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Title
The role of sterics and electronics of PNP pincer ligands in Iron(II) and manganese(I) chemistry / von Mathias Glatz
Additional Titles
Sterische und elektronische Einflüsse auf PNP Pincer Liganden in der Eisen(II) und Mangan(I) Chemie
AuthorGlatz, Mathias
Thesis advisorKirchner, Karl
PublishedWien, 2018
DescriptionIV, 105 Blätter : Illustrationen
Institutional NoteTechnische Universität Wien, Dissertation, 2018
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Zusammenfassung in deutscher Sprache
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Abweichender Titel nach Übersetzung der Verfasserin/des Verfassers
LanguageEnglish
Document typeDissertation (PhD)
Keywords (EN)Pincer Ligands / Pincer Complexes / Base Metals / Iron / Manganese
URNurn:nbn:at:at-ubtuw:1-110717 Persistent Identifier (URN)
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 The work is publicly available
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The role of sterics and electronics of PNP pincer ligands in Iron(II) and manganese(I) chemistry [20.74 mb]
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Abstract (English)

Base metal catalysis is an emerging field in organometallic chemistry to replace precious metals by earth abundant metals. To achieve so, a suited ligand backbone to support the non-precious metals is needed, in order to get catalytic activity. The influence of well designed ligands on base metal chemistry is exampled on a series of iron(II) and manganese(II) compounds. The research bases on tridentate “pincer” ligands with a pyridine backbone connected with two phosphine donors (PNP-ligands). The ligands vary in the set-up of linkers (CH2, NH, NMe, O) and phosphine moiety PR2. A new class of iron(II) PNP pincer complexes, made up of two pincer ligands in different bonding modes (tridentate and bidentate) is described. The complexes of general formula 3,2-[Fe(PNP)2X]+ are only observed when small phosphines (PR2; R = Me, Et, nPr, nBu, Ph) and a NH linker is apparent in the PNP ligands. In solution, the formation is inevitable, even when altering the stoichiometry. The 31P The results suggest that bifunctionality of the ligand along with ligand-metal cooperation is essential for the mechanism. Turnover numbers (TON) of up to 10.000 could be achieved. The hydrogenation proceeds at room temperature, without additives in protic media. Analogue rhenium(I) PNP pincer complexes [Re(PNP)(CO)2H] had inferior performance below 100 TONs. Additionally, the hydrido complexes [Mn(PNP)(CO)2H] and [Re(PNP)(CO)2H] activate carbon dioxide (CO2) at ambient conditions. The 1,2-addition of CO2 leads to a series of formate complexes of the types [Mn(PNP)(CO)2(OCHO)] and [Re(PNP)(CO)2(OCHO)]. In summary, these results offer a guide for Mn(I) and Fe(II) pincer chemistry allowing to alter the chemical properties in a modular fashion.

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