scholarly journals STRUCTURAL CHARACTERIZATION OF 2-AMINO-2-OXOACETIC ACID BY X-RAY POWDER DIFFRACTION AND QUANTUM CHEMISTRY

2019 ◽  
Vol 16 (33) ◽  
pp. 516-523
Author(s):  
G. E. DELGADO ◽  
L. M. BELANDRIA ◽  
M. GUILLEN ◽  
A.. J. MORA ◽  
L. E. SEIJAS
Keyword(s):  
Hydrogen Bonds ◽  
Single Crystal ◽  
Structural Study ◽  
Powder Diffraction ◽  
Structural Characterization ◽  
Structure Determination ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray

2-amino-2-oxoacetic acid, carbamoyl formic acid, or oxamic acid is an active pharmaceutical ingredient (API) of great importance mainly because is an inhibitor of lactic dehydrogenase (LDH). It acts as an inhibitor to the metabolic pathways of the tumor cells and exhibited significant anticancer activity against nasopharyngeal carcinoma (NPC) cells in vitro and can be considered as a potential drug for the treatment of type 2 diabetes. Also, this compound could be used as a building block in the design of supramolecular architectures based on hydrogen bonds through the complimentary hydrogen-bond functionalities of the carbonyl and amide functional groups present. Single-crystal X-ray diffraction is the most powerful technique for crystal structure determination of small molecules. However, for several materials, including oxamic acid, it could be complicated to grow single crystals of suitable size and quality that make them appropriated to structure analysis. For this reason, the structural study was conducted with powder X-ray diffraction which is a process significantly more challenging than structure determination from single-crystal data. Oxamic acid has been characterized by FT-IR and NMR spectroscopic techniques, thermal TGA-DSC analysis, semi-empirical PM7 calculations, and X-ray powder diffraction. The title compound crystallizes in the monoclinic system with space group Cc, Z=4, and unit cell parameters a= 9.4994(4) Å, b= 5.4380(2) Å, c= 6.8636(3) Å, b= 107.149(2)°, V= 338.79(2) Å3. The molecule has a trans conformation. The molecular structure and crystal packing are stabilized mainly by intra- and intermolecular O--H···O and N--H···O hydrogen bonds. The structural characterization of this type of API compound is important to understand its mechanisms of action due to its considerable biological effects. In particular, for oxamic acid, this structural study would allow subsequent examination of its medicinal properties as an antitumor and antidiabetic agent.

Structural Characterization of the Reaction Products of Vanadium(II) and Endrin as 2 Isomers of 1,8,exo-9,10,11-Pentachloropentacyclo[6.2.1.13,6.02,7.04,10]dodecan-5-one

1989 ◽  
Vol 42 (6) ◽  
pp. 959
Author(s):  
DE Clegg ◽  
PC Healy ◽  
GJ Patch ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Structural Characterization ◽  
Structure Determination ◽  
Title Compound ◽  
Reaction Products ◽  
X Ray

Two dechlorinated products (B) and (D), formed in the reaction between endrin (C12H8Cl6O) and vanadium(II) for the purpose of confirmation of identity, are shown by single-crystal X-ray structure determination to be isomers of the title compound, C12H9Cl5O. Crystals of both are monoclinic, P21/c. For isomer (B), a 7.432(8), b 12.76(1), c 14.55(2) � , β 108.32(9)�, Z=4; R was 0.038 for 2594 observed reflections. For isomer (D), a 9.037(4), b 12.004(4), c 14.436(6) � , β 124.91(2)°, Z= 4; R was 0.041 for 1826 reflections. The geometries of the two isomers are compared.

