Cluster Chemistry. XLIII. Sulfur-Carbon Bond Cleavage Reactions in the Hydrogenation of Some Sulfur-Containing Ruthenium Carbonyl Cluster Complexes: X-Ray Structure of Ru3(μ-H)2(μ3-S)(μ-(Z)-Ph2PCH=CHPPH2)(CO)7

1986 ◽  
Vol 39 (7) ◽  
pp. 1109 ◽  
Author(s):  
MI Bruce ◽  
OB Shawkataly ◽  
MR Snow ◽  
ERT Tiekink
Keyword(s):  
Least Squares Method ◽  
Bond Cleavage ◽  
Unit Cell Parameters ◽  
Tertiary Phosphine ◽  
Cluster Chemistry ◽  
X Ray ◽  
Cell Parameters ◽  
Ruthenium Carbonyl ◽  
Cleavage Reactions ◽  
Sulfur Containing

Reactions between Ru3(μ-H)(μ3-SBut)(CO)9 and dppm have given Ru3(μ-H)(μn- SBut)(μ-dppm)(CO)10-n(n = 2,3); hydrogenation of all three complexes resulted in S-C bond cleavage and formation of Ru3(μ-H)2(μ3-S)(CO)7(L2) [L2 = (CO)2, μ-dppm]. Facile substitution of 2CO in Ru3(μ-H)2(μ3-S)(CO)9 by dppm, dpam or ebdp (L2), catalysed by Na+[Ph2CO]- or [ppn][OAc], gave Ru3(μ-H)2(μ3-S)(μ-L2)(CO)7, in which the bis-tertiary phosphine (or arsine) bridges an edge of the Ru3 triangle, with the P (or As) atoms occupying equatorial positions. In the case of L2 = ebdp, this edge is also bridged by H, as shown by a single-crystal X-ray structure determination. Crystals of the title compound are mcnoclinic, space group P21/n, with unit cell parameters a 13.454(3), b 17.748(2), c 14.706(2) Ǻ, and β 94.50(1)°. The structure was refined by a full-matrix least-squares method; at convergence R and Rw were 0.036 and 0.038, respectively, for 4729 reflections with I ≥ 3.0σ(I).

X-ray diffraction studies on the effect of ball-milling speed on the structure of Cu(In,Ga)Se2 nanoparticles

2013 ◽  
Vol 28 (S1) ◽  
pp. S28-S31 ◽  
Author(s):  
L. Fu ◽  
Y.Q. Guo ◽  
S. Zheng
Keyword(s):  
Ball Milling ◽  
Least Squares Method ◽  
Unit Cell ◽  
Chalcopyrite Structure ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Cigs Nanoparticles

Cu(In,Ga)Se2 (CIGS) semiconductors were prepared by arc melting and the vacuum solid reaction. CIGS nanoparticles were synthesized by the mechanical alloy method. The influences of various ball-milling speeds on phase structures for CIGS nanoparticles were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystal structures and unit-cell parameters of CIGS nanoparticles were determined using TREOR program and the least squares method. A Rietveld structural refinement was used to determine the atomic occupations and atomic numbers of CIGS prepared under various ball-milling speeds. The least size of agglomerated CIGS nanoparticles should be around 200 nm. CIGS nanoparticles milled at various milling speeds with a tetragonal chalcopyrite structure were obtained according to XRD analyses. However, Ga content in CIGS depends on milling speeds. Based on the structural refinements, the unit-cell parameters are a = 5.693(8)–5.744(9) Å and c = 11.334(9)–11.524(4) Å with gallium content ranging from 0.3 to 0.5. The atomic occupations are corresponding to the 4a crystal site for Cu atoms, the 4b site for In and the 8d site for Se. Ga prefers to occupy the 4b crystal site.

scholarly journals Crystallization and preliminary X-ray crystallographic studies of the ArsI C–As lyase fromThermomonospora curvata

2014 ◽  
Vol 70 (6) ◽  
pp. 761-764 ◽  
Author(s):  
S. Venkadesh Nadar ◽  
Masafumi Yoshinaga ◽  
Palani Kandavelu ◽  
Banumathi Sankaran ◽  
Barry P. Rosen
Keyword(s):  
Anthropogenic Activities ◽  
Bond Cleavage ◽  
Inorganic Arsenic ◽  
Thermophilic Bacterium ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Environmental Element ◽  
Methylarsonous Acid

