Asymmetric Copper–Catalyzed Propargylic Amination with Amine Hydrochloride Salts

2021 ◽  
Author(s):  
Jian Huang ◽  
Hanhan Kong ◽  
Sijia Li ◽  
Ruijin Zhang ◽  
Haodong Qian ◽  
...  
Keyword(s):  
Amine Hydrochloride ◽  
Copper Salts ◽  
Propargylic Esters ◽  
First Time ◽  
P Ligands

The highly enantioselective copper-catalyzed propargylic amination of propargylic esters with amine hydrochloride salts has been realized for the first time using copper salts with chiral N,N,P-ligands. This method features a...

The Infra-Red Absorption Spectra of the Addition Complexes of Quinoline with Copper Salts

1964 ◽  
Vol 19 (3) ◽  
pp. 363-370
Author(s):  
C. S. Williams ◽  
K. F. Fouché
Keyword(s):  
Absorption Spectra ◽  
Copper Salts ◽  
Frequency Shifts ◽  
Infra Red ◽  
Halide Complexes ◽  
First Time

The infra-red spectra of a number of halide, acetate and thiocyanate quinoline and quinolinium complexes of copper have been recorded for the first time. The significance of the frequency shifts of the quinoline bands in the complexes and the influence of the electronegativity of the halide ion on the frequency shifts in the monoquinoline cuprous halide complexes are discussed. Evidence is presented that the Cu (NCS) 2.2 Q complex is probably binuclear.

Synthesis of free and ligated 1,2-thiaphosphetanes – expanding the pool of strained P-ligands

2019 ◽  
Vol 55 (11) ◽  
pp. 1615-1618 ◽  
Author(s):  
Andreas Wolfgang Kyri ◽  
Florian Gleim ◽  
David Becker ◽  
Gregor Schnakenburg ◽  
Arturo Espinosa Ferao ◽  
...  
Keyword(s):  
Metal Complex ◽  
Coordination Sphere ◽  
Free Ligand ◽  
First Time ◽  
P Ligands

The 1,2-thiaphosphetane heterocycle could be synthesized for the first time in the coordination sphere of a metal complex (I) from which the free ligand (II) could be obtained, too.

Reactions of Carbenes with Unsaturated Polymers

1967 ◽  
Vol 40 (3) ◽  
pp. 934-935 ◽  
Author(s):  
M. S. Lishanskii ◽  
V. A. Tsitokhtsev ◽  
N. D. Vinogradova
Keyword(s):  
Ethyl Ester ◽  
Trichloroacetic Acid ◽  
Main Chain ◽  
Sodium Methylate ◽  
Side Chains ◽  
Copper Salts ◽  
Chain Reactions ◽  
Decomposition Reactions ◽  
Polar Substituents ◽  
First Time

Abstract The literature has a limited amount of data on chain reactions of unsaturated polymers, in particular diene polymers. The appearance of a paper dealing with addition of dichlorocarbene to polyisoprene and to polybutadiene has impelled us to publish results of studies we made on reactions of unsaturated polymers with carbenes, which have made it possible for the first time to obtain polymers containing in the main chain, or in the side chains, cyclopropane groups with polar substituents. Addition of carbenes to cis-1, 4-polyisoprene, trans-1, 4-polyisoprene, 1, 4-polybutadiene, and 1, 2-polybutadiene was accomplished through decomposition reactions of diazoacetic esters catalyzed by copper salts (for carbethoxycarbene and carbomethoxycarbene) and the reaction of the ethyl ester of trichloroacetic acid with sodium methylate (for dichlorocarbene).

scholarly journals New Thiophene Monolayer-Protected Copper Nanoparticles: Synthesis and Chemical-Physical Characterization

2008 ◽  
Vol 2008 ◽  
pp. 1-6 ◽  
Author(s):  
Elisabetta Foresti ◽  
Guido Fracasso ◽  
Massimiliano Lanzi ◽  
Isidoro Giorgio Lesci ◽  
Luisa Paganin ◽  
...  
Keyword(s):  
Metallic Nanoparticles ◽  
Morphological Evolution ◽  
Wide Band ◽  
Phase System ◽  
Water Medium ◽  
Copper Salts ◽  
Transmission Electron ◽  
Synthetic Reactions ◽  
Irreversible Aggregation ◽  
First Time

