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    Electronic structure perturbation induced by fluorine substitution in methylamine: a comparative DFT, spectroscopic and molecular recognition study
    (Springer Int Publ Ag, 2026) Fto, Ahmed Muhsin Mohammed Youns; Tahhan, Omar M. Saeed Younus; Abed, Mahmood Dahham Abed; Hssain, Ala Hamd; Kebiroglu, Mehmet Hanifi; Bulut, Niyazi
    This study presents a comparative theoretical investigation of methylamine and fluoromethylamine to explain the electronic and spectroscopic consequences of single fluorine substitution. Geometry optimization and electronic structure calculations were carried out at the B3LYP/6-311G(d, p) level within the framework of density functional theory. Frontier molecular orbital analysis showed that fluorination significantly reduced the HOMO-LUMO energy gap, suggesting enhanced electronic reactivity of the fluorinated derivative. Global reactivity descriptors further revealed an increase in electrophilic character following fluorine substitution. Simulated NMR and UV-Vis spectra showed noticeable spectral changes associated with charge redistribution and fluorine-induced polarization effects. Molecular electrostatic potential and density of states analyses confirmed substantial change in the electronic environment of the molecule. In addition, molecular docking calculations were performed to evaluate the molecular recognition behavior of both compounds toward RhCG, providing insight into their possible interaction propensity. The results show that minimal structural modification by fluorination can induce measurable changes in the electronic structure, spectroscopic response, and exploratory molecular-recognition tendency of methylamine.
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    Halogen-dependent electronic regulation of reactivity and acetylcholinesterase recognition in halomethyl acetates: a predictive DFT-docking framework
    (Springer, 2026) Abed, Mahmood Dahham Abed; Tahhan, Omar M. Saeed Younus; Fto, Ahmed Muhsin Mohammed Youns; Kebiroglu, Mehmet Hanifi; Bulut, Niyazi
    In this work, we propose a halogen-tuning framework that links electronic reactivity descriptors to enzyme recognition for halomethyl acetates (fluoromethyl, chloromethyl, and bromomethyl acetate). Density Functional Theory calculations were performed at the B3LYP/6-311G(d, p) level to explain structure property relationships across the F/Cl/Br substitution axis. Geometry optimization shows a systematic elongation of the C5-X bond (F < Cl < Br), while the ester carbonyl remains nearly invariant, suggesting a localized substituent effect. Frontier orbital energies analysis and global descriptors reveal that bromomethyl acetate is the softest and most electronically labile derivative, exhibiting the smallest HOMO-LUMO energy gap, whereas the fluorinated analogue demonstrates the highest kinetic stability. Simulated FT-IR, H-1/C-13 NMR (GIAO), and TD-DFT UV-Vis spectra provide complementary fingerprints showing halogen-driven electronic modulation. Topological analyses (MEP, DOS, RDG/NCI/DORI) map the redistribution of electron density and weak interaction regions that rationalize the observed trends. Molecular docking against acetylcholinesterase (AChE; PDB: 1EVE) indicates a monotonic enhancement of binding affinity with increasing halogen polarizability, with bromomethyl acetate exhibiting the strongest predicted affinity. Collectively, these results establish a predictive structure reactivity recognition reasoning for halomethyl acetates and support their consideration as electrophile-tuned model systems for exploring substituent-dependent recognition tendencies.