Abstract
In order to control the reactivity of biscyanamide resins, we synthesized biscyanamide resins having o-substituted alkyl groups and analyzed the relationship between the structure and reaction rate. It was found that the reaction rate decreased with the size of the alkyl group, and we tried to find the reason of the phenomena with the semi-empirical molecular orbital method. As the alkyl group becomes large, the angle of cyanamide group and phenyl ring becomes large due to the steric hindrance of o-substituted alkyl groups. As a result, the conjugation of π-electrons of the phenyl ring and cyanamide group becomes small, and the difference of energy levels (ΔE) between HOMO and LUMO becomes large.
