Bond dissociation energies and the Hammett correlation, Part 1: Remotely substituted aromatic compounds and vitamin E

2002 ◽  
Vol 34 (8) ◽  
pp. 453-466 ◽  
Author(s):  
Yu-Ran Luo

The paper reports the effects of substituents on C— Br bond dissociation energy in substituted bromobenzenes. The following substituents introduced in various positions of benzene ring were investigated: F, Cl, Br, CH 3 , C 6 H 5 , CN and OH. In addition, the studies were extended to bromopyridines and bromothiophene. Assuming that the frequency factor is constant for the series of decompositions, the following values were obtained for the difference ∆ D = D ( Ph — Br) - D ( Ph s — Br), where Ph s Br denotes a molecule of substituted bromobenzene: substituent ∆D (kcal/mole) substituent ∆D (kcal/mole) p -F 0-5 m -C 6 H 5 0-8 p -Cl 0-6 o -C 6 H 5 2-7 m -Cl 1-0 p -CN 0-3 o -Cl 1-2 m -CN 0-8 p -Br 0-3 o -CN 0-6 o -Br 1-8 p -OH 3-9 P -CH 3 0-2 o -OH 3-8 m -CH 3 0-2 3-bromopyridine -5-0 o -CH 3 0-8 2-bromopyridine -0-6 p -C 6 H 5 0-2 2-bromothiophene 2-4 The significance of these results is discussed, and a tentative explanation of the observed effects is proposed.


2017 ◽  
Vol 417 ◽  
pp. 69-75 ◽  
Author(s):  
David Gatineau ◽  
Antony Memboeuf ◽  
Anne Milet ◽  
Richard B. Cole ◽  
Héloïse Dossmann ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document