π-Olefin-Iridium-Komplexe, XXII [1]. C-H-Aktivierung von aromatischen und aliphatischen Solvensmolekülen RH bei der Reaktion von [Cp*IrCI2]2 mit Butadienmagnesium unter Bildung von [Cp*Ir(η3-C4H7)R] sowie Kristallstruktur von [Cp*Ir(η3-C4H7)C6H5] / π-Olefin Iridium Complexes, XXII [1]. C-H Activation of Aromatic and Aliphatic Solvent Molecules RH in the Reaction of [Cp*IrCl2]2 with Butadienemagnesium with Formation of [Cp*Ir(η3-C4H7)R], and Crystal Structure of [Cp*Ir(η3-C4H7)C6H5]

1994 ◽  
Vol 49 (12) ◽  
pp. 1645-1653 ◽  
Author(s):  
Jörn Müller ◽  
Petra Escarpa Gaede ◽  
Ke Qiao
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Diffraction Analysis ◽  
Iridium Complexes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nmr Spectrometry ◽  
Benzene Toluene ◽  
Solvent Molecules ◽  
Mechanism Of The Reaction

Reactions of [Cp*IrCl2]2 (Cp*=η3-C5Me5) with [MgC4H6·2 THF]n at low temperature give [Cp*Ir(η4-C4H6)] together with [Cp*Ir(η3-C4H7)R] compounds, the latter being formed via C-H activation of solvent molecules RH (RH = benzene, toluene, anisole, thiophene, furane, N-methylpyrrole, pentane, cyclohexane. THF). In the case of pyrrole, C-N -activation occurs. The ratio of syn and anti isomers of the 1-methylallyl complexes as well as the sites of C-H activation of RH were investigated by NMR spectrometry. An enantiomorphous crystal of [Cp*Ir(η3-C4H7)C6Hs] was characterized by X-ray diffraction analysis which reveals trigonal planar coordination at the Ir atom and an exo, syn conformation of the 1-methylallyl ligand. A mechanism of the reaction which involves 16-electron intermediates is discussed. The corresponding system [Cp*RhCl2]2/butadienemagnesium/RH gives only [Cp*Rh(η4-C4H6)], and no C-H activation is observed.

Synthesis, structure and biological activity of four new picolinohydrazonamide derivatives

2020 ◽  
Vol 76 (7) ◽  
pp. 673-680
Author(s):  
Małgorzata Szczesio ◽  
Katarzyna Gobis ◽  
Izabela Korona-Głowniak ◽  
Ida Mazerant-Politowicz ◽  
Dagmara Ziembicka ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Biological Activity ◽  
Nmr Spectroscopy ◽  
Low Temperature ◽  
Hydrogen Bonds ◽  
Essential Role ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zwitterionic Form ◽  
Solvent Molecules

Four new picolinohydrazonamide derivatives, namely, 6-methyl-N′-(morpholine-4-carbonothioyl)picolinohydrazonamide, C12H17N5OS, 6-chloro-N′-(morpholine-4-carbonothioyl)picolinohydrazonamide methanol monosolvate, C11H14ClN5OS·CH3OH, 6-chloro-N′-(4-phenylpiperazine-1-carbonothioyl)picolinohydrazonamide, C17H19ClN6S, and 6-chloropicolinohydrazonamide, C6H7ClN4, have been synthesized and characterized by NMR spectroscopy and single-crystal low-temperature X-ray diffraction. In addition, their antibacterial and anti-yeast activities have been determined. The first three compounds adopt the zwitterionic form in the crystal structure regardless of the presence or absence of solvent molecules in the structure. They also adopt the same symmetry, i.e. P21/c (P21/n), unlike the fourth structure which is chiral and has the space group P212121. For all the studied cases, intermolecular N—H...O and N—H...N hydrogen bonds play an essential role in the formation of the structures.

scholarly journals X-ray diffraction analysis of kaolin M1 and M2 via the Williamson–Hall and Warren–Averbach methods

2021 ◽  
pp. 174751982098472
Author(s):  
Lalmi Khier ◽  
Lakel Abdelghani ◽  
Belahssen Okba ◽  
Djamel Maouche ◽  
Lakel Said
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Low Temperature ◽  
Diffraction Analysis ◽  
Mechanical Resistance ◽  
X Ray Diffraction ◽  
Integral Breadth ◽  
X Ray ◽  
Mullite Phase

Kaolin M1 and M2 studied by X-ray diffraction focus on the mullite phase, which is the main phase present in both products. The Williamson–Hall and Warren–Averbach methods for determining the crystallite size and microstrains of integral breadth β are calculated by the FullProf program. The integral breadth ( β) is a mixture resulting from the microstrains and size effect, so this should be taken into account during the calculation. The Williamson–Hall chart determines whether the sample is affected by grain size or microstrain. It appears very clearly that the principal phase of the various sintered kaolins, mullite, is free from internal microstrains. It is the case of the mixtures fritted at low temperature (1200 °C) during 1 h and also the case of the mixtures of the type chamotte cooks with 1350 °C during very long times (several weeks). This result is very significant as it gives an element of explanation to a very significant quality of mullite: its mechanical resistance during uses at high temperature remains.

