Fischer and N-heterocyclic carbene complexes of Group (VII) transition metals

English: The synthetic methodology, structure characteristics and catalytic application of Fischer- and N-heterocyclic carbene (NHCs) complexes of the group VII transition metals were investigated. By using density function theory calculations, the structural and electronic parameters could be elucidated and the fundamental bonding interactions between the carbene ligands and transition metals defined. The bonding definition provided a platform for the comparison of different carbene-metal bonding interactions, an area of research that has been historically misunderstood. Finally, application prospects for both the Fischer- and N-heterocyclic carbene complexes were explored. Both dimetallic Fischer carbene complexes and NHCs containing the cymantrenyl moiety illustrated possible catalytic activity in the dimerization of thiols. Using DFT calculations, the plausible mechanism and energy cycle for the catalytic activity were postulated. Sepedi: Mokgwa wa sintektiki, diponagalo tša sebopego le tirišo ya catalytic ya Fischer- le N-heterocyclic carbene (NHCs) tša dimetale tša phetogo ya sehlopha sa VII di ile tša nyakišišwa. Ka go šomiša dipalo tša teori ya mošomo wa segokanyipalo, ditekanyetšo tša sebopego le tša elektroniki di be di ka hlathollwa gomme ditirišano tša motheo tša kgokagano magareng ga dilitšente tša carbene le ditšhipi tša phetogo di hlalošitšwe. Tlhaloso ya kgokagano e file sekgoba sa go bapetša ditirišano tše di fapanego tša kgokagano ya khabene-metale, e lego lefelo la nyakišišo leo le sa kwešišwego gabotse go ya ka histori. Mafelelong, ditebelelo tša tirišo ya bobedi dikomponi tša khapine tša Fischer- le N-heterocyclic di ile tša hlahlobja. Bobedi ditlhakatlhakano tša methaliki wa khapine ya Fischer le di-NHC ye e nago le karolo ya simanthrenili e bontšhitše kgonego ya mošomo wa khathalistiki ka go e tswakanya le thiols. Ka go šomiša dipalo tša DFT, mokgwa wo o kwagalago le modikologo wa maatla bakeng sa mošomo wa khathalithiki di ile tša akanyetšwa pele. Afrikaans: Die sintetiese metodologie, struktuurkenmerke en katalitiese toepassing van Fischer- en N-heterosikliese karbeen- (NHC-)komplekse van die groep VII-oorgangsmetale is ondersoek. Deur gebruik te maak van digtheidsfunksieteorieberekeninge, kon die strukturele en elektroniese parameters uitgelig word en die fundamentele bindingsinteraksies tussen die karbeenligande en oorgangsmetale gedefinieer word. Die bindingsdefinisie het 'n platform gebied vir die vergelyking van verskillende karbeen-metaalbindingsinteraksies, 'n navorsingsgebied wat histories verkeerd verstaan is. Laastens is toepassingsvooruitsigte vir beide die Fischer- en N-heterosikliese karbeenkomplekse ondersoek. Beide dimetalliese Fischer-karbeenkomplekse en NHC's wat die simantreniel-deel bevat, het moontlike katalitiese aktiwiteit in die dimerisering van tiole geïllustreer. Deur gebruik te maak van DFT-berekeninge is die aanneemlike meganisme en energiesiklus vir die katalitiese aktiwiteit gepostuleer. IsiZulu: Indlela yokuhlela, izimpawu zesakhiwo kanye nokusetshenziswa kwe-catalytic ye-Fischer- okuphitheneyo kwe-N-heterocyclic carbene (ama-NHC) eqembu le-VII lezinsimbi eziguquguqukayo yaphenywa. Ngokusebenzisa izibalo zethiyori yokusebenza kokuminyana, imingcele yesakhiwo nephathelene nama-elekthronikhi ingacaciswa futhi ukuhlangana okuqavile okwenzelanayo phakathi kwama-carbene ligand nezinsimbi eziguquguqukayo kuchazwe. Incazelo yokuhlangana ihlinzeke inkundla yokuqhathanisa ukusebenzisana okuhlukile kokuhlangana kwe-carbene-nezinsimbi, okuwumkhakha wocwaningo obungaqondakali kahle ngokomlando. Ekugcineni, amathemba okusebenzisa kokubili i-Fischer- nokuphitheneyo kweN-heterocyclic carbene kwahlolisiswa. Kokubili ama-dimetallic Fischer carbene aphitheneyo kanye nama-NHC aqukethe i- cymantrenyl moiety kubonise umsebenzi ongaba khona we-catalytic ekunciphiseni ama-thiols. Ngokusebenzisa izibalo ze-DFT, indlela ezwakalayo kanye nomjikelezo wamandla womsebenzi we-catalytic waphecwa.

Grantor dc:publisher

University of Pretoria

Year dc:date.issued

2016

Advisor dc:contributor.advisor

• Landman, Marile

• UCTD

Statement dc:rights

• © 2017 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.

Language dc:language.iso

en

Dc Identifier Other

A2016

OAI identifier oai:identifier

oai:repository.up.ac.za:2263/59106