Crystal Structure of a Novel Furo-Furan Lactone from Heliotropium eichwaldi

2012 ◽  
Vol 67 (3) ◽  
pp. 269-271
Author(s):  
Sadiqa Firdous ◽  
Nida Hassan Ansari ◽  
Seik Weng Ngb ◽  
Sammer Yousuf ◽  
Abdul Malik
Keyword(s):  
Crystal Structure ◽  
Ethyl Acetate ◽  
Soluble Fraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Report ◽  
First Time

A novel furo-furan lactone 1 has been isolated as fine needles from the ethyl acetate-soluble fraction of Heliotropium eichwaldi. This is the first report of any furo-furan from the genus Heliotropium. β -Sitosterol 3-O-β -D-glucoside 2 has also been obtained for the first time from this source. The structure of 1 was elucidated by X-ray diffraction studies.

O,O-diethyl O-[2-(dimethylamino)ethyl] phosphorothioate: structural evidence of the decomposition product and its oxalate salt

2019 ◽  
Vol 234 (9) ◽  
pp. 613-621
Author(s):  
Marc André Althoff ◽  
Jörn Frederik Martens ◽  
Marco Reichel ◽  
Manfred Metzulat ◽  
Thomas Matthias Klapötke ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Title Compound ◽  
Analytical Methods ◽  
Decomposition Product ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rearrangement Process ◽  
Study Support ◽  
First Time

Abstract The molecular and single crystal structure of O,O-diethyl O-[2-(dimethylamino)ethyl] phosphorothioate oxalate, as determined by single crystal X-ray diffraction studies, is described for the first time; although this compound is well-known by industry and research from the mid-20th century. The known decomposition product of pure O,O-diethyl O-[2-(dimethylamino)ethyl] phosphorothioate could also be structurally characterized. Additionally, the compounds are characterized by recent analytical methods e.g. NMR. The findings of our study support the thesis that the isolated decomposition product must be a by-product of the thiono-thiolo rearrangement process of the title compound.

Influence of the presence of the heme cofactor on the JK-loop structure in indoleamine 2,3-dioxygenase 1

2020 ◽  
Vol 76 (12) ◽  
pp. 1211-1221
Author(s):  
Manon Mirgaux ◽  
Laurence Leherte ◽  
Johan Wouters
Keyword(s):  
Crystal Structure ◽  
Cancer Research ◽  
Active Site ◽  
Loop Structure ◽  
X Ray Diffraction ◽  
Dynamic Information ◽  
X Ray ◽  
Indoleamine 2,3 Dioxygenase ◽  
First Time ◽  
Heme Cofactor

Indoleamine 2,3-dioxygenase 1 has sparked interest as an immunotherapeutic target in cancer research. Its structure includes a loop, named the JK-loop, that controls the orientation of the substrate or inhibitor within the active site. However, little has been reported about the crystal structure of this loop. In the present work, the conformation of the JK-loop is determined for the first time in the presence of the heme cofactor in the active site through X-ray diffraction experiments (2.44 Å resolution). Molecular-dynamics trajectories were also obtained to provide dynamic information about the loop according to the presence of cofactor. This new structural and dynamic information highlights the importance of the JK-loop in confining the labile heme cofactor to the active site.

Structure of fluorite-like compound based on Nd5Mo3O16with lead partly substituting for neodymium

2015 ◽  
Vol 71 (2) ◽  
pp. 186-193 ◽  
Author(s):  
Alexander M. Antipin ◽  
Natalia I. Sorokina ◽  
Olga A. Alekseeva ◽  
Alexandra N. Kuskova ◽  
Elena P. Kharitonova ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Single Crystal ◽  
Experimental Verification ◽  
X Ray Diffraction ◽  
Transmission Microscopy ◽  
X Ray ◽  
Oxygen Ion ◽  
First Time ◽  
Edx Microanalysis

A single crystal of Nd5Mo3O16with lead partly substituting for neodymium, which has a fluorite-like structure, was studied by precision X-ray diffraction, high-resolution transmission microscopy and EDX microanalysis. The crystal structure is determined in the space group Pn\bar 3n. It was found that the Pb atoms substitute in part for Nd atoms in the structure and are located in the vicinity of Nd2 positions. Partial substitutions of Mo cations for Nd positions and of Nd for Mo positions in crystals of theLn5Mo3O16oxide family are corroborated by X-ray diffraction for the first time. The first experimental verification of the location of an additional oxygen ion in the voids abutting MoO4tetrahedra was obtained.