Lewis-Base Adducts of Group 11 Metal(I) Compounds. LI. Synthesis and Structural Characterization of Mononuclear Chloro-, Bromo- and Iodo-pyridinebis(triphenylphosphine)copper(I) Complexes

1989 ◽  
Vol 42 (6) ◽  
pp. 895 ◽  
Author(s):  
LM Engelhardt ◽  
PC Healy ◽  
JD Kildea ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Structural Characterization ◽  
Structure Determination ◽  
Copper Atom ◽  
Lewis Base ◽  
X Ray

Complexes [ XCu ( py )(PPh3)2], X = Cl, Br, I, py = pyridine, have been synthesized and characterized by single-crystal X-ray structure determination. Chloride and iodide derivatives have similar cells [ isomorphous (?) but not isostructural ], triclinic, pi, a = 19.5 A, b = 10.5, c = 9.6 � , α ≈ 66, β ≈ 86, γ ≈ 83�, Z = 2; the bromide is monoclinic, Cc, a 13.568(9), b 15.760(12), c 16.545(8) � , β 95.65(5)�, Z = 4. Cl, Br, I structures were refined to residuals of 0.042, 0.055, 0.039 for 4288, 2241, 4808 'observed' reflections. In all cases, the copper atom is four-coordinate; for such an array, Cu-X lengths are unusually short [2.318(2), 2.459(2), 2.636(1) � (Cl, Br, I) and Cu-N unusually long (2.14(1) � ], while (Cu-P) increase from 2.264 to 2.288 � across the series. The dominant aspect of the complexes is thus that of XCu (PPh3)2 solvated by pyridine.

Synthesis and Characterization of the nido-Platinaborane 7,7-(PPh3)2-7-PtB10H11-11-OC(O)Me

2011 ◽  
Vol 66 (4) ◽  
pp. 387-391
Author(s):  
Jinling Miao ◽  
Yong Nie ◽  
Haiyan Chen ◽  
Daqi Wang ◽  
Markus Enders ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Elemental Analysis ◽  
Chain Structure ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ir And Nmr Spectroscopy

The reaction of closo-B10H102− with PtCl2(PPh3)2 in the presence of MeCOSH afforded the title platinaborane nido-7,7-(PPh3)2-7-PtB10H11-11-OC(O)Me (1), which has been characterized by IR and NMR spectroscopy, MS, elemental analysis, and single-crystal X-ray diffraction. In contrast to the known products having exo-polyhedral Pt-S-C-O-B ring(s) from the same reaction with Ph- COSH, compound 1 has a B-acetoxy group on the open PtB4 face of the nido-PtB10 cluster. The structure of 1 features both intramolecular/intermolecular C-H· · ·O hydrogen bonds and intramolecular C-H· · ·H-B dihydrogen bonds, which link the molecules into a 1-D chain structure.

Synthesis and structural characterization of two copper(II) complexes with 3-(4-(1H-benzo[d]imidazol-1-yl)-4-methoxyphenyl)-1-phenylprop- 2-en-1-one ligands

2015 ◽  
Vol 70 (3) ◽  
pp. 165-169 ◽  
Author(s):  
Gao-Feng Wang
Keyword(s):  
Infrared Spectroscopy ◽  
Single Crystal ◽  
Structural Characterization ◽  
X Ray Diffraction ◽  
Distorted Octahedral Environment ◽  
X Ray ◽  
Octahedral Environment ◽  
Distorted Octahedral ◽  
Elemental Analyses

AbstractThe synthesis of two new copper(II) complexes with benzimidazole type ligands, Cu(tta)2(L1)2 (1) and Cu(tta)2(L1) (2) (where L1 is 3-(4-(1H-benzo[d]imidazol-1-yl)-4-methoxy phenyl)-1-phenylprop-2-en-1-one; tta is 2-thenoyltrifluoroacetonate), are reported. Their structures have been characterized by infrared spectroscopy, elemental analyses and single-crystal X-ray diffraction. The copper(II) ion of 1 is in a distorted octahedral environment, while that of 2 is in a distorted square-pyramidal environment. In both cases, the donor atoms are provided by oxygen atoms of the tta ligands and nitrogen atoms of the L1 ligands.

