Experimental evidence for gaseous diaminocarbene H2NCNH2 and its radical cation

Dissociative electron impact ionization of aminoguanidine, HNC(NH2)NHNH2 cleanly produces diaminocarbene radical cations H2NCNH+2. Their reduction by single electron transfer in neutralization—reionization mass spectrometric experiments yields the prototype nucleophilic carbene H2NC̈NH2 as a stable species in the gas phase, distinct from its isomer formamidine, H2NC(H)NH. Deuterium labelling and multiple collision experiments confirm …