Kinetic Studies of the Reactions of SiC and SiSi Bonds

The Addition of a Cyclopropyl Alkyne to an Asymmetrically-Substituted Disilene: A Mechanistic Study

“…If the reaction were to proceed via a zwitterion derived from nucleophilic attack by the alkyne on the disilene, then the cyclopropyl ring would regioselectively open toward the methoxy substituent, and the regiochemistry of the phenyl and methoxy substituents of 7 and 8 would be reversed. Although we cannot formally exclude the possibility that 9 and 10 are formed via a concerted [2 + 2] cycloaddition or from nucleophilic attack by the disilene on the alkyne, there is no evidence that supports or suggests such reaction pathways. , …”

Addition of Nitriles to Two Brook Silenes

“…A mechanism for the addition of nitriles to naturally polarized silenes has been proposed, , which begins with initial coordination of the nitrile to the silenic silicon to give a zwitterionic complex. In Brook silenes, the electrophilicity of the silicon is reduced and direct evidence for complex formation has not been obtained; ,,, thus, coordination of acetonitrile and propionitrile to silenes 8 and 12 seems unlikely. Perhaps, the mechanism of addition of nitriles to silenes 8 and 12 involves the formation of radical intermediates as has been demonstrated in the addition of aldehydes and alkynes to silenes 8 and 12 .…”

“…In a landmark paper, Wiberg examined the influence of the structure of alcohols, amines, alkenes and dienes on the reactivity of silenes of the type R 2 SiC(SiR 3 ) 2 . However, the main factor affecting the chemistry of silenes is the polarity of the silicon–carbon double bond, which has only been detailed for a limited number of reactions including dimerization, the addition of water and alcohols, the addition of dienes and the addition of carbonyl compounds . In our ongoing efforts to understand how the polarity of the SiC in silenes influences their reactivity, we have examined the addition of aldehydes and alkynes to both naturally polarized silenes and Brook silenes ((Me 3 Si) 2 SiC(OSiMe 3 )R), which have a SiC bond of reduced polarity, and have observed notable differences in the types of products observed and in the reaction mechanisms.…”

Silicene is a phantom material

“…Essentially similar but quantitatively different is the situation for the Si=C bond of silaethylene. As seen in the figure, at equilibrium, the molecule is open-shell one, the radicalization of which requires 0.153e.It is well documented that both silaethylene and disilene molecules are highly reactive and their stabilization usually occurs at low temperatures in rare gas matrices [26].…”