Conformational behaviour of 3-methyl-4-(4-methylbenzoyl)-1-phenyl-pyrazol-5-one: a sudden story of three desmotropes

RSC Advances ◽  
2015 ◽  
Vol 5 (90) ◽  
pp. 73859-73867 ◽  
Author(s):  
Vanya B. Kurteva ◽  
Boris L. Shivachev ◽  
Rositsa P. Nikolova ◽  
Svetlana D. Simova ◽  
Liudmil M. Antonov ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Gas Phase ◽  
X Ray Diffraction ◽  
X Ray

The conformational behaviour of 3-methyl-4-(4-methylbenzoyl)-1-phenyl-pyrazol-5-one was studied using a combination of X-ray diffraction, NMR spectroscopy in solution and the solid state, and DFT calculations in the gas phase.

Configurations and conformations of glycosyl sulfoxides

2010 ◽  
Vol 88 (11) ◽  
pp. 1154-1174 ◽  
Author(s):  
Hong Liang ◽  
Micheline MacKay ◽  
T. Bruce Grindley ◽  
Katherine N. Robertson ◽  
T. Stanley Cameron
Keyword(s):  
Solid State ◽  
Dft Calculations ◽  
Gas Phase ◽  
Density Functional ◽  
Lone Pair ◽  
Azido Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
Comparison Of The Results ◽  
P Type

X-ray crystallographic studies of two axial glycosyl sulfoxides having RS configurations (derivatives of phenyl 2-azido-2-deoxy-1-thio-α-d-galactopyranoside S-oxide) show that they adopt anti conformations in the solid state, in contrast to previous observations and assumptions. Density functional theory (DFT) calculations at the B3lYP6–311G+(d,p)/6–31G(d) level confirm that anti conformations of both phenyl and methyl RS glycosyl sulfoxides of 2-azido-2-deoxy-α-d-pyranosides are more stable than exo-anomeric conformations in the gas phase. 1D NOE measurements indicate that the more polar exo-anomeric conformers are only populated to a slight extent in solution. The anti conformations are distorted so that the glycosyl substituents are closer to being eclipsed with H1. This distortion allows S n → σ* overlap if the sulfur lone pair is a p-type lone pair. Evidence for this overlap comes from short C1–S bond distances, as short as the comparable bond distances in the X-ray crystal structure and in the results from DFT calculations for the SS glycoside, which does adopt the expected exo-anomeric conformation, both in the solid state and in solution, and has normal n → σ* overlap. For 2-deoxy derivatives not bearing a 2-azido group, gas-phase DFT calculations at the same level indicate that the anti- and exo-anomeric conformers have comparable stabilities. Comparison of the results of the two series shows that electronegative substituents in equatorial orientations at C2 destabilize conformations with parallel S–O arrangements, the conformation favored by having an endocyclic C–O dipole antiparallel to the S–O dipole, by about 2.5 kcal mol–1 (1 cal = 4.184 J). An equatorial glycosyl sulfoxide, (SS) phenyl 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-1-thio-β-d-glucopyranoside S-oxide, also adopts an anti conformation in the solid state as shown by X-ray diffraction. It also adopts this conformation in solution, in contrast to studies of other equatorial glycosyl sulfoxides.

Study of Molecular Dynamics and the Solid State Phase Transition Mechanism for Unsymmetrical Thiopyrophosphate Using X-ray Diffraction, DFT Calculations and NMR Spectroscopy

2006 ◽  
Vol 110 (2) ◽  
pp. 761-771 ◽  
Author(s):  
Marek J. Potrzebowski ◽  
Grzegorz D. Bujacz ◽  
Anna Bujacz ◽  
Sebastian Olejniczak ◽  
Paweł Napora ◽  
...  
Keyword(s):  
Phase Transition ◽  
Molecular Dynamics ◽  
Solid State ◽  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transition Mechanism

scholarly journals Synthesis, characterization and modeling of self-assembled porphyrin nanorods

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1346-1354 ◽  
Author(s):  
Danielle Laurencin ◽  
Pascal G. Yot ◽  
Christel Gervais ◽  
Yannick Guari ◽  
Sébastien Clément ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Powder Diffraction ◽  
Solid State Nmr ◽  
Molecular Level ◽  
Ion Association ◽  
Free Base ◽  
X Ray ◽  
Solid State Nmr Spectroscopy

