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Synthesis of porphyrin-chromophore conjugates

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posted on 28.03.2022, 01:46 authored by Rajesh Kisan Raut
Several porphyrin-chromophore conjugate systems have been synthesized for future energy /electron transfer studies. This thesis discusses the systematic approach used in the synthesis of three chromophores (boranils, α-cyanostilbenes and 1,3-diketone boron complexes) linked toporphyrins via either covalent bonds or supramolecular interactions. The UV-visible absorption and fluorescence emission spectra, together with the relative quantum yields of the conjugates were examined in order to establish any structure-property relationships that may exist. Three different porphyrin frameworks were prepared for use in the syntheses of covalently linked porphyrin-chromophore conjugates. The first of these was a porphyrin ring mono-functionalised on one of the meso-aryl rings. The second framework had a functionalised phenyl ring connected to animidazole ring that was fused to the porphyrin at adjacent β-pyrrolic carbons. The third framework was functionalised on a quinoxaline ring that was fused to the porphyrin at adjacent β-pyrroliccarbons. Porphyrin-boranil conjugates were synthesized by condensation of amine-functionalised porphyrins with salicylaldehyde or 2-hydroxynaphthaldehyde to afford the corresponding 2-hydroxyaryl imines (also known as anils), followed by reaction with boron trifluoride to afford the boron complexes. Aldehyde-functionalised porphyrins were condensed with the reactive methylene group present in 4-nitrophenylacetonitrile, 4-bromophenylacetonitrile and benzyl cyanide to afford α-cyanostilbeneporphyrin conjugates. Two series of 1,3-diketone boron complexes were synthesized for future studies involving a supramolecular approach to porphyrin-chromophore conjugate assembly. One series contains a 4-hydroxyphenyl unit (for coordination to tin(IV) porphyrins) and the second series contains a 4-pyridyl unit (for coordination to zinc(II) porphyrins). A titration experiment (monitored with UV visible spectroscopy) was conducted with one of the 4-pyridyl appended 1,3-diketone boron complexes and a zinc(II) porphyrin. The results indicated that a complex was formed. The 4-pyridyl appended 1,3-diketone boron complexes were converted to their N-methylpyridinium salts, and a computational study was also conducted to calculate their non-linear optical properties.

History

Table of Contents

Chapter One. Introduction -- Chapter Two. Porphyrin building blocks -- Chapter Three. Porphyrin-boranil conjugates -- Chapter Four. Porphyrin-α-cyanostilbene conjugates -- Chapter Five. Boron difluoride 1,3-diketonates -- Chapter Six. Supramolecular assembly -- Chapter Seven. Synthesis and theoretical nonlinear optical properties of pyridyl containing 1,3-diketone boron complexes and their quaternary salts -- Chapter Eight. Overview of the project : outcomes and future directions.

Notes

Includes bibliographical references Empirical thesis.

Awarding Institution

Macquarie University

Degree Type

Thesis PhD

Degree

PhD, Macquarie University, Faculty of Science and Engineering, Department of Chemistry and Biomolecular Sciences

Department, Centre or School

Department of Chemistry and Biomolecular Sciences

Year of Award

2014

Principal Supervisor

Andrew C. Try

Rights

Copyright Rajesh Kisan Raut 2014. Copyright disclaimer: http://mq.edu.au/library/copyright

Language

English

Extent

1 online resource (xvi, 210 pages) diagrams, graphs, tables

Former Identifiers

mq:69076 http://hdl.handle.net/1959.14/1250472