Applications of Quantum Chemistry. I. Energetics and Bonding in Conjugated Free Radical Chains

1971 ◽  
Vol 49 (2) ◽  
pp. 338-340 ◽  
Author(s):  
N. C. Baird
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Quantum Chemistry ◽  
Molecular Orbital ◽  
Heats Of Formation ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Carbon Bond ◽  
Bond Lengths ◽  
Carbon Carbon Bond

The heats of formation at 25 °C and the equilibrium carbon–carbon bond lengths are calculated by the neglect of nonbonded differential overlap molecular orbital theory for a series of conjugated, acyclic free radicals containing from one to nine unsaturated carbon atoms. The total bonding energies in the radicals exceed the values expected from polyene bond terms by 5–9 kcal/mol, depending on the length and branching of the chain.

Conformational preferences of the fluoromethyl group in p-methylbenzyl fluoride and some derivatives

1980 ◽  
Vol 58 (12) ◽  
pp. 1178-1182 ◽  
Author(s):  
Ted Schaefer ◽  
Walter P. Niemczura ◽  
Rudy Sebastian ◽  
Leonard J. Kruczynski ◽  
Werner Danchura
Keyword(s):  
Benzene Ring ◽  
Molecular Orbital ◽  
Molecular Orbital Theory ◽  
Conformational Preference ◽  
Orbital Theory ◽  
Carbon Bond ◽  
Carbon Carbon Bond ◽  
Conformational Preferences ◽  
Good Agreement

The coupling over seven bonds between 19F nuclei and protons in p-methylbenzyl fluoride and a series of ring-substituted derivatives is used to estimate the value for a conformation in which the C—F bond lies in a plane perpendicular to the benzene ring. The J method is then used to show that in CS2 solution, the Conformational preference of the fluoromethyl group is very weak in 3,5-dichloro-4-methylbenzyl fluoride and in 3,5-dibromo-4-methylbenzyl fluoride. The barrier to rotation about the exocyclic carbon—carbon bond is perhaps as large as 0.2 kcal/mol. In p-methylbenzyl fluoride, the C—F bond prefers a plane perpendicular to the benzene plane by ca. 0.9 kcal/mol. Good agreement is found with the Conformational preferences based on couplings over six or seven bonds between the methylene protons and the para ring or methyl protons. The deductions are compared with calculations at various levels of molecular orbital theory.

Bonding in Transition Metal Silyl Dimers. Molecular Orbital Theory

1989 ◽  
Author(s):  
Alfred B. Anderson ◽  
Paul Shiller ◽  
Eugene A. Zarate ◽  
Claire A. Tessier-Youngs ◽  
Wiley J. Youngs
Keyword(s):  
Transition Metal ◽  
Molecular Orbital ◽  
Molecular Orbital Theory ◽  
Orbital Theory
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