Porphyrin nanorods were prepared by ion-association between free-base meso 5,10,15,20-tetrakis-(4-[Formula: see text]-methylpyridinium)porphyrin cations and tetraphenylborate anions. The nanorods have variable lengths (up to a few micrometers long) and diameters ([Formula: see text]50–500 nm). Their structure at the molecular level was elucidated by combining multinuclear solid state NMR spectroscopy, synchrotron X-ray powder diffraction and DFT calculations.

Structure of 1-methyl-2-oxo-pyrido[2,1b][3,4]dihydropyrimidinium bromide studied by X-ray diffraction, FTIR and NMR spectroscopy and DFT calculations

2007 ◽  
Vol 843 (1-3) ◽  
pp. 107-115 ◽  
Author(s):  
M. Szafran ◽  
I. Kowalczyk ◽  
E. Bartoszak-Adamska ◽  
M. Jaskólski ◽  
B. Nowak-Wydra
Keyword(s):  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
X Ray Diffraction ◽  
X Ray

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.

Investigation of the disorder of dibromo- and dichloromethane in their tri-ortho-thymotide clathrates using X-ray diffraction and solid-state 2H NMR spectroscopy

2011 ◽  
Vol 89 (7) ◽  
pp. 854-862
Author(s):  
Glenn A. Facey ◽  
Ilia Korobkov
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Guest Molecule ◽  
Type B ◽  
X Ray Diffraction ◽  
Guest Molecules ◽  
X Ray ◽  
Twofold Axis ◽  
H Nmr ◽  
Heavy Atoms

The tri-ortho-thymotide (TOT) clathrates of dibromo- and dichloromethane were characterized by single crystal X-ray diffraction at 200 K and solid-state 2H NMR spectroscopy as a function of temperature. The host structure was found to be typical of other cage-type TOT clathrates. The X-ray results showed a substantial amount of disorder among the guest molecules. In both clathrates, multiple guest molecule positions could be modeled. The heavy atoms of all the guest molecule positions lie approximately in the same plane, with some out-of-plane distortion. The guest molecules were of two different types in positions symmetric about the crystallographic twofold rotation axis: type A guests, with carbon atoms well removed from the crystallographic twofold axis, and type B guests, with carbon atoms very close to the twofold axis. The 2H NMR spectra for the guests confirmed that the disorder was dynamic. The experimental results could be accounted for by the presence of three simultaneous types of molecular motion, all fast with respect to the 2H quadrupolar interaction: (i) twofold molecular flips about the molecular C2 symmetry axis, (ii) exchange between the type A and type B sites in a single plane, and (iii) a two-site libration of the plane containing the heavy atoms of the A and B guest sites with a temperature-dependent amplitude.

Sila-Pharmaka, 26. Mitt. [1]. Darstellung und Eigenschaften potentiell curarewirksamer Silicium-Verbindungen, III / Sila-Pharmaca, 26th Communication [1]. Preparation and Properties of Silicon Compounds with Potential Curare-Like Activity, III

1982 ◽  
Vol 37 (11) ◽  
pp. 1461-1471 ◽  
Author(s):  
Reinhold Tacke ◽  
Haryanto Linoh ◽  
Moayad T. Attar-Bashi ◽  
William S. Sheldrick ◽  
Ludger Ernst ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Neuromuscular Blocking ◽  
Neuromuscular Blocking Agents ◽  
X Ray Diffraction ◽  
Silicon Compounds ◽  
X Ray ◽  
Structure Activity Relationships ◽  
H Nmr ◽  
Structure Activity

The potentially curare-like silicon compounds 8a-8f wore synthesized and investigated with respect to their structure-activity relationships. The conformations of the com­pounds in the solid state and in solution were studied by X-ray diffraction analysis (8a-8e) and 1H NMR spectroscopy (8a-8f), respectively. The muscle relaxing properties of 8a-8f were investigated on the mouse. The observed structure-activity relationships are not in accordance with the classical “14 Å model” for neuromuscular blocking agents.

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