Synthesis, multinuclear magnetic resonance spectra, and chemistry of some complexes [(μ-SR)6(MX)4]2− (R = alkyl; M = Zn or Cd; X = Cl, Br, or I) and the X-ray structural analysis of (Et4N)2[(μ-SPri)6(CdBr)4]

1992 ◽  
Vol 70 (3) ◽  
pp. 779-791 ◽  
Author(s):  
Philip A. W. Dean ◽  
Jagadese J. Vittal ◽  
Yuyang Wu
Keyword(s):  
Self Assembly ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Monoclinic Space Group ◽  
Cadmium Complex ◽  
X Ray ◽  
Assembly Method ◽  
Alkyl Groups ◽  
Wide Range ◽  
Thiolate Complexes

The self-assembly method has been used to prepare a wide range of new adamantane-like anions of the type [(μ-SR)6(MX)4]2− (M = Zn or Cd; R = alkyl or benzyl; X = Cl, Br, or I) as their Et4N+ salts. Metal (111 or 113Cd) NMR data have been measured for the cadmium complexes, and also for many of the possible mixed-metal complexes [(μ-SR)6(CdX)n(ZnX)4−n]2−. In the complexes with mixed metals, the effects of Zn substitution on the metal chemical shifts are generally larger for the alkyl- and benzyl-thiolate complexes than for related benzenethiolate complexes. However, for [(μ-SPri)6(CdX)n(CdX′)4−n]2− (X/X′ = Cl/Br, Cl/I, or Br/I), substituent effects are no larger than found in some PhS−-bridged complexes. The reaction of [(μ-SPri)6(CdX)4]2− (X = Cl, Br, or I) with E′8 (E′ = S or Se) in CH2Cl2 gives [Cd4(μ4-E′) (μ-SPri)12(CdX)4]2− as the major species detectable by metal, 13C, and, where applicable, 77Se NMR. However, the reaction does not occur stoichiometrically. The compound (Et4N)2[(μ-SPri)6(CdBr)4] crystallizes in the monoclinic space group P21/c with cell dimensions a = 24.079(3) Å, b = 11.365(2) Å, c = 22.561(3) Å, β = 113.89(1), and Z = 4. The structure was refined to R(Rw) = 0.0663(0.0703) with the use of 2669 unique data with I > 2.5σ(I). The anion contains an adamantane-type (μ2-S)6Cd4 cage composed of a nearly regular Cd4 tetrahedron and a distorted S6 octahedron, the irregularity of which is caused by 1,3-interactions of the substituent groups on the sulfur atoms. The axial or equatorial dispositions of the six alkyl groups in the four fused M3S3 rings are [aae, aae, aee, aee]. For the zinc-group elements, this is the first example of an adamantane-like (μ-Salkyl)6M4 cage that has been characterized crystallographically. Keywords: cadmium complex, cadmium-111/113 NMR, thiolate complex, X-ray analysis, zinc complex.

Preparation and Characterization of Polyaniline Nanotubes Doped with Different Acid

2013 ◽  
Vol 401-403 ◽  
pp. 663-666
Author(s):  
Xue Lian Bai ◽  
Jian Ting Mei ◽  
Zhong Guo Mu ◽  
Yun Bai
Keyword(s):  
Acetic Acid ◽  
Self Assembly ◽  
Ammonium Persulfate ◽  
Tetraacetic Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Property ◽  
Assembly Method ◽  
Polyaniline Nanotubes

Polyaniline (PANI) nanotubes were synthesized separately using amino acetic acid (AA), ethylenediamine tetraacetic acid (EDTA), oxalic acid (OA) as dopant and ammonium persulfate (APS) as oxidant by a self-assembly method. SEM, TEM,FTIR and X-ray diffraction (XRD) and applying the 4 probes method characterized the morphology, structure and property of the product. It was found that nanotubes morphology were synthesized when the [Aci/[A ratio is 1:2.The room template conductivity of the products were studied.

