Publication Date

2018-06-26

Availability

Embargoed

Embargo Period

2020-06-25

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Chemistry (Arts and Sciences)

Date of Defense

2018-05-10

First Committee Member

Ramamurthy Vaidhyanathan

Second Committee Member

Burjor Captain

Third Committee Member

James N. Wilson

Fourth Committee Member

Mahesh Pattabiraman

Abstract

The research work presented in this thesis describes the photochemical reactions carried out in the solid-state and X-ray structural studies to understand the photochemical behavior of cis-cinnamic acids by exploiting topochemical postulates. The photochemistry of excited cis-cinnamic acids can be understood from the photochemistry of corresponding trans-cinnamic acids but not from cis-cinnamic acids alone. Existence of dual reactive centers and its photoreactivity of cis-olefinic crystals are thoroughly investigated. Similar to trans-cinnamic acids, cis-cinnamic acids can also undergo direct photodimerization when the intermolecular distance of double bonds is less than 4.2 Å. Key contributing factors for the isomerization of cis-cinnamic acids are well explained. Unlike trans-cinnamic acids, polymorphic changes of cis-cinnamic acids during photoirradiation are highlighted using photochemistry and X-ray crystal structures. The role of intermolecular distance and displaced nature of reactive olefinic pairs in the photochemistry of cis-cinnamides is extensively studied. The important factors responsible for one-way isomerization of cis-cinnamides and implications of displaced nature of halogen substituted cis-cinnamides that led to multiple products are well investigated. Furthermore, uniqueness of water as a solvent is explained with the concept of “in water and on water” photoreactions of cis-cinnamic acids in an aqueous medium.

Keywords

cis-Cinnamic acids; cis-Cinnamides; Topochemical postulates; Solid-state photochemistry; Geometric isomerization; "in and on water" photoreactions

Available for download on Thursday, June 25, 2020

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