LE3 .A278 2013

2013

Ellis, Bobby

Acadia University

Bachelor of Science

Honours

Chemistry

Chemistry

Several N,N-bound halophosphine precursors and subsequent phosphenium cations were synthesized and characterized by 31P{1H} NMR spectroscopy. N,C-bound and C,C-bound halophosphines were also synthesized and characterized by 31P{1H} NMR spectroscopy. These compounds were then treated with an N-heterocyclic carbene in THF, in an attempt to form a compound with a heteronuclear double bond between phosphorus and carbon. All reactions with the carbene produced a colourless precipitate, in a filtrate which ranged in colour from yellow to red, depending on the phosphorus species used. The filtrate and precipitate were both characterized by 31P{1H} NMR spectroscopy. The reactions with the carbene and the C,C-bound halophosphines showed the most potential in the formation of a compound with phosphorus-carbon bonds, as the 31P{1H} NMR chemical shifts of the colourless precipitates occurred from −27 ppm to −50 ppm, which is consistent with reported values for related species, and was similar to values as predicted by DFT calculations. The reactions with the carbene and phosphenium cations were found to be least successful in forming phosphorus-carbon bonds, as the 31P{1H} NMR chemical shifts of the filtrate suggested that the counter anion had been attacked by the carbene, regenerating the halophosphine precursors.

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https://scholar.acadiau.ca/islandora/object/theses:968