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1.
The single crystal structure of LaPS4, (1), is reported. The space group is tetragonal, I4(1)/acd. Unit cell dimensions are a = 10.9641(3) Å and c = 19.4828(9) Å. The far infrared absorption and Raman spectra (100-600 cm−1) are consistent with the groups being in a distorted tetrahedral geometry. The room temperature emission spectrum of LaPS4 doped with Er3+ is also presented. Emission peaks at 529, 534, 549, and 554 nm were observed when the sample was excited at 492 nm. The compound reported here is isomorphous and isostructural to several other lanthanide orthothiophosphates. 相似文献
2.
Flash photolysis with time-resolved infrared (TRIR) spectroscopy was used to elucidate the photochemical reactivity of the hydroformylation catalyst precursor Co2(CO)6(PMePh2)2. Depending on reaction conditions, the net products of photolysis varied significantly. A model is presented that accounts for the net reactivity with two initial photoproducts, the 17-electron species Co(CO)3(PMePh2) and the coordinatively unsaturated dimer Co2(CO)5(PMePh2)2. No evidence was found for photochemical formation of Co2(CO)6(PMePh2). Time-resolved spectroscopic studies allowed for the direct observation of transient species and for kinetics studies of certain reactions; for example, the reactions of Co(CO)3PMePh2 with CO and with PMePh2 gave the respective rate constants 1.5 × 105 and 1.2 × 107 M−1 s−1, while the analogous reactions with Co2(CO)5(PMePh2)2 gave the rate constants of 2.6 × 106 M−1 s−1 and 3.9 × 107 M−1 s−1. 相似文献
3.
A novel organic-inorganic hybrid pentaborate [Ni(C4H10N2)(C2H8N2)2][B5O6(OH)4]2 has been synthesized by hydrothermal reaction and characterized by FT-IR, Raman spectroscopy, elemental analyses and DTA-TGA. Its crystal structure was determined from single crystal X-ray diffraction. The structure consists of isolated polyborate anion [B5O6(OH)4]− and nickel complex cation of [Ni(C4H10N2)(C2H8N2)2]2+, in which the two kinds of ligands come from the decomposition of triethylenetriamine material. The [B5O6(OH)4]− units are connected to one another through hydrogen bonds, forming a three-dimensional framework with large channel along the a and c axes, in which the templating [Ni(C4H10N2)(C2H8N2)2]2+ cations are located. The assignments of the record FT-IR absorption frequencies and Raman shifts were given. 相似文献
4.
Salvatore V. Pizzo John J. Pasqua 《Biochimica et Biophysica Acta (BBA)/General Subjects》1982,718(2):177-184
The clearance of human fibrinogen fragments D1, D2, D3 and fibrin fragment D1 dimer were studied in the mouse model. Clearance of these fragments is a complex process involving clearance from blood into three other compartments. The overall clearance of fragment D1 and its dimer were essentially identical. Fragments D2 and D3 cleared at a progressively slower rate. Competition studies were performed between 125I-labeled fragment D1 and large molar excesses of unlabelled human fragments D1, D2, D3, D1 dimer, fragment E, fibrinogen, macroalbumin, mannan and asialooroscomucoid. Of these ligands only the fragment D variants competed for the clearance of 125I-labeled fragment D1. Cross-competition was observed when 125I-labeled fragment D1 dimer was cleared in the presence of large molar excesses of fragment D1. Autopsies demonstrated that injected fragments D1, D2, D3 and D1 dimer cleared primarily in liver and kidneys. In some clearance studies, livers were perfused with tissue culture fluid, subjected to light microscopic autoradiography, and silver grain counts performed to localize cleared fragment D1. These experiments indicated that 80% of the liver uptake was in hepatocytes. However, when silver grain counts were normalized for the number of parenchymal and nonparenchymal cells, the distribution of silver grains was essentially identical (1.8 and 1.6 grains per cell, respectively). It is concluded that fragments D1, D2, D3 and D1 dimer are recognized by a similar clearance pathway. Since neither fibrinogen nor fragment E competed for the clearance of fragment D1, it is suggested that determinants present in the fragment D domain become exposed after plasmin attack on fibrinogen and are responsible for clearance. 相似文献
5.
