Triplet excited state chemistry has enabled a range of important organic transformations by accessing reaction pathways inaccessible to photoredox chemistry. Such photoreactions are triggered by triplet photosensitizers, which absorb visible-light photons and transfer the energy to the substrate or to a co-catalyst through triplet-triplet energy transfer (TT EnT). The most popular triplet photosensitizers, metal complexes and organic chromophores, have proven useful in a range of pericyclic reactions, bond dissociations, and isomerizations, but they have several characteristics related to their chemical and electronic structure that limit their selectivity, energy efficiency, and sustainability. This dissertation describes the next generation of photocatalysts for TT EnT-driven organic transformations, colloidal quantum dots (QDs). These sub-5-nm particles have the large catalytic surface and electronic/optical tunability of homogenous catalysts, and the easy separation, and surface templating effects of heterogeneous catalysts. Their optical and electric properties, small singlet-triplet energy splitting, narrow emission linewidths and high photostability enhance their performance as triplet photosensitizers. These following chapters describe these advantages in the context of TT EnT-driven [2+2] photocycloaddition and deracemizations, and highlight the advantages and challenges associated with using related emerging materials, specifically lead halide perovskite QDs and quasi-2D nanoplatelets, as photocatalysts for triplet excited state chemistry.

Creator

• Jiang, Yishu

DOI

• https://doi.org/10.21985/n2-vesx-8063

Subject

• Chemistry

Language

• en

Alternate Identifier

• http://dissertations.umi.com/northwestern:15941
• etdadmin_upload_879745

Date created

• 2022-01-01

Resource type

• Dissertation

Rights statement

• In Copyright