Synthesis and X-ray diffraction analysis of the tetrazole peptide analogue Pro-LeuΨ[CN4]Gly-NH2

1988 ◽  
Vol 53 (11) ◽  
pp. 2863-2876 ◽  
Author(s):  
Giovanni Valle ◽  
Marco Crisma ◽  
Kuo-Long Yu ◽  
Claudio Toniolo ◽  
Ram K. Mishra ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Diffraction Analysis ◽  
Dopamine Receptor ◽  
Torsion Angle ◽  
Peptide Bond ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conformationally Restricted ◽  
Bond Characteristic

The synthesis of an analogue of the neuropharmacologically active peptide Pro-Leu-Gly-NH2 in which the Leu-Gly peptide bond has been replaced with a tetrazole moiety was carried out. The molecular and crystal structure of the tetrazole analogue Pro-Leuψ[CN4]Gly-NH2 was determined by X-ray diffraction and a comparison was made with the published X-ray structure of Pro-Leu-Gly-NH2. The tetrazole annular system turns out to be a good conformationally-restricted replacement for the cis-peptide bond in terms of bond lengths, bond angles and the ω torsion angle. The molecule was found to be folded at the -Leuψ[CN4]Gly- sequence, but it did not form the intramolecular N-H···O=C hydrogen bond characteristic of the type Vla β-bend conformation. In contrast to Pro-Leu-Gly-NH2, Pro-Leuψ[CN4]Gly-NH2 was found to be unable to enhance the binding of dopamine receptor agonists to the dopamine receptor.

scholarly journals X-ray Crystallographic Study of Ranaconitine

2011 ◽  
Vol 6 (11) ◽  
pp. 1934578X1100601
Author(s):  
Yang Li ◽  
Jun-Hui Zhou ◽  
Gui-Jun Han ◽  
Min-Juan Wang ◽  
Wen-Ji Sun ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Diffraction Analysis ◽  
Critical Role ◽  
X Ray Diffraction ◽  
Monoclinic System ◽  
X Ray ◽  
Crystallographic Study ◽  
Cell Dimensions ◽  
Unit Cell Dimensions

The crystal structure of natural diterpenoid alkaloid ranaconitine isolated from Aconitum sinomontanum Nakai has been determined by single crystal X-ray diffraction analysis. The crystal presents a monoclinic system, space group C2 with Z = 4, unit cell dimensions a = 30.972(19) Å, b = 7.688(5) Å, and c = 19.632(12) Å. Moreover, the intermolecular O–H···O hydrogen bonds and weak π-π interactions play a critical role in expanding the dimensionality.

X-ray diffraction analysis of double molibdates CsDy(MoO4)2 and CsDy0.93Eu0.07(MoO4)2: 1. Crystal structure

1996 ◽  
Vol 175 (1) ◽  
pp. 85-89 ◽  
Author(s):  
S. D. El'chaninova ◽  
V. P. Kuznetsov ◽  
E. E. Lakin ◽  
S. V. Matveev ◽  
O. D. Kolotiy ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Diffraction Analysis ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Darstellung von μ-Nitroso-bis(pentahydro-closo-hexaborat)(3-) und Kristallstruktur von Cs3[B6H5(NO)B6H5] / Preparation of μ-nitroso-bis(pentahydro-closo-hexaborate)(3-) and crystal structure of Cs3[B6H5(NO)B6H5]

1994 ◽  
Vol 49 (9) ◽  
pp. 1263-1266 ◽  
Author(s):  
A. Franken ◽  
W. Preetz
Keyword(s):  
Crystal Structure ◽  
Ion Exchange ◽  
Single Crystal ◽  
Diffraction Analysis ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Diethylaminoethyl Cellulose

By electrochemical oxidation of [B6H6]2- in the presence of nitrite ions and of the base DBU in dichlorom ethane solution the μ-nitroso-bis(pentahydrohexaborate) [B6H5(NO)B6H5]3- ion is formed and can be isolated by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structure of the Cs salt has been determined from single crystal X-ray diffraction analysis. Cs3[B6H5(NO)B6H5] is orthorhombic, space group Pnma with a = 16.2303(13), b = 12.245(6), c = 25.444(2) Å. The unit cell contains three crystallographically independent anions with nearly C2v symmetry but differently distorted B6 cages

