Synthesis and functionalization of novel meso-substituted tetrabenzotriazaporphyrins

Alharbi, Nuha (2014) Synthesis and functionalization of novel meso-substituted tetrabenzotriazaporphyrins. Doctoral thesis, University of East Anglia.

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Phthalocyanine derivatives have seen many important developments since their discovery in 1907 by Braun and Tcherniac. These interesting materials are one of the most significant classes of macroheterocyclic organic materials owing to their remarkable electrical and physical properties which can be tuned by suitable derivatization of their rigid inner core. A brief summary of the syntheses, properties and applications of these complexes is clarified in Chapter 1.
The work described in this thesis concerns the synthesis of phthalocyanine (Pc)/tetrabenzoporphyrin (TBP) hybrids – intermediates between the widely studied Pc and TBP parents. Such hybrids have received a very little attention, mainly because they have previously proved difficult to synthesise. Among the series of the phthalocyanine/tetrabenzoporphyrin hybrids, tetrabenzotriazaporphyrins (TBTAPs) are the most widely studied and they are the focus of this thesis. They have a single meso-carbon linkage which can offer an additional site for the attachment of various functional groups, thus would provide a wide range of functionalized TBTAP derivatives.
The syntheses of the phthalonitriles have been achieved successfully through the investigation of different strategies. Phthalonitriles have been constructed by the nickel or palladium catalysed Kumada cross-coupling reaction using 1,2-dichlorobenzene as precursor, followed by electrophilic bromination and Rosenmund von Braun cyanation reaction in the last step. An alternative route towards the formation of the phthalonitriles was used in order to synthesise alternative target
phthalonitriles in good yield; the method employed Kumada cross-coupling reaction using 4,5-dibromoveratrole as precursor followed by a sequence of synthetic steps and finally cyanation reaction following the procedure described by Hanack and Drechsler. A series of meso-phenyl substituted tetrabenzotriazaporphyrins (TBTAPs) bearing different functional groups has been prepared successfully via the investigation of various approaches. The traditional synthetic methods and their new modified versions via Grignard reagents have been developed as well as the modern technique via aminoisoindoline that was discovered recently by our group. Most importantly, synthesis of functionalised TBTAPs has been achieved.
Expansion of the π-conjugated system of TBTAPs has been attempted as first experimental examinations in this field through several chemical and photochemical cyclisation methods, but the desired products were not isolated. Finally, transformations of the functionalised meso-phenyl TBTAP macrocycles through the palladium-catalysed Suzuki and copper-free Sonogashira cross-coupling reactions have been accomplished successfully resulting in the formation of a new series of materials. The new strategies combine to open up the potential for many new hybrid structures.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Chemistry
Depositing User: Users 2593 not found.
Date Deposited: 18 Feb 2015 13:00
Last Modified: 30 Jan 2018 01:38

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