The Great Barrier Reef Expedition 1928–29: The crystal structure and occurrence of weddellite, ideally CaC2O4·2.5H2O, from the Low Isles, Queensland

2016 ◽  
Vol 80 (2) ◽  
pp. 399-406 ◽  
Author(s):  
Stuart J. Mills ◽  
Andrew G. Christy
Keyword(s):  
Crystal Structure ◽  
Coral Reef ◽  
Low Temperature ◽  
Great Barrier Reef ◽  
Single Crystal ◽  
Structure Study ◽  
Barrier Reef ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Report

Abstract“Envelope crystals” collected during The Great Barrier Reef Expedition in May 1929 have been studied using low-temperature synchrotron single-crystal X-ray diffraction. The crystals are shown to be weddellite, with the largest content of zeolitic water reported to date. A new H2O site has been located within the crystal structure. Study of the crystals show that the end-member formula for weddellite should be reported as CaC2O4·(2.5 – x)H2O, where 0≤x≤ 0.25, instead of CaC2O4·(2H2O or CaC2O4·(2 + x )H2O. This is also the first report of weddellite occurring in a coral reef.

Strukturen und Schwingungsspektren des Tetramethylammonium -a -dodekawolframatosilikats und des Tetrabutylammonium-β-dodekawolframatosilikats / Structures and Vibrational Spectra of Tetramethylammonium a-Dodecatungstosilicate and Tetrabutylammonium β-Dodecatungstosilicate

1981 ◽  
Vol 36 (2) ◽  
pp. 161-171 ◽  
Author(s):  
Joachim Fuchs ◽  
Axel Thiele ◽  
Rosemarie Palm
Keyword(s):  
Crystal Structure ◽  
Vibrational Spectra ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Crystal Water ◽  
Space Group ◽  
X Ray ◽  
First Time

Abstract Dodecatungstosilicates free of crystal water were prepared for the first time by using tetraalkylammonium as cation. The crystal structure of the tetramethylammonium a-dodeeatungstosilicate [N(CH3)4]4SiW12O40 (1) and tetrabutylammonium) β-dodecatungstosilicate, [N(C4H9)4]4SiWi2040 (2) were solved by X-ray diffraction. (1) crystallizes tetragonal in the space group 14̅ with lattice parameters a = 14.642 Å; c= 12.706 Å; (2) orthorhombic, space group P212121 with a = 29.277 Å, b = 22.181 Å and c = 15.381 Å. The differences between the two isomeric heteropolyanions are discussed, especially the distances and angles between the tungsten atoms. Comparison of characteristic differences in the vibrational spectra permits the identification of the isomeric anions.

Structure and ionic conductivity of the octahydrate of tetralithium salt of calix[4]arenesulfonic acid

2021 ◽  
Author(s):  
Anna Pisareva ◽  
Gennady V. Shilov ◽  
Alexander Karelin ◽  
Rostislav Pisarev ◽  
Nadezhghda Bukun ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ionic Conductivity ◽  
Diffraction Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arenesulfonic Acid ◽  
First Time

Octahydrate of tetralithium salt of calix[4]sarenesulfonic acid was isolated for the first time The crystal structure of salt was determined by X-ray diffraction analysis. Compound crystallized in triclinic syngony, P-1,...

Zur Kristallstruktur von Ba3(CrO4)2 / On the Crystal Structure of Ba3 (CrO4) 2

1972 ◽  
Vol 27 (7) ◽  
pp. 739-744 ◽  
Author(s):  
Hj. Mattausch ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Time

For the first time single crystals of Ba3 (CrO4)2 have been examined by X-ray diffraction. The already well known isotypy with Ba3 (PO4)2 has been completed by exact parameters. There are isolated tetrahedrons of O2- surrounding Cr5+ and octahedrons surrounding BaI. The complicated coordination of BaII is discussed.

