Stability and molecular dynamics of chloroxylenol (API of antiseptics and drugs) in solid state studied by 35Cl-NQR spectroscopy and DFT calculations

Abstract: Thermal stability of 4-chloro-3,5-dimethyl-phenol (chloroxylenol) in solid state has been studied by 35Cl-NQR spectroscopy. Two NQR resonance lines at the frequencies 34.348 and 34.415MHz at 77K have been assigned to chlorine atoms from two crystallographically inequivalent molecules on the basis of the B3LYP/6-311++G∗∗ results. The temperature dependence of the resonance frequency and full width at half maximum suggest the occurrence of small-angle torsional oscillations of the mean activation energy of 3.83kJ/mol and rotation of both methyl groups around their symmetry axis C3 with the activation energies 12.49 and 11.27kJ/mol for CH3 in molecule A and B, respectively. B3LYP/6-311++G∗∗ method reproduced very well the activation energies of both motions. [Copyright &y& Elsevier]