Remarkable stability of tetrabenzo[a,c,g,i]fluorenyl ammonium salts in water: syntheses, reactions, and crystal structures

Deprotonation of 8bH-tetrabenzo[a,c,g,i]fluorene (8bH-Tbf), an extremely large benzannulated cyclopentadienyl derivative, by [NR3R′][OH] (R = nBu, Et; R′ = nBu, Et, Bn) leads to a series of Tbf ammonium salts of the type [NR3R′][Tbf]. These cyclopentadienide analogs were smoothly isolated from a hydrous medium and structurally characterized by single X-ray diffraction. Subsequent reactions demonstrate the high potential of derivatization by converting the presented [Tbf] anions into functionalized Tbf compounds.