Wide Range Two-Crystal Vacuum X-ray Spectrometer for Chemical State Analysis

1982 ◽  
Vol 36 (2) ◽  
pp. 171-174 ◽  
Author(s):  
Y. Gohshi ◽  
H. Kamada ◽  
K. Kohra ◽  
T. Utaka ◽  
T. Arai
Keyword(s):  
Coordination Number ◽  
Chemical Shifts ◽  
Fluorescence Analysis ◽  
Chemical State ◽  
X Ray ◽  
Wide Range ◽  
Scanning Range ◽  
Excellent Reproducibility ◽  
Design And Construction ◽  
State Analysis

The design and construction of a new two-crystal x-ray spectrometer are described together with the observed Mg Kα, Al Kα, Si Kα, S Kα, and Cu Kα1 spectra. The spectrometer is designed for x-ray fluorescence analysis and has a wide scanning range (2° to 146° 2θ) under vacuum. Excellent reproducibility of 0.4 s in arc is attainable, which makes possible the observation of chemical shifts in x-ray spectra. Magnesium Kα was found to be influenced by the coordination number, proving that the spectrometer is useful for chemical state analysis.

Zur Struktur des Enols von Benzoylaceton / On the Structure of the Enol of Benzoylacetone

1979 ◽  
Vol 34 (11) ◽  
pp. 1606-1611 ◽  
Author(s):  
W. Winter ◽  
K.-P. Zeller ◽  
S. Berger
Keyword(s):  
Structural Model ◽  
Chemical Shifts ◽  
Ring System ◽  
Coupling Constants ◽  
Spin Coupling ◽  
X Ray ◽  
Wide Range ◽  
Spin Coupling Constants ◽  
C Nmr ◽  
Oxygen Atoms

Abstract A low temperature X-ray study of the enol of benzoylacetone indicates fixed positions of the C and O atoms within the enolic ring system and an extensive bond delocalisation over these atoms. The distribution of electron density between the two oxygen atoms shows that the enolic hydrogen is spread over a wide range. This is in accordance with a structural model proposed by de la Vega, whereupon the C and O atoms are kept fixed in their average positions during a tunneling process of the hydrogen between the two oxygen atoms. With this conception, the chemical shifts in the 17O and 13C NMR spectra, the 13C13C spin coupling constants and the temperature independance of these values can be explained.

Crystal and molecular structure of Z- and E-1,2-dichloro-1,2-bis(2-chlorophenyl)ethylene. An X-ray and NMR study

1995 ◽  
Vol 73 (9) ◽  
pp. 1520-1525
Author(s):  
Luciano Antolini ◽  
Ugo Folli ◽  
Dario Iarossi ◽  
Adele Mucci ◽  
Silvia Sbardellati ◽  
...  
Keyword(s):  
Chemical Shifts ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Nmr Study ◽  
Phenyl Rings ◽  
A Cell ◽  
C Nmr

The crystal structures of the title compounds were determined by single crystal X-ray diffraction techniques. The molecule of the Z isomer, which crystallizes in the monoclinic space group C2/c with Z = 4 in a cell of dimensions a = 14.891 (2), b = 10.780(2), c = 8.769(1) Å, β = 97.47(2)°, V = 1395.7(7) Å3 has crystallographic twofold symmetry. The E form crystallizes in the orthorhombic space group Pbca with a = 11.730(1), b = 6.932(1), c = 16.841(1) Å, V = 1369.4(2) Å3 and Z = 4. Its molecules have crystallographically dictated [Formula: see text] symmetry. In both isomers the phenyl rings are roughly perpendicular to the average ethylene plane. The atoms characterizing this plane show significant deviations from planarity in the Z isomer. Marked bond-angle distortions at the ethene carbons of both structures are observed. The 1H and 13C NMR spectra of the compounds were measured and, particularly in the case of the 1H chemical shifts, fall into two quite separate spectral regions. At low temperature, two conformational isomers, those with different relative orientation of the C—Cl bonds of the phenyl rings, are observed in the spectrum of each compound. Keywords: chlorostilbenes, overcrowded molecules. X-ray structure, conformations, NMR spectroscopy.

