New Synthesis and Crystal Structures of Platinum(II) L-Ascorbate Complexes

1996 ◽  
Vol 25 (5) ◽  
pp. 375-376 ◽  
Author(s):  
Hidetaka Yuge ◽  
T. Ken Miyamoto
Keyword(s):  
Crystal Structures ◽  
New Synthesis ◽  
Ascorbate Complexes

Crystal Structures of Intermediates in a New Synthesis of Antitumor Drug Cabozantinib

Heterocycles ◽  
2016 ◽  
Vol 93 (1) ◽  
pp. 323
Author(s):  
Sven Nerdinger ◽  
Gerhard Laus ◽  
Erwin Schreiner ◽  
Volker Kahlenberg ◽  
Klaus Wurst ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Antitumor Drug ◽  
New Synthesis

2-Acylidene-3,5-diaryl-2,3-dihydro-1,3,4-thiadiazoles and related compounds: a question of hypervalent S … O interactions

1993 ◽  
Vol 71 (4) ◽  
pp. 561-571 ◽  
Author(s):  
Naresh Pandya ◽  
Anthony J. Basile ◽  
Ajay K. Gupta ◽  
Patrick Hand ◽  
Cindy L. MacLaurin ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Carbonyl Oxygen ◽  
Side Chain ◽  
Molecular Mechanics Calculations ◽  
New Synthesis ◽  
Cell Dimensions ◽  
Thiadiazole Ring ◽  
Hypervalent Interaction ◽  
Related Compounds ◽  
Selective Deacetylation

A new synthesis of 1 by selective deacetylation of 2 is reported. The acylation step implied in earlier syntheses of 1 and related compounds is exemplified by direct acylations of 3 to give 4a and 4b. Several new 2-acylidene-3-(2,4-dibromophenyl)-5-phenyl-2,3-dihydro-1,3,4-thiadiazoles (11) and thioacylidene analogues (12) are described. The crystal structures of 11a, 11b, 11c, and 11d reveal a hypervalent interaction, ca. 2.45–2.7 Å long, between the sulfur and carbonyl oxygen atoms. The dibromophenyl ring is nearly perpendicular to the thiadiazole ring plane in the crystal structures, and NMR data suggest that this conformation is maintained in solution. Molecular mechanics calculations show that the S … O interaction need only be a few kilocalories in order to stabilize the observed acylidene side chain configuration over other possible isomers. Crystals of 11a are triclinic, [Formula: see text] with cell dimensions a = 12.937(2), b = 13.429(2), c = 13.489(2) Å, α = 60.14(1)°, β = 74.59(1)°, γ = 58.70(1)°, Z = 4, and R = 0.044 for 3287 observed reflections. Crystals of 11b are monoclinic, P21/c, with cell dimensions a = 10.512(1), b = 12.084(2), c = 16.268(4) Å, β = 96.91(1)°, Z = 4, R = 0.050 for 1938 observed reflections. Crystals of 11c are monoclinic, P21/c, with cell dimensions a = 17.492(4), b = 16.979(1), c = 14.962(1) Å, β = 106.46(1)°, Z = 8, R = 0.057 for 3112 observed reflections. Crystals of 11d are monoclinic, P21/c, with cell dimensions a = 11.749(1), b = 8.533(1), c = 22.670(4) Å, β = 100.17(1)°, Z = 4, and R = 0.059 for 2265 observed reflections.

A new synthesis of acetato porphyrinato indium(III) from indium(III) oxide and X-ray crystal structures of In(tpyp)(OAc) and In(tmpp)(OAc)

Polyhedron ◽  
1996 ◽  
Vol 15 (15) ◽  
pp. 2647-2654 ◽  
Author(s):  
Tay-Ning Hong ◽  
Yeong-Horng Sheu ◽  
Keh-Wen Jang ◽  
Jyh-Horung Chen ◽  
Shin-Shin Wang ◽  
...  
Keyword(s):  
Crystal Structures ◽  
X Ray ◽  
New Synthesis

Pollutant Identification by Selected Area Electron Diffraction

1974 ◽  
Vol 32 ◽  
pp. 532-533
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson ◽  
C. W. Walker
Keyword(s):  
Thermal Treatment ◽  
Electron Diffraction ◽  
Sample Preparation ◽  
Crystal Structures ◽  
Water Samples ◽  
Environmental Samples ◽  
Short Review ◽  
Selected Area Electron Diffraction ◽  
Multiple Component

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.

