Synthesis and characterization of perfluorinated nitriles and the corresponding sodium 5-perfluoroalkyltetrazolate salts

The high-yield syntheses of trifluoroacetonitrile (1a), pentafluoropropionitrile (1b) and heptafluorobutyronitrile (1c) under mild reaction conditions using readily available starting materials (trifluoroacetamide, pentafluoropropionamide, heptafluorobutanamide) are described. Furthermore, the reactions of the perfluoroalkyl nitriles with sodium azide in acetonitrile forming sodium 5-trifluoromethyltetrazolate (2a), sodium 5-pentafluoroethyltetrazolate (2b) and sodium 5-heptafluoropropyltetrazolate (2c) were undertaken. The 5-perfluoroalkyltetrazolate salts were characterized using vibrational (Raman and infrared) and multinuclear (¹³C, ^14/15N, ¹⁹F) NMR spectroscopy, differential scanning calorimetry, mass spectrometry and elemental analysis. Additionally, the single crystal X-ray structure of the monohydrate of 2a was determined. Crystal data: 2a·H₂O: monoclinic, C2/m, a = 18.8588(6) Å, b = 7.1857(2) Å, c = 9.3731(3) Å, β = 102.938(3)°, V = 1237.94(7) Å³, Z = 8, D_calc = 1.911 g cm⁻³.