Structure, Vibrations, Molecular Orbitals, Reactivity Properties of 3-Trifluoromethylphenylchloroformate by FT-IR, FT-Raman, FT-NMR and DFT Studies

摘要

The geometry of 3-trifluoromethylphenylchloroformate (FMPCF) was optimized with B3LYP method using 6-311++G** and cc-pVTZ basis sets. The molecular structural parameters and thermodynamic properties of the compound have been determined. The vibrational frequencies of the fundamental modes of the compound have been precisely assigned, analyzed and the theoretical results were compared with the experimental data. The energies of important molecular orbitals of the compound are also evaluated from DFT method. The Frontier orbital energy gap (Elumo-Ehomo) is found to be 6.2143 eV. The extreme limits of the electrostatic potential is +8.301e x 10~(-3) to -8.301e x 10~(-3) while the total electron density spreads between +3.835e x 10~(-2) to -3.835e x 10~(-2). 1H NMR and 13C NMR chemical shifts are measured and compared with their gauge independent atomic orbital (GIAO) calculated values. The n(07) —> π*(C13-O14) and π(Cl-C6) -> π*(C2-C3) transitions are best stablized with 48.40 and 21.03 kcal mol10~(-1), respectively. In 3-trifluoromethylphenylchloroformate, the atoms CI3 is favourable for electrophilic attack. The atoms C2 and C8 are more favourable for nucleophilic attack. The dual descriptors (Afk, Ask and Adh) revealed that the order of nucleophilic attack is C1 > C4 > C2 > C8 > C5. Thus, the present investigation provides complete structure, vibrations and reactivity characteristics of the compound.