Saudi Cultural Missions Theses & Dissertations
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Item Restricted Novel Syntheses of Porphyrazine-Phthalocyanine Hybrids(University of East Anglia, 2024) Almaneai, Norah Mohammad; Almaneai,NorahAbstract Porphyrazines Pzs, are intermediate structures between phthalocyanines and porphyrines, each bearing the same core but with phthalocyanines having benzo-fusion on each pyrrolic unit. Phthalocyanine and porphyrin hybrids, where mixtures of C and N bridges exist, have received significant attention over recent years, in part due to the synthetic breakthroughs achieved by our group at UEA. However, C/N hybrid systems are still rare, and C/N porphyrazine-phthalocyanine hybrids (mixed C/N bridges and partial benzo-fusion) are unknown, to the best of our knowledge. The research by the Cammidge group has reported a new synthetic pathway involving the use of an AB dimer intermediate (formed from an aminoisoindoline and phthalonitrile) for the synthesis of meso‐aryl tetrabenzotriazaporphyrins TBTAPs. In this study, we have employed a similar synthetic strategy to investigate and develop new porphyrazine hybrid derivatives. The synthesis described in Chapter 2 is based on the formation of key AB dimer intermediates from trans-2,3-diphenyldinitrile derivatives starting materials, which are reacted with aminoisoindoline precursors. This dimer undergoes self-condensation in the presence of a Magnesium or Zinc template to give mixtures of M-porphyrazine complexes (unsymmetrical and symmetrical Pzs ABBA, ABBB-Ar, ABBB-N and BBBB), which were isolated and purified. The work culminated in the successful synthesis, purification, and characterisation of a wide array of porphyrazine hybrids using NMR spectroscopy, MALDI-TOF mass spectrometry, X-ray crystallography, and UV-Vis absorption spectroscopy, and experimental details are recorded in Chapter 3. Of particular note is the first direct observation of benzyl elimination during macrocyclization. While this step has been inferred from other syntheses of related hybrids, the observation of a mono-benzofused, all-N hybrid proves this process can operate under the reaction conditions.9 0Item Restricted Phthalocyanine hybrids; old chemistry revisited and new syntheses(University of East Anglia, 2024-05-28) Farhan, Nora; Cammidge, AndrewThe work described in this thesis is concerned with the investigation of synthetic pathways toward tetrabenzoporphyrin/phthalocyanine hybrid macrocycles, specifically tetrabenzomonoazaporphyrins (TBMAPs) or other less-nitrogenous hybrids. The initial investigation was conceived to modify the latest synthetic procedure developed in the Cammidge group whereby utilisation of a less nitrogenous precursor (alkynylbenzonitrile, 1 x N) replaced phthalonitrile (2 x N) as co-macrocyclisation partner with an aminoisoindoline. Unfortunately, no hybrids were formed and instead the formation of a six- membered ring isoquinoline from the acetylene was observed under these conditions. Linstead’s method to synthesise TBMAPs was then revisited, and different malonyl aminoisoindolines were synthesised and isolated. These precursors proved to be unstable under many conditions which resulted in the formation of their keto-esters and dimers during their purification process. Fusion of these precursors with zinc dust at 220oC proved to give a mixture of hybrids but no evidence for the expected TBMAPs’ formation, according to MALDI-MS analysis. Isolation of the hybrids was challenging and complicated by slow decomposition during chromatography. We switched to investigate Linstead’s conditions of fusion in the presence of zinc metal at high temperature on our proposed reactants (alkynylbenzonitrile with aminoisoindoline) and, interestingly, formation of ZnTBTAP, cisTBDAP, transTBDAP and traces of ZnTBMAP were observed. However, the formation of these hybrids proved to be a result of macrocyclisation of one reactant only – the aminoisoindoline. Full analysis of all hybrids was obtained, except ZnTBMAP due to its low quantity. In the final part of the thesis, we further explored the latest Cammidge procedure to synthesise TBTAPs by employing substituted phthalonitriles (“B”) with aminoisoindolines (“A”), in this case using different metals to track the origin of each unit in the final TBTAPs. ABBB TBTAPs were selectively obtained in high yield when zinc chloride was utilised while a mixture of ABBB and ABBA TBTAPs were obtained when different metals were employed. Full characterisation of the obtained hybrids and intermediates was achieved. The formation of these hybrids is somewhat surprising and no obvious mechanisms for their formation are apparent.17 0