1,4,5,8‐Tetrakis(dimethylamino)naphthalene: Synthesis, Structure, “Proton Sponge” and Electron Donor Properties

Abstract

The “double proton sponge” 1 undergoes diprotonation by strong acids (pKa(1), = 9.8, pKa(2) = 4.9; dimethyl sulfoxide scale) and is a strong electron donor (Eox = − 0.501 V; Fc/Fc⊕ = 0.0 V). X-ray structure analyses show that the pronounced twisting of 1 around the central C(4a)–C(8 a) bond (1 8.8°) is suppressed by the diprotonation and the accompanying formation of two strong N …︁ H …︁ N hydrogen bonds.