Density Functional Theory Studies of Tricyanofuran Based Compounds’ Reaction Mechanism

Tricyanofuran (TCF) based compounds are an important electron acceptor used in organic second-order nonlinear optical (NLO) materials due to its strong electron withdrawing abilities and outstanding thermal stability. Despite its importance, the synthesis of TCF using sodium ethoxide as catalyst suffers from low yields, and the exact reaction mechanism does not reach a consensus. This study investigates the complete reaction pathway of TCF synthesis using Density Functional Theory (DFT) calculations performed via ORCA software. The computational analysis successfully lists out all intermediates and transition states, the two major rate-determining steps are identified, the nucleophilic addition of a malononitrile anion to an imine carbon and the ammonia elimination step. Furthermore, the studies demonstrate the important role of the ethanol solvent network in facilitating intramolecular proton transfer processes. To propose synthetic improvements, the catalytic effects of different bare metal ions and Lewis acids were studied. The findings reveal that multivalent metal ions have high charge density, strong polarizing power, and strong coordinating ability such as Zn²⁺ and Sc³⁺ significantly stabilize the transition states and lower activation barriers