The gas-phase interactions of TEMPO radicals with Fe+ ions.
The gas-phase ligation of the 2,2,6,6-tetramethylpiperidyl-1-oxide (TEMPO) radical (1) and its 4-hydroxy derivative (2) with Fe+ ions in a 3 T Fourier transform ion cyclotron resonance (FTICR) mass spectrometer was investigated. Triple ligation may occur: the first ligation produces a transient species prone to either charge exchange or a stable second ligation; the third ligand adds slowly, with fragmentation. 1 and 2 differ in that 1 binds exclusively at the nitroxyl oxygen while 2 also binds at the OH site after the loss of a H-radical. Calculations combined with steric considerations support such a mechanism for 2. The site and the mechanism of the important side reaction of 1 that involves OH addition from a water impurity to yield an FeR2 + species remain unexplained.
The Ruder Bosković Institute, Bijenicka 54, HR-10002 Zagreb, Croatia.
Snjezana P
SP
Kazazić
Leo
L
Klasinc
Marko
M
Rozman
Dunja
D
Srzić