ChemInform Abstract: FRAGMENT INTERACTION ANALYSIS IN THE FRAMEWORK OF AB INITIO UHF MO COMPUTATIONS. PART II. CONFORMATIONAL PREFERENCES IN SUBSTITUTED ETHYL RADICALS

1985 ◽  
Vol 16 (14) ◽  
Author(s):  
F. BERNARDI ◽  
A. BOTTONI ◽  
J. FOSSEY ◽  
J. SORBA
Keyword(s):  
Ab Initio ◽  
Interaction Analysis ◽  
Conformational Preferences ◽  
Ethyl Radicals ◽  
Fragment Interaction Analysis ◽  
Fragment Interaction

Fragment interaction analysis in the framework of ab-initio UHF-MO computations

Tetrahedron ◽  
1986 ◽  
Vol 42 (20) ◽  
pp. 5567-5580 ◽  
Author(s):  
Fernando Bernardi ◽  
Andréa Bottoni ◽  
Jacques Fossey ◽  
Jeanine Sorba
Keyword(s):  
Ab Initio ◽  
Interaction Analysis ◽  
Fragment Interaction Analysis ◽  
Fragment Interaction

Fragment interaction analysis in the framework of ab-initio UHF-MO computations

1989 ◽  
Vol 183 (3-4) ◽  
pp. 301-309 ◽  
Author(s):  
Fernando Bernardi ◽  
Andreà Bottoni ◽  
Jacques Fossey ◽  
Janine Sorba
Keyword(s):  
Ab Initio ◽  
Interaction Analysis ◽  
Fragment Interaction Analysis ◽  
Fragment Interaction

Fragment interaction analysis based on local MP2

2007 ◽  
Vol 118 (5-6) ◽  
pp. 937-945 ◽  
Author(s):  
Takeshi Ishikawa ◽  
Yuji Mochizuki ◽  
Shinji Amari ◽  
Tatsuya Nakano ◽  
Hiroaki Tokiwa ◽  
...  
Keyword(s):  
Interaction Analysis ◽  
Fragment Interaction Analysis ◽  
Fragment Interaction

An application of fragment interaction analysis based on local MP2

2008 ◽  
Vol 463 (1-3) ◽  
pp. 189-194 ◽  
Author(s):  
Takeshi Ishikawa ◽  
Yuji Mochizuki ◽  
Shinji Amari ◽  
Tatsuya Nakano ◽  
Shigenori Tanaka ◽  
...  
Keyword(s):  
Interaction Analysis ◽  
Fragment Interaction Analysis ◽  
Fragment Interaction

Ab initio studies on amides: conformational preferences of diacetamide and barriers to interconversion of the conformers

1980 ◽  
Vol 33 (11) ◽  
pp. 2337 ◽  
Author(s):  
L Radom ◽  
NV Riggs
Keyword(s):  
Hydrogen Atom ◽  
Ab Initio ◽  
Internal Rotation ◽  
Model Systems ◽  
Methyl Groups ◽  
Electrostatic Repulsion ◽  
Conformational Preferences ◽  
Out Of Plane ◽  
Model Transition ◽  
Good Agreement

Diacetamide, like other diacylamines, is capable of existing in three basic conformations about the N-C bonds. Optimization (STO-3G) of model systems in which all first-row atoms and the amido hydrogen atom are held coplanar predicts that the E,Z conformer (3) is of lowest energy, the Z,Z conformer (2) of somewhat higher energy (4.2 kJ mol-1), and the E,E conformer (1) of highest energy (23.6 kJ mol-1); 4-31G evaluation of the energies suggests that (1) and (2) are each of higher energy than (3) by 27-28 kJ mol-1. It is suggested that (2) is destabilized with respect to (3) by electrostatic repulsion of the two negatively charged oxygen atoms whereas destabilization of (1) is due to substantial methyl-methyl steric interactions as reflected in the very wide <CNC (136°); the energy of (1) is, however, raised by out-of-plane or rotational movements of the methyl groups, i.e., the preferred structure (excluding methyl hydrogens) is planar. The calculated height of the barrier to internal rotation of (3) by either of two model transition states is 41-45 kJ mol-1, in good agreement with an experimental value of 45.2 kJ mol-1 in solution at -60°.

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