2,4,6-Triphenylpyrylium fluoride

Triphenylpyrylium fluoride (20 mmol) and the primary amine (20 mmol) in magnesium-dried EtOH/ sodium-dried benzene (lOOmL, 1 1 v/v) were heated in a Dean Stark apparaus for 12 h. The solvents were removed in vacuo (25 C/20 Torr) and the resulting oil triturated with Et20 to give w hite crystals... 

Measurement of ionization potentials has shown that 2,4,6-triphenylpyrylium salts undergo a thermal reduction in the mass spectrometer giving the corresponding free radicals. Steric properties preclude dimerization (74OMS(9)80>. This type of reduction appears to be largely independent of the nature of the anion the bromide and iodide salts behave identically. However, in the case of the tetrafluoroborate salt, adduct formation between a cation and a fluoride ion gave a minor peak. Anomalous behaviour is displayed by the perchlorates the anion effects oxidation of the cation upon evaporation giving a base peak which corresponds to [M + 0-H]+. 

---