scholarly journals Isolation and structure determination of a tetrameric sulfonyl dilithio methandiide in solution based on crystal structure analysis and 6Li/13C NMR spectroscopic data

2020 ◽  
Vol 16 ◽  
pp. 2057-2063
Author(s):  
Jürgen Vollhardt ◽  
Hans Jörg Lindner ◽  
Hans-Joachim Gais

Dilithio sulfonyl methandiides are a synthetically and structurally highly interesting group of functionalized geminal dianions. Although very desirable, knowledge of the structure of dilithio methandiides in solution was lacking up to now. Herein, we describe the isolation and determination of the structure of tetrameric dilithio (trimethylsilyl)(phenylsulfonyl) methandiide in solution and in the crystal. The elucidation of the structure of the tetramer is based on crystal structure analysis and 13C/6Li NMR spectroscopic data. A characteristic feature of the structure of the tetramer is the C 2 symmetric C–Li chain, composed of four doubly Li-coordinated dianionic carbon and five Li atoms. Three Li atoms are devoid of a contact to a dianionic C atom. The tetramer, the dianionic C atoms of which undergo fast exchange, is in THF solution in fast equilibrium with a further aggregate, which is stable only at low temperatures.

1960 ◽  
Vol 4 ◽  
pp. 1-18
Author(s):  
Arnold Hargreaves

AbstractOptical transforms are of particular value In the earlier stages of crystal-structure determination; they enable trial structures to be tested rapidly and may indicate the nature of changes which will improve a postulated structure. The optical transforms are produced in a simple instrument called an optical diffractometer. The projected positions of the atoms in a postulated structure are represented by a set of holes punched in a mask, and the diffractometer produces the Fraunhofer diffraction pattern of the mask. The distribution of intensity in the optical transform is comparable, when sampled at suitable Intervals, with the distribution of intensity among the observed intensities in a particular zone of X-ray reflections. The use of optical transforms in the determination of crystal structures and in the study of imperfect structures will be illustrated by examples.


1984 ◽  
Vol 39 (6) ◽  
pp. 721-726 ◽  
Author(s):  
Irene Brüdgam ◽  
Hans Hartl ◽  
Dieter Lentz

AbstractThe unstable trifluorom ethylisocyanide can be stabilized on the Fe3(CO)11 framework. Infrared data suggest that the isocyanide ligand occupies bridging positions in the solid state and in solution. This fact has been confirmed by the crystal structure analysis and by 13C NMR measurements.


1999 ◽  
Vol 23 (9) ◽  
pp. 578-579
Author(s):  
Rainer Schobert ◽  
Hermann Pfab ◽  
Jutta Böhmer ◽  
Frank Hampel ◽  
Andreas Werner

Racemates of (η3-allyl)tricarbonyliron lactone complex Fe(CO)3{η1:η3-C(O)XCH2CHCMeCH2} 1a (X = O) and (η3-allyl)tricarbonyliron lactam complex 2a (X = NMe) are resolved on a preparative scale by HPLC on cellulose tris(3,5-dimethylphenyl)carbamate/silica gel RP-8 and the absolute configuration of (-)-2a is determined by X-ray crystal structure analysis.


IUCrData ◽  
2019 ◽  
Vol 4 (7) ◽  
Author(s):  
H. E. Bollard ◽  
M. G. Banwell ◽  
J. S. Ward

While the crystal structure analysis of the title compound, C26H38O15, a synthetic derivative of sucrose, was originally reported 40 years ago [Drew et al. (1979). Carbohydr. Res. 71, 35–42], the present work has allowed for the determination of its absolute configuration through the application of resonant scattering techniques.


1987 ◽  
Vol 40 (7) ◽  
pp. 1169 ◽  
Author(s):  
JA Elix ◽  
KL Gaul ◽  
M Sterns ◽  
MW Binsamsudin

The structure determination of thiomelin (2,4-dichloro-1,8-dihydroxy-5-methoxy-6-methyl-9H-xanthen-9-one) (3), an unusual lichen metabolite probably derived biosynthetically by oxidative ring opening of a precursor anthraquinone, is reported. The crystal structure of thiomelin diacetate (4) was determined by X-ray diffraction, while that of the cogenors 8-O-methylthiomelin (5), 4-dechlorothiomelin (7), 4-dechloro-8- O- methylthiomelin (9), 2-dechloro-8- O- methylthiomelin (10) and 2,4-dichloro-l-hydroxy-7-methoxy-6,8-dimethyl-9H-xanthen-9-one (12) were deduced from spectroscopic data.


1995 ◽  
Vol 50 (1) ◽  
pp. 66-70 ◽  
Author(s):  
Inge Pabst ◽  
Peter Sondergeld ◽  
Mirjam Czjzek ◽  
Hartmut Fuess

The title compound has been prepared in two different ways: First, by boiling single crystals of [(C2H5)4N]HgCl3 in a mixture of n-hexane/n-octane [4:1] at T = 350 K, and second, in a synthesis from stoichiometric quantities of the components. X-ray structure analysis gave the stoichiometry [(C2H5)4N]2Hg3Cl8, monoclinic, space group P21, a = 7.538(3), b = 19.909(6), c = 10.274(3) Å, β = 95.13(1)°, V = 1535.7(9) A3, Z = 2. The basic [Hg3Cl8]2--units form broken zig-zag chains along [100]. The Hg–Cl distances within the [Hg3Cl8]2- clusters range from 2.315(3) to 2.755(4) Å. This is a new coordination type for halomercurates.


2007 ◽  
Vol 123 (6) ◽  
pp. 358-364 ◽  
Author(s):  
Süheyla Özbey ◽  
Arzu Karayel ◽  
Gülten Kavak ◽  
Zeynel Seferoğlu ◽  
Nermin Ertan

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