الخلاصة:
As part of this thesis, we determined firstly the crystal structure of pentachlorotoluene (PCT) from
the X-ray diffraction to 293K and also the molecular conformation of this compound from the
calculations of the theory of the density functional (DFT).
In this compound the substituents are assigned a high agitation because of désodre thermiquie.
The structure determination by X-rays showed what was this disorder and its nature.
Calculations from the B3LYP functional and MPW1PW91 and the basic game DGDZVP offer after
geometrical optimization Cs symmetry of conformations have almost the same energy training.
Of the two conformations Cs predicted by calculations of quantum mechanics, the conformation
which gives results very close to those obtained from the experience is the conformation obtained
from the B3LYP functional and basic play / 6311G.
