Table of Contents:
The aim of this Phd work was to get an insight into phosphine groups in order
to model them by Effective Group Potentials (EGP).
After a concise report of the main approximations and theories of quantum
chemistry, the design of a pseudopotential for the carbonyl group is carried out.
This particular case helps to explain the EGP method.
Following this a preliminary overview of the hybrid methods is shown. Subsequently
the possibility of using pseudopotentials to treat the frontier between
QM and MM regions working with hybrid methods is investigated.
The ONIOM method and the pseudopotential replacing SiH3 are chosen
to carry out the first tests.
Next there is an introduction for energy partition analysis. The usefulness of
this kind of method in attempting to find out why the trihalide boron
compound BF3 is a weaker Lewis acid than BCl3 with respect to
strong Lewis bases as NH3 is illustrated.
Afterwards the results using energy decompositions on various compounds
containing phosphorus is detailed. The amine and phosphine groups
in different donor-acceptor complexes (metallic complexes or complexes containing
boron and aluminum) are detailed.
The final chapter deals with the molecules in which the elements P, As, Sb
and Bi of group 15 are bonded to chromium metallic fragments in an unusual way.
The conclusion details the original results of this work before revealing