scholarly journals Rationalisation of Patterns of Competing Reactivity by X-ray Structure Determination: Reaction of Isomeric (Benzyloxythienyl)oxazolines with a Base

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7690
Author(s):  
Robert Alan Aitken ◽  
Andrew D. Harper ◽  
Alexandra M. Z. Slawin
Keyword(s):  
Structure Determination ◽  
X Ray Diffraction ◽  
Strong Base ◽  
Wittig Rearrangement ◽  
X Ray ◽  
Shortest Distance ◽  
Intermediate Distance ◽  
Reactive Groups

Three isomeric (benzyloxythienyl)oxazolines 9, 11 and 13 have been prepared and are found, upon treatment with a strong base, to undergo either Wittig rearrangement or intramolecular attack of the benzylic anion on the oxazoline function to give products derived from cleavage of the initially formed 3-aminothienofuran products. This pattern of reactivity is directly linked to the distance between the two reactive groups as determined by X-ray diffraction, with the greatest distance in 11 leading to exclusive Wittig rearrangement, the shortest distance in 13 giving exclusively cyclisation-derived products, and the intermediate distance in 9 leading to both processes being observed. The corresponding N-butyl amides were also obtained in two cases and one of these undergoes efficient Wittig rearrangement leading to a thieno[2,3-c]pyrrolone product.

Structure determination of ultrathin NbSe2 films by Grazing incidence x-ray diffraction

1994 ◽  
Vol 89 (7) ◽  
pp. 583-586 ◽  
Author(s):  
Toshihiro Shimada ◽  
Yukito Furukawa ◽  
Etsuo Arakawa ◽  
Kunikazu Takeshita ◽  
Tadashi Matsushita ◽  
...  
Keyword(s):  
Structure Determination ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray

Structure determination of modulated structures by powder X-ray diffraction and electron diffraction

2016 ◽  
Vol 3 (11) ◽  
pp. 1351-1362 ◽  
Author(s):  
Zhengyang Zhou ◽  
Lukáš Palatinus ◽  
Junliang Sun
Keyword(s):  
Electron Diffraction ◽  
Structure Determination ◽  
X Ray Diffraction ◽  
X Ray ◽  
Modulated Structures ◽  
Conventional Methods

The combination of PXRD and ED is applied to determine modulated structures which resist solution by more conventional methods.

Interrupted silicogermanate with 10-ring channels: synthesis and structure determination by combining rotation electron diffraction and powder X-ray diffraction

2017 ◽  
Vol 4 (10) ◽  
pp. 1654-1659 ◽  
Author(s):  
Yilin Wang ◽  
Yunchen Wang ◽  
Jie Su ◽  
Xiaowei Song ◽  
Wei Wan ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Structure Determination ◽  
X Ray Diffraction ◽  
X Ray

Structure determination of silicogermanate with sti layers pillared by D4R/Ge7 units by rotation electron diffraction and powder X-ray diffraction.

STRUCTURE DETERMINATION BY X-RAY DIFFRACTION

Biopolymers ◽  
1973 ◽  
pp. 84-125
Author(s):  
Alan G. Walton ◽  
John Blackwell
Keyword(s):  
Structure Determination ◽  
X Ray Diffraction ◽  
X Ray

Structure determination of fatty acid ester biofuels via in situ cryocrystallisation and single crystal X-ray diffraction

CrystEngComm ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Siriyara Jagannatha Prathapa ◽  
Cara Slabbert ◽  
Manuel A. Fernandes ◽  
Andreas Lemmerer
Keyword(s):  
Crystal Structure ◽  
Fatty Acid ◽  
Fatty Acid Ester ◽  
Structure Determination ◽  
Homologous Series ◽  
Methyl Esters ◽  
X Ray Diffraction ◽  
X Ray

In situ cryocrystallisation enabled the crystal structure determination of a homologous series of low-melting n-alkyl methyl esters Cn−1H2n+1CO2CH3.

Structure determination of a partially ordered layered silicate material with an NMR crystallography approach

2017 ◽  
Vol 73 (3) ◽  
pp. 184-190 ◽  
Author(s):  
Darren Henry Brouwer ◽  
Sylvian Cadars ◽  
Kathryn Hotke ◽  
Jared Van Huizen ◽  
Nicholas Van Huizen
Keyword(s):  
Nmr Spectroscopy ◽  
Structure Determination ◽  
Three Dimensional ◽  
Layered Silicate ◽  
Silicate Layer ◽  
Silicate Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nmr Crystallography

Structure determination of layered materials can present challenges for conventional diffraction methods due to the fact that such materials often lack full three-dimensional periodicity since adjacent layers may not stack in an orderly and regular fashion. In such cases, NMR crystallography strategies involving a combination of solid-state NMR spectroscopy, powder X-ray diffraction, and computational chemistry methods can often reveal structural details that cannot be acquired from diffraction alone. We present here the structure determination of a surfactant-templated layered silicate material that lacks full three-dimensional crystallinity using such an NMR crystallography approach. Through a combination of powder X-ray diffraction and advanced 29Si solid-state NMR spectroscopy, it is revealed that the structure of the silicate layer of this layered silicate material templated with cetyltrimethylammonium surfactant cations is isostructural with the silicate layer of a previously reported material referred to as ilerite, octosilicate, or RUB-18. High-field 1H NMR spectroscopy reveals differences between the materials in terms of the ordering of silanol groups on the surfaces of the layers, as well as the contents of the inter-layer space.

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