Diphenyl phosphonitrile Fluoride Trimer

The compound 1,1-NsPsF4(CsHc)i can be prepared by the reaction between (monophenyl)phosphonitrile fluoride trimer and benzene in the presence of anhydrous aluminum chloride and triethylamine.2 In the absence of triethylamine, the product is contaminated with difficultly separable biphenyl. Triethylamine also improves the conversion of phosphonitrile chloride trimer to the geminally substituted diphenyl derivative6 by the Friedel-Crafts procedure.7 The Friedel-Crafts reaction can be used also for the preparation of the geminally substituted 

The reaction is allowed to continue for 24 hours. The stirrer is then stopped, and the reaction mixture is allowed to cool to room temperature. The contents of the flask are then hydrolyzed by pouring into a 1000-ml. beaker which is half-filled with ice and contains 5 ml. of 12 M hydrochloric acid.f After hydrolysis is complete, the liquid layers are separated, and the aqueous layer is washed once with benzene. The benzene layer and benzene washings are combined and washed 

The washed benzene solution is dried over anhydrous magnesium sulfate and decolorized with charcoal. The benzene is then removed by means of a rotary evaporator. The resulting yellow oil is dissolved in a minimum volume of n-pentane and the solution cooled in a Dry Ice-acetone bath. The crystals which are formed are removed and purified by sublimation at 70°C. and 0.025 mm. Hg. Yield, based upon (monophenyl)-phosphonitrile fluoride trimer, is 13 g. (71 %). Anal. Calcd. for NJ J,4(C H ) C, 39.45 H, 2.74 N, 11.51 mol. wt., 365. Found C, 39.85 H, 2.76 N, 11.58 mol. wt., 359. 

The (1,1-diphenyl) phosphonitrile fluoride trimer is a colorless crystalline solid that melts at 68.5-69.5°C. It can be recrystallized from n-pentane, n-heptane, petroleum ether, or absolute methanol. It is also soluble in diethyl ether, carbon disulfide, and chloroform, but it is insoluble in and not attacked by water. The infrared spectrum shows a strong phosphorus-nitrogen stretching mode at 1250-1265 cm. 1. Strong bands at 914-920, 900-906 cm. 1 and at 812-820 cm. 1 are associated, respectively, with phosphorus-fluorine asymmetric and symmetric stretching modes. 

The compound 1,1-N3P8F4(C6H5)2 reacts with an equimolar quantity of phenyllithium to form 1,1,3-N3PsF3(C6H5)3.2 

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