C50Cl10, a planar aromatic fullerene. Computational study of 13C-NMR chemical shift anisotropy patterns and aromatic properties

2018 ◽  
Vol 20 (41) ◽  
pp. 26325-26332 ◽  
Author(s):  
Alan Miralrio ◽  
Luis E. Sansores ◽  
Bruce King ◽  
Alvaro Muñoz-Castro
Keyword(s):  
Chemical Shift ◽  
Dft Calculations ◽  
13C Nmr ◽  
Computational Study ◽  
Chemical Shift Anisotropy ◽  
Interesting Case ◽  
Face To Face ◽  
Aromatic Character ◽  
The Face

The structural characterization of D5h-C50Cl10 as an IPR-violating fullerene provides an interesting case of an oblate structure displaying a planar-aromatic character provided by the face-to-face disposition of two IPR structural motifs, as unraveled by DFT calculations.

13C NMR Relaxation Rates:  Separation of Dipolar and Chemical Shift Anisotropy Effects

2004 ◽  
Vol 108 (29) ◽  
pp. 6096-6099 ◽  
Author(s):  
W. Robert Carper ◽  
Phillip G. Wahlbeck ◽  
Andreas Dölle
Keyword(s):  
Chemical Shift ◽  
13C Nmr ◽  
Chemical Shift Anisotropy ◽  
Nmr Relaxation ◽  
Relaxation Rates

Isolation and structural elucidation of novel fusicoccan dehydroxypericonicin A from Roussoella sp.

2021 ◽  
Author(s):  
Ayane Hayasaka ◽  
Kazuaki Tanaka ◽  
Masaru Hashimoto
Keyword(s):  
Density Functional Theory ◽  
Chemical Shift ◽  
Dft Calculations ◽  
Absolute Configuration ◽  
13C Nmr ◽  
Density Functional ◽  
Functional Theory ◽  
Spectral Comparison ◽  
Relative Structure ◽  
Chemical Shift Calculations

Abstract A potent antifungal fusicoccane dehydroxypericonicin A (1) was isolated from Roussoella sp. along with known allantofuranone (2). The relative structure of 1 was fully elucidated by NMR spectroscopic manner. The suggested relative structure was confirmed by DFT (density functional theory)-based 13C NMR chemical shift calculations. The absolute configuration was investigated by a spectral comparison of the experimental ECD (electronic circular dichroism) spectrum with that based on the DFT calculations.

ChemInform Abstract: 13C NMR Study of the C60 Cluster in the Solid State: Molecular Motion and Carbon Chemical Shift Anisotropy.

ChemInform ◽  
2010 ◽  
Vol 22 (13) ◽  
pp. no-no
Author(s):  
C. S. YANNONI ◽  
R. D. JOHNSON ◽  
G. MEIJER ◽  
D. S. BETHUNE ◽  
J. R. SALEM
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
13C Nmr ◽  
Molecular Motion ◽  
Chemical Shift Anisotropy ◽  
Nmr Study ◽  
Carbon Chemical Shift

COMPUTATIONAL NICS AND 13C NMR ChARACTERIZATION OF SUBSTITUTION PATTERNS OF C60-nNn FULLERENES (n = 1–12)

2013 ◽  
Vol 12 (03) ◽  
pp. 1350009 ◽  
Author(s):  
MARYAM ANAFCHEH ◽  
REZA GHAFOURI ◽  
FERESHTEH NADERI
Keyword(s):  
Dft Calculations ◽  
13C Nmr ◽  
Chemical Shifts ◽  
Nmr Chemical Shifts ◽  
Ring Currents ◽  
Nmr Characterization ◽  
Dopant Atoms ◽  
Isotropic Chemical Shifts ◽  
Stable Structures

DFT calculations are applied to evaluate the effects of atomic arrangements of dopant atoms on electronic features of the most stable structures of C 60−n N n(n = 1–12) fullerenes. Our study reveals that 13 C isotropic chemical shifts (δiso) of the nuclei at C–N pentagon–hexagon (ph) junctions appear at downfield values while there are no tangible values of δiso for the nuclei at C–N hexagon–hexagon (hh) junctions; the carbon sites attached to the first neighbors of nitrogen at hh junctions (the second neighboring effect) yield upfield values of δiso. Moreover, compensation between diatropic and paratropic ring currents leads to slightly less negative NICS value in C59N heterofullerene (-3.6) compared to the parent fullerene C60 (-4.25). However, with incorporating more nitrogen atoms into the cage the aromaticity first increases, up to the 66π-system C54N6 and C53N7 , yielding the most negative NICS values of -26.3 and -26.8, respectively, and then decreases so that NICS finally reaches the value of -6.6 ppm for C48N12 heterofullerene. On the basis of distinct value predicted for each heterofullerene, one expects that NICS values may also be useful for identification of the molecules through their endohedral 3 He NMR chemical shifts.

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