INTRINSIC COORDINATION PROPERTIES OF IRON IN FEO- KINETICS AT 294+( )-3 K FOR GAS-PHASE REACTIONS OF THE GROUND-STATES OF FE+ AND FEO+ WITHINORGANIC LIGANDS CONTAINING HYDROGEN, NITROGEN, AND OXYGEN/

The coordination of the electronic ground states of Fe+ (D-6) and FeO ((6) Sigma(+)) has been investigated in the gas phase with the inorga nic molecules H-2, HD, D-2, H2O, CO, NO, N-2, O-2, CO2, NO2, and N2O. Reaction rate coefficients and product distributions were measured wit h the Selected-Ion Flow Tube (SIFT) technique operating at 294 +/- 3 K and a helium buffer-gas pressure of 0.35 +/- 0.01 Torr. Except with N O2 and N2O, Fe+ was found to be unreactive: there was no evidence for the ligation of Fe+ with H-2, HD, D-2, H2O, CO, NO, N-2, O-2, and CO2 under the conditions of the experiments, and Fe+ was observed to react in a bimolecular fashion with NO2 and N2O by O-atom transfer to yield FeO+. FeO+ generally was observed to be much more reactive than Fe+. While no reactions were seen to occur with NO and O-2, FeO+ reacted wi th H-2, HD, D-2, and CO to produce Fe+ and with NO2 by O- transfer to produce NO+ + FeO2. A very slow sequential addition of two molecules w as seen with N-2. With N2O, CO2, and H2O, FeO+ was observed to add seq uentially three ligand molecules; this corresponds to the availability of three coordination sites around iron in FeO+. Rate coefficients we re measured for each addition and structures have been proposed for th e ligated FeO+. Further addition, but at a much reduced rate, was obse rved with H2O, but this was attributed to a second coordination shell involving hydrogen-bond formation. Also, experimental evidence is prov ided for the extension of the catalytic role of FeO+ in the oxidation of CO to CO2 to the ligated ions FeO-(N2O)(n)(+)with n = 1-3.