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Synthetic investigation of Mn(I) and Re(I) N-heterocyclic carbene complexes
Dissertation (MSc)--University of Pretoria, 2010.
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| Format: | Thesis |
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University of Pretoria
2013
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| _version_ | 1867613442113798144 |
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| access_status_str | Open Access |
| author2 | Landman, Marile |
| author_browse | Landman, Marile |
| author_facet | Landman, Marile |
| collection | Thesis |
| dc_rights_str_mv | © 2010, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc)--University of Pretoria, 2010. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/25922 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:36:12.613Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/25922 Synthetic investigation of Mn(I) and Re(I) N-heterocyclic carbene complexes Landman, Marile Bezuidenhout, Daniela Ina beefstar@hotmail.com Van der Westhuizen, Belinda Diverse methods of synthesis Manganese transition metals UCTD Dissertation (MSc)--University of Pretoria, 2010. The study involves synthetic approaches towards the preparation of novel NHC complexes of low valent rhenium and manganese transition metals. Diverse methods of synthesis were studied. The direct approach, in which the ylidene obtained from deprotonation of 1,3-bis(2,4,6- trimethylphenyl)imidazolium chloride was added to the metal substrate, proved to be unsuccessful as isolation of the free carbene should rather be performed in an argon filled glove box under extreme inert conditions. By way of further investigation the ylidene was prepared by in situ methods and then quenched with the metal substrate. Different bases for deprotonation purposes and reaction conditions were explored. All routes employed were investigated and compared using group VII transition metal substrates Re(CO)5Br, Mn(CO)5Br, Re2(CO)10 and Mn2(CO)10. Isolation and purification of these products proved to be very challenging due to the insolubility in some organic solvents with consequent problematic spectroscopic analyses of the complexes. The tendency of the products to undergo various side reactions is observed in all reactions. Specifically, hydrolysis of the imidazolium ligand, followed by vinyl formation, yielded the mesitylformamide compound (3). The results obtained for some of the monometal substrates indicated that the target complexes were formed but could not be isolated. However, the synthesis route employing deprotonation by nBuLi as base and [Mn2(CO)10] as dimetal substrate lead to the isolation of the target dinuclear complex [Mn2(CO)9IMes] (9). Other novel complexes obtained during the course of this study include the biscarbene tetrarhenium complex [Re2(CO)9.C(OEt)C4H2OC(OEt)Re2(CO)9] (12) and various side reaction products. In many cases, metal-metal bond cleavage and carbonyl insertion was observed, as is evident in the complex IMesH[ReO4] (6) and ketene product (13). Structural and theoretical studies were performed to investigate the bond character between the carbene ligand and the metal. Chemistry unrestricted 2013-09-07T01:22:34Z 2011-07-04 2013-09-07T01:22:34Z 2011-04-05 2010 2011-06-28 Dissertation Van der Westhuizen, B 2010, Synthetic investigation of Mn(I) and Re(I) N-heterocyclic carbene complexes, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/25922 > E11/434/gm http://hdl.handle.net/2263/25922 http://upetd.up.ac.za/thesis/available/etd-06282011-160910/ © 2010, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Diverse methods of synthesis Manganese transition metals UCTD Synthetic investigation of Mn(I) and Re(I) N-heterocyclic carbene complexes |
| title | Synthetic investigation of Mn(I) and Re(I) N-heterocyclic carbene complexes |
| title_full | Synthetic investigation of Mn(I) and Re(I) N-heterocyclic carbene complexes |
| title_fullStr | Synthetic investigation of Mn(I) and Re(I) N-heterocyclic carbene complexes |
| title_full_unstemmed | Synthetic investigation of Mn(I) and Re(I) N-heterocyclic carbene complexes |
| title_short | Synthetic investigation of Mn(I) and Re(I) N-heterocyclic carbene complexes |
| title_sort | synthetic investigation of mn i and re i n heterocyclic carbene complexes |
| topic | Diverse methods of synthesis Manganese transition metals UCTD |
| url | http://hdl.handle.net/2263/25922 http://upetd.up.ac.za/thesis/available/etd-06282011-160910/ |