Chiral Thioaldehyde Complexes of Rhenium, X-Ray Structure Determination of [Cp(NO)(Ph3P)Re(η2-S=CHPh)]PF6 [1]

1994 ◽  
Vol 49 (12) ◽  
pp. 1633-1639 ◽  
Author(s):  
Wolfdieter A. Schenk ◽  
Nicolai Burzlaff ◽  
Hans Burzlaff
Keyword(s):  
Structure Determination ◽  
Monoclinic Space Group ◽  
Space Group ◽  
X Ray ◽  
Acid Cleavage ◽  
Hydride Abstraction ◽  
Thiolate Complexes

Chiral thiolate complexes [Cp(NO)(Ph3P)ReSCH2R] (R=Ph, 4-C6H4Cl, 4-C6H4OMe, H, Me) are obtained from [Cp(NO)(Ph3P)ReCH3] by acid cleavage in the presence of thiol and subsequent deprotonation. Small amounts of (chloromethyl)thioether complexes [Cp(NO)(Ph3P)ReS(CH2Cl)CH2R]BF4 are formed when dichloromethane is used as a sol­ vent in this reaction. Hydride abstraction using [Ph3C]PF6 converts the thiolate complexes into ionic thioaldehyde complexes [Cp(NO)(Ph3P)Re(η2-S=CHR)]PF6. These are obtained as pure (RR,SS)-diastereomers as shown spectroscopically and by X-ray structure determination of [Cp(NO)(Ph3P)Re(η2-S=CHPh)]PF6. Crystals are monoclinic, space group I2/a (No. 15), a = 25.877(3), b = 18.785(2), c = 13.768(1) Å , β = 104.93(1)°, Z -8.

Synthesis and Characterization of Polyaniline Nanotubes Doped with Amino Acetic Acid

2012 ◽  
Vol 184-185 ◽  
pp. 1285-1288 ◽  
Author(s):  
Xue Lian Bai ◽  
Jian Ting Mei ◽  
Yun Bai ◽  
Zhong Guo Mu
Keyword(s):  
Acetic Acid ◽  
Self Assembly ◽  
Ammonium Persulfate ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure And Property ◽  
Assembly Method ◽  
Doped Polyaniline

Doped polyaniline (PANI) nanostructure has been prepared at room temperature using amino acetic acid (AA) as dopant and ammonium persulfate (APS) as oxidant by a self-assembly method. The structure and property of polyaniline nanostructure were characterized by SEM, TEM，IR and X-ray diffraction (XRD) and applying the 4 probes method. The results showed the production was PANI. The effect of molar ratio of AA to An affected the morphology of the product and room template conductivity of the products were studied.

Preparation and tribological characteristics of graphene/triangular copper nanoplate composites as grease additive

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jing Wang ◽  
Hongying Mi ◽  
Weigui Zhou ◽  
Xin Yang ◽  
Yan He
Keyword(s):  
Tribological Properties ◽  
Self Assembly ◽  
Electrostatic Force ◽  
Friction Reduction ◽  
Tribological Characteristics ◽  
Wear Loss ◽  
Content Type ◽  
X Ray ◽  
Assembly Method ◽  
Theoretical Support

Purpose This study aims to the preparation and tribological characteristics of graphene/triangular copper nanoplate composites (abbreviated as GN/Cu nanoplates) as grease additive and clarifies the growth mechanism and tribological mechanism of GN/Cu nanoplates by different analysis methods. In this paper, it is expected to alleviate the problems of easy aggregation and poor dispersion stability of graphene in lubricants and provide theoretical support for the application of graphene and its composites in the tribology field. Design/methodology/approach In this study, the GN/Cu nanoplates have been successfully prepared by the electrostatic self-assembly method. The structural characteristics of GN/Cu nanoplates were analyzed via transmission electron microscopy and X-ray diffraction. Then the tribological properties of GN/Cu nanoplates were investigated under different loads with SRV-IV [Schwingung, Reibung, Verschleiß (German); oscillating, friction, wear (English translation)] tribotester. White-light interferometry was applied to quantify the wear loss of the disk. The element chemical state on worn surfaces was analyzed by an X-ray photoelectron spectroscope to clarify the tribological mechanism of graphene composites. Findings The electrostatic force between the negative charge of graphene and the positive charge of triangular copper nanoplates promotes the self-assembly of GN/Cu nanoplates. With the addition of GN/Cu nanoplates, the wear loss and average friction coefficient under the load of 200 N have been decreased by 72.6% and 18.3%, respectively. It is concluded that the combined action of graphene deposition film and the copper melting film formed on the worn surface could effectively improve the antiwear ability and friction reduction performance of the grease. Originality/value This manuscript fulfills a new approach for the preparation of GN/Cu nanoplates. At the same time, its tribological properties and mechanism as a lubricating additive were studied which provide theoretical support for the application of graphene and its composites in the tribology field.

