Show simple item record

dc.contributor.authorLiebenberg, Deseréen_US
dc.date.accessioned2011-08-19T14:10:03Z
dc.date.available2011-08-19T14:10:03Z
dc.date.issued2010en_US
dc.identifier.urihttp://hdl.handle.net/10394/4393
dc.descriptionThesis (M.Sc. (Chemistry))--North-West University, Potchefstroom Campus, 2011.
dc.description.abstractCoupling homogeneous catalysts to dendrimers with rigid nuclei is one possible strategy to recycle these compounds in an industrial environment. During this study attempts were made to attach the well-defined ruthenium carbene complex 2 to the alicyclic compound 1A. To achieve this goal attempts were made to functionalise 1A with anime groups to facilitate the attachment of phosphine groups. The catalyst 2 would then be attached through a phosphine exchange reaction. Oximes were used as precursors in attempts to prepare cage amines from 1A. For this purpose, the dioxime 28 was prepared from 1A. Reduction of 28 was unsuccessful. Molecular modelling showed that the lobes of the LUMOs of the oxime carbon atoms of 28 do not protrude from the total electron density of this molecule. This observation indicates that 28 would probably not react with nucleophiles, such as the hydride ion. Molecular modelling was used to probe the unreactive nature of oxime 28. The probe revealed that the imide ring deactivates the oxime groups in this compound. Based on these results, attempts were made to change the carbon framework of 1A to eliminate unwanted interaction between the carbonyl groups. Clemmensen reduction of 1A did not yield the expected ketol 40, but gave a mixture of 62 and 63. Extended reaction times yielded 63 only. Reduction of 1A with zinc and acetic acid produced a mixture of 62 and 40 that could not be separated. Consequently, the applicability of 62 as a possible dendrimer nucleus was investigated. Compound 62 was obtained by oxidisation of the diol 63 with sodium periodate. Attempts to synthesise the dioxime 69 from 62 failed and only the mono oxime 71 was obtained. Reduction of 71 with lithium aluminium hydride was unsuccessful. Molecular modelling revealed that the oxime carbon atom does not have a LUMO and that the carbonyl carbon atom would probably be unreactive towards nucleophiles. Several other attempts were made at reducing the oxime 71 to an amine. None of these attempts met with any success. The reason for the unreactive nature of 71 is less clear than in the case of 28. Failure to produce a cage amine from 1A or derivatives of 1A meant failure in functionalising the cage system with phosphine groups and coupling the Grubbs-I catalyst. It seems that cage compounds based on 1A are generally not suitable as starting materials for amine-functionalised dendrimer nuclei.en_US
dc.publisherNorth-West University
dc.subjectHokstruktureen_US
dc.subjectHokamieneen_US
dc.subjectDendrimeeren_US
dc.subjectAlisikliese dendrimeerligandeen_US
dc.subjectDendritiese katalisatoreen_US
dc.subjectCage compoundsen_US
dc.subjectCage aminesen_US
dc.subjectDendrimeren_US
dc.subjectAlicyclic dendrimer ligandsen_US
dc.subjectDendritic catalysisen_US
dc.titleModellering en sintese van alisikliese dendrimeerligande vir alkeenmetatese / Deseré Liebenbergen_US
dc.typeThesisen_US
dc.description.thesistypeMastersen_US


Files in this item

Thumbnail
Thumbnail

This item appears in the following Collection(s)

  • ETD@PUK [6298]
    This collection contains the original digitized versions of research conducted at the North-West University (Potchefstroom Campus)

Show simple item record