Non-coordinated phenolate anions and their application in SF6activation

Weitkamp R, Neumann B, Stammler H-G, Hoge B. Non-coordinated phenolate anions and their application in SF6activation. Chemistry - A European Journal . 2020;27:460 –6464.The reaction of the strong monophosphazene base with the weakly acidic phenol leads to the formation of a phenol-phenolate anion with a moderately strong hydrogen bond. Application of the more powerful tetraphosphazene base (Schwesinger base) renders the isolation of the corresponding salt with a free phenolate anion possible. This compound represents the first species featuring the free phenolate anion [H5C6-O]-. The deprotonation of phenol derivatives with tetraphosphazene bases represents a great way for the clean preparation of salts featuring free phenolate anions and in addition allows the selective syntheses of hydrogen bonded phenol-phenolate salts. Herein we present a phosphazenium phenolate salt with a redox potential of -0.72V and its capability for the selective activation of the chemically inert greenhouse gas SF6. The performed two-electron reduction of SF6leads to phosphazenium pentafluorosulfanide ([SF5]-) and fluoride salts. © 2020 Wiley-VCH GmbH