A computational and synthetic study of poly(benzyl phenyl ether) dendrimers

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dc.contributor.advisorMoss, John Ren_ZA
dc.contributor.advisorNaidoo, Kevin Jen_ZA
dc.contributor.authorHughes, Samantha Jayneen_ZA
dc.date.accessioned2016-02-23T07:26:51Z
dc.date.available2016-02-23T07:26:51Z
dc.date.issued1998en_ZA
dc.descriptionIncludes bibliographies.en_ZA
dc.description.abstractOrganic and organochromium poly(benzyl phenyl ether) dendrimers have been investigated by synthetic · and computational methods. The first generation organic benzyl alcohol and bromide wedges have been prepared, and a first generation organic dendrimer was synthesised. The preparation of novel organochromium dendrimers has been investigated. Several chromium arene complexes were prepared by different routes, and the halogenation methodology was thoroughly explored with various reagents. The target compound, a chromium complexed first generation dendritic wedge, was not accessible by any of the methods investigated. The novel compound (dibenzyl ether)bis[tricarbonylchromium(O)] has been prepared by two routes and the crystal structure of this complex was determined. Several other chromium arene complexes were synthesised, and the crystal structure of one of these, (benzyl methyl ether)tricarbonylchromium(O), was determined. The structure and properties of the organic and organochromium dendrimers have been investigated by molecular mechanics and molecular dynamics techniques. The existing CHARMm polymer force field was extended to include parameters for the tricarbonylchromium moiety. The two crystal structures solved as part of the synthetic effort, were used in this regard. The accuracy of the new parameters was assessed by simulation of the crystal structure of ( dibenzyl ether)bis[tricarbonylchromium(O)]. The important ether linkage torsion angle parameter, which plays a significant role in the topology of the dendrimer, was singled out for refinement. The torsion angle was parameterised with the model compound benzyl phenyl ether, by fitting the CHARMm results for rotation about the dihedral, to ab initio torsional data. Molecular dynamics simulations have been performed on generations one through five of the organic and organochromium dendrimers. The radius of gyration and RMS variation were investigated as a function of generation for both dendrimer series. The radius of gyration was found to increase exponentially with generation, whereas the relationship of RMS variation to generation was not as well defined. Density distributions were calculated for all five generations of the organic and organometallic dendrimers. In addition, the distribution of the monomers from each generation within the dendrimer was analysed. In the later generation dendrimers, the monomers belonging to the earlier generations are extended, while the terminal groups are mobile and found in all regions of the dendrimer. The solvent accessible surface was calculated for the organochromium dendrimers. It was concluded from these results that although the terminal groups are mobile, the majority of these monomers remain on the periphery of the dendrimer, or in solvent accessible areas.en_ZA
dc.identifier.apacitationHughes, S. J. (1998). <i>A computational and synthetic study of poly(benzyl phenyl ether) dendrimers</i>. (Thesis). University of Cape Town ,Faculty of Science ,Department of Chemistry. Retrieved from http://hdl.handle.net/11427/17221en_ZA
dc.identifier.chicagocitationHughes, Samantha Jayne. <i>"A computational and synthetic study of poly(benzyl phenyl ether) dendrimers."</i> Thesis., University of Cape Town ,Faculty of Science ,Department of Chemistry, 1998. http://hdl.handle.net/11427/17221en_ZA
dc.identifier.citationHughes, S. 1998. A computational and synthetic study of poly(benzyl phenyl ether) dendrimers. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Hughes, Samantha Jayne AB - Organic and organochromium poly(benzyl phenyl ether) dendrimers have been investigated by synthetic · and computational methods. The first generation organic benzyl alcohol and bromide wedges have been prepared, and a first generation organic dendrimer was synthesised. The preparation of novel organochromium dendrimers has been investigated. Several chromium arene complexes were prepared by different routes, and the halogenation methodology was thoroughly explored with various reagents. The target compound, a chromium complexed first generation dendritic wedge, was not accessible by any of the methods investigated. The novel compound (dibenzyl ether)bis[tricarbonylchromium(O)] has been prepared by two routes and the crystal structure of this complex was determined. Several other chromium arene complexes were synthesised, and the crystal structure of one of these, (benzyl methyl ether)tricarbonylchromium(O), was determined. The structure and properties of the organic and organochromium dendrimers have been investigated by molecular mechanics and molecular dynamics techniques. The existing CHARMm polymer force field was extended to include parameters for the tricarbonylchromium moiety. The two crystal structures solved as part of the synthetic effort, were used in this regard. The accuracy of the new parameters was assessed by simulation of the crystal structure of ( dibenzyl ether)bis[tricarbonylchromium(O)]. The important ether linkage torsion angle parameter, which plays a significant role in the topology of the dendrimer, was singled out for refinement. The torsion angle was parameterised with the model compound benzyl phenyl ether, by fitting the CHARMm results for rotation about the dihedral, to ab initio torsional data. Molecular dynamics simulations have been performed on generations one through five of the organic and organochromium dendrimers. The radius of gyration and RMS variation were investigated as a function of generation for both dendrimer series. The radius of gyration was found to increase exponentially with generation, whereas the relationship of RMS variation to generation was not as well defined. Density distributions were calculated for all five generations of the organic and organometallic dendrimers. In addition, the distribution of the monomers from each generation within the dendrimer was analysed. In the later generation dendrimers, the monomers belonging to the earlier generations are extended, while the terminal groups are mobile and found in all regions of the dendrimer. The solvent accessible surface was calculated for the organochromium dendrimers. It was concluded from these results that although the terminal groups are mobile, the majority of these monomers remain on the periphery of the dendrimer, or in solvent accessible areas. DA - 1998 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1998 T1 - A computational and synthetic study of poly(benzyl phenyl ether) dendrimers TI - A computational and synthetic study of poly(benzyl phenyl ether) dendrimers UR - http://hdl.handle.net/11427/17221 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/17221
dc.identifier.vancouvercitationHughes SJ. A computational and synthetic study of poly(benzyl phenyl ether) dendrimers. [Thesis]. University of Cape Town ,Faculty of Science ,Department of Chemistry, 1998 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/17221en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDepartment of Chemistryen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherChemistryen_ZA
dc.titleA computational and synthetic study of poly(benzyl phenyl ether) dendrimersen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMScen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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