For the first time copper 3-(6-mercaptohexyl)thiophene-protected nanoparticles (Cu T6SH) have been synthesized by a one-phase system, utilizing anNaBH4/LiCl mixture in diglyme as the reducing reagent and avoiding water medium dissolving copper salts. The prepared nanoclusters, characterized by transmission electron microscopy (TEM), have shown a constant spherical morphology with a size dimension of 5-6 nm in diameter. After their synthesis, no morphological evolution and irreversible aggregation process has been observed after a storage inCH2Cl2at low temperature for a period up to six months long. Cu T6SH nanoparticles have been investigated by UV-Visible (UV-Vis) and Fourier transmission infrared (FTIR) spectroscopes to characterize the alkylthiophenes monolayer conformations and the particles optoelectronic properties. The UV-Vis reveals the lack of the surface plasmonic band, previously observed in Cu-nanosized clusters at about 556–570 nm, and shows a wide-band centered at 293 nm, probably due to the high-conformational surface ordering of thiophene rings on the Cu core. The results highlight the importance of the modifications ported to the well-known one-phase synthetic reactions to obtain a clear lack, even after a storage of six months, of any irreversible aggregation that has always characterized chain thiophene-protected metallic nanoparticles.

A series of Keggin-based compounds constructed by conjugate ring-rich pyrazine and quinoxaline derivatives

2016 ◽  
Vol 45 (35) ◽  
pp. 13925-13936 ◽  
Author(s):  
Aixiang Tian ◽  
Yan Tian ◽  
Yali Ning ◽  
Xue Hou ◽  
Huaiping Ni ◽  
...  
Keyword(s):  
Quinoxaline Derivatives ◽  
Keggin Anions ◽  
First Time ◽  
P Ligands

Ligands L1 and L2 are utilized in POM chemistry for the first time. Different Keggin anions induce distinct 2D structures of compounds 1/2 and 3/4 in Ag–L1 and Ag–L2 systems, respectively. By adding AgI and CuI to the PMo12–L2 system different 3 and 5 were formed.

Annulate lamellae in the Sertoli cells of guinea pig testis after unilateral torsion of the spermatic cord

1984 ◽  
Vol 42 ◽  
pp. 196-197
Author(s):  
J. Chakraborty ◽  
A. P. Sinha Hikim ◽  
J. S. Jhunjhunwala
Keyword(s):  
Sertoli Cells ◽  
Guinea Pigs ◽  
Spermatic Cord ◽  
Present Report ◽  
Cell Types ◽  
Annulate Lamellae ◽  
Spermatogenic Cells ◽  
Electron Microscopic ◽  
Structural Details ◽  
First Time

Although the presence of annulate lamellae was noted in many cell types, including the rat spermatogenic cells, this structure was never reported in the Sertoli cells of any rodent species. The present report is based on a part of our project on the effect of torsion of the spermatic cord to the contralateral testis. This paper describes for the first time, the fine structural details of the annulate lamellae in the Sertoli cells of damaged testis from guinea pigs.One side of the spermatic cord of each of six Hartly strain adult guinea pigs was surgically twisted (540°) under pentobarbital anesthesia (1). Four months after induction of torsion, animals were sacrificed, testes were excised and processed for the light and electron microscopic investigations. In the damaged testis, the majority of seminiferous tubule contained a layer of Sertoli cells with occasional spermatogonia (Fig. 1). Nuclei of these Sertoli cells were highly pleomorphic and contained small chromatinic clumps adjacent to the inner aspect of the nuclear envelope (Fig. 2).

Electron spectroscopic imaging and diffraction

1991 ◽  
Vol 49 ◽  
pp. 706-707
Author(s):  
M. Rühle ◽  
J. Mayer ◽  
J.C.H. Spence ◽  
J. Bihr ◽  
W. Probst ◽  
...  
Keyword(s):  
Materials Science ◽  
Electron Spectroscopic Imaging ◽  
Magnetic Filter ◽  
Magnetic Imaging ◽  
Illumination System ◽  
Probe Size ◽  
Diffraction Patterns ◽  
Fritz Haber ◽  
Koehler Illumination ◽  
First Time

A new Zeiss TEM with an imaging Omega filter is a fully digitized, side-entry, 120 kV TEM/STEM instrument for materials science. The machine possesses an Omega magnetic imaging energy filter (see Fig. 1) placed between the third and fourth projector lens. Lanio designed the filter and a prototype was built at the Fritz-Haber-Institut in Berlin, Germany. The imaging magnetic filter allows energy-filtered images or diffraction patterns to be recorded without scanning using efficient area detection. The energy dispersion at the exit slit (Fig. 1) results in ∼ 1.5 μm/eV which allows imaging with energy windows of ≤ 10 eV. The smallest probe size of the microscope is 1.6 nm and the Koehler illumination system is used for the first time in a TEM. Serial recording of EELS spectra with a resolution < 1 eV is possible. The digital control allows X,Y,Z coordinates and tilt settings to be stored and later recalled.

