INVESTIGADORES
SANCHO Matias Israel
artículos
Título:
An experimental and theoretical study of the complexation mechanism of Al(III) with 2-hydroxy-4-methoxy-benzophenone
Autor/es:
MARIA C. ALMANDOZ; MATIAS I. SANCHO; SONIA E. BLANCO
Revista:
Physical Chemistry: an Indian Journal
Editorial:
Trade Science Inc. Indian S Press
Referencias:
Año: 2006 vol. 1 p. 32 - 40
Resumen:
The complexation reaction between AlCl3 and 2(OH)4(OCH3)-benzophenone
was investigated by theoretical and experimental procedures, with
the purpose of providing further information that supports the recently
proposed reaction mechanism for the complexation of 2(OH)-
benzophenone with AlCl3. The kinetic experiments were carried out by
means of UV-visible spectroscopy varying the temperature (15-30 C),
ionic strength (5.37x10-4-1.05x10-2 mol/l) and permittivity (24.55 and
32.63) of the reaction medium. In the theoretical study, thermodynamic
magnitudes, torsional angles, length bonds, energy and reactivity
indices were used. The calculations were performed by means of the
B3LYP/6-31G(d) method and using the PCM model. The specific
reaction rate increased when permittivity was decreased and decreased
when the ionic strength of the reaction medium was increased. The
kinetic results obtained permitted to confirm a three-step reaction
mechanism that contemplates the acid-base dissociation of 2(OH)4
(OCH3)-benzophenone, the reaction between AlCl3 and a solvated proton
to form the AlCl2+ cation, and the ionic reaction between the anion
of benzophenone and the metal cation. This reaction between two ions
of opposite charges is the rate-determining step of the complexation
reaction analyzed. On the other hand, the magnitudes theoretical are in
good agreement with the experimental data.