Journal of Physical Chemistry, Vol.99, No.29, 11405-11411, 1995
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.
Keywords:COLLISION-INDUCED DISSOCIATION;TRANSFORM MASS-SPECTROMETRY;ION-CYCLOTRON RESONANCE;GAS-PHASE;BOND-ENERGIES;METAL-IONS;NITROGEN-FIXATION;BINDING-ENERGIES;CLUSTER IONS;BASIS-SETS