Gas-phase C-H and N-H bond activation by a high valent nitrido-iron dication and ⟨NH⟩-transfer to activated olefins

A tetrapodal pentaclentate nitrogen ligand (2,6-bis(1,1-di(aminomethyl)ethyl)pyridine, 1) is used for the synthesis of the azido-iron(III) complex [(1)Fe(N-3)]X-2 where X is either Br or PF6. By means of electrospray ionization mass spectrometry, the dication [(1)Fe(N-3)](2+) can be transferred into the gas phase as an intact entity. Upon collisional activation, [(1)Fe(N-3)](2+) undergoes an expulsion of molecular nitrogen to afford the dicationic nitriclo-iron species [(1)FeN](2+) as an intermediate, which upon further activation can intramolecularly activate C-H- and N-H bonds of the chelating ligand 1 or can transfer an (NH) unit in bimolecular reactions with activated Clef ins. The precursor clication [(1)Fe(N-3)](2+), the resulting nitrido species [(1)FeN](2+), and its possible isomers are investigated by mass spectrometric experiments, isotopic labeling, and complementary computational studies using density functional theory.