The High Reactivity of the CS Double Bond in 1,3-Dipolar Cycloadditions of Nitrones: A Molecular Orbital Theoretical Analysis

1995 ◽  
Vol 117 (38) ◽  
pp. 9679-9685 ◽  
Author(s):  
Reiner Sustmann ◽  
Willi Sicking ◽  
Rolf Huisgen
Keyword(s):  
Double Bond ◽  
Theoretical Analysis ◽  
Molecular Orbital ◽  
High Reactivity ◽  
Dipolar Cycloadditions

Dual Substituent Parameter Treatment of 13C Substituent Chemical Shifts in 5-Substitued 2-Thenylidenemalononitriles and Molecular Orbital Theoretical Analysis at the CNDO/2 Level

Heterocycles ◽  
1986 ◽  
Vol 24 (10) ◽  
pp. 2827 ◽  
Author(s):  
Sankar Prasad Bhattacharyya ◽  
Sumana Datta ◽  
Asish De ◽  
Sankar Orasad Bhattacharyya ◽  
Chitrani Medhi ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Molecular Orbital ◽  
Chemical Shifts

C60 Framework Response to Halogen Addition: the Stable Isomers of C60Br2m

1994 ◽  
Vol 47 (1) ◽  
pp. 131 ◽  
Author(s):  
JB Peel ◽  
RG Rothwell
Keyword(s):  
Double Bond ◽  
Molecular Orbital ◽  
High Stability ◽  
Structural Information ◽  
Spectroscopic Characterization ◽  
The Other ◽  
Semiempirical Calculations ◽  
Elementary Model ◽  
Local Distortion

The isolation and spectroscopic characterization of halogenated fullerene-60 compounds has not advanced greatly during the 2 years of effort in this area. While the fully fluorinated C60F60 has been studied in some detail, other halogen addition processes have indicated chlorination up to C60Cl24 and bromination up to C60Br24. However, definitive structural information has to date only been provided for three compounds, namely C60Br6, C60Br6 and C60Br24. Iodine does not appear to form genuine addition compounds. In the work reported here semiempirical calculations using the AM1 approximation with the MOPAC molecular orbital program have been directed to comparing the possible stable isomers of the 1:1 addition compounds C60X2 for X = F, Cl and Br. The favoured isomers can be described as 1,2-additions (to a double bond at a hexagon-hexagon fusion) and 1,4-additions (to the terminal carbons of a butadiene moiety) with higher-energy isomers resulting from 1,6- and 1,8-additions. The other isomers represented by 1,3- 1,5- and 1,7-additions are only stable relative to dissociation in the case of the fluorine addition compounds. By contrast for Br2 addition only the 1,2- and 1,4-isomers are stable toward dissociation. The calculations show that, at and near the addition site carbons, X2 addition is adequately described in terms of local distortion of the C60 sphere. The elementary model of C60 as comprising formal single and double bonds is relevant since C60 behaves as a 'poly- alkene ', with sp3 carbons replacing sp2 carbons at the addition sites. This model offers an explanation for the unique structures observed for C60Br6 and C60Br24 which the AM1calculations show to be very stable toward dissociation. However, the experimental C60Br8 structure is found to be relatively less stable than another isomer. Also high-stability isomers of C60Br4, C60Br10, C60Br12 and C60Br18 are predicted.

Charge transfer in single- and double-strand DNAs: Theoretical analysis based on molecular orbital method

2006 ◽  
Vol 106 (15) ◽  
pp. 3270-3277 ◽  
Author(s):  
Kenichi Dedachi ◽  
Takayuki Natsume ◽  
Taisuke Nakatsu ◽  
Yasuyuki Ishikawa ◽  
Noriyuki Kurita
Keyword(s):  
Charge Transfer ◽  
Theoretical Analysis ◽  
Molecular Orbital ◽  
Orbital Method ◽  
Molecular Orbital Method

scholarly journals Theoretical analysis of pKa shifts of bacteriorhodopsin using linear scale molecular orbital method

2000 ◽  
Vol 40 (supplement) ◽  
pp. S39
Author(s):  
N. Kamiya ◽  
K. Ohno ◽  
S. Nakajima ◽  
Y. Inoue ◽  
M. Sakurai
Keyword(s):  
Theoretical Analysis ◽  
Molecular Orbital ◽  
Orbital Method ◽  
Molecular Orbital Method ◽  
Linear Scale ◽  
Pka Shifts

A Direct Synthesis of a Strongly Zwitterionic 6,6'-Diaminofulvalene

2014 ◽  
Vol 69 (5) ◽  
pp. 580-588 ◽  
Author(s):  
Dominic Schmid ◽  
Alexander Seyboldt ◽  
Doris Kunz
Keyword(s):  
Double Bond ◽  
Theoretical Analysis ◽  
Dft Calculations ◽  
Structure Analysis ◽  
Direct Synthesis ◽  
Exocyclic Double Bond ◽  
X Ray ◽  
One Step ◽  
Initial Route ◽  
Guanidinium Salt

Upon reaction of the dipyrido-anellated guanidinium salt 1 with one equivalent of CpNa we were able to synthesize the dipyrido-anellated diaminofulvalene 4 in one step in 33% isolated yield. This shortens the initial route that applies a literature-known fulvalene synthesis via uronium salt 3 by two steps and avoids the need for a sacrificial equivalent of CpNa. Although the X-ray structure analysis reveals a shorter exocyclic double bond than observed in the diaminofulvalene V, a theoretical analysis based upon DFT calculations shows a stronger zwitterionic character for the dipyridofulvalene 4.

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