TY - JOUR
T1 - Theoretical study of factors controlling rates of cyclization of radical intermediates from diallylamine and diallylammonium monomers in radical polymerizations
AU - Tüzün, N. S.
AU - Aviyente, V.
AU - Houk, K. N.
PY - 2002/7/26
Y1 - 2002/7/26
N2 - The radical cyclization reactions of models for the growing radical chains formed from N,N-diallylamine (1), N-methyl-N,N-diallylamine (2), N,N-diallylammonium (3), N-methyl-N,N-diallylammonium (4) and N,N-dimethyl-N,N-diallylammonium (5) have been investigated computationally by DFT theory, using the B3LYP functional. Models formed by hydrogen atom addition to dienes 1-5 undergo five-membered ring cyclization reactions with activation energies predicted to be 7.2, 5.0, 8.6, 6.4, and 6.2 kcal/mol, respectively. Methyl substitution on nitrogen decreases the barrier to cyclization. One methyl has a larger effect on the cyclization rate than the second methyl. This rate enhancement is attributed to a decrease in gauche interactions in the transition state as compared to the initial structure and to different destabilizing effects when an H is replaced by a methyl group. These predicted rate effects are in agreement with the experimental data on polymerization efficiencies.
AB - The radical cyclization reactions of models for the growing radical chains formed from N,N-diallylamine (1), N-methyl-N,N-diallylamine (2), N,N-diallylammonium (3), N-methyl-N,N-diallylammonium (4) and N,N-dimethyl-N,N-diallylammonium (5) have been investigated computationally by DFT theory, using the B3LYP functional. Models formed by hydrogen atom addition to dienes 1-5 undergo five-membered ring cyclization reactions with activation energies predicted to be 7.2, 5.0, 8.6, 6.4, and 6.2 kcal/mol, respectively. Methyl substitution on nitrogen decreases the barrier to cyclization. One methyl has a larger effect on the cyclization rate than the second methyl. This rate enhancement is attributed to a decrease in gauche interactions in the transition state as compared to the initial structure and to different destabilizing effects when an H is replaced by a methyl group. These predicted rate effects are in agreement with the experimental data on polymerization efficiencies.
UR - http://www.scopus.com/inward/record.url?scp=0037178338&partnerID=8YFLogxK
U2 - 10.1021/jo0256639
DO - 10.1021/jo0256639
M3 - Article
C2 - 12126390
AN - SCOPUS:0037178338
SN - 0022-3263
VL - 67
SP - 5068
EP - 5075
JO - Journal of Organic Chemistry
JF - Journal of Organic Chemistry
IS - 15
ER -