The Imaging of Crystal Structures and Crystal Defects

1978 ◽  
Vol 36 (3) ◽  
pp. 207-217
Author(s):  
J.M. Cowley
Keyword(s):  
Electron Microscope ◽  
Crystal Structures ◽  
Phase Contrast ◽  
Crystal Defects ◽  
Atom Density ◽  
Lack Of Information ◽  
Spatial Frequencies

The problem of "understandinq" electron microscope imaqes becomes more acute as the resolution is improved. The naive interpretation of an imaqe as representinq the projection of an atom density becomes less and less appropriate. We are increasinqly forced to face the complexities of coherent imaqinq of what are essentially phase objects. Most electron microscopists are now aware that, for very thin weakly scatterinq objects such as thin unstained bioloqical specimens, hiqh resolution imaqes are best obtained near the optimum defocus, as prescribed by Scherzer, where the phase contrast imaqe qives a qood representation of the projected potential, apart from a lack of information on the lower spatial frequencies. But phase contrast imaqinq is never simple except in idealized limitinq cases.

Transmission electron microscope studies in special ceramics

1978 ◽  
Vol 36 (1) ◽  
pp. 268-269
Author(s):  
A. Zangvil ◽  
L.J. Gauckler ◽  
G. Schneider ◽  
M. Rühle
Keyword(s):  
Phase Diagrams ◽  
Crystal Structures ◽  
Thin Foil ◽  
Limited Extent ◽  
Complex Materials ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Lattice Resolution

The use of high temperature special ceramics which are usually complex materials based on oxides, nitrides, carbides and borides of silicon and aluminum, is critically dependent on their thermomechanical and other physical properties. The investigations of the phase diagrams, crystal structures and microstructural features are essential for better understanding of the macro-properties. Phase diagrams and crystal structures have been studied mainly by X-ray diffraction (XRD). Transmission electron microscopy (TEM) has contributed to this field to a very limited extent; it has been used more extensively in the study of microstructure, phase transformations and lattice defects. Often only TEM can give solutions to numerous problems in the above fields, since the various phases exist in extremely fine grains and subgrain structures; single crystals of appreciable size are often not available. Examples with some of our experimental results from two multicomponent systems are presented here. The standard ion thinning technique was used for the preparation of thin foil samples, which were then investigated with JEOL 200A and Siemens ELMISKOP 102 (for the lattice resolution work) electron microscopes.

Advancing the use of Voronoi–Dirichlet polyhedra to describe interactions in organic molecular crystal structures by the example of galunisertib polymorphs

CrystEngComm ◽  
2021 ◽  
Author(s):  
Viktor N. Serezhkin ◽  
Anton V. Savchenkov
Keyword(s):  
Crystal Structures ◽  
Molecular Crystal ◽  
Noncovalent Interactions ◽  
Organic Molecular Crystal ◽  
Universal Approach ◽  
Structure Properties

The universal approach for studying structure/properties relationships shows that every polymorph of galunisertib is characterized with unique noncovalent interactions.

Crystal structures of Magnaporthe oryzae trehalose-6-phosphate synthase (MoTps1) suggest a model for catalytic process of Tps1

2019 ◽  
Vol 476 (21) ◽  
pp. 3227-3240 ◽  
Author(s):  
Shanshan Wang ◽  
Yanxiang Zhao ◽  
Long Yi ◽  
Minghe Shen ◽  
Chao Wang ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Conformational Changes ◽  
Magnaporthe Oryzae ◽  
Structural Information ◽  
Complex Structure ◽  
Critical Role ◽  
Catalytic Process ◽  
Structural Basis ◽  
Salt Bridges ◽  
Terminal Domain

Trehalose-6-phosphate (T6P) synthase (Tps1) catalyzes the formation of T6P from UDP-glucose (UDPG) (or GDPG, etc.) and glucose-6-phosphate (G6P), and structural basis of this process has not been well studied. MoTps1 (Magnaporthe oryzae Tps1) plays a critical role in carbon and nitrogen metabolism, but its structural information is unknown. Here we present the crystal structures of MoTps1 apo, binary (with UDPG) and ternary (with UDPG/G6P or UDP/T6P) complexes. MoTps1 consists of two modified Rossmann-fold domains and a catalytic center in-between. Unlike Escherichia coli OtsA (EcOtsA, the Tps1 of E. coli), MoTps1 exists as a mixture of monomer, dimer, and oligomer in solution. Inter-chain salt bridges, which are not fully conserved in EcOtsA, play primary roles in MoTps1 oligomerization. Binding of UDPG by MoTps1 C-terminal domain modifies the substrate pocket of MoTps1. In the MoTps1 ternary complex structure, UDP and T6P, the products of UDPG and G6P, are detected, and substantial conformational rearrangements of N-terminal domain, including structural reshuffling (β3–β4 loop to α0 helix) and movement of a ‘shift region' towards the catalytic centre, are observed. These conformational changes render MoTps1 to a ‘closed' state compared with its ‘open' state in apo or UDPG complex structures. By solving the EcOtsA apo structure, we confirmed that similar ligand binding induced conformational changes also exist in EcOtsA, although no structural reshuffling involved. Based on our research and previous studies, we present a model for the catalytic process of Tps1. Our research provides novel information on MoTps1, Tps1 family, and structure-based antifungal drug design.

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