The geometry of 4-(1-ethoxyethylidene)-5-oxazolones and thiazolones: 1H and 13C studies and the crystal structure of 4-[(Z)-1-ethoxyethylidene]-2-phenyl-5-oxazolone

1985 ◽  
Vol 63 (12) ◽  
pp. 3618-3630 ◽  
Author(s):  
R. A. Bell ◽  
R. Faggiani ◽  
C. J. L. Lock ◽  
R. A. McLeod
Keyword(s):  
Crystal Structure ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Side Chain ◽  
Oxazole Ring ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cell Dimensions ◽  
Ring Nitrogen ◽  
E And Z Isomers

A series of E and Z isomers of substituted 4-(1-ethoxyethylidene)-5-oxazolones and thiazolones have been prepared and their 1H and 13C spectra recorded. The vinylic methyl 1H chemical shifts showed minimal differences between E and Z isomers whereas the vinylic OCH21H signals differed by 0.15–0.43 ppm, with the Z isomer being consistently the more deshielded. Both vinylic methyl and OCH2 groups showed different 13C resonances for each isomer, with the Z isomers being the more deshielded. The Z geometry was conclusively defined for one isomer of 4-(1-ethoxyethylidene)-2-phenyl-5-oxazolone, 5, by X-ray crystallography and this was sufficient to assign the geometry of the remaining pairs of E and Z isomers. Oxazolone 5 has the space group P21/n and cell dimensions a = 9.219(3), b = 19.899(5), c = 7.459(1) Å, β = 118.01(2)°, and has four formula units in the unit cell. Intensities were measured with use of MoKα radiation and a Nicolet P3 diffractometer. The crystal structure was determined by standard methods and refined to R1 = 0.0709, R2 = 0.0696 based on 1419 independent reflections. The molecule is essentially planar and most bond lengths and angles are normal. Exceptions are the very short C(olefin)—O(ether) bond (1.339(4) Å) and the large ether C—O—C angle (122.1(3)°) caused by extreme delocalization in the O(ether)CCCO(carbonyl) system. The planarity causes a number of strong intramolecular repulsive interactions, causing an exceptionally small external olefin angle, O(ether)CC(methyl), of 108.1(4)°. The ethoxyl side chain of 5 adopts a conformation in the solid state which places the methylene of the OCH2 group adjacent to the oxazole ring nitrogen. This conformation is proposed to persist in solution phases and is consistent with the observed 13C chemical shifts and known γ and δ substituent effects.

Preparation, Characterization, and Photocatalytic Performance of Bismuth and Boron Co-Doped Mesporous TiO2 by EISA Method

2014 ◽  
Vol 953-954 ◽  
pp. 1003-1007
Author(s):  
Yu Xiu Zhang ◽  
Li Yang ◽  
Dai Mei Chen ◽  
Shuang Deng ◽  
Ying Jie Shi
Keyword(s):  
Visible Light ◽  
Self Assembly ◽  
Photocatalytic Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Assembly Method ◽  
Transmission Electron ◽  
Evaporation Induced Self Assembly ◽  
Crystallite Sizes ◽  
Mesoporous Structures

Abstract. The large-pore mesoporous Bi-B-TiO2 nanoparticles with the different Bi/Ti rations were prepared by EISA(evaporation-induced self-assembly) method. The prepared catalysts were characterized by X-ray diffraction, transmission electron microscopy, N2 absorption-desorption, ultraviolet visible light spectroscopy and photoluminescence spectroscopy technologies. The results revealed that all the samples are large aperture mesoporous structures. The crystallite sizes were in the range7-11nm, as confirmed by the results obtained from TEM images. The photodecomposition experiments showed that the photodegradation activity of Bi-B-doped TiO2 was higher than that of undoped TiO2 in degradation of 2, 4–dichlorophenol under visible light irradiation.

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