LE3 .A278 2014

2014

Ellis, Bobby

Acadia University

Bachelor of Science

Honours

Chemistry

Chemistry

Several N,N-, N,C- and C,C-bound tin and lead carbenoids and phosphenium cation precursors, R2PCl, were synthesised as synthons for asymmetric double bonds. Two phosphorus-tin adducts were successfully synthesised and characterised using 31P{1H} NMR spectroscopy. Plumbylenes were investigated as reactive carbenoids but showed no reactivity, likely due to the non-bonding electrons being too stable due to the inert pair effect. Previous research using carbenes showed that the chloride ion acted as a weakly coordinating counter ion, lacking any bonding interaction to the carbon centre. The crystal structure of one of the phosphorus-tin adducts confirmed that the electron deficient tin centre accepted electron density from the chloride ion, forming a covalent bond. Salt metathesis and halide abstraction were used an attempt to remove the tin-bound chloride, but were not successful. A computational study of phosphenium cation and phosphenium cation precursors interacting with Group 14 carbenoids was investigated. Computational data agreed with experimental observations by predicting that using divalent lead as a carbenoid is less favorable than divalent tin. This suggests that lighter main group elements such as silicon and germanium are viable carbenoids to synthesise an asymmetric double bond.

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https://scholar.acadiau.ca/islandora/object/theses:1101