Concerning the ‘Wanzlick equilibrium’

A negative crossover experiment performed in the 1960s which ruled out Wanzlickʹs tetraaminoethylene–diaminocarbene equilibrium gave erroneous results, according to a recent claim by Denk. In response, this system has been reinvestigated. When potassium hydride is present to preclude electrophilic catalysis, no crossing over occurs and starting tetraaminoethylenes are recovered unchanged. The original conclusion regarding the proposed equilibrium is thus reaffirmed.