scholarly journals Selective Hydration of Nitriles to Corresponding Amides in Air with Rh(I)-N-Heterocyclic Complex Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 125 ◽  
Author(s):  
Csilla Enikő Czégéni ◽  
Sourav De ◽  
Antal Udvardy ◽  
Nóra Judit Derzsi ◽  
Gergely Papp ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Catalytic Properties ◽  
13C Nmr Spectroscopy ◽  
Synthetic Method ◽  
X Ray Diffraction ◽  
Nitrile Hydration ◽  
X Ray

A new synthetic method for obtaining [RhCl(cod)(NHC)] complexes (1–4) (cod = η4-1,5-cyclooctadiene, NHC = N-heterocyclic carbene: IMes, SIMes, IPr, and SIPr, respectively) is reported together with the catalytic properties of 1–4 in nitrile hydration. In addition to the characterization of 1–4 in solution by 13C NMR spectroscopy, the structures of complexes 3, and 4 have been established also in the solid state with single-crystal X-ray diffraction analysis. The Rh(I)-NHC complexes displayed excellent catalytic activity in hydration of aromatic nitriles (up to TOF = 276 h−1) in water/2-propanol (1/1 v/v) mixtures in air.

Imidazole-containing Bispidine Ligands: Synthesis, Structure and Cu(II) Complexation

2011 ◽  
Vol 66 (7) ◽  
pp. 721-728 ◽  
Author(s):  
Martin Walther ◽  
Madlen Matterna ◽  
Stefanie Juran ◽  
Silke Fähnemann ◽  
Holger Stephan ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Enol Form ◽  
Trans Configuration ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Impact ◽  
Configurational Isomerism

The preparation and characterization of tris-pyridyl bispidine (3,7-diazabicyclo[3.3.1]nonane) derivatives with benzimidazole and imidazole donor groups at the N-3 position of the bispidine skeleton and their copper(II) complexes are reported. The impact of the hetaryl substituents on the configurational isomerism of piperidones and their corresponding bispidones has been studied by NMR spectroscopy, revealing the exclusive appearance in the enol form for the piperidones in solution and the trans-configuration regarding the two pyridyl substituents, as well as the sole formation of the unsymmetric exo-endo isomers for the corresponding bispidones. Thus, the bispidones are preorganized ligands for building pentacoordinated complexes, confirmed by the preparation and characterization of the corresponding Cu(II) complexes. Of the di-pyridyl piperidones with benzimidazole and imidazole substituents, and of the Cu(II) complex of the benzimidazole-containing bispidone, crystals have become available for the analysis by X-ray diffraction, showing that the piperidones form the enol tautomers also in the solid state.

Synthesis, Characterization, and Catalytic Activity of a Series of Aluminium–Amidate Complexes

2015 ◽  
Vol 68 (3) ◽  
pp. 357 ◽  
Author(s):  
Kevin P. Yeagle ◽  
Darryl Hester ◽  
Nicholas A. Piro ◽  
William G. Dougherty ◽  
W. Scott Kassel ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Nmr Spectroscopy ◽  
Diffraction Analysis ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
X Ray Diffraction ◽  
Metathesis Reaction ◽  
Chloride Complexes ◽  
1H And 13C Nmr ◽  
X Ray

The aluminium complexes {[κ2-N,O-(t-BuNCOPh)]AlMe2}2 (2), [κ2-N,O-(t-BuNCOPh)]2AlMe (3), and [κ2-N,O-(t-BuNCOPh)]3Al (4) were prepared through the protonolysis reaction between trimethylaluminium and one, two, or three equivalents, respectively, of N-tert-butylbenzamide. Complex 2 was also prepared via a salt metathesis reaction between K(t-BuNCOPh) and dimethylaluminium chloride. Complexes 2–4 were characterized using 1H and 13C NMR spectroscopy. Single-crystal X-ray diffraction analysis of the complexes corroborated ligand : metal stoichiometries and revealed that all the amidate ligands coordinate to the aluminium ion in a κ2 fashion. The Al–amidate complexes 2–4 were viable catalyst precursors for the Meerwein–Ponndorf–Verley–Oppenauer reduction–oxidation manifold, successfully interconverting several classes of carbonyl and alcohol substrates.

Advances in Structural Studies on Alkylaluminum Species in the Solid State via Challenging 27Al–13C NMR Spectroscopy and X-ray Diffraction

2013 ◽  
Vol 117 (35) ◽  
pp. 18091-18099 ◽  
Author(s):  
Frédérique Pourpoint ◽  
Yohann Morin ◽  
Régis M. Gauvin ◽  
Julien Trébosc ◽  
Frédéric Capet ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
X Ray

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.

Characterization of some mesogenic alkyl 1-thioglycosides

2002 ◽  
Vol 80 (8) ◽  
pp. 1162-1165 ◽  
Author(s):  
B Henrissat ◽  
G K Hamer ◽  
M G Taylor ◽  
R H Marchessault
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Solid State ◽  
Solid State Nmr ◽  
Liquid Crystalline ◽  
Liquid Crystal Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Liquid Crystalline Phases

A series of dodecyl 1-thio-β-D-glycosides has been synthesized and characterized (DSC, NMR, CP MAS, X-ray diffraction) as possible new marking materials with liquid-crystalline properties. These compounds undergo solid to liquid crystal phase transitions at various temperatures, which depend on the nature of the carbohydrate part of the structure. Their liquid-crystalline phases show extreme shear thinning behaviour.Key words: liquid crystal, powder X-ray diffraction, phase transition, thioglycoside, solid-state NMR, marking material

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