Synthesis of new N-silylphosphinimines: phosphazene precursors

Synthesis of Alkoxysilyl Substituted Cyclophosphazenes and their Properties in the Sol-Gel Process

“…The cyclophosphazene ring is formed by a thermal decomposition reaction of (H 3 C) 2 BrP=NSi(CH 3 ) 3 . A modi®cation of the pyrolysis reaction of the N-silyl-Pbromophosphinimine established by Neilson et al [6] leads to decamethylcyclopentaphosphazene in a yield of 84%.…”

Isolation of donor-stabilized N-silylphosphoranimine cations and the discovery of an ambient temperature route to Poly(alkyl/aryl)phosphazenes

“…Therefore, the next logical step in the pursuit of phosphine-stabilized phosphoranimine cations involved monohalogeno(diorgano)phosphoranimines. In the direct reaction between the BrMe 2 P@NSiMe 3 (14) [14] and the tertiary phosphines R 3 P (R = n Bu and Me) the novel phosphine-stabilized cationic phosphoranimine salts [R 3 PPMe 2 @NSiMe 3 ]Br ( [15]Br) were obtained (Scheme 6). Interestingly, these salts exhibit remarkably small one-bond phosphorus-phosphorus coupling constants [ 1 J PP = 23 Hz (R = n Bu) and 13 Hz (R = Me)] [15,16] (see Fig.…”

“…2). We expanded this chemistry to the phosphoranimine Br(CF 3 CH 2 O) 2 P@NSiMe 3 (16) [14], which bears electronwithdrawing trifluoroethoxy substituents (Scheme 6). Treatment of Br(CF 3 CH 2 O) 2 P@NSiMe 3 with n Bu 3 P or Me 3 P the generation of analogous phosphine-stabilized phosphoranimine cations [R 3 PP(CF 3 CH 2 O) 2 @NSiMe 3 ] Br ([17]Br) were obtained.…”

“…If an electron push-pull mechanism was indeed operating within the phosphoranimine cations [15] + and [17] + , then large coupling constants would be anticipated when electron-withdrawing substituents are present on the phosphorus donor and electron-donating substituents are present on the phosphoranimine acceptor. This postulation was investigated through our reactivity studies between BrMe 2 P@NSiMe 3 (14) and the phosphorus donor (MeO) 3 P.…”

Polyphosphazenes from Condensation Polymerization

“…On the other hand, their stability could potentially make them useful biostructural materials. The synthesis of the N-silylphosphoranimine precursors for condensation polymerization utilizes well-established, relatively straightforward reactions [7,9] (Scheme 1). This facilitates the incorporation of P-C-bonded organic groups on phosphorus in the small molecule precursors and avoids problems such as incomplete substitution and chain degradation that occur with attempts to substitute preformed [Cl 2 PN] n with alkyl or aryl moieties using organometallic reagents.…”