Single Crystal X-Ray Structural Characterization of [BiX2(S2CNEt2)]Infinity∞, X=Cl, Br

1994 ◽  
Vol 47 (2) ◽  
pp. 405 ◽  
Author(s):  
PK Bharadwaj ◽  
AM Lee ◽  
BW Skelton ◽  
BR Srinivasan ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Sulfur Atom ◽  
Structural Characterization ◽  
Structure Determination ◽  
Room Temperature ◽  
X Ray ◽  
Structure Determinations

Single-crystal room-temperature X-ray structure determinations of the title compounds have been carried out. The two compounds are isomorphous, and isomorphous with the previously determined iodide analogue, being monoclinic, P 21/c, a ≈ 10.0, b ≈ 14.9, c ≈ 7.8 Ǻ, β ≈ 92°, Z = 4 formula units; residuals were 0.037, 0.036 for 2197, 1654 'observed' reflections for X = Cl , Br respectively. As in the iodide, the complexes are infinite polymers, with successive bismuth atoms bridged by the two halides and one sulfur atom of the ligand , which also chelates each bismuth. The structure determination of C5H5NCONEt2]2 [Cl5Bi(NC5H5)], isostructural with its thiocarbamoyl analogue, is also recorded.

Synthesis and Structural Characterization of Palladium Dicarbene Complexes Bearing Labile Co-Ligands

2009 ◽  
Vol 62 (9) ◽  
pp. 983 ◽  
Author(s):  
Han Vinh Huynh ◽  
Hui Xian Seow
Keyword(s):  
Single Crystal ◽  
Structural Characterization ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Metathesis Reaction ◽  
X Ray ◽  
Low Activity

Dicarbene complexes [Pd(OAc)2(diNHC)] (2), [Pd(O2CCF3)2(diNHC)] (3), and [Pd(CNCH3)2(diNHC)](SO3CF3)2 (4) bearing labile acetato, fluoroacetato, and acetonitrile co-ligands have been synthesized via metathesis reaction of the respective precursor [PdBr2(diNHC)] (1) with Ag-salts. All complexes are stable towards air and moisture and have been fully characterized by spectroscopic and spectrometric methods. Notably and in comparison to diphosphine analogues, they resist ligand disproportionation in solution. Their molecular structures have also been determined by single crystal X-ray diffraction. A preliminary catalytic study showed low activity in the hydroamination reaction, but revealed an interesting co-ligand influence.

Structural characterization of La2−xMxCuO4 (M = Sr,Ba) samples by synchrotron x-ray and neutron powder diffraction techniques

1988 ◽  
Vol 3 (6) ◽  
pp. 1327-1335 ◽  
Author(s):  
D. E. Cox ◽  
S. C. Moss ◽  
R. L. Meng ◽  
P. H. Hor ◽  
C. W. Chu
Keyword(s):  
High Resolution ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
Structural Characterization ◽  
Neutron Powder Diffraction ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
Neutron Data ◽  
X Ray

High-resolution synchrotron x-ray powder diffraction studies on samples of La2−xMxCuO4 (M = Sr,Ba) prepared by standard ceramic techniques show that macroscopic compositional inhomogeneities may exist that are unlikely to be revealed by conventional x-ray diffraction methods. Rietveld refinement of neutron data collected at 200, 50, and 11 K from one such sample, nominally La1.8Sr0.2CuO4, gave satisfactory fits to a tetragonal structure of K2NiF4 type at all three temperatures. However, careful individual peak fits revealed that part of the sample transforms to orthorhombic between 200 and 50 K. It is suggested that this multiphase character has an important influence on the superconducting properties.

Lewis-Base Adducts of Lead(II) Compounds. III. Synthesis and Structural Characterization of Mononuclear (Nitrato-O,O′)bis(1,10-phenanthroline)-(thiocyanato-N)lead(II)

1989 ◽  
Vol 42 (2) ◽  
pp. 335 ◽  
Author(s):  
LM Engelhardt ◽  
JM Patrick ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Structural Characterization ◽  
Structure Determination ◽  
Title Compound ◽  
Lone Pair ◽  
Lewis Base ◽  
Lead Atom ◽  
X Ray

The isolation and single-crystal X-ray structure determination of the title compound, [(phen)2Pb(NCS)(O2NO)] is described; crystals are triclinic, P1, a 15.554(7), b 9-670(4), c 8.429(3) α 72.53(3), β 81.90(3), γ 72.88(3)� Z = 2, yielding R 0.052 for 3405 independent 'observed' reflections. The lead atom is seven-coordinate [Pb-N 2.49(1)-2.60(1) (phen), 2.89(1) (NCS); Pb-O 2.75(1), 2.89(1) �] with a large vacancy in the coordination sphere, possibly indicative of a stereochemically active lone pair.

