Date of Award
Master of Science (MS)
Department of Chemistry
Timothy D. Lash
Carbaporphyrins and carbachlorins are porphyrin analogs in which one of the nitrogens is replaced with a carbon atom within a porphyrin-like cavity. These systems form stable organometallic derivatives and exhibit unusual chemical reactivity. In the monocarbaporphyrinoids such as benzocarbaporphyrins, one of the pyrrole rings is replaced by an indene unit. Although syntheses of monocarbaporphyrins with fused rings have been widely investigated over the past 20 years, a few examples of carbaporphyrins without fused rings have been reported in the literature.
In this thesis, two projects were conducted to further explore carbaporphyrin and carbachlorin chemistry. The first project utilized a ‘3+1’ condensation of tripyrrane dicarboxylic acid with dimethyl 3,5-diformylcyclopentane-1,2-dicarboxylate in the presence of trifluoroacetic acid, followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), to yield a novel carbaporphyrin system in 40% yield together with a 10% yield of a related carbachlorin. This new carbaporphyrinoid system retained macrocyclic aromaticity and afforded stable silver(III) and gold(III) complexes. In addition, alkylation with methyl iodide and potassium carbonate gave a C-methyl derivative and this underwent metalation with palladium(II) acetate and nickel(II) acetate to afford related organometallic species. The second project dealt with the development of a new route for synthesizing carbachlorins. Chlorins are a group of dihydroporphyrins and are important biological pigments. The study of core-modified chlorins has been limited compared to that of core modified porphyrins. Carbachlorins are chlorin analogues where carbon atom is inserted into the chlorin core. They are interesting compounds in several aspects and are also promising candidates in many practical applications. Based on a “3+1” methodology, a novel carbachlorin was synthesized and characterized through various spectroscopic techniques, including, NMR, UV-Vis spectroscopy, and mass spectrometry. The coordination chemistry of this carbachlorin was also investigated.
Sahota, Navneet, "Development of New Routes for the Synthesis of Carbaporphyrins and Carbachlorins" (2017). Theses and Dissertations. 773.