DFT Study on Mechanism of the Reaction of Acetaldehyde with Isophorondiamine
Abstract
In this study, it was theoretically investigated which of the two different amine (-NH2) groups in the isophorondiamine (IPDA) molecule would react while forming Schiff base. By optimizing the transition states (TS) and intermediate products (IN) of two different Schiff bases (L1 and L2), their energy and frequency values are calculated using DFT B3LYP method and 6-31+G(d,p) basis set with Gaussian package program. All frequency values obtained in a normal frequency calculation are expected to be positive. If all frequency values are positive, it means that all vibration and rotational movements of the molecule are optimized to the minimum. On the other hand, in transition states, the molecule transitions from one state to another, and the movement showing this transition in frequency values is expected to be negative. The decisive step of this reaction is the TS2 transition, which is the second transition state of the reaction. The energy values calculated for the L1 and L2 ligand using the DFT method are 248.22 kJ/mol and 249.21 kJ/mol, respectively. According to the DFT calculations, which is in good agreement with literature, it was determined that the Schiff base would be formed by the amine (L1) which has less steric hindrance.
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