Spectroscopic and synthetic studies relating to a dirhodium hydroformylation catalyst

The main goal of this dissertation research was to further study and characterize our bimetallic hydroformylation catalyst, rac-[Rh₂(nbd)₂(et,ph-P4)](BF₄)₂, and to fully identify the catalytically inactive mono- and dirhodium complexes formed upon fragmentation of the catalyst under hydroformylation conditions. Various in situ NMR methods such as 1D ¹H and ³¹P, and 2D COSY, HMBC, and HMQC were employed and indicated the formation of the key catalyst, [rac-Rh₂H₂(μ-CO)₂(CO)₄(et,ph-P4)]²⁺, 4, and a number of other Rh-phosphine species on and off the catalytic cycle. Detailed spectroscopic data was used to propose the structures of these catalytically inactive fragmentation complexes, namely [RhH₂(η⁴-et,ph-P4)]⁺, 10, and [rac,rac-Rh(η⁴-et,ph-P4)₂RhH₂]²⁺, 11. Mono- and bimetallic rhodium tetraphosphine compounds, RhCl₂(η⁴-et,ph-P4)BF₄, 12, Rh(Cl)(CH₂Cl)(η⁴-et,ph-P4)BF₄, 13, and [Rh₂(η⁴-et,ph-P4)₂](BF₄)₂, 14 were synthesized, characterized, and their NMR spectroscopic data was obtained. The ³¹P analyses of these compounds were correlated with the spectroscopic data obtained from the in situ NMR studies of [Rh₂(nbd)₂(et,ph-P4)](BF₄)₂ catalyst precursor and indicated that none of these three complexes are present during hydroformylation catalysis. The above compounds were studied to help us expand our knowledge about the bimetallic catalyst and the possible mechanism of the fragmentation process occurring during hydroformylation. In addition, me,ph-P4 ligand, a variation of the et,ph-P4, and dirhodium me,ph-P4 catalyst were synthesized. Separation of meso and racemic diastereomers of this ligand was also achieved. Research in this area involved the synthesis of dimethylchlorophosphine, Me₂PCl, and the halogenated methylene bridged bisphosphine, Cl₂PCH₂PCl₂.

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

Chemistry

Year dc:date.available

2004

Author dc:creator

• Gueorguieva, Petia Gueorguieva

• dirhodium hydroformylation catalyst

Statement dc:rights

• unrestricted
• Release the entire work immediately for access worldwide.

Identifier

etd-11112004-111407
https://repository.lsu.edu/gradschool_dissertations/1381

OAI identifier oai:identifier

oai:repository.lsu.edu:gradschool_dissertations-2380