A Novel TEM Technique for Characterizing As-Grown CVD Diamond Films

1991 ◽  
Vol 49 ◽  
pp. 956-957 ◽  
Author(s):  
Z.L. Wang ◽  
J. Bentley ◽  
R.E. Clausing ◽  
L. Heatherly ◽  
L.L. Horton
Keyword(s):  
Diamond Films ◽  
Chemical Vapor ◽  
Growth Direction ◽  
Dark Field ◽  
Growth Surface ◽  
Specimen Preparation ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
First Time ◽  
Microstructural Studies

Microstructural studies by transmission electron microscopy (TEM) of diamond films grown by chemical vapor deposition (CVD) usually involve tedious specimen preparation. This process has been avoided with a technique that is described in this paper. For the first time, thick as-grown diamond films have been examined directly in a conventional TEM without thinning. With this technique, the important microstructures near the growth surface have been characterized. An as-grown diamond film was fractured on a plane containing the growth direction. It took about 5 min to prepare a sample. For TEM examination, the film was tilted about 30-45° (see Fig. 1). Microstructures of the diamond grains on the top edge of the growth face can be characterized directly by transmitted electron bright-field (BF) and dark-field (DF) images and diffraction patterns.

A microscopic marker experiment study on high temperature oxidation of Ni-Al alloy

1986 ◽  
Vol 44 ◽  
pp. 514-515
Author(s):  
Shou-kong Fan
Keyword(s):  
Transport Mechanism ◽  
High Temperature Oxidation ◽  
Transverse Section ◽  
Al Alloy ◽  
Metal Interface ◽  
Electron Microscopic ◽  
Temperature Oxidation ◽  
Analytical Electron ◽  
Microscopic Studies ◽  
First Time

Transmission and analytical electron microscopic studies of scale microstructures and microscopic marker experiments have been carried out in order to determine the transport mechanism in the oxidation of Ni-Al alloy. According to the classical theory, the oxidation of nickel takes place by transport of Ni cations across the scale forming new oxide at the scale/gas interface. Any markers deposited on the Ni surface are expected to remain at the scale/metal interface after oxidation. This investigation using TEM transverse section techniques and deposited microscopic markers shows a different result,which indicates that a considerable amount of oxygen was transported inward. This is the first time that such fine-scale markers have been coupled with high resolution characterization instruments such as TEM/STEM to provide detailed information about evolution of oxide scale microstructure.

Direct imaging of charge transfer

1996 ◽  
Vol 54 ◽  
pp. 680-681
Author(s):  
Yimei Zhu ◽  
J. Tafto
Keyword(s):  
Charge Transfer ◽  
Electron Diffraction ◽  
Scattering Amplitude ◽  
High Temperature Superconductors ◽  
Charge Carriers ◽  
Image Charge ◽  
Net Charge ◽  
Long Time ◽  
Electron Holes ◽  
First Time

The electron holes confined to the CuO2-plane are the charge carriers in high-temperature superconductors, and thus, the distribution of charge plays a key role in determining their superconducting properties. While it has been known for a long time that in principle, electron diffraction at low angles is very sensitive to charge transfer, we, for the first time, show that under a proper TEM imaging condition, it is possible to directly image charge in crystals with a large unit cell. We apply this new way of studying charge distribution to the technologically important Bi2Sr2Ca1Cu2O8+δ superconductors.Charged particles interact with the electrostatic potential, and thus, for small scattering angles, the incident particle sees a nuclei that is screened by the electron cloud. Hence, the scattering amplitude mainly is determined by the net charge of the ion. Comparing with the high Z neutral Bi atom, we note that the scattering amplitude of the hole or an electron is larger at small scattering angles. This is in stark contrast to the displacements which contribute negligibly to the electron diffraction pattern at small angles because of the short g-vectors.

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