IONIC LEWIS SUPERACIDS IN THE GAS-PHASE .4. CF3+ INITIATED ION MOLECULE REACTION PATTERNS IN THE GAMMA-RADIOLYSIS OF CF4/N-BASES GASEOUS-MIXTURES/

A study of the gas-phase reactions between n-type nucleophiles (alcoho ls and amines) and the CF3+ ion, radiolytically (Co-60 gamma-rays) gen erated from CF4, is reported. Experiments have been carried out at 600 -700 Torr total pressure, under conditions where radical routes to the products can be safely excluded. The major products from attack of CF 3+ on the selected nucleophiles are the corresponding carbonyl derivat ives. Thus, low yields of carbonates are recovered from alcohols, whil e ureas are produced in abundant yields from secondary amines. No prod ucts are obtained from a tertiary amine, as N-methylpiperidine. In alc ohol/secondary amine mixtures, the corresponding carbamate accompanies formation of the carbonate and the urea. In alcohol/tertiary amine mi xtures, only the carbonate and the carbamate are recovered. The mechan ism of defluorination of the CF3 moiety after attack of CF3+ on the nu cleophile is discussed and compared with the behavior of CF3+ toward t he same nucleophiles, as observed under low-pressure (about 10(-6) Tor r) Fourier-transform ion cyclotron resonance conditions, and predicted by ab initio MO calculations.