ORGANOMETALLIC AND PHOTOCHEMISTRY OF CERIUM AND THORIUM COMPLEXES AND PHOTOCATALYTIC SYSTEMS FOR THE GENERATION OF CHLORINE RADICALS.

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Degree type
PhD
Graduate group
Chemistry
Discipline
Chemistry
Subject
actinide
chlorine radical
lanthanide
photochemistry
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Copyright date
01/01/2022
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Yang, Qiaomu
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Abstract

Our interest has focused on the 1) coordination chemistry and electronic structure of the lanthanide and actinide complexes, 2) electronic transitions and photochemistry of the cerium complexes, and 3) systems that generates chlorine radicals. For theIn search of new coordination chemistry offor high oxidation state (+4) lanthanides, we investigated several ligand frameworks, including glutarimide dioxime (chapter 2), TriNOx3− (chapter 3 with alkyne ligands, 4.3-4.5 with imido and oxo ligands), atrane3− (chapter 4.2), and proposed TriNP*3− (chapter 4.6). As a result, a ligand withThe coordination of coordinating oxygen or nitrogen atoms of the ligand, and a zwitterionic resonance structure with oxygen or nitrogen anion in the coordination can help stabilize the high oxidation state cerium(IV) complexes, to afford the studies of the electronic structure and f- orbitals involvement. For the studyingIn our study of the photochemistry of the [CeIVCl6]2− and [CeIIICl6]3− complexes, we investigated the mechanisms in of alkane amination reactions, developed alkane and arene oxygenation reactions, and studied the influence of alcohols (such as CH3OH or HOCH2CCl3) as an additives in the reaction. The reaction has a rate-limiting step of lLight irradiation is the rate-limiting step in reactions withusing cerium(IV) catalysts. A cChlorine radical is generated during light irradiation and activates C-H bonds for yielding a carbon centered radical. This carbon radical can be trapped in an amination reaction and or an oxygenation reaction for utilization. An induction period When using cerium(III) pre-catalyst, an induction period was discussedobserved using cerium(III) pre-catalyst,. Aand alcohols can assist cerium(IV) catalyst generation duringin the induction period for cerium(IV) catalyst generation. For the exploring ofTo explore the systems that generate chlorine radicals under light irradiation, we expanded the systems scope beyond cerium(IV)-chloride to titanium(IV)-chloride, iodide(I)-chloride, niobium(V)-chloride, tantalum(V)-chloride and vanadium(V)-chloride. These systems have different efficiency in quantum yields, different redox potentials and different absorption spectramaxima., while tThey can be applied for various purposesin different scenarios., where nNiobium(V)-chloride and, tantalum(V)-chloride has have been applied forin elemental separations. V, and vanadium(V)-chloride has been applied in catalytic reactions using green/blue light irradiation in addition to blue light, which uses covered a broaderer scope part of the sunlight spectrum.

Advisor
Shelter, Eric, J.
Date of degree
2022
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