Chemical analysis of the surface of microorganisms by X-ray photoelectron spectroscopy 总被引:1,自引:0,他引:1
D.E. Amory N. Mozes M.P. Hermesse A.J. Leonard P.G. Rouxhet 《FEMS microbiology letters》1988,49(1):107-110
Abstract A collection of microorganisms, including a microfungus and various yeasts and bacteria has been analyzed by X-ray photoelectron spectroscopy (XPS). A correlation is observed between the N/P atomic concentration ratio of the cell surface and the cell electrophoretic mobility measured at pH 4, indicating that the dehydrated surface analyzed by XPS is representative of the cell surface in contact with water.
Deprotonation of phosphate groups plays a predominant role in the development of the cell negative charge, and carboxylic groups are not involved appreciably; a partial neutralization is allowed by protonation of free amino groups of proteins.
These results advocate a broader use of XPS in order to understand physicochemical properties (electrostatic charge, hydrophobicity, ion binding) of the surface of cells, which are of prime importance in various processes occurring in nature and technology. 相似文献
Deprotonation of phosphate groups plays a predominant role in the development of the cell negative charge, and carboxylic groups are not involved appreciably; a partial neutralization is allowed by protonation of free amino groups of proteins.
These results advocate a broader use of XPS in order to understand physicochemical properties (electrostatic charge, hydrophobicity, ion binding) of the surface of cells, which are of prime importance in various processes occurring in nature and technology. 相似文献
6.
Articular cartilage posesses unique material properties due to a complex depth-dependent composition of sub-components. Raman spectroscopy has proven valuable in quantifying this composition through cartilage cross-sections. However, cross-sectioning requires tissue destruction and is not practical in situ. In this work, Raman spectroscopy-based multivariate curve resolution (MCR) was employed in porcine cartilage samples (n = 12) to measure collagen, glycosaminoglycan, and water distributions through the surface for the first time; these were compared against cross-section standards. Through the surface Raman measurements proved reliable in predicting composition distribution up to a depth of approximately 0.5 mm. A fructose-based optical clearing agent (OCA) was also used in an attempt to further improve depth of resolution of this measurement method. However, it did not; mainly due to a high-spectral overlap with the Raman spectra of main cartilage sub-components. This measurement technique potentially could be used in situ, to better understand the etiology of joint diseases such as osteoarthritis (OA). 相似文献
7.
Doping of fullerenes has received considerable attention, both experimentally and theoretically, as a tool to fine tuning their physical and chemical properties. In this contribution, we report the results of quantum-chemical calculations on several isomers of the boron and nitrogen doped fullerene derivative C48B6N6. Optimized structures, relative stability and spectroscopic properties were computed at the B3LYP/6-31G∗ level of theory. The more stable structures were characterized by computing vibrational frequencies along with Raman and IR intensities and by modeling their absorption spectra with semiempirical and TD-DFT calculations of excitation energies and intensities. Owing to the symmetry lowering with respect to C60, the first allowed transitions of the more stable C48B6N6 cages appear at lower energies. Despite this, the HOMO-LUMO energy gap, a measure of the semiconducting property, is only slightly reduced, compared to C60. The calculated atomic charge distributions indicate considerable localization of charge on the heteroatoms. As a result, these isomers are expected to have more interesting condensed phase properties than C60 owing to their enhanced intermolecular interactions. Among the isomers considered, the reduced structural deformation and favorable electrostatic interactions lead to a preference for the S6 structure in which two B3N3 aggregates are located on opposite hexagons on the cage. 相似文献
8.
