The Library
The solid-state chemistry of rhodium pincer complexes
Tools
Longcake, Alexandra (2022) The solid-state chemistry of rhodium pincer complexes. PhD thesis, University of Warwick.
|
PDF
WRAP_Theses_Longcake_2022.pdf - Submitted Version - Requires a PDF viewer. Download (9Mb) | Preview |
Official URL: http://webcat.warwick.ac.uk/record=b3913378
Abstract
Oxidative addition (OA) is a fundamental organometallic process which is of interest both academically and industrially, but it can be difficult to study in solution due to the highly reactive intermediates implicit in the reaction. The solid-state represents an attractive medium in which to control reactivity via external stimuli. This thesis focuses on the application of crystallographic methods to the study of OA in the solid-state. The proposed approach involved the synthesis of rhodium pincer complexes featuring Rh∙∙∙X–E interactions (X–E = Cl–C, H–B) which were studied by X-ray diffraction, initially under conventional conditions, but ultimately with more elaborate variable pressure techniques, in an effort to promote pressure-induced oxidative addition. Where possible, solid-state reactivity was compared with solution phase behaviour.
The solution phase chemistry of {Rh(PONOP)(ĸCl-ClR)}+ (R = alkyl, aryl; PONOP = 2,6-(tBu2PO)2C5H3N) adducts were explored, leading to the discovery of concerted (C(sp2)–Cl) and radical (C(sp3)–Cl) OA mechanisms. Thermally induced oxidative addition was also achieved in solid-state samples of [Rh(PONOP)(ĸ1-ClCH2Cl)][BArF4]. Efforts to increase the likelihood of pressure-induced reactivity in complexes of {Rh(pincer)}+ prompted the exploration of alternative pre-activated substrates (σ-borane complexes). An isomorphous phase transition in [Rh(PONOP)(ɳ2-HBcat)][BArF4] (HBcat = HBO2C6H4; ArF = 3,5-(CF3)2C6H3) promoted further activation of the complex from a ‘classical’ to an ‘elongated’ σ-borane complex. Furthermore, OA adducts for the structurally related complexes [Rh(PNP)(ɳ2-HBcat)][X] (PNP = 2,6-(tBu2PCH2)2C5H3N; X = SbF6, BArF204; ArF20 = C6F5) were obtained under ambient conditions upon crystallisation as a result of crystal packing effects. A single crystal to single crystal transformation was discovered upon exposure of [Rh(PNP)(H)(Bcat)][BArF204] to carbon monoxide, which afforded [Rh(PNP)(CO)][BArF204] and free HBcat. Although pressure-induced OA ultimately proved elusive, several novel SC-SC transformations induced by various control parameters such as temperature, pressure and gas were observed for a range of rhodium pincer complexes.
Item Type: | Thesis (PhD) | ||||
---|---|---|---|---|---|
Subjects: | Q Science > QD Chemistry | ||||
Library of Congress Subject Headings (LCSH): | Oxidation-reduction reaction, Rhodium, Solid state chemistry, Organometallic chemistry -- Research, Crystallography | ||||
Official Date: | December 2022 | ||||
Dates: |
|
||||
Institution: | University of Warwick | ||||
Theses Department: | Department of Chemistry | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Chaplin, Adrian ; Senn, Mark S. | ||||
Format of File: | |||||
Extent: | xxi, 303 pages : illustrations | ||||
Language: | eng |
Request changes or add full text files to a record
Repository staff actions (login required)
View Item |