Vibrational, nuclear magnetic resonance and electronic spectra, quantum chemical investigations of 2-amino-6-fluorobenzothiazole

Abstract

Abstract The FT-IR (4000–400 cm−1) and FT-Raman (4000–100 cm−1) spectral measurements of 2-amino-6-fluorobenzothiazole (2A6FBT) and complete assignments of the observed spectra have been proposed. Ab initio and DFT calculations have been performed and the structural parameters of the compound are determined from the optimised geometry with 6-31G(d,p), 6-311++G(d,p) and cc-pVDZ basis sets and giving energies, harmonic vibrational frequencies, depolarisation ratios, IR intensities, Raman activities and atomic displacements. 1H and 13C NMR spectra were recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. UV–Visible spectrum of the compound was recorded and the electronic properties, such as HOMO and LUMO energies, were measured by time-dependent DFT (TD-DFT) approach. The geometric parameters, energies, harmonic vibrational frequencies, IR intensities, Raman activities chemical shifts and absorption wavelengths were compared with the available experimental data of the molecule. The influences of fluoro and amino group on the skeletal modes and on the proton chemical shifts have been investigated.