The reliability of MINDO method for characterizing the transition state structures in radical addition reactions

1982 ◽  
Vol 47 (3) ◽  
pp. 802-808 ◽  
Author(s):  
Robert Ponec ◽  
Jaroslav Málek
Keyword(s):  
Hydrogen Atom ◽  
Transition State ◽  
Ab Initio ◽  
Radical Addition ◽  
Addition Reactions ◽  
Methyl Radical ◽  
Transition State Structures

The additions of the methyl radical and hydrogen atom to ethylene were chosen to test the reliability of MINDO method for predicting the transition state structures. It has been shown that the structures obtained at the level of the MINDO method differ markedly from the ab initio calculated structures.

Homolytic Substitution at Phosphorus: An Ab initio Study of the Reaction of Hydrogen Atom and Methyl Radical With Phosphine and Methylphosphine

1995 ◽  
Vol 48 (2) ◽  
pp. 175 ◽  
Author(s):  
CH Schiesser ◽  
LM Wild
Keyword(s):  
Hydrogen Atom ◽  
Ab Initio ◽  
Phosphorus Atom ◽  
Methyl Radical ◽  
Orbital Theory ◽  
Energy Barriers ◽  
Radical Intermediates ◽  
Phosphoranyl Radical ◽  
High Level ◽  
Homolytic Substitution

Homolytic substitution reactions of hydrogen atom and methyl radical at the phosphorus atom in phosphine and methylphosphine have been examined by high-level ab initio molecular orbital theory. MP4SDTQ/6-31G**//MP2(FC)/6-31G** calculations predict that free-radical attack at the phosphorus atom in phosphines is facile, with energy barriers of 14-33 kJ mol-1 and likely to involve hypervalent phosphoranyl radical intermediates. These intermediates, in turn, are found to have dissociative energy barriers of 10-31 kJ mol-1, depending on leaving group, and are unlikely to undergo pseudorotation prior to dissociation. MP5/6-31G**//MP2/6-31G** calculations indicate that permutational isomerism of phosphoranyl radical is likely to involve barriers of 145 and 127 kJ mol-1 for mechanisms involving transition states of D4h and C4v symmetry respectively.

Markovnikov free radical addition reactions, a sleeping beauty kissed to life

2016 ◽  
Vol 45 (3) ◽  
pp. 577-583 ◽  
Author(s):  
Reinhard W. Hoffmann
Keyword(s):  
Free Radical ◽  
Double Bond ◽  
Hydrogen Atom ◽  
Sleeping Beauty ◽  
Radical Addition ◽  
Addition Reactions ◽  
Free Radical Addition

This review covers free radical additions, which are initiated by the formal addition of a hydrogen atom to a CC double bond.

Sign in / Sign up

Export Citation Format

Share Document