GENERATION AND STRUCTURAL CHARACTERIZATION OF THE CATIONIC IRON-DINITROGEN COMPLEX FE(N-2)(+)

Gas-phase experiments in conjunction with CCSD(T) calculations were used to characterize the Fe(N-2)(+) complex in terms of electronic structure and binding energy. Theory clearly indicates a clear preference for an end-on structure of the N-2 ligand to the transition-metal cation, resulting in a (4) Sigma(-) state. At the highest level of theory, including estimated corrections, the binding energy amounts to 11.9 +/- 2.3 kcal/mol. From Ligand exchange reactions, equilibration measurements, and theoretical considerations we further conclude N-2 is at least 1 kcal/mol more strongly bound to Fe+ than CO2 and 1.7 +/- 1.5 kcal/mol more strongly bound that Xe. Entropy drives the replacement of N-2 by Xe in the Fe(N-2)(+) complex at 300 K.