Pincer Ligands with Strong σ-Donors at the Central Position

Borau-Garcia, Javier

Pincer Ligands with Strong σ-Donors at the Central Position

atmire.migration.oldid	582
dc.contributor.advisor	Roesler, Roland
dc.contributor.author	Borau-Garcia, Javier
dc.date.accessioned	2013-01-15T20:42:46Z
dc.date.available	2013-06-15T07:01:44Z
dc.date.issued	2013-01-15
dc.date.submitted	2013	en
dc.description.abstract	Pincer ligands have been extensively investigated due to the ease by which their steric and electronic properties can be tuned. One of the most important features of pincer metal complexes is their robustness, which renders them excellent candidates for a wide variety of applications such as catalysis, medicinal chemistry, and chemical sensing. The increased robustness of pincer complexes is not associated with a loss of reactivity at the metal center, which renders them good ancillary ligands. Proper tuning of the electron donating properties of pincer ligands has allowed for some of their metal complexes to display unprecedented reactivity. The objective of the research described herein was the synthesis and characterization of novel pincer ligand architectures, with a particular interest in ligands with strong electron donating moieties at the central position. Two PBP pincer ligand precursors with a 2-chloro-1,3,2-diazaborane central moiety were synthesized. The coordination of the ligand precursors to palladium via a B-Cl bond activation was investigated. The synthesized PBP ligands represent two of the first examples of pincer ligands with a boryl at the central donor position, and their palladium complexes are the first ever (PBP)Pd complexes. These complexes displayed good thermal stability but no catalytic activity under Heck cross-coupling reaction conditions. The synthesis of PBP and NBN pincer ligand precursors with an acyclic backbone was also explored. PCP pincer ligand precursors with six and five membered N-heterocyclic carbene (NHC) moieties at the central donor position, which upon coordination would generate two five membered metallacycles, were synthesized and characterized. Double C-H bond activation by rhodium in PCP-carbene precursors yielded the desired compounds with six membered NHC backbones. These are among the rare examples where a double C-H bond activation leads to the formation of an NHC complex. The rhodium complexes displayed good thermal stability and promising reactivity. The analogous PCP-carbene precursor with a five membered NHC backbone could be readily deprotonated to the free carbene, allowing for the synthesis of rhodium, palladium, nickel and molybdenum complexes. These complexes have some of the shortest M-CNHC bonds reported for each metal, suggesting a strong interaction between the metal center and the ligand.	en_US
dc.identifier.citation	Borau-Garcia, J. (2013). Pincer Ligands with Strong σ-Donors at the Central Position (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/27360	en_US
dc.identifier.doi	http://dx.doi.org/10.11575/PRISM/27360
dc.identifier.uri	http://hdl.handle.net/11023/423
dc.language.iso	eng
dc.publisher.faculty	Graduate Studies
dc.publisher.institution	University of Calgary	en
dc.publisher.place	Calgary	en
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject	Chemistry--Inorganic
dc.subject.classification	Pincer Ligands	en_US
dc.subject.classification	N-Heterocyclic Carbenes	en_US
dc.subject.classification	Boryl Ligands	en_US
dc.title	Pincer Ligands with Strong σ-Donors at the Central Position
dc.type	doctoral thesis
thesis.degree.discipline	Chemistry
thesis.degree.grantor	University of Calgary
thesis.degree.name	Doctor of Philosophy (PhD)
ucalgary.item.requestcopy	true