Activation of Acetonitrile with (C 2 F 5 ) 3 PF 2 and Amines

Acetonitrile is deprotonated by a combination of the strong Lewis acid (C 2 F 5 ) 3 PF 2 and triethylamine. The resulting cyanomethyl function is bound to the phosphorus moiety, affording the highly stable salt [HNEt 3 ][P(C 2 F 5 ) 3 F 2 (CH 2 CN)]. Salt metathesis reactions furnished the corresponding [Cu(MeCN) 2 ] + and [Ag(MeCN)] + derivatives in which the CH 2 CN substituent of the anion [P(C 2 F 5 ) 3 F 2 (CH 2 CN)] − coordinates to the metal. An investigation of the gas separation capability of the silver salt [Ag(MeCN)][P(C 2 F 5 ) 3 F 2 (CH 2 CN)] shows an uptake of 1.7 equivalents of isobutene from a propane/isobutene mixture. The reaction of (C 2 F 5 ) 3 PF 2 with acetonitrile and diethylamine furnishes [P(C 2 F 5 ) 3 F 2 {NHC(CH 3 )NEt 2 }]—a phosphate featuring an amidine ligand which formally results from hydroamination of acetonitrile by HNEt 2 . Exchange of HNEt 2 with the primary amines H 2 NPh and H 2 NBu leads to comparable amidine salts that exhibit a solvent‐dependent conformational isomerism.