Date of Award
Doctor of Philosophy (PhD)
Eric J. Schelter
Part I: Ligand design is at the crux of molecular f-block element chemistry where well-defined ligand frameworks allow rational coordination and reaction chemistry. In the first part of this work, the C−F→Ln/An interaction, a type of non-covalent interaction, was incorporated into amide complexes of f-block cations. Solid-state and solution evidence for the presence of C−F→Ln/An interactions was presented. Collective impacts of multiple C−F→Ln/An interactions on the molecular geometries and electronic structures were investigated through experimental and computational studies. The labile nature of C−F→Ln/An interactions allowed their displacement by donor molecules opening a venue toward unconventional coordination chemistry of f-block cations.
Part II: The replacement of the element samarium for cerium in one-electron reduction reactions is desirable for economic and sustainability reasons. Notably, cerium is comparable to base metals in terms of abundance. At the crux of such replacement is the capability of producing cerium(III) species with comparable or superior reduction potentials than samarium(II) iodides. In the second part of this work, this issue was tackled with photochemical methods taking advantage of energetically accessible 4f→5d absorptive transitions of cerium(III) cations. Luminescent cerium(III) complexes in their long-lived doublet d-orbital based excited states are more reducing than in ground states, allowing for their electron transfer to substrates. Significant insight is provided into the photophysics of cerium luminescence through the preparation and comparison of two complete mixed-ligand series of luminescent cerium(III) complexes. The photochemical reactivity of excited-state cerium(III) complexes were demonstrated in both stoichiometric and catalytic fashions.
Yin, Haolin, "C−f→ln/an Interactions and Molecular Cerium(III) Photochemistry" (2016). Publicly Accessible Penn Dissertations. 2116.