Purified plasma membranes of mouse EL4 lymphoma cells were fractionated by means of affinity chromatography on concanavalin A-Sepharose into two subfractions; one (MF1) eluted freely from the affinity column, the second (MF2) adhered specifically to Con A-Sepharose. Both membrane subfractions proved to be of plasma membrane origin, as evidenced by the following criteria. (i) The ratio of cholesterol to phospholipid was nearly identical in plasma membrane and both subfractions. (ii) When isolated plasma membranes were labelled with tritiated NaBH4, both subfractions exhibited identical specific radioactivities. (iii) After enzymatic radioiodination of the cells, the total content of labelled proteins was very similar in isolated plasma membranes and in both subfractions. (iv) Some plasma membrane marker enzymes exhibited nearly identical specific activities in plasma membranes, MF1 or MF2 including γ-glutamyl transpeptidase, 5′-nucleotidase and Mg2+-ATPase. Both subfractions exhibited characteristic differences. Thus the specific activities of (Na+ + K+)-ATPase, Ca2+-ATPase and lysophosphatidylcholine acyltransferase were several-fold enriched in MF2 compared to MF1. SDS-polyacrylamide gel electrophoresis revealed a different polypeptide composition of the two subfractions. Polypeptides of apparent molecular mass of 116, 95, 42, 39, 30 and 28 kDa were highly enriched in MF2, whereas MF1 contained another set of proteins, of apparent molecular mass of 70, 55 and 24 kDa. The phospholipid fatty acid composition of the subfractions proved to be different, as well, MF2 contained more saturated fatty acids than MF1. The data suggest the existence of plasma membrane domains in the plasma membranes of the mouse EL4 lymphoma cells, containing a set of polypeptides, among others membrane bound enzymes, embedded in a different phospholipid milieu. 相似文献
9.
Bruno Therrien Ludovic Vieille-Petit Georg Süss-Fink 《Inorganica chimica acta》2004,357(11):3289-3294
The trinuclear arene-ruthenium cluster cation [H3Ru3(C6H6)(C6Me6)2(O)]+, containing a μ3-oxo cap and three arene ligands that span a hydrophobic pocket above the metal skeleton, has been crystallised as tetrafluoroborate salt in the presence of various guest molecules. The host-guest complexes have been characterised by single-crystal X-ray structure analysis. With chloroform as the guest molecule, a CHCl3 molecule sits perfectly in the hydrophobic pocket, the hydrogen atom being encapsulated inside the cavity. When dioxane is added during the crystallisation process, the cluster forms infinite chains which are connected by a complex network of hydrogen bonds involving the μ3-oxo ligand, water and dioxane molecules. Interestingly, in the presence of phenol, a water molecule is hydrogen-bonded between the μ3-oxo ligand and the phenol molecule, forming a one-dimensional μ3-O ? H2O ? HO hydrogen-bonded chain. Finally, with benzoic acid, a head-to-tail host-guest chain is obtained, the phenyl ring being incorporated in the hydrophobic pocket, while the acid group is hydrogen-bonded to the μ3-oxo ligand. 相似文献
10.
Brian T. Heaton Jonathan A. Iggo Vadim I. Ponomarenko Sergey P. Tunik 《Inorganica chimica acta》2010,363(3):549-554
Addition of excess CF3CO2H (HTFA) to [Rh2Pt2(CO)7(PPh3)3], I, under nitrogen results in the formation of a salt (X2+ Y2−), which contains only the second example of a di-cationic carbonyl hydride tetra-nuclear cluster, [H2Rh2Pt2(CO)7(PPh3)3]2+, X2+, and a presently partially characterized polymetallic anion Y2−. The di-cation X2+ has been characterized by mass spectrometry and a variety of multinuclear NMR methods. Since there is no difference in the electron count for I and X2+, it is probable that both I and X2+ adopt similar butterfly metallic frameworks with a Rh-Rh hinge; in X2+, there are two bridging hydrides to the same wing-tip Pt but the phosphine site occupancies on the Rh2Pt2-framework in I and X2+ are different. 相似文献
11.
12.
