and H2O contents in air to form a molecular complex： piperidium-1-piperidinecarboxylate-H2O. The structure of the complex was characterized by FT-IR and NMR. The complex is stabilized via five hydrogen bonds between the three components, N…O electrostatic interaction and O…O interaction （electron transfer） betweenl-piperidinecarboxylate and H2O. Through electron transfer from the carbamate ion, the oxygen atom in water molecule is strongly negatively charged and the O-H bond is considerably shorter than that of free water molecule. The formation of the molecular complex is a reversible process and will decompose upon heating. The mechanism of formation and stabilization is further investigated herein.
基金Supported by Autonomous Research Foundation (DC10040106)Central University Special Research Foundation
文摘9,10-Anthraquinone forms a series of molecular complexes with NO and NO 2,which are stable in solid state or in organic solutions at room temperature and will decompose to original anthraquinone and NO/NO 2 upon heating.The molecular complexes are formed via charge transfer,which is confirmed by a high-resolution mass spectroscopy.By means of reduction,the complexes can be converted to anthrahydroquinone.The mechanism of formation is investigated herein.
基金Supported by the National Natural Science Foundation of China
文摘Topological properties of charge distribution for the title complexes and their constituent are analyzed by using ab initio calculations at 3-21G basis set. The results obtained are compared with those originated from ab initio and energy decomposition method. It has been determined that the title molecular complexes are T-shaped. The characteristics of the bonds and the changes originated from the formation of the complexes are discussed.
基金Supported by the Outstanding Youngs Science Foudation of Henan Province(1999)
文摘The palladium complex of the molecular complex of poly(4 vinylpyridine) with acetic acid(PVP/ HAc Pd) was prepared. Its catalytic activity for the hydrogenation of nitrobenzene was found much higher than that of the corresponding palladium complex of poly(4 vinylpyridine). In the presence of a strong inorganic alkali, especially potassium hydroxide, the catalytic activity is greatly improved. The suitable hydrogenation condition for PVP/HAc Pd is to use 0 1 mol/L ethanol solution of potassium hydroxide as the hydrogenation medium and the hydrogenation is carried out at 45 ℃.
文摘The inclusion complexes of poorly water-soluble cephalosporin, cefuroxime axetil(CFA), were prepared with β-cyclodextrin(βCD) with or without addition of L-arginine(ARG) to improve its physicochemical properties. We also investigated the effect of ARG on complexation efficiency(CE) of βCD towards CFA in an aqueous medium through phase solubility behaviour according to Higuchi and Connors. Although phase solubility studies showed AL(linear) type of solubility curve in presence and absence of ARG, the CE and association constant(Ks) of βCD towards CFA were significantly promoted in presence of ARG,justifying its use as a ternary component. The solid systems of CFA with βCD were obtained by spray drying technique with or without incorporation of ARG and characterized by differential scanning calorimetry(DSC), X-ray powder diffractometry(XRPD), scanning electron microscopy(SEM), and saturation solubility and dissolution studies. The molecular modeling studies provided a better insight into geometry and inclusion mode of CFA inside βCD cavity. The solubility and dissolution rate of CFA were significantly improved upon complexation with βCD as compared to CFA alone. However, ternary system incorporated with ARG performed better than binary system in physicochemical evaluation. In conclusion, ARG could be exploited as a ternary component to improve the physicochemical properties of CFA via βCD complexation.
基金Universiti Sains Malaysia -Science Fund Grant No.1001/PK1M1A/823003 and RU Grant No. 1001/PKIMIA/811196 for the financial support of this work
文摘Thiosemicarbazones of 2-amino-5-chlorobenzophenone and 3-aminobenzophenone （L1-La） have been synthesized and their Cu（II） complexes （1-4） were afforded via coordination with cupric chloride. All these compounds were characterized by UV-vis and lR spectroscopy together with CHN elemental analysis. NMR spectroscopy was also applied to characterize the ligands. In vitro cholinesterase inhibitory assays for the complexes （1-4） showed ICso values less than 10 ~molJL, with complex 1 exhibiting the most activity, ICso = 2.15 ~molJL and 2.16 i^molJL for AChE and BuChE, respectively. Molecular modeling simulation revealed the binding interaction template for complex I with the AChE and BuChE receptors. In DPPH assay, the complexes also showed more in vitro antioxidant activities in comt）arison tn their narent li^ands.