Darstellung, 11B-NMR- und Schwingungsspektren von c/s-Monoethylmononitrotetrahydro- c/050-hexaborat(2-) sowie Kristallstruktur von cis (Ph4As)2[B6H4(C2H5)(NO2)] / Synthesis, 11B NMR and Vibrational Spectra of cis-Monoethylmononitrotetrahydroc-closo-hexaborate(2-) and Crystal Structure of cis-(Ph4As)2[B6 H4 (C2H5 )(NO2)]

1999 ◽  
Vol 54 (6) ◽  
pp. 772-776 ◽  
Author(s):  
C. Drewes ◽  
W. Preetz
Keyword(s):  
Crystal Structure ◽  
Diffraction Analysis ◽  
Vibrational Spectra ◽  
X Ray Diffraction ◽  
Nmr Spectrum ◽  
Dichloromethane Solution ◽  
Triclinic Space Group ◽  
X Ray ◽  
11B Nmr ◽  
Ir And Raman

By electrochemical oxidation of (n-Bu4N)[B6H5Hfac(C2H5)] in the presence of nitrite ions and of the base DBU in dichloromethane solution cis-[B6H4(C2H5)(NO2)]2- is formed. X-ray diffraction analysis has been performed on a single crystal of cis-(Ph4 As)2[B6H4(C2H5)(NO2)] (triclinic, space group P1; a = 10.673(4). b = 10.907(4), c = 21.237(4) A, α = 80.789(4), β = 83.117(4), γ = 66.548(2)°, Z = 2). The 11B NMR spectrum is consistent with a disubstituted octahedral B6 cage with local Cs symmetry. The IR and Raman spectra exhibit characteristic CH3, CH2, NO2, BN, BH and B6 vibrations

Crystal structure of a polychloroquinone soil pigment

1978 ◽  
Vol 31 (11) ◽  
pp. 2441 ◽  
Author(s):  
DW Cameron ◽  
CL Raston ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Title Compound ◽  
X Ray Diffraction ◽  
Chlorine Atoms ◽  
X Ray ◽  
Pigment Molecule ◽  
Solvent Molecules

The crystal structure of the title compound, C20H4Cl6O5,C6H6, has been determined by single-crystal X-ray diffraction at 298 K. Crystals are monoclinic, C2/c, a 7.258(4), b 19.530(7), c 17.027(11) Ǻ, β 93.59(3)°, Z 4. Both pigment and solvent molecules are located about crystallographic 2 axes; the pigment molecule is considerably distorted as a result of interaction between substituent chlorine atoms on adjacent rings.

scholarly journals PicW2 fromPicea wilsonii: preparation, purification, crystallization and X-ray diffraction analysis

2018 ◽  
Vol 74 (6) ◽  
pp. 363-366 ◽  
Author(s):  
Bei Zhang ◽  
Gangxing Guo ◽  
Fang Lu ◽  
Ying Song ◽  
Yong Liu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Gel Filtration ◽  
Three Dimensional ◽  
Temperature Tolerance ◽  
Diffusion Method ◽  
Limiting Factor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters

Low temperature is a major limiting factor for plant growth and development. Dehydrin proteins are generally induced in response to low-temperature stress. In previous research, a full-length dehydrin gene,PicW2, was isolated fromPicea wilsoniiand its expression was associated with hardiness to cold. In order to gain insight into the mechanism of low-temperature tolerance by studying its three-dimensional crystal structure, prokaryotically expressed PicW2 dehydrin protein was purified using chitosan-affinity chromatography and gel filtration, and crystallized using the vapour-diffusion method. The crystal grew in a condition consisting of 0.1 MHEPES pH 8.0, 25%(w/v) PEG 3350 using 4 mg ml−1protein solution at 289 K. X-ray diffraction data were collected from a crystal at 100 K to 2.82 Å resolution. The crystal belonged to space groupC121, with unit-cell parametersa= 121.55,b= 33.26,c= 73.39 Å, α = γ = 90.00, β = 109.01°. The asymmetric unit contained one molecule of the protein, with a corresponding Matthews coefficient of 2.87 Å3 Da−1and a solvent content of 57.20%. Owing to a lack of structures of homologous dehydrin proteins, molecular-replacement trials failed. Data collection for selenium derivatization of PicW2 and crystal structure determination is currently in progress.

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