Infrared and Raman spectra of solid trans-dichloro-bis[diperfluoroethyl(phenyl)phosphine]platinum(II), trans-Pt[PPh(CF3CF2)2]2Cl2, have been studied at high external pressures up to ∼50 kbar with the aid of a diamond-anvil cell. A gradual, pressure-induced phase transition, most probably second order, was observed in the 21-34 kbar pressure range. In the IR spectra, the bands assigned to the CF stretching modes of the CF3 groups exhibit larger pressure sensitivities than do those associated with the CF stretching modes of the CF2 groups, most probably because of their physical location on the outside in the molecules in the unit cell. The fairly high pressure sensitivities of the symmetric PtCl stretching mode in both the low and high pressure phases (0.46 and 37 cm−1/kbar, respectively) are considered to reflect the low force constant associated with the long PtCl bond length thus making this vibration more susceptible to compression. 相似文献
13.
Emanuela Tamburri Valeria Guglielmotti Silvia Orlanducci Maria Letizia Terranova 《Inorganica chimica acta》2011,377(1):170-176
The present paper focuses on the impact of different electro-synthesis processes, used to produce poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) systems in aqueous medium, on the polymer backbone and its electro-catalytic activity.FE-SEM and micro-Raman spectroscopy were used to analyze the samples obtained by varying the conditions of the electro-polymerization processes. The I2/I− redox behaviour of various PEDOT-PSS layers has been comparatively examined in relation to the surface morphology and structural characteristics of the polymer. A response similar to that of a conventional Pt electrode has been revealed for the films produced by chronoamperometric technique.The study has demonstrated that the polymer structure plays an important role in the electro-activity, providing a possibility to improve the redox performance of PEDOT-PSS films by a proper choice of the synthesis methods. Moreover, the use of aqueous solution as a reaction medium can be welcomed as a sustainable chemistry way involving the use of environmentally friendly chemicals. 相似文献
14.
Three bulky silanes, [SiH2Mes2] (1), [SiHMeMes2] (2), SiHMes3 (3), two novel amines, [NH(SiHMes2)2] (4), NH2(SiMeMes2) (5), and three novel alkali metal ion complexes, [Na{N(SiHMes2)2}(OEt2)] (6), Li{N(SiHMes2)2} (7), K{N(SiHMes2)2} (8), have been synthesized and characterized by multinuclear NMR and mass spectroscopy. The structures of compounds 1, 4 and 6 have been determined by X-ray crystallography. The spectroscopy and structural results are discussed. 相似文献
15.
β-Amylase (EC 3.2.1.2) from Bacillus megaterium B6 was immobilized in gelatin by covalent cross-linking with organic hardeners, formaldehyde and gluteraldehyde, of which gluteraldehyde was proved to be better. The effect of temperature, pH, incubation time, substrate concentration, different surfactants and thiol inhibitors on immobilized β-amylase had been investigated. Reuse efficiency and cross-linker concentration was also studied. The data indicated that enhanced resistance to thermal and chemical denaturation, increased temperature optima (from 60° to 65°C) and rapid rate of substrate saturation were achieved after immobilization. The gelatin-bound enzyme could also be reutilized for repeated batch experiments. 相似文献
16.
Yu Zhiyong Author Vitae Author Vitae M. Bensimon Author Vitae Author Vitae 《Inorganica chimica acta》2008,361(3):589-594
This review summarizes the recent developments of thin film polymer coated photocatalysis with TiO2 mediating the discoloration/degradation of the azo-dye Orange II under light irradiation. The stable anchoring of TiO2 on non-heat resistant but chemically inert flexible polymer films is described. The nature of the polymer films used, the pretreatment of the film for the TiO2 loading and the testing of the photocatalytic activity are addressed for different inert polymer films not having the conventional functional surface groups to bind TiO2. The discoloration of Orange II in the presence of LDPE/TiO2 is completed in about 10 h. This is a significantly longer times than the one observed for the same process when Tedlar/TiO2 and Parylene/TiO2 were used in the dye discoloration process. This points out to specific effects particular to each the polymer support used to graft the photoactive TiO2 particles. 相似文献
17.