文摘This work studied the effect of copper ions concentration chelated by functional groups in chitosan on its molecular dynamic. Chitosan Copper complexes prepared having different copper concentrations by the electrochemical oxidation technique in aqueous-acetic acid medium. It was carried out at constant voltage (2 volt.) at room temperature at different electro-oxidation time. The result of partial elemental analysis and XRD studies of chitosan copper complexes compared with chitosan confirmed that the percentage composition of the complexes were found to be depend on the time of electrolysis which is in good agreement with our previous work. Interpretation of the effect of copper ions concentration on molecular motion of chitosan studied using dielectric spectroscopy, the results showed that dielectric constant of chitosan is higher than that of chitosan copper complexes. This may be attributed to the relatively fast segmental motion of chitosan chain slowed down by complexation with copper ions of all complex samples. Calculated activation energy from Arrhenius variation showed increase in value with increasing the copper concentration and all in the range that required for ionic conduction. Temperature dependence part of dielectric parameters gives very useful representation in the glass transition temperature determination.
文摘Assembly of carbohydrates on nickel (Ⅱ) center by utilizing N-glycosidicbond formation with a branched amine: tris(2-aminoethyl)amine (tren), an unprecedentedchiral inversion around the metal center (Co or Mn) induced by an interaction betweensugars and sulfate anions, peroxo-bridged dinuclear cobalt (Ⅲ) complex containing N-glycoside ligands from tren and D-glucose and its reversible dioxygen binding property,and novel trimanganese complexes with a linear Mn_3 (Ⅱ, Ⅲ, Ⅱ) assemblage bridged bycarbohydrates are described.
基金This work was supported by the Research Fund for the Doctoral Program of Higher Education and the National Natural Science Foundation of China (No. 20074025).
文摘Six water-soluble polysaccharide-protein complexes coded as GM1, GM2, GM3, GM4, GM5 and GM6 wereisolated from the mycelium of Ganoderma tsugae by extracting with 0.2 mol/L phosphate buffer solution at 25, 40 and80℃, water at 120℃, 0.5 mol/L aqueous NaOH solution at 25 and 65℃, consecutively. Their chemical components wereanalyzed by using IR, GC, HPLC and ^(13)C-NMR, and some new results were obtained. The four samples GM1, GM2, GM3and GM4 are heteropolysaccharide-prote in complexes, in which, α- (1→3) linked D-glucose is the major monosaccharidewhile galactose, mannose and ribose are the secondary ones. GM5 and GM6 are β-(1→3)-D-glucan-protein complexes. Theprotein content increased from 32% to 69% with the progress of isolation. Weight-average molecu1ar mass M_w and theintrinsic viscosity [η] of the GM samples in 0.5 mol/L aqueous NaCl solution at 25℃ were measured systematically by laserlight scartering (LLS), size exclusion chromatography (SEC) combined with LLS, and viscometry. The M_w of GM1 to GM6are 35.5, 46.8, 58.9, 41.6, 3.3 and 22.0×10~4, respectively. The conformation and molecular mass of the two fractions of sample GM5 were characterized satisfactorily by SEC-LLS without further fractionation.
文摘In view of the growing interest in molecular orbitals (MOs) encountered in certain complex oxides, we review some of their properties from the band theory perspective and provide detailed examples based on real materials. Our discussion includes some technical aspects of identifying MOs in electronic structure calculations and considers cases when MOs can be both orthogonal and non-orthogonal. We also describe orthonormalization of MOs, a procedure converting them into Wannier functions, and discuss the problem of Wannier functions possibly being rather spatially extended and how using MO, rather than atomic orbital, based effective Hamiltonians might be a better choice in describing certain strongly correlated systems as well as systems with strong electron-phonon coupling. Furthermore, we address the problem of strongly correlated MOs and how it can be treated in band theory calculations.
文摘The crystal and molecular structure of copper(Ⅱ) dimeric complex of S-methyl-B-N-(pyridine N-oxide-2-ylmethylidene) dithiocarbazate with acetonitrile, [CuL (CH3CN)]2 (ClO4)2, was determined by X-ray diffraction. The complex crystalizes in monoclinic system with space group P21/n, a= 7. 685(2), 6=20.160(6), c= 10. 847(5) A ,B = 107.89(3), Z=2,Dc=1.788 g/cm3, F(000) = 835. 8, u= 18. 17 cm-1(Moka,R= 0. 057.Each Cu(Ⅱ) ion in the complex is surrounded by a distorted square pyramidal. The basal plane is comprised of S, N and O atoms of one ligand together with a N atom of the solvent--acetonitrile, while the axial position is occupied by the S atom of the other ligand. The bond length of Cu-S(bridging) is 3. 038A . and Cu-Cu distance is 3. 700A.
