Conformational and Vibrational Studies of Triclosan

The conformational equilibrium of triclosan (5‐chloro‐2‐(2, 4‐dichlorophenoxy) phenol) have been calculated using density functional theory (DFTe/B3LYP/6‐311++G(d, p)) method. Four different geometries were found to correspond to energy minimum conformations. The IR spectrum of triclosan was measured in the 4000–400 cm−1 region. We calculated the harmonic frequencies and intensities of the most stable conformers in order to assist in the assignment of the vibrational bands in the experimental spectrum. The fundamental vibrational modes were characterized depending on their total energy distribution (TED%) using scaled quantum mechanical (SQM) force field method.