Date of Award


Degree Type


Degree Name

Doctor of Philosophy




Dr. Kim Baines


In this thesis, various aspects of E=C compound reactivity are reported. Alkyne addition to three different phosphaalkenes and a germene has been investigated. The results were compared to those reported from previous work on the addition of alkynes to silenes. Formal [2+2] cycloaddition does not appear to be a general pathway for the addition of alkynes to E=C compounds. Some cycloadducts were observed; however, ene-addition and CH-insertion of the terminal alkynyl bond across the E=C bond were also prominent. The favoured pathway of addition depends heavily on the polarity of the E=C bond, which varies with the main group element (E) and the electronic nature of the substituents.

Alkyne cycloaddition and CH-insertion pathways were modeled for silenes and germenes using computational chemistry. Cycloaddition involving the formation of a diradical intermediate was found to be the lowest energy pathway for both silenes and germenes.

Addition polymerization o f a silene, Mes2Si=C(H)CH2® u , and germene, Mes2Ge=C(H)CH2fBu, has also been investigated. The use of anionic and radical initiators is reported. The polymers contain a regularly alternating metalloid-carbon backbone.

Conditions for the living anionic polymerization of Mes2Ge=C(H)CH2iBu have been explored. Low molecular weight polygermene can be synthesized in a controlled fashion in an ether-THF cosolvent using iBuLi as the initiator. The conditions developed

for the radical polymerization of Mes2Ge=C(H)CH2tBu have been applied to the synthesis of germene-styrene copolymers.


Addition Polymerization Alkyne Addition CH-Insertion Copolymer Cycloaddition 1,2-Dihydrophosphinine DFT

Ene-addition Germacyc lobutene Germene Germylacetylene Inorganic Polymer Mechanism Phosphaalkene Polycarbogermane Polycarbosilane Silacyclobutene Silene



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