Graduation Term

Summer 2025

Degree Name

Master of Science (MS)

Department

Department of Chemistry

Committee Chair

Timothy D. Lash

Committee Member

Susil Baral

Committee Member

Shawn R. Hitchcock

Abstract

Carbaporphyrins are porphyrin-like molecules where a carbon atom takes the place of one of the nitrogen atoms typically found within the central core. These compounds are notable for their ability to create stable organometallic structures that can function as catalysts. For the last two decades, researchers have explored carbaporphyrins that incorporate fused ring systems. Common instances of these include benzocarbaporphyrins, and naphthocarbaporphyrins, where a cyclopentadiene ring merged with benzene-based structures substitutes for a standard pyrrole ring. In this thesis, the synthesis, chemical reactivity and characterization of quinone-fused carbaporphyrins was investigated. Initially, a ‘3+1’ methodology was used to condense a tripyrrane dicarboxylic acid with dimethoxynaphthoquinone dicarbaldehyde in the presence of trifluoroacetic acid, followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), to yield the novel dimethoxynaphthoquinone carbaporphyrin in 8.1% yield. However, attempts to convert the products into a naphthoquinone-carbaporphyrin gave poor results and it was necessary to devise an alternative approach. This involved synthesizing diacetoxynaphthoquinone carbaporphyrin u sing the ‘3+1’ condensation and a subsequent removal of the acetoxy groups to yield the desired naphthoquinone carbaporphyrin. The proton NMR spectrum for this new carbaporphyrinoid system demonstrated that it is highly aromatic as the meso-protons were highly shielded and the internal methine proton was shifted upfield to -5.82 ppm. We adopted the same approach to synthesize benzoquinone carbaporphyrin which also shared similar spectroscopic properties as the naphthoquinone system. Anthraquinone carbaporphyrin was syntheisized by a direct ‘3+1’ condensation of anthraquinone dialdehyde with tripyrrane dicarboxylic acid to give anthraquinone carbaporphyrin in 21.5% yield and characterized using various spectroscopic techniques such as UV-vis spectroscopy, mass spectrometry and NMR. The chemical reactivity as well as metal complexation was also investigated. The carbaporphyrin with a fused anthraquinone ring also exhibited strongly aromatic properties. Reaction with methyl iodide and potassium carbonate afforded a C-methyl derivative which further underwent metalation with palladium(II) acetate and nickel(II) acetate to afford related organometallic complexes. The quinone-fused carbaporphyrins are interesting compounds with unique electronic spectra and are also promising candidates in many industrial and medical applications.

Access Type

Thesis-Open Access

DOI

https://doi.org/10.30707/ETD.1763755358.805156

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Available for download on Monday, September 10, 2029

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