Crystal structure of phenanthrenide salts stabilized by 15-crown-5 and 18-crown-6

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Natalie Eichstaedt ◽  
Kasper P. van der Zwan ◽  
Lina Mayr ◽  
Renée Siegel ◽  
Jürgen Senker ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Coordination Number ◽  
Solid State Nmr ◽  
Inert Atmosphere ◽  
Potassium Cation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solvent Molecules

Abstract Potassium 15-crown-5 phenanthrenide and potassium 18-crown-6 phenanthrenide were synthesized and characterized by powder X-ray diffraction and 39K solid state NMR spectroscopy. While the radical carbanion is very reactive in solution, the crystals are stable and storable under inert atmosphere. For 15-crown-5, a sandwich-like complex of potassium is formed with two molecules of crown ether per potassium resulting in a coordination number of 10. For the larger 18-crown-6 ligand, a 1:1 complex is obtained and a coordination number of 6 for the potassium cation. In neither crystal structure solvent molecules are incorporated. The 15-crown-5 compound crystallizes faster and is less soluble in THF as compared to the 18-crown-6 compound. Both compounds form solid phenanthrenide that is easy to handle and can be applied for reduction reactions.

Influence of fluorine side-group substitution on the crystal structure formation of benzene-1,3,5-trisamides

CrystEngComm ◽  
2014 ◽  
Vol 16 (39) ◽  
pp. 9273-9283 ◽  
Author(s):  
Christoph Zehe ◽  
Marko Schmidt ◽  
Renée Siegel ◽  
Klaus Kreger ◽  
Venita Daebel ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Structure Formation ◽  
Solid State Nmr ◽  
Quantum Chemical ◽  
Side Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Structure Formation

The crystal structure of 1,3,5-tris(2-fluoro-2-methylpropionylamino)benzene was solved by combining powder X-ray diffraction, solid-state NMR spectroscopy and quantum chemical calculations.

Model compounds of aromatic nylons. 3. The conformation of the 4T Nylon, poly(tetramethylene terephthalamide), using X-ray diffraction, solid-state 13C nmr spectroscopy and ir spectroscopy

1989 ◽  
Vol 67 (5) ◽  
pp. 840-849 ◽  
Author(s):  
Josée Brisson ◽  
Johanne Gagné ◽  
François Brisse
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Solid State Nmr ◽  
13C Nmr Spectroscopy ◽  
X Ray Diffraction ◽  
Model Compounds ◽  
X Ray ◽  
Structure Determinations

Three model compounds of poly(tetramethylene terephthalamide) or 4T Nylon have been synthesized and characterized using single crystal X-ray diffractometry, infrared spectroscopy, and 13CCP/MAS nmr spectroscopy. The model compounds are the para-substituted N,N′-tetramethylene dibenzamides, where the substituents are the—OMe, —tBu, —CN, and —CH3 groups. The crystal structure determinations reveal three distinct conformations for the CO—NH—(CH2)4—NH—CO sequence of atoms. The conformation is all trans for OMe, tgtttg−t for the tBu substituent, and tsttts−t for the CN substituent ([Formula: see text], [Formula: see text], and [Formula: see text]). In all three derivatives, the dihedral angle between the aromatic ring and the amide plane is around 30°. The OMe and tBu para-substituted molecules are interconnected by nearly linear hydrogen bonds of normal N … O distances. However, for the CN derivative the N … O distance is exceptionally short, 2.402(4) Å. On the basis of its infrared and solid state nmr spectra, it is proposed that N,N′-tetramethylene di-para-methyl benzamide has a crystal structure comparable to that of its unsubstituted analog. The methylenic sequence of the parent polyamide, 4T Nylon, has the tgtttg−t conformation. Furthermore, the polyamide chains form sheets within which the chains, parallel to one another, are connected through hydrogen bonds. Keywords: polyamide, crystal structure, solid-state nmr.

scholarly journals Exploiting the Synergy of Powder X-ray Diffraction and Solid-State NMR Spectroscopy in Structure Determination of Organic Molecular Solids

2013 ◽  
Vol 117 (23) ◽  
pp. 12258-12265 ◽  
Author(s):  
Dmytro V. Dudenko ◽  
P. Andrew Williams ◽  
Colan E. Hughes ◽  
Oleg N. Antzutkin ◽  
Sitaram P. Velaga ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Structure Determination ◽  
Solid State Nmr ◽  
Molecular Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solid State Nmr Spectroscopy

Polypeptide Adsorption on a Synthetic Montmorillonite: A Combined Solid-State NMR Spectroscopy, X-ray Diffraction, Thermal Analysis and N2 Adsorption Study

2003 ◽  
Vol 2003 (7) ◽  
pp. 1366-1372 ◽  
Author(s):  
Régis D. Gougeon ◽  
Michel Soulard ◽  
Marc Reinholdt ◽  
Jocelyne Miehé-Brendlé ◽  
Jean-Michel Chézeau ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
X Ray Diffraction ◽  
N2 Adsorption ◽  
Adsorption Study ◽  
X Ray ◽  
Solid State Nmr Spectroscopy

scholarly journals Linear dicoordinate beryllium: a 9Be solid-state NMR study of a discrete zero-valent s-block beryllium complex

2018 ◽  
Vol 96 (7) ◽  
pp. 646-652 ◽  
Author(s):  
C. Leroy ◽  
J.K. Schuster ◽  
T. Schaefer ◽  
K. Müller-Buschbaum ◽  
H. Braunschweig ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Chemical Shift Tensor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quadrupolar Coupling ◽  
Nmr Study ◽  
Tensor Data

Beryllium-9 (9Be) quadrupolar coupling and chemical shift tensor data are reported for bis(1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidine-2-ylidene)beryllium (Be(CAAC)2). These are the first such data for beryllium in a linear dicoordinate environment. The 9Be quadrupolar coupling constant, 2.36(0.02) MHz, is the largest recorded in the solid state to date for this isotope. The span of the beryllium chemical shift tensor, 22(2) ppm, covers about half of the known 9Be chemical shift range, and the isotropic 9Be chemical shift, 32.0(0.3) ppm, is the largest reported in the solid state to our knowledge. DFT calculations reproduce the experimental data well. A natural localized molecular orbital approach has been used to explain the origins and orientation of the beryllium electric field gradient tensor. The single-crystal X-ray structure of a second polymorph of Be(CAAC)2 is also reported. Inspection of the powder X-ray diffraction data shows that the new crystal structure is part of the bulk product next to another crystalline phase. Therefore, experimental X-ray powder data for the microcrystalline powder sample and the SSNMR data do not fully match either the originally reported crystal structure (Arrowsmith et al. Nat. Chem. 2016, 8, 890–894) or the new polymorph. The ability of solid-state NMR and powder X-ray diffraction to characterize powdered samples was thus particularly useful in this work.

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