Arsenic is a ubiquitous and carcinogenic environmental element that enters the biosphere primarily from geochemical sources, but also through anthropogenic activities. Microorganisms play an important role in the arsenic biogeochemical cycle by biotransformation of inorganic arsenic into organic arsenicals andvice versa. ArsI is a microbial nonheme ferrous-dependent dioxygenase that transforms toxic methylarsonous acid to the less toxic inorganic arsenite by C–As bond cleavage. An ArsI ortholog from the thermophilic bacteriumThermomonospora curvatawas expressed, purified and crystallized. The crystals diffracted to 1.46 Å resolution and belonged to space groupP43212 or its enantiomerP41212, with unit-cell parametersa=b= 42.2,c= 118.5 Å.

X-ray powder diffraction pattern for lactitol and lactitol monohydrate

1994 ◽  
Vol 9 (3) ◽  
pp. 213-216 ◽  
Author(s):  
J. Valkonen ◽  
P. Perkkalainen ◽  
I. Pitkänen ◽  
H. Rautiainen
Keyword(s):  
Powder Diffraction ◽  
Least Squares Method ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
Cell Dimensions ◽  
Diffraction Patterns ◽  
Unit Cell Dimensions

Diffraction patterns were recorded, and unit cell dimensions refined by the least-squares method, for lactitol and lactitol monohydrate. Refined unit cell parameters for lactitol are: a =7.622(1) Å, b = 10.764(2) Å, c = 9.375(1) Å, β= 108.25(1)° in space group P21, and those for lactitol monohydrate a =7.844(1) Å, b = 12.673(2) Å, c = 15.942(2) Å in space group P212121.

scholarly journals Synthesis, Crystal Structure and IR Spectrum studies of 2-(4-Methyl-2-phenyl-4,5-dihydro-oxazol-4-ylmethyl)- isoindole-1,3-dione

2019 ◽  
Vol 9 (2) ◽  
pp. 116-124 ◽  
Author(s):  
Alami Anouar ◽  
Khadim Dioukhane ◽  
Younas Aouine ◽  
Mohamed El Omari ◽  
Lahcen El Ammari ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Least Squares Method ◽  
Spectroscopic Studies ◽  
Amino Compound ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Parameters ◽  
Complete Matrix

The organo-amino compound of title 2-(4-methyl-2-phenyl-4,5-dihydro-oxazol-4-ylmethyl)-isoindole-1,3-dione was synthesized by the mixture of (4-methyl-2-phenyl-4,5-dihydrooxazol-4-yl)methyl-4-methylbenzenesulfonate and isoindoline-1,3-dione in N,N-dimethylformamide with a yield of around 65%. The structural study of the compound, C19H16N2O3, is realized using single crystal X-Ray diffraction which shows that this compound crystallizes in the monoclinic system (P21/c, Z = 4) with the unit cell parameters: a = 14.3728 (13) Ã…, b = 9.6829 (10) Ã…, c = 11.8964 (12) Ã… and β = 107.384 (3). The refinement of the structure by the least-squares method with complete matrix leads to the following reliability factors R/Rw are 0.044/0.130.In the crystal, the molecules are linked together by hydrogen bonds and π…π interactions.The Infrared spectroscopic studies show the bands confirming the presence of the groups C=O, C-O, C-N, -CH3, -CH2 and =CH. 

scholarly journals Expression, crystallization and preliminary X-ray crystallographic analysis of cystathionine β-lyase fromAcinetobacter baumanniiOXA-23

2014 ◽  
Vol 70 (10) ◽  
pp. 1368-1371
Author(s):  
Diem-Quynh Nguyen ◽  
Ho-Phuong-Thuy Ngo ◽  
Yeh-Jin Ahn ◽  
Sang Hee Lee ◽  
Lin-Woo Kang
Keyword(s):  
Drug Targets ◽  
Multidrug Resistant ◽  
Crystallographic Analysis ◽  
Second Step ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Transsulfuration Pathway ◽  
Sulfur Containing ◽  
Metabolic Interconversion

