DFT investigation of C–H bond activation of malononitrile in the presence of amines†
Abstract
DFT investigations of the isomerization and deprotonation of malononitrile by the amines were performed at the B3LYP/6-31++G** level. Calculations indicate that isomerization of malononitrile is difficult to achieve without promoters because of high energy barriers. Basic N atoms in amines can abstract an H atom from malononitrile. Activation barriers for proton abstraction are highly correlated with the available or estimated pKa values of protonated amines. The reaction mechanism can be deduced from the slope of the Brönsted plot. This work suggests an efficient catalyst, N-1, based on computational results.