Katti, Kattesh V and Krishnamurthy, Setharampattu S (1985) Studies of phosphazenes. Part 21. Associative and dissociative pathways in the aminolysis reactions of halogenocyclotriphosphazenes. In: Journal of the Chemical Society, Dalton Transactions: Inorganic Chemistry, 2 . 285 -289.
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The rates of stepwise replacement of chlorine from hexachlorocyclotriphosphazene $\[(N_3P_3Cl_6\]$) by –$\[NMe_2\]$, the last chlorine atom from $\[N_3P_3(OPh)_5Cl\]$ by alkylamines, and the first fluorine atom from $\[N_3P_3F_6\]$, by –$\[NMe_2\]$, in methyl cyanide, have been determined at three temperatures. Detailed analysis of the kinetic data suggests a concerted $\[S_N\]2(P)$ mechanism for the first and second Cl substitutions. A sharp changeover from an $\[S_N\]2(P)$ to an $\[S_N\]1(P)$ mechanism occurs at the fourth substitution; the replacement of chlorine from $\[N_3P_3(OPh)_5\]Cl$ also occurs by an $\[S_N\]1(P)$ pathway. The first F substitution from $\[N_3P_3F_6\]$ by –$\[NMe_2\]$ proceeds ca. 20 times slower than the analogous reaction for $\[N_3P_3Cl_6\]$; the kinetic data for these two reactions are in accord with a two-step $\[S_N\]2(P)$ pathway. Many diverse findings reported for the aminolysis reactions of halogenocyclophosphazenes are explained in terms of the continuous spectrum of mechanisms established in the present study.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Royal Society of Chemistry.|
|Department/Centre:||Division of Chemical Sciences > Inorganic & Physical Chemistry|
|Date Deposited:||07 Jul 2008|
|Last Modified:||19 Sep 2010 04:46|
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