scholarly journals Synthesis and Conformational Analysis of Naphthoxazine-Fused Phenanthrene Derivatives

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2524 ◽  
Author(s):  
Khadija Belasri ◽  
Leila Topal ◽  
Matthias Heydenreich ◽  
Andreas Koch ◽  
Erich Kleinpeter ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Conformational Analysis ◽  
Density Functional ◽  
Mannich Bases ◽  
Ring Closure ◽  
Quinone Methides ◽  
Functional Theory ◽  
Conformational Studies ◽  
Nmr Structures ◽  
Dft Modelling

The synthesis of new phenanthr[9,10-e][1,3]oxazines was achieved by the direct coupling of 9-phenanthrol with cyclic imines in the modified aza-Friedel–Crafts reaction followed by the ring closure of the resulting bifunctional aminophenanthrols with formaldehyde. Aminophenanthrol-type Mannich bases were synthesised and transformed to phenanthr[9,10-e][1,3]oxazines via [4 + 2] cycloaddition. Detailed NMR structural analyses of the new polyheterocycles as well as conformational studies including Density Functional Theory (DFT) modelling were performed. The relative stability of ortho-quinone methides (o-QMs) was calculated, the geometries obtained were compared with the experimentally determined NMR structures, and thereby, the regioselectivity of the reactions has been assigned.

A Density Functional Theory Study of the Isomerization of Substituted 2and#39;-hydroxychalcones to the Corresponding Flavanones

2021 ◽  
Vol 43 (1) ◽  
pp. 25-25
Author(s):  
Said Abdelqadar Said Said Abdelqadar Said ◽  
Omar A Shareef and Abdulkhalik S Alkazzaz Omar A Shareef and Abdulkhalik S Alkazzaz
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Ring Closure ◽  
Basis Set ◽  
Functional Theory ◽  
Rate Determining Step ◽  
The Density Functional Theory ◽  
Electronic And Structural Properties ◽  
Maximum Hardness Principle

The transformation of 2and#39;-hydroxychalcones to their corresponding flavanones was studied theoretically by the use of the density functional theory (DFT) with B3-LYP/ 6-311G basis set to get important information about the role of both of electronic and structural properties in this process. The obtained energies were found to be in agreement with our previous results that obtained from HPLC studies. The estimated hardness, polarizability, and electrophilicity profiles were found to obey the maximum hardness principle (MHP), minimum polarizability principle (MPP), and the minimum electrophilicity principle (MEP) respectively. Flavanone ring closure was found to be the rate-determining step.

scholarly journals Conformational Studies of Poly(9,9-dialkylfluorene)s in Solution Using NMR Spectroscopy and Density Functional Theory Calculations

2009 ◽  
Vol 113 (35) ◽  
pp. 11808-11821 ◽  
Author(s):  
Licínia L. G. Justino ◽  
M. Luísa Ramos ◽  
Paulo E. Abreu ◽  
Rui A. Carvalho ◽  
Abilio J. F. N. Sobral ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Nmr Spectroscopy ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Conformational Studies

scholarly journals DFT Modelling of Tripeptides (Lysine-Tryptophan-Lysine) Interacting with Single Walled Carbon Nanotubes

2010 ◽  
Vol 7 (3) ◽  
pp. 870-874 ◽  
Author(s):  
Navaratnarajah Kuganathan
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Density Functional ◽  
Single Walled Carbon Nanotubes ◽  
Binding Energies ◽  
Functional Theory ◽  
Model Calculations ◽  
Walled Carbon Nanotubes ◽  
Dft Modelling ◽  
Covalent Nature

Model calculations are performed to predict the nature of interaction between SWNT and a tripeptide (Lys-Trp-Lys) and to calculate the binding energies and charge transfer between these two species using density functional theory. DFT calculations indicate that the interaction is of a non covalent nature. Minimal charge transfer is observed between SWNT and Lys-Trp-Lys.

Polarity and structure of derivatives of bis(2-phenylethyl)selenophosphinic acid

2017 ◽  
Vol 89 (3) ◽  
pp. 393-401 ◽  
Author(s):  
Yana Vereshchagina ◽  
Rezeda Khanafieva ◽  
Denis Chachkov ◽  
Eleonora Ishmaeva ◽  
Svetlana Malysheva ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Conformational Analysis ◽  
Density Functional ◽  
Conformational Equilibrium ◽  
Dipole Moments ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Derivatives Of

AbstractConformational analysis of derivatives of bis(2-phenylethyl)selenophosphinic acid was carried out by the method of dipole moments and density functional theory calculations. The conformations of the examined compounds fit into the overall conformational picture for the PIV compounds: these derivatives exist as conformational equilibrium of non-eclipsed gauche and trans forms with propeller arrangement of the substituents relative to the P=Se bond. We stipulate that the eclipsed cis orientation of substituent may be caused by the formation of H-contact.

scholarly journals Conformational Analysis in Solution of a Chiral Bisoxazoline Molecule: Vibrational Circular Dichroism Spectroscopy and Density Functional Theory Study

2011 ◽  
Vol 2011 ◽  
pp. 1-11
Author(s):  
A. Aamouche ◽  
P. J. Stephens
Keyword(s):  
Density Functional Theory ◽  
Circular Dichroism ◽  
Conformational Analysis ◽  
Density Functional ◽  
Circular Dichroism Spectroscopy ◽  
Vibrational Circular Dichroism ◽  
Kcal Mole ◽  
Functional Theory ◽  
High Degree ◽  
Circular Dichroïsm

The conformations of the chiral bisoxazoline: 2,2′-methylenebis[3a,8a-dihydro-8H-indeno[1,2-d]oxazole] (also named IndaBOX), have been studied. Density functional theory (DFT) calculations identify four inequivalent stable conformations. Two, I and II have, C2 symmetry; two, III and IV, have C1 symmetry. The electronic energies of I–IV are ordered: I<II<III<IV. The span in energy is <1.0 kcal/mole. Vibrational unpolarised absorption and circular dichroism spectra have been predicted for the four conformations using DFT. Comparison of population-weighted spectra to experimental spectra of CHCl3 and CDCl3 solutions in mid-IR region strongly supports the DFT predictions of the number, structures, and relative energies of the conformations of IndaBOX. This shows that DFT predicts spectra with a high degree of reliability. We will undoubtedly illustrate the advantage added by vibrational circular dichroism spectroscopy in conformational analysis and in the absolute configuration determination.

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