C<sub>2</sub>-Symmetric Pyrazole-Bridged Ligands and Their Application in Asymmetric Transition-Metal Catalysis

Böhnisch, Torben

dc.contributor.advisor	Meyer, Franc Prof. Dr.
dc.contributor.author	Böhnisch, Torben
dc.date.accessioned	2016-06-03T08:22:20Z
dc.date.available	2016-06-03T08:22:20Z
dc.date.issued	2016-06-03
dc.identifier.uri	http://hdl.handle.net/11858/00-1735-0000-0028-876A-6
dc.identifier.uri	http://dx.doi.org/10.53846/goediss-5677
dc.language.iso	eng	de
dc.publisher	Niedersächsische Staats- und Universitätsbibliothek Göttingen	de
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/4.0/
dc.subject.ddc	540	de
dc.title	C<sub>2</sub>-Symmetric Pyrazole-Bridged Ligands and Their Application in Asymmetric Transition-Metal Catalysis	de
dc.type	doctoralThesis	de
dc.contributor.referee	Meyer, Franc Prof. Dr.
dc.date.examination	2015-07-23
dc.description.abstracteng	Within the scope of this thesis the synthesis of a plethora of examples of in total three types of C<sub>2</sub>-symmetric pyrazole-bridged ligand systems (namely PyrBOX, PyrBPyBOX and ProPyrazole) could be established (Chapter 4). <br /> Subsequently, the PyrBOX ligands proofed to be versatile ligands for asymmetric allylic substitution reactions (Chapter 7). Starting from three different palladium allyl precursors and four PyrBOX ligands in total twelve different complexes could be isolated. The investigations of these intermediate dinuclear allyl palladium complexes in solution (e.g., EXSY, VT-NMR) and in solid state further allowed gaining a deeper understanding of the catalytic process. These studies furthermore revealed the presence of solvation and cooperative effects in such dinuclear palladium catalysts.<br /> Combination of the same PyrBOX ligand scaffold with other transition metal ions gave rise to variety of helical supramolecular structures (Chapter 9). For instance, the diastereoselective formation of a pentanuclear cluster helicate could be observed. Further investigations lead to the isolation of, to the best of knowledge, first examples of helical mesocate complexes of the general formula [(Lx)3M2]+ (M = Mn(II), Cd(II)). While potential applications of these and related chiral, multinuclear structures remain to be explored, the introduction of a rigid bridging group and the resulting properties certainly extended the class of helical multimetallic supramolecular compounds.<br /> Finally, a very promising catalyst system, based on the ProPyrazole ligand scaffold, for the atropselective oxidative coupling of 2-naphthols was introduced (Chapter 11). Sophisticated kinetic and ESI-MS studies were performed, which allowed the targeted optimization of the catalyst systems and revealed new key insights into the mechanism of such transformations.<br /> The obtained results therefore may offer a glimpse of the potential of C<sub>2</sub>-symmetric pyrazole-bridged ligands for cooperative asymmetric catalysis.	de
dc.contributor.coReferee	Clever, Guido Prof. Dr.
dc.contributor.thirdReferee	Waitz, Thomas Prof. Dr.
dc.contributor.thirdReferee	Diederichsen, Ulf Prof. Dr.
dc.contributor.thirdReferee	Stalke, Dietmar Prof. Dr.
dc.contributor.thirdReferee	Koszinowski, Konrad Prof. Dr.
dc.subject.eng	Pyrazole-Bridged Ligands	de
dc.subject.eng	Asymmetric Transition-Metal Catalysis	de
dc.subject.eng	Cooperative Asymmetric Catalysis	de
dc.subject.eng	Enantioselective Catalysis	de
dc.subject.eng	Two-Center Catalysis	de
dc.subject.eng	Pyrazole	de
dc.subject.eng	PyrBOX	de
dc.subject.eng	PyrBPyBOX	de
dc.subject.eng	ProPyrazole	de
dc.subject.eng	Tsuji-Trost	de
dc.subject.eng	Allyl Palladium	de
dc.subject.eng	Asymmetric Allylic Substitutions	de
dc.subject.eng	Asymmetric Allylic Alkylations	de
dc.subject.eng	Solvation Effects	de
dc.subject.eng	Cooperative Effects	de
dc.subject.eng	EXSY	de
dc.subject.eng	Helicate	de
dc.subject.eng	Mesocate	de
dc.subject.eng	Cluster Helicate	de
dc.subject.eng	Chiral Supramolecular Coordination Compounds	de
dc.subject.eng	Atropisomerism	de
dc.subject.eng	Atropselective Oxidative Coupling	de
dc.subject.eng	2-Napthol	de
dc.subject.eng	Reaction Progress Kinetic Analysis (RPKA)	de
dc.identifier.urn	urn:nbn:de:gbv:7-11858/00-1735-0000-0028-876A-6-5
dc.affiliation.institute	Fakultät für Chemie	de
dc.subject.gokfull	Chemie (PPN62138352X)	de
dc.identifier.ppn	86043558X

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C₂-Symmetric Pyrazole-Bridged Ligands and Their Application in Asymmetric Transition-Metal Catalysis