Crystal structure of Bis(2,2':6',2''-terpyridyl)cobalt(III) chloride

1983 ◽  
Vol 36 (8) ◽  
pp. 1563 ◽  
Author(s):  
BN Figgis ◽  
ES Kucharski ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Title Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Time

The crystal structure of the title compound [CO(C15H11N3)2]Cl3 has been determined by single crystal X-ray diffraction methods at 295 K and refined by least-squares methods to a residual of 0.069 for 2953 'observed' reflections. Crystals are triclinic, PI, a 9.018(4), b 11.751(4), c 18.085(6)�, α 9O.82(6), β 9O.66(7), γ 90.79(7)�, Z 2. The determination establishes for the first time metal-nitrogen distances in the bis(terpyridyl)cobalt(III) species; (Co-N)(central, distal) are 1.86, 1.93 �. The precision of the determination is adversely affected by widespread solvent/anion disorder.

Palladium-Cadmium Ordering In Repdcd (Re = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb) And Comparison With Isotypic Indium Compounds

2002 ◽  
Vol 57 (3) ◽  
pp. 275-279 ◽  
Author(s):  
Thomas Fickenscher ◽  
Rolf-Dieter Hoffmann ◽  
Ratikanta Mishra ◽  
Rainer Pöttgen
Keyword(s):  
Crystal Structure ◽  
High Frequency ◽  
Rare Earth Metals ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Variable Parameters ◽  
X Ray ◽  
Trivalent Rare Earth ◽  
Indium Compounds ◽  
First Time

AbstractTernary intermetallic compoundsREPdCd (RE=La, Ce, Pr, Nd, Sm, Eu, Tb)were synthesized by reaction of the elements in sealed tantalum tubes in a high-frequency furnace. All compounds were investigated by X-ray diffraction on powders. Those with RE = La, Ce, Pr, Nd, Sm, and Tb contain trivalent rare earth metals and they crystallize with the hexagonal ZrNiAl type structure. NdPdCd [a = 764.8(3), c = 401.3(2) pm] and TbPdCd [a = 756.5(2), c = 389.0(1) pm] are reported here for the first time as well as EuPdCd. The compounds with La, Ce, Pr, and Sm [J. Alloys Compd. 182, 87 (1992)] are confirmed. The crystal structure of EuPdCd was refined from X-ray single crystal diffractometer data: TiNiSi type, Pnma, a = 745.9(3), b = 439.8(2), c = 863.7(3) pm, wR2 = 0.0405, 683 F2 values, and 20 variable parameters. The three-dimensional [PdCd] substructure consists of strongly puckered, orthorhombically distorted Pd3Cd3 hexagons with Pd-Cd distances ranging from 283 to 285 pm. The europium atoms fill the cavities within the [PdCd] network. Chemical bonding in the series REPdCd and REPdIn is compared.

scholarly journals Synthesis, crystal structure, and electrochemical hydrogenation of the La2Mg17-xMx (M = Ni, Sn, Sb) solid solutions

2021 ◽  
Vol 12 (2) ◽  
pp. 197-203
Author(s):  
Vasyl Kordan ◽  
Vitalii Nytka ◽  
Ivan Tarasiuk ◽  
Oksana Zelinska ◽  
Volodymyr Pavlyuk
Keyword(s):  
Crystal Structure ◽  
Solid Solutions ◽  
Chemical Characteristics ◽  
Initial Structure ◽  
Electrochemical Hydrogenation ◽  
X Ray Diffraction ◽  
Hexagonal Symmetry ◽  
X Ray ◽  
Physical And Chemical ◽  
First Time

The crystal structure of La2Mg17-xSnx solid solution was determined by single crystal X-ray diffraction for the first time. This phase crystallizes in hexagonal symmetry with space group P63/mmc (a = 10.3911(3), c = 10.2702(3) Å, V = 960.36(6) Å3, R1 = 0.0180, wR2 = 0.0443 for the composition La3.65Mg30Sn1.10) and is related to the structure of CeMg10.3 and Th2Ni17-types which are derivative from the CaCu5-type. A series of isotypical solid solutions La2Mg17-xMx (M = Ni, Sn, Sb, x ~0.8) was synthesized and studied by X-ray powder diffraction, energy dispersive X-ray spectroscopy and fluorescent X-ray spectroscopy. All solid solutions crystallize with the structure related to the Th2Ni17-type. The electrochemical hydrogenation confirmed the similar electrochemical behavior of all studied alloys. The amount of deintercalated hydrogen depends on the physical and chemical characteristics of doping elements and increases in the sequence Sn < Mg < Sb < Ni. The most geometrically advantageous sites are octahedral voids 6h of the initial structure, thus a coordination polyhedron for H-atom is an octahedron [HLa2(Mg,M)4].

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