Publication Date

2018-05-04

Availability

Embargoed

Embargo Period

2019-10-26

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Chemistry (Arts and Sciences)

Date of Defense

2018-03-26

First Committee Member

V. Ramamurthy

Second Committee Member

Francisco M. Raymo

Third Committee Member

Jamie D. Walls

Fourth Committee Member

Abraham Joy

Abstract

This thesis comprises a detailed investigation on the photochemical and photophysical properties of various organic molecules encapsulated in molecular containers. Exploiting these photochemical and photophysical properties of fascinating organic molecules are often frustrating and tricky as they tend to get influenced by several environmental factors. For instance, in the solution phase, solvent can influence the properties of short-lived and reactive intermediates that are generated upon excitation. In order to control these properties, one of the promising approaches is to encapsulate them in an inert and confined environment. This strategy involves the encapsulation of the desired molecule in a stable enclosure, which subsequently drives the distribution of reactive intermediates into a variety of new environments or media. This avenue opens up new vistas and offers tremendous opportunities for systematic exploration of environmental effects on the photochemical and photophysical properties of organic molecules and enables their mechanistic investigations. In addition, the inert medium offers an additional advantage such as extending the lifetime of reactive intermediates. Furthermore, the enclosed medium reduces the relaxation process that usually occurs in the solvent phase. In this thesis a molecular container with a deep cavity called octa acid (OA) was exploited as host for various guest molecules such as 7-methoxy and 7-diethyl amino coumaryl esters, o-nitrobenzyl esters and their photochemical behavior has been investigated subsequently. Further, BODIPY derivatives and oilgothiophenes molecules were also used as guest molecules to investigate their photophysical properties. Remarkably, when in an aqueous environment, two of the host (OA) molecules can self-assemble each other to form a capsule by encapsulating a guest molecule inside them. The inner cavity of the OA capsule is hydrophobic and inert in nature, which is favorable to conduct and control various photochemical and photophysical reactions of insoluble guest molecules in water. Especially, studying the photochemical properties of coumaryl photocages within OA capsule provided a pathway to radical-derived products inside the OA capsule and ion-derived products outside of it. We also synthesized water-soluble cavitand functionalized gold nanoparticles and explored the photophysical properties of AuNPs surface assisted small organic molecules.

Keywords

Photochemistry, Photophysics, Supramolecular chemistry, Organic synthesis, Gold nanoparticles, Analysis

Available for download on Saturday, October 26, 2019

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