Master of Science
Baines, Kim M.
The reactivity of tetramesityldisilene 4 and tetramesityldigermene 5 towards organophosphorus oxides was explored in this thesis. The reaction of dialkyl and diarylphosphine oxides and phosphites with ditetrelenes 4 and 5 resulted in a 1,3-addition to form diorganodisilyl and digermyl phosphinites 27, 28, 31, 32 and disilyl phosphites 35 and 36. The 1,3-addition resulted in a mild two electron reduction of the P(V) centre of the phosphine oxide and phosphite to a P(III) centre in the products, without the use of heat or a catalyst. The reaction of organophosphorus oxides provides another example of a main group oxide that can be activated by ditetrelenes 4 and 5 in addition to nitro and sulfonyl containing compounds, CO and CO2.
The mechanism for the reaction of diorganophosphorus oxides and phosphites with ditetrelenes 4 and 5 was investigated through deuterium labelling studies and KIE experiments. The mechanism for the formation of disilyl and digermyl phosphinites and phosphites was determined to proceed through a nucleophilic addition. An exchange phenomenon between the OP(pentyl)2 moiety of 32 and an OPPh2 group from diphenylphosphine oxide was discovered and insights into the mechanism of this exchange were obtained.
Summary for Lay Audience
Just as houses can only be utilized after first laying down a stable foundation, understanding the fundamental chemistry of compounds is important for the future development of applications of the chemistry. In this thesis, reactions with compounds containing silicon and germanium are explored. These compounds are of interest because of their ability to easily react with numerous reagents to form new compounds that are not easily synthesized in any other way. The addition of phosphorus oxides to the silicon or germanium species was investigated. The new compounds formed were identified using state-of-the-art analytical techniques and the pathways to these compounds were elucidated using physical inorganic methodology. The chemistry reported is simple to perform and, with the mechanistic insights provided, it is hoped that the chemistry can be utilized in applications such as the organic functionalization of semiconductor surfaces.
Belcina, Maissa, "The Reactivity of Ditetrelenes Towards Organophosphorus Oxides" (2019). Electronic Thesis and Dissertation Repository. 6522.