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The reactions of LiC-CSiMe, with N3P3F6 lead to the new alkynylphosphazenes N3P3F6-n(C-CSiMe3)n (n = 1 or 2). Both the geminal and non-geminal isomers are observed in the 3IP and '9F n.m.r. spectra. A reinvestigation of the reaction of LiC-CC6H5 with N3P3F6 showed that, at the stage of bis substitution, in addition to the previously reported major product, gem-N3P3F4( CrCC6H5)2, small amounts of the non-geminal N3P3F4(CfCC6H5)2 isomers are formed. The reactions of N3P3F6-,( C-CSiMe3), (n = 1 or 2) with KF in anhydrous ethanol lead to the terminal acetylene derivatives, N3P3F4-,(OC2H5)2(CZH)n (n = 1 or 2).The reactions of organolithium and Grignard reagents with halogenophosphazenes have been shown to be valuable routes to organophosphazenes.2 Much of the effort in this area has been devoted to a r ~l -~-~ and a l k ~l -~* ~* substituted species with alkenyl 1*2*6-8 and especially alkynyl 2*9*10 derivatives being less common. We are particularly interested in alkenyl-and alkynyl-phosphazenes because of the potential, as shown in our work on propenylphosphazenes, for further synthetic transformations into organophosphazene polymers 2*11*12 and new organopho~phazenes.~~~*~~ A previous study by Chivers involving phosphazene derivatives of phenylacetylene, N3P3F6-,(CXC6H5), (n = 1 or 2), demonstrated the viability of synthesis of alkynylphosphazenes. Alkynylphosphazenes have also been observed in the reactions of copper or lithiophosphazene anions with prop-2-ynyl bromide leading to materials of the type N3P3C14R(CH2C-CH) (R = alkyl or allyl).'O Rearrangement from the prop-2ynyl to the prop-I-ynyl derivative, N3P3C14R(C-CCH3), was also observed.'O A prop-I-ynyl derivative, N3P3F5(CfCCH3), was previously reported as a by-product in the reaction of the 1 it hiopropene LiCH=CHCH3 with N3P3F6 .7In this paper we describe the synthesis of phosphazenes with trimethylsil ylacet ylene and terminal acetylene subs t i t uen t s. ExperimentalMaterials and Methods.-Hexafluorocyclotriphosphazene, N3P3F6, was prepared from N3P3C16 (Ethyl Corp.) by a previously reported pro~edure.'~ Phenylacetylene and n-butyllithium (1 3 5 mol dm-3 solution in hexane) were obtained from Aldrich Corp. Trimethylsilylacetylene was obtained from Petrarch systems. Diethyl ether and tetrahydrofuran were distilled from sodium benzophenone ketyl. Light petroleum (b.p. 35-55 "C) was distilled over sodium.N.m.r. spectra (in CHCI,) were recorded on a Bruker WM250 spectrometer operating at 250.1 ('H), 62.9 (13C), 235.2 (19F), or 101.2 MHz ("P). For 31P n.m.r., 85% H J P O ~ was used as external reference, for 19F, CFCl, was used. The I3C, I9F, and ,lP n.m.r. spectra were recorded under conditions of broad-band decoupling. Due to the complex second-order nature of the 19F and 31P spectra, parameters reported for these systems are approximate. Chemical shifts upfield of the reference are assigned a negative sign. Infrared (i.r.) spectra were obtained from thin films (NaCl discs) on a Beckman IR 20A spectrometer. Mass spectra were recorded on a Perkin-Elmer RMU-6D...

The cyclic phosphazenes N3P3F6(CMe3), N3P3F6Ph, zion-gem-NaPaCUMea, non-gem-NaPaCUEta, (NPClMe)3, and (NPCIMeU have been polymerized to macromolecules of formula [(NPF2)2-NPFR]", [NPC12(NPC1R)2]", and (NPC1R)". Species (NPClMe)a and (NPClEt)a were copolymerized with (NPC12)3 to yield polymers of type [(NPCl2)x(NPClR)y]n. The halogen atoms in the high polymers were replaced by trifluoroethoxy groups to yield hydrolytically stable derivatives. The influence of the alkyl or aryl groups on the properties of the polymers is described. The new polymers are elastomers, with glass transition temperatures in the -40 to -60 °C range.The main method for the synthesis of stable polyphosphazenes involves the polymerization of hexachlorocyclotriphosphazene, (NPC12)3, to high molecular weight poly-(dichlorophosphazene), (NPC12)", followed by replacement of the halogen atoms in this polymer by alkoxy, aryloxy, or amino groups.1-4 In general, these polymers are microcrystalline materials if the side groups are OCH2CF3, OPh, or substituted phenoxy units and if only one type of side group is present along each chain. By contrast, polyphosphazenes with flexible side groups, such as OMe, OEt, or OCH2CH2OCH2CH2OCH3, are elastomers. However, polymers that bear two or more different fluoroalkoxy or aryloxy side groups attached to the same chain are elastomers.5-8 This is because the random distribution of different side groups along the chain prevents crystallization and allows the inherent flexibility of the polyphosphazene backbone to dominate the solid-state properties. Mixed-substituent fluoroalkoxyphosphazene polymers are used in technology as low-Tg solvent-, oil-, and oxidation-resistant elastomers.