EXPERIMENTAL AND THEORETICAL STUDY ON LINEAROL ISOLATED FROM SIDERITIS SPECIES

The molecular geometry, vibrational frequencies and gauge independent atomic orbital (GIAO) H-1- and C-13-NMR chemical shifts values of linearol (ent-3,7-dihidroksi,18-asetoksi-kaur-16-ene) in the ground state have been investigated using the Hartree-Fock (HF) and Density Functional Theory (DFT) employing the 6-31G and 6-31G(d) basis sets. The fundamental vibrational wavenumbers as well as their intensities were calculated and a good agreement between observed and calculated wavenumbers has been achieved. The optimized geometrical parameters obtained by theoretical calculations are in good conformity with single crystal X-ray data. The H-1- and C-13-nuclear magnetic resonance (NMR) chemical shifts of the molecule were compared with experimental values, which yield good agreement between the observed and calculated values.