Multidrug-resistantAcinetobacter baumannii(Ab) has emerged as a leading nosocomial pathogen because of its resistance to most currently available antibiotics. Cystathionine β-lyase (CBL), a pyridoxal 5′-phosphate (PLP)-dependent enzyme, catalyzes the second step in the transsulfuration pathway, which is essential for the metabolic interconversion of the sulfur-containing amino acids homocysteine and methionine. The enzymes of the transsulfuration pathway are considered to be attractive drug targets owing to their specificity to microbes and plants. As a potential target for the development of novel antibacterial drugs, the AbCBL protein was expressed, purified and crystallized. An AbCBL crystal diffracted to 1.57 Å resolution and belonged to the trigonal space groupP3112, with unit-cell parametersa=b= 102.9,c= 136.5 Å. The asymmetric unit contained two monomers, with a correspondingVMof 2.3 Å3 Da−1and a solvent content of 46.9%.

Structural Study of a new Compound Based on Acid 1,4-Cyclohexanedicarboxylic (1,4-CDC)

2010 ◽  
Vol 6 (1) ◽  
pp. 891-896
Author(s):  
Manel Halouani ◽  
M. Dammak ◽  
N. Audebrand ◽  
L. Ktari
Keyword(s):  
Aqueous Solution ◽  
Water Molecules ◽  
Carboxyl Group ◽  
X Ray Diffraction ◽  
Compound I ◽  
Unit Cell Parameters ◽  
Monoclinic System ◽  
X Ray ◽  
Cell Parameters ◽  
Cyclohexanedicarboxylic Acid

One nickel 1,4-cyclohexanedicarboxylate coordination polymers, Ni2 [(O10C6H4)(COO)2].2H2O  (I), was hydrothermally synthesized from an aqueous solution of Ni (NO3)2.6H2O, (1,4-CDC) (1,4-CDC = 1,4-cyclohexanedicarboxylic acid) and tetramethylammonium nitrate. Compound (I) crystallizes in the monoclinic system with the C2/m space group. The unit cell parameters are a = 20.1160 (16) Å, b = 9.9387 (10) Å, c = 6.3672 (6) Å, β = 97.007 (3) (°), V= 1263.5 (2) (Å3) and Dx= 1.751g/cm3. The refinement converged into R= 0.036 and RW = 0.092. The structure, determined by single crystal X-ray diffraction, consists of two nickel atoms Ni (1) and Ni (2). Lots of ways of which is surrounded by six oxygen atoms, a carboxyl group and two water molecules.

scholarly journals Crystallization and preliminary X-ray diffraction analysis of the Csu pili CsuC–CsuA/B chaperone–major subunit pre-assembly complex fromAcinetobacter baumannii

2015 ◽  
Vol 71 (6) ◽  
pp. 770-774 ◽  
Author(s):  
Natalia Pakharukova ◽  
Minna Tuittila ◽  
Sari Paavilainen ◽  
Anton Zavialov
Keyword(s):  
Diffusion Method ◽  
X Ray Diffraction ◽  
Hanging Drop ◽  
Unit Cell Parameters ◽  
Gram Negative ◽  
X Ray ◽  
Cell Parameters ◽  
Abiotic Surfaces ◽  
Vapour Diffusion ◽  
Fimbrial Adhesins

The attachment of many Gram-negative pathogens to biotic and abiotic surfaces is mediated by fimbrial adhesins, which are assembledviathe classical, alternative and archaic chaperone–usher (CU) pathways. The archaic CU fimbrial adhesins have the widest phylogenetic distribution, yet very little is known about their structure and mechanism of assembly. To elucidate the biogenesis of archaic CU systems, structural analysis of the Csu fimbriae, which are used byAcinetobacter baumanniito form stable biofilms and cause nosocomial infection, was focused on. The major fimbriae subunit CsuA/B complexed with the CsuC chaperone was purified from the periplasm ofEscherichia colicells co-expressing CsuA/B and CsuC, and the complex was crystallized in PEG 3350 solution using the hanging-drop vapour-diffusion method. Selenomethionine-labelled CsuC–CsuA/B complex was purified and crystallized under the same conditions. The crystals diffracted to 2.40 Å resolution and belonged to the hexagonal space groupP6422, with unit-cell parametersa=b= 94.71,c = 187.05 Å, α = β = 90, γ = 120°. Initial phases were derived from a single anomalous diffraction (SAD) experiment using the selenomethionine derivative.

