Synthesis, Conformational Interconversion, and Photophysics of Tethered Porphyrin-Fullerene Dyads with Parachute Topology

2009 ◽  
Vol 15 (31) ◽  
pp. 7698-7705 ◽  
Author(s):  
Michael A. Fazio ◽  
Alexander Durandin ◽  
Nikolai V. Tkachenko ◽  
Marja Niemi ◽  
Helge Lemmetyinen ◽  
...  
Keyword(s):  
Conformational Interconversion

scholarly journals Ab Initioand DFT Studies of Conformational Properties of Heteroatom Containing Ketene Analogues and Their Comparison with the Related Cyclic Analogues

2012 ◽  
Vol 9 (1) ◽  
pp. 193-202 ◽  
Author(s):  
S. Zahra Sayyed-Alangi ◽  
Mohammad T. Baei
Keyword(s):  
Transition State ◽  
Minimum Energy ◽  
Basis Set ◽  
Global Minima ◽  
Stable Conformer ◽  
Trans Conformation ◽  
Conformational Interconversion ◽  
Conformational Properties ◽  
Torsional Angles ◽  
Single Bonds

Minimum-energy and transition state geometries of 3-thioxoprop-2-enethial, 3-thioxoacrylaldehyde, 3-oxoprop-2-enethial, 3-selenoxoprop-2-enethial, 3-thioxoprop-2-eneselenal, 3-selenoxoprop-2-eneselenal, 3-oxoacrylaldehyde, 3-selenoxoacrylaldehyde and 3-oxoprop-2-eneselenal were calculated using HF, B3LYP and MP2 levels of theory and 6-31+G*basis set by rotation around the related -C-C- single bonds. In all of the above mentioned molecules, the s-trans conformation was obtained as the most stable conformer with the 180°dihedral angle, apart from 3-oxoprop-2-enethial and 3-thioxoprop-2-eneselenal which theirs-cisconformers were appeared more stability than related tos-transforms. Their perpendicular geometries, with torsional angles approximately 90°, were as transition state for conformational interconversion between the two global minima forms. Cyclic structures all of the above mentioned molecules were unstable than their linear forms.

Semi Empirical Study of a System Containing a Six-membered Ring

2004 ◽  
Vol 59 (11) ◽  
pp. 853-856
Author(s):  
H. Kara ◽  
Y. Yahsi ◽  
Y. Elerman ◽  
A. Elmali
Keyword(s):  
Chemical Potential ◽  
Chair Conformation ◽  
Membered Ring ◽  
Chemical Hardness ◽  
Mo Calculations ◽  
Lumo Energy ◽  
Conformational Interconversion ◽  
Homo And Lumo ◽  
Semi Empirical ◽  
Homo And Lumo Energy

Semi-empirical AM1 SCF-MO calculations have been used to find the structure optimization and conformational interconversion pathways of a system containing a six-membered ring. The system has the two symmetrical energy-minimum conformations, chair and twist. The chair conformation has the most stable geometry. Some quantum parameters such as HOMO and LUMO energy, the chemical hardness and chemical potential are discussed

Molecular Motion and Conformational Interconversion of Azobenzenes in Crystals as Studied by X-ray Diffraction

1997 ◽  
Vol 53 (4) ◽  
pp. 662-672 ◽  
Author(s):  
J. Harada ◽  
K. Ogawa ◽  
S. Tomoda
Keyword(s):  
Temperature Dependence ◽  
Crystal Structures ◽  
Torsional Vibration ◽  
Molecular Motion ◽  
X Ray Diffraction ◽  
Dynamic Disorder ◽  
X Ray ◽  
Conformational Interconversion ◽  
Free Molecules

Crystal structures of (E)-azobenzene (1), (E)-2,2′- dimethylazobenzene (2), (E)-3,3′-dimethylazobenzene (3) and (E)-4,4′-dimethylazobenzene (4) were determined by X-ray diffraction at various temperatures. An apparent shrinkage of the N=N bond and its temperature dependence were observed and are interpreted in terms of an artifact caused by the torsional vibration of the N—Ph bonds in crystals. In the crystal structures of (1), (3) and (4) the dynamic disorder was observed. The disorder is accounted for by the torsional vibration whose amplitude is large enough to give rise to the conformational interconversion. No disorder was observed for a crystal of (2). This is ascribed to the large difference in energy of the two conformers as free molecules. The true length of the N=N bond in azobenzenes was estimated to be 1.26–1.27 Å.

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