文摘A novel ligand N-4-hydroxyacetophenone isonicotinoyl hydrazone and its manganese(II) and nickel(II) metal complexes have been synthesized. The synthesized Schiff base and its metal complexes have been characterized by physical state determination, melting point and solubility measurements in different solvents, infrared, proton nuclear magnetic resonance, mass spectrometric and powder X-ray spectroscopic techniques. The thermal properties of the prepared compounds were obtained from TG/DTG measurements. On the basis of the analytical techniques, the ligand was found to be bidentate in nature coordinating to the metal ions through the azomethine nitrogen and carbonyl oxygen atoms leading to distorted octahedral geometries of the metal complexes which were modeled using MM2 force field. The ligand and its metal(II) complexes were evaluated for antifungal activity against <i>Aspergillus fumigatus, Aspergillus niger, Candida albicans and Rhizopus stolonifera.</i> The antifungal evaluation results revealed an enhanced activity upon coordination of the ligand with the metal(II) ions. The activity of the metal complex to the tested fungal strains was in the order Ni(II) > Mn(II).
文摘Theoretical investigation on the structures of the octacoordinated [Nd(CO3)4]5-and the nonacoordinated [Nd(CO3)4.OH2]5-complexes, using the SPARKLE parameters of the lanthanides within MOPAC, revealed that they possessed dodecahedral and square antiprismatic structures respectively with an average Nd-O distance of 0.249 nm. These structures and the Nd-O distances agreed well with those experimentally found in the crystal structures. Replacing the water molecule with a fluoride ion or a mondentatecarbonato ligand resulted in a nonacoordinated distorted square antiprismatic structures where the trans-carbonato groups were twisted. The corresponding decacoordinated structures with two fluoride ions or a bidentatecarbonato group, [Nd(CO3)4·F2]7-and [Nd(CO3)5]7-, were also investigated. In both cases considerable twisting of the transcarbonato groups was observed.
文摘The synthesis and structural characterization of cobalt(II) complexes of amino acid Schiff bases was prepared from Salicylaldehyde and three amino acid (Valine, Leucine, and Isoleucine)?in basic medium. The metal complexes was synthesized by treating an ethanolic solution of the ligand with appropriate amount of metal salts [1:2] [M:L] ratio. The synthesized Schiff bases and their metal complexes have been investigated on the bases of elemental chemical analysis, FTIR, electronic spectral,?1HNMR,?13CNMR, MS, molar conductance and magnetic susceptibility measurements. The electronic spectra of the metal complexes and their magnetic susceptibility measurements suggest octahedral structures are the probable coordination geometries for the isolated complexes. The Schiff bases and their metal complexes were preliminary scanned against various strains of microbes to study their biological effect.
文摘The crystal structure of the title complex salt has been determined by single-crystal X-ray structure analysis. The crystal data are as follows; Monoclinic, P21/c, a=15.6480(10)A,b=16.7870(10)A, c=10.347(2)A, β=90.790(10), V=2717.7(6)A3, Z=3, and R=0.0333 for 4789 unique reflections. The complex anion has a pseudo-octahedral structure distorted more than the CrⅢand CoⅢ analogs, in which cach iminodiacetato ligand (ida2-) is coordinated in a facial fashion with the two N atoms in a cis configuration, resulting in an unsyin-fac structure.
基金Project supported by The National Natural Science Foundation of China and Science and Technology Foundation of State Education Commision of China
文摘Studies on the electronic structure,molecular design,syntheses of some novel series of tetranuclear rare earth complexes in our laboratory have been reviewed.Spin-unrestricted localized INDO method was used to calculate the electronic structure and the chemical bonding in the typical rare earth cluster Sc[Sc_6Cl_(12)Co]was discussed.
文摘The reaction of the cobalt(II) meso-tetraphenylporphyrin (TPP) starting material with an excess of 2-aminophenol (Hon) in organic solvents, yields the cobalt(II) porphyrin species [CoII(TPP)(Hon)2] (1). This compound has been characterized by UV-vis., IR, MSI MS and 1H NMR spectroscopy. The UV-vis data and especially the proton NMR results, for the isolated product, indicated that complex 1 is a Co(II) mesoporphyrin derivative.The X-ray molecular structure of the title compound bis(2-aminophenol) (tetraphenylporphyrinato) cobalt(II) has been determined. This structure is the first one reported of a metalloporphyrin with a 2-aminophenol axial ligand species. The central metal is hexacoordinated by the four nitrogen atoms of the pyrrole rings and the nitrogen atoms of the two Hon trans axial ligands.
文摘I. THE COMPLEXITY OFBIOLOGICAL RESPONSESFor an organism, to be living or notdepends on its response to foreign matters.Facing the increasing amount and diversi-ty of chemicals, natural and synthetic, tounderstand the principles of the biologicalresponses becomes extremely importantin pursuing the way of rational utiliza-tion and governing the foreign matters.However, most biological responses aretoo complex to explore their nature. Forinstance, the risk to human beings andorganisms related to the application ofrare earths in agriculture, forestation, fish-ery and husbandry has been argued
