Activation of Carbon Dioxide by Pincer Supported Transition Metal Complexes [electronic resource].

9781303719325

1 online resource (132 p.)

Access is available to the Yale community.

Access restricted by licensing agreement.

The synthesis, characterization, and catalytic activity of a highly active carbon dioxide hydrogenation PNPir catalyst (PNP = HN((alkyl) 2PCH2CH2)2) is detailed. Computational and X-ray diffraction experiments indicate a secondary coordination sphere H-bond interaction is crucial for carbon dioxide insertion reactivity. The synthesis and characterization of a family of PNPFe complexes is presented. Substitution of the pincer isopropyl groups for larger cyclohexyl and tert-butyl groups results in a dramatic attenuation in reactivity. Dihydrogen bonding is present in a number of these PNPFe complexes and has lead to the isolation of the first example of a bimetallic transition metal borohydride structure in which each of the two Fe atoms are bridged by one B-H bond of the borohydride ligand (mu,eta1-H2BH2). A pathway of formation for this unique dinuclear complex is proposed based on experimental and x-ray diffraction data. A family of PCPNi complexes (PCP = bis-2,6-di-tert-butylphosphinomethylbenzene) was also synthesized and their reactivity with carbon dioxide was investigated. A number of these PCPNi complexes were found to insert carbon dioxide to provide the corresponding unidentate carboxylate complexes while other PCPNi complexes proved inert toward carbon dioxide. A number of disparate insertion mechanisms for the family of PCPNi complexes based on experimental and computational data is proposed and important structural requirements for carbon dioxide insertion reactivity are detailed.

Books / Online / Dissertations & Theses

English

July 25, 2014

Thesis (Ph.D.)--Yale University, 2014.

Yale University.