Síntesi, caracterització i avaluació com a catalitzadors de nous complexos quirals de platí
- Autores: Josep Duran i Carpintero
- Directores de la Tesis: Juli Real i Obradors (dir. tes.), Alfonso Polo Ortiz (dir. tes.)
- Lectura: En la Universitat de Girona ( España ) en 2003
- Idioma: catalán
- ISBN: 84-688-1297-8
- Depósito Legal: GI-423-2002
- Tribunal Calificador de la Tesis: Joan Carles Bayón Rueda (presid.), M. Angeles Martínez Lorente (secret.), Guillermo Muller Jevenois (voc.), Lluisa Matas Jordi (voc.), Ramón Yáñez López (voc.)
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
The oxidative addition proved to be a useful method to prepare platinum (II) hydridotiolate by reaction of tetrakis(triphenylphosphine)platinum(0) with aminothiolate and phosphinothiolate ligands like cysteamine, cysteine ethyl and methyl Esther, 2-(diphenylphosphino)ethanetiol and 2-(diphenylphosphino)propanetiol.
The complexes are square-planar and the aminothiolate or phosphinothiolate ligands are chelated to platinum (II). The hydrido ligand is trans to the sulfur and the other coordination position is occuped by a triphenylphosphine ligand. The complexes are mononuclear and they show low symmetry. The only symmetry element, the plan is broke if the ligand is branched, obtaining asymmetric complexes C1.
If the ligand has electronic or esteric impediments the reaction doesnt run and the starting products are recovered. This was observed with N,N-dimethylcysteamine and penicylamine methyl esther ligands. In the special case of orthoaminotiophenol the hydridotiolate was obtained but the ligand was not chelated.
The aminothiolate complexes dont show solution equilibrium. Otherwise, the complexe with 2-(diphenylphosphino)ethanetiol show an isomerisation equilibrium which forms cis isomer as a minor component. The complexe with 2-(diphenylphosphino)-propanetiol shows a conformational equilibrium between chair and twist forms.
The complexes have been tested as catalyst precursors in hydroformylation and hydrosilylation reactions.
The hydroformylation reaction runs only in presence of SnCl2 as cocatalyst. Catalytic activity depends on the presence of triphenylphosphine and, with less magnitude, CO and H2 pressure. We also studied the enantioselectivity using a chiral complexe.
In the hydrosililation reaction, catalysts run with good results (<90%) using triethylsilane as silicon hydride. Dehydrogenative addition product has been also found in this reaction.