Silicate-germanate K2Y[(Si3Ge)O10(OH)] with unusual complex corrugated layer and its correlation to ring silicate gerenite and chain silicate chkalovite

2020 ◽  
Vol 235 (4-5) ◽  
pp. 167-172
Author(s):  
Anastasiia P. Topnikova ◽  
Elena L. Belokoneva ◽  
Olga V. Dimitrova ◽  
Anatoly S. Volkov ◽  
Leokadiya V. Zorina
Keyword(s):  
Low Temperature ◽  
Cross Section ◽  
Complex Anion ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Chain Silicate ◽  
Novel Complex

AbstractA new silicate-germanate K2Y[(Si3Ge)O10(OH)] was synthesized hydrothermally in a system Y2O3:GeO2:SiO2 = 1:1:2 (T = 280 °C; P = 90–100 atm.); K2CO3 was added to the solution as a mineralizer. Single-crystal X-ray diffraction experiment was carried out at low temperature (150 K). The unit cell parameters are a = 10.4975(4), b = 6.9567(2), c = 15.4001(6) Å, β = 104.894(4)°; V = 1086.86(7) Å3; space group is P 21/c. A novel complex anion is presented by corrugated (Si,Ge) tetrahedral layers connected by couples of YO6 octahedra into the mixed microporous framework with the channels along b and a axes, the maximal size of cross-section is ~5.6 Å. This structure has similarity with the two minerals: ring silicate gerenite (Ca,Na)2(Y,REE)3Si6O18 · 2H2O and chain silicate chkalovite Na2BeSi2O6. Six-member rings with 1̅ symmetry as in gerenite are distinguished in the new layer. They are mutually perpendicular to each other and connected by additional tetrahedra. Straight crossing chains in chkalovite change to zigzag four-link chains in the new silicate-germanate layer.

X-ray powder diffraction data of LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites

2021 ◽  
pp. 1-6
Author(s):  
Mariana M. V. M. Souza ◽  
Alex Maza ◽  
Pablo V. Tuza
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Pechini Method ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Modified Pechini Method ◽  
Scanning Electron

In the present work, LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites were synthesized by the modified Pechini method. These materials were characterized using X-ray fluorescence, scanning electron microscopy, and powder X-ray diffraction coupled to the Rietveld method. The crystal structure of these materials is orthorhombic, with space group Pbnm (No 62). The unit-cell parameters are a = 5.535(5) Å, b = 5.527(3) Å, c = 7.819(7) Å, V = 239.2(3) Å3, for the LaNi0.5Ti0.45Co0.05O3, a = 5.538(6) Å, b = 5.528(4) Å, c = 7.825(10) Å, V = 239.5(4) Å3, for the LaNi0.45Co0.05Ti0.5O3, and a = 5.540(2) Å, b = 5.5334(15) Å, c = 7.834(3) Å, V = 240.2(1) Å3, for the LaNi0.5Ti0.5O3.

scholarly journals Crystal Structure Refinements of Four Monazite Samples from Different Localities

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1028 ◽  
Author(s):  
M. Mashrur Zaman ◽  
Sytle M. Antao
Keyword(s):  
Crystal Structure ◽  
Electron Probe ◽  
Unit Cell Volume ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
X Ray ◽  
Cell Parameters ◽  
Large Unit Cell ◽  
A Site

This study investigates the crystal chemistry of monazite (APO4, where A = Lanthanides = Ln, as well as Y, Th, U, Ca, and Pb) based on four samples from different localities using single-crystal X-ray diffraction and electron-probe microanalysis. The crystal structure of all four samples are well refined, as indicated by their refinement statistics. Relatively large unit-cell parameters (a = 6.7640(5), b = 6.9850(4), c = 6.4500(3) Å, β = 103.584(2)°, and V = 296.22(3) Å3) are obtained for a detrital monazite-Ce from Cox’s Bazar, Bangladesh. Sm-rich monazite from Gunnison County, Colorado, USA, has smaller unit-cell parameters (a = 6.7010(4), b = 6.9080(4), c = 6.4300(4) Å, β = 103.817(3)°, and V = 289.04(3) Å3). The a, b, and c unit-cell parameters vary linearly with the unit-cell volume, V. The change in the a parameter is large (0.2 Å) and is related to the type of cations occupying the A site. The average <A-O> distances vary linearly with V, whereas the average <P-O> distances are nearly constant because the PO4 group is a rigid tetrahedron.

Sign in / Sign up

Export Citation Format

Share Document