Norberto S GonçalvesLucia K Noda Paulo S SantosAdailton J Bortoluzzi Ademir Neves Ivo Vencato 《Inorganica chimica acta》2002,329(1):141-146
The ligand N,N′-bis(2-hydroxybenzyl)-2-ol-1,3-propanediamine (H3bbpnol) reacts with iron(III) perchlorate forming two dinuclear bis-μ-alkoxo complexes, a ‘cis-trans’ isomer (complex 1) previously reported and a ‘cis-cis’ isomer (complex 2) characterized in this work. The main differences found in complex 2 structure are, (a) the four phenolic oxygens are trans to the alkoxo bridges; (b) each ligand is shared by the two Fe(III) ions occupying two coordination positions at each center. The Fe(III) centers in the resulting centrosymmetric structure in complex 2 have a distorted-octahedral geometry with the equatorial plane occupied by the phenolic and alcoholic oxygen atoms and the apical positions are filled by the aminic nitrogen atoms. The resonance Raman (RR) spectra of these two isomeric complexes are somewhat different with the intensity of some low-frequency modes increasing in the less symmetric core. The electronic spectra of both complexes are similar, but the molar absorptivities are substantially increased in complex 2, indicating the presence of an electronic coupling between the phenolate moieties trans in relation to the alkoxo bridge, and that phenolates coordinated cis to the alkoxo bridge do not seem to contribute to LMCT oscillator strength. This is directly reflected in the Raman excitation profiles (REP) of the chromophore modes, with the vibrational modes of the ‘cis-cis’ isomer showing a greater intensification compared with the ‘cis-trans’ isomer. 相似文献
18.
A novel organic-inorganic hybrid complex [(2-NH2CH2C5H4N)ZnCl3] has been hydrothermally synthesized and characterized by single crystal X-ray diffraction, thermal analysis and spectroscopic studies. The compound crystallizes in the triclinic system, space group , a = 7.5339(9), b = 7.589(2), c = 9.365(2) Å, α = 104.55(2)°, β = 97.22(1)°, γ = 87.88(2)°, V = 513.6(2), Z = 2. In the title compound the 2-aminomethylpyridine acts as a ligand covalently linked to Zn(II) cation to form a slightly distorted ZnCl3N tetrahedral environment. Each [Zn(C6H8N2)Cl3] unit is connected to one neighbor by a pair of hydrogen bonds between the apical chlorides and amine hydrogen atoms and to the other by a couple of π-π stacking interactions between the aromatic rings of the coordinated ligands forming a novel one-dimensional chain-like arrangement. The title complex is the first one that contains both coordinated and hydrogen bonded 2-aminomethylpyridine. Solid state 13C and 15N CP-MAS-NMR spectroscopies are in agreement with the X-ray structure. Ab initio calculations allow the attribution of carbons and nitrogen to the independent crystallographic sites. The Raman spectroscopy confirmed the presence of Zn-Cl and Zn-N bonds. 相似文献
19.
First-principles density functional theory calculations have been used to study the relative stability and analyse the chemical bonding of novel cross-linked carborane polymers. Atomic charges with several population analysis methods based on fully relaxed structures were calculated to interpret the chemical binding energy shifts of XPS spectra of these boron carbide polymers. The results indicate that a base structure with one aromatic linking unit with carborane is energetically favoured. The linear relationship between experimental core-level photoemission binding energies and computational partial atomic charges from four population analysis methods (Mulliken, Hirshfeld, atoms-in-molecules (AIM) and natural bond order (NBO)) were analysed and the results indicate that cross-linking occurs at icosahedral B sites non-adjacent to icosahedral carbon sites, in agreement with recently reported experimental results. The role of basis set size in determining partial atomic charges was found to vary with population analysis method. Best linear correlations were identified with the more robust population analysis methods (Hirshfeld, AIM and NBO) with the AIM methods noted as being particularly sensitive to basis set size. 相似文献
20.
Rats injected with LiCl after they consumed a sweetened milk solution subsequently avoided the milk. ACTH4--10 injection prior to a retention test for the aversion augmented the behavioral measure of the aversion. Rats consuming milk paired earlier with LiCl showed elevated plasma levels of corticosterone. The augmented avoidance response in ACTH4--10 injected rats was not paralleled by an augmented pituitary-adrenal response. 相似文献