Novel bulky fluorinated ligands for homogeneous catalysis
Abstract
A series of novel monodentate and bidentate phosphine ligands substituted with bulky
tert-butyl and fluorinated aryl groups have been synthesised. Borane protection has
proved to be an excellent method for easy synthesis and purification of bidentate ligands
in some cases. However, several of the bulky fluorinated ligands do not form stable
borane complexes leading to complications in the synthesis and purification of these
compounds. By reaction with transition metal platinum and palladium precursors, it was
possible to form dichloride complexes from the synthesised ligands, which were
characterised by X-ray crystallography. The complexes were found to be effective
catalysts for the hydroxycarbonylation of vinyl arenes (yields of up to 95 % with 3
mol% catalyst). An unsymmetrical bidentate complex (3.18) in combination with paratoluenesulfonic
acid and LiCl promoters has given exceptional (for a diphosphine ligand)
regioselectivity for the branched acid (98.7 % branched) in the hydroxycarbonylation of
styrene. The role of the promoters has been found to be crucial in deciding the activity
and selectivity in this reaction.
Type
Thesis, PhD Doctor of Philosophy
Description
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