Mechanism Of Formation Of Bicyclic Phosphazenes - Isolation Of A Versatile Tetrakis(Amino) Intermediate, N4p4cl4(Nme2)2(Nhet)2

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New initiators for the ring-opening thermal polymerization of hexachlorocyclotriphosphazene: synthesis of linear poly(dichlorophosphazene) in high yields

Ring-opening thermal polymerization of hexachlorocyclotriphosphazene (N3P3C&h)a s been investigated at 250 "C and at 1.333-Pa pressure using chlorocyclotriphosphazenes N3P3C15(N=PPh3) and N3P3Cl,.,(NMe2), (n = 2-4), salt hydrates, triphenylphosphine, and benzoic acid as initiators. The linear poly (dich1orophosphazene) products are phenoxylated, and the phenoxy polymers are characterized by gel permeation chromatography and dilute solution viscometry. Among the various initiators investigated, CaS04.2H20b rings about a high conversion (>60%) of N3P3C&to the linear [NPC12], polymer which possesses a high molecular weight (>5 X lo6). The rationale for the choice of the initiators and possible mechanism(s) of polymerization is discussed. Several mixed substituent polymers, [NP(OPh),(OC6H4Me-p)2,1, and [NP(OPh),(OCHzCF3)2,]nh, ave been prepared and their thermal properties evaluated

Studies of phosphazenes. Part 16. Spectroscopic investigations of bicyclic phosphazenes of the type N4P4(NHR)6(NR)N_4P_4(NHR)_6(NR) and N4P4(NMe2)5N_4P_4(NMe_2)_5(NHR)(NR)

Octachlorocyclotetraphosphazene $(N_4P_4Cl_8)$ reacts with an excess of $RNH_2 (R = Pr, Me_2CH, Bu)$ in $CHCl_3$ to give a mixture of bicyclic phosphazene, $N_4P_4(NHR)_6(NR)$, and octakis(amino) deriv., N_4P_4(NHR)_8. The bicyclic phosphazenes are only formed in low yields when $R = Me_2CH$, Bu; formation of bicyclic phosphazene has not been detected in the reaction of $N_4P_4Cl_8$ with $PhCH_2NH_2$. 31P NMR and IR spectra of the products are presented. 31P NMR parameters for six asym. substituted bicyclic phosphazenes $N_4P_4(NMe_2)_5(NHR)(NR)$ have been obtained by computer analysis and these results are also discussed