| Density Functional Theory Investigation of Aldehyde Substituent effects on the Knoevenagel reaction Mechanism |
| کد مقاله : 1338-ICOC |
| نویسندگان |
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فرشته یعقوبی *1، اعظم شیری2 1دانشگاه بوعلی سینا- مجتمع آموزش عالی نهاوند 2دانشگاه ملایر- گروه شیمی آلی |
| چکیده مقاله |
| In this study, density functional theory (DFT) investigation was carried out to evaluate the effect of aldehyde substituents on the reaction mechanism and activation energies of the Knoevenagel condensation catalyzed by triethylamine (NEt3). All calculations were performed using the Gaussian 09 package [1] at the B3LYP/def2-TZVP level of theory in acetonitrile solvent using CPCM model. Four different aldehydes were examined, including unsubstituted benzaldehyde and three para-substituted derivatives bearing (p-OCH₃), (p-Cl), and (p-CN) groups. A comparison of energy diagrams indicates that electron-withdrawing substituents, particularly the CN group, significantly lower the activation barrier, whereas the electron-donating methoxy group increases the transition state energy (Fig. 1). These trends highlight the critical role of electronic substituent effects on aldehyde reactivity and provide molecular-level insight into how substituent nature modulates the energetics of the Knoevenagel reaction in polar aprotic media [2,3]. Also, the natural bond orbital (NBO) analysis was used to understand the nature of interactions at the TS structures. |
| کلیدواژه ها |
| DFT, Knoevenagel, Solvent, Gibbs Free Energy, Aldehyde Substituent |
| وضعیت: پذیرفته شده |