A Combined Experimental and Theoretical Study of Iron Dinitrogen Complexes: Fe(N2), Fe(NN)x (x=1-5), and Fe(NN)3-

Reactions of laser-ablated iron atoms with dinitrogen in excess neon produce the iron dinitrogen complexes Fe(N-2), Fe(NN)(x) (x = 1-5), and Fe(NN)(3)(-) through capture of the ablated electron. The reaction products are characterized on the basis of isotopic shifts, mixed isotopic splitting patterns, stepwise annealing, change of reagent concentration and laser energy, CCl4-doping experiments, and comparison with theoretical predictions from density functional theory calculations. The overall agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts supports the identification of these species from the matrix infrared spectra. Natural bond orbital analysis and reaction pathways for the formation of the products are discussed.