Synthesis and characterization of dicarboranylmethylammonium polyoxometallates

2010 ◽  
Vol 75 (11) ◽  
pp. 1075-1096 ◽  
Author(s):  
Ramón Macías ◽  
John D. Kennedy ◽  
Jonathan Bould ◽  
Mark Thornton-Pett
Keyword(s):  
Hydrogen Bonds ◽  
Single Crystal ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pyridinium Cation ◽  
Network Of Hydrogen Bonds ◽  
Work Up ◽  
Acetone Hexane

The reaction of [C2B10H11CH2NH3]Cl (3) with [NH4]6[Mo7O24][H2O]4 in water instantly afforded a white precipitate: crystallization from acetone–hexane thence gave the hybrid dicarborane octamolybdate salt, [C2B10H11CH2NH3]2[C2B10H11CH2NH=CMe2]2[Mo8O26][Me2CO]4.5 (5), whereas crystallization from acetonitrile–ether gave three further salts: [C2B10H11CH2NH3]2[C2B10H11CH2NH2CHMe2]2[Mo8O26][MeCN]2 (6), [C2B10H11CH2NH3]4[Mo8O26][MeCN]2[Et2O]2 (7) and [C2B10H11CH2NH3]2[C2B10H11CH2NH2Et]2[Mo8O26][MeCN]2 (8). Similarly, treatment of an acidified solution of Na2WO4 with [C2B10H11CH2NH3]Cl (3) in water also yielded a white precipitate: crystallization from acetone–hexane afforded the salt [C2B10H11CH2NH=CHMe2]4[W10O32][H2O]2[Me2CO]4 (10), whereas crystallization from acetonitrile–ether gave the double salt [C2B10H11CH2NH3]2[C5H5NH]2[W10O32][MeCN]2-[Et2O] (11). All these ‘globule–globule’ salts 5, 6, 8, 10 and 11 have been characterized by single-crystal X-ray diffraction analyses. Crystal structures reveal the presence of various small solvate molecules, together with an extensive network of hydrogen bonds between ammonium groups and oxygen atoms of the isopolyoxometallates. The isopropyl substituent in one of the carborane cations of the salts 6 and the ethyl substituent in one of the carborane cations of salts 8 may result from occluded isopropanol and ethanol in the starting salt 3 with alkylations of the primary ammonium group being assisted by isopolymolybdate anions. The presence of the pyridinium cation in 11 is believed to arise from contamination during work-up the reaction mixture.

Synthesis, structural characterization, and hydrogen bonds of Co9(OH)14[SO4]2

2017 ◽  
Vol 72 (7) ◽  
pp. 505-510
Author(s):  
Hamdi Ben Yahia ◽  
Masahiro Shikano ◽  
Ilias Belharouak
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Structural Characterization ◽  
Diffraction Data ◽  
Atmospheric Oxygen ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Triclinic System

AbstractThe new compound Co9(OH)14[SO4]2 was synthesized using a hydrothermal method from LiF, Na2SO3, and Co(CH3COO)2·4H2O in a molar ratio of 1:1:1 in the presence of atmospheric oxygen. Its crystal structure was determined from single crystal X-ray diffraction data. Co9(OH)14[SO4]2 crystallizes in the triclinic system, space group P1̅ with a=7.693(2) Å, b=8.318(2) Å, c=8.351(2) Å, α=82.375(5)°, β=77.832(4)°, γ=68.395(4)°, V=484.8(2) Å3, and Z=2. Its structure is composed of cobalt-containing sheets interconnected by SO4 tetrahedra. Bent and symmetrically trifurcated hydrogen bonds have been observed. Furthermore, structural similarities with hydrozincite and brucite minerals have been noticed.

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