Methyl-trimethylsilylmethyl tetrachlorocyclotriphosphazene

In a nitrogen-filled glove bag, 45 mL of 2.9 M CH3MgCl (0.13 mol) in THF is transferred to an addition funnel, which is then attached to a 1-L flask. The CHaMgCl solution is then added dropwise to the THF solution of N3P3Cl5(CH2SiMe3), which has been cooled to 0° with an ice-water bath. On completion of addition, the solution is allowed to warm to 25° and is stirred for 16 hr. 

The tube is removed from the oven, allowed to cool, then opened (shattered by percussion) in a nitrogen-filled glove bag. The contents of the tube and shattered glass are transferred to a 500-mL airless fiask equipped with a magnetic stir bar. The conversion of ge/n-N3P3Cl4(CH3)(CH2SiMe3) to the high polymer is approximately 50-60%. 

To the polymer [NPCl2]2—[NP(CH3)(CH2SiMe3)] and the residual cyclic trimer, ge/n-N3P3Cl4(CH3)(CH2SiMe3), in an airless flask is added 300 mL of dry toluene (distilled over sodium benzophenone). This mixture is stirred under an atmosphere of dry nitrogen until the contents of the broken tube dissolve (3-4 hr). The toluene solution is then transferred to a 500-mL addition funnel under a nitrogen atmosphere via a double-tipped syringe needle. 

The reaction mixture is allowed to cool to 25° and the insoluble materials 

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