Abstract:
In this study, the radical cyclopolymerization mechanism of diallylamine and diallyl ether monomers and their derivatives has been investigated by computational modeling. The calculations were performed by the Density Functional Theory using the B3LYP/6-31G* basis set. In the first part of the study, a correlation has been built between the stucture of the monomer and the polymerizability. The experimentally measured 13C NMR chemical shifts of the diallylamine monomers, which were in line with their polymerizabilities, could be successfully correlated to the descriptors derived from calculations. The charges, bond orders, reaction barriers have successfully reproduced the polymerizability trend. In the second and third parts of this study, the regioselectivities and stereoselectivities of ring closure reactions of diallylamine and derivatives have been explained by considering steric and electronic factors. Diallylamine monomers formed 5-membered rings even though the thermodynamically more stable 6-membered rings would be expected to form. It has been shown that the 5-membered rings have lower barriers for cyclization. The fourth part of the study includes the modeling of diallylether monomers and their derivatives. The fast and efficient polymerizability of diallylether monomer has been investigated by considering the similarities and differences between this compound and its amine analogue. In the last part of the study, the competing reactions, homopolymerization and H-transfer reactions, as well as standard cyclopolymerization reactions have been considered. The efficiencies of the competing reactions have been investigated in their relation to the standard cyclopolymerization reactions. Comparison of free energies of activation for cyclopolymerization and competing reactions has shown that competing reactions are less efficient in the case of cationic monomers
