Structure and energetics in dissociative electron attachment to HFeCo3(CO)12

Here we report structural parameters on the heteronuclear transition metal complex HFeCo3(CO)(12) and its anion formed upon electron attachment, as well as the thermochemical thresholds for sequential CO loss and the loss of the apical group (as Fe(CO)(3)(-) and Fe(CO)(4)(-)). Geometrical parameters from single crystal X-ray diffraction are compared with calculated values from density functional theory calculations, for the neutral and anionic ground state of this transition metal cluster. Further, experimental appearance energies for sequential CO loss and the formation of Fe(CO)(3)(-) and Fe(CO)(4)(-) are compared to the respective calculated threshold values. Geometry optimizations were performed at the BP86/def2-TZVP level of theory while the threshold energies were calculated at the PBE0/ma-def2-TZVP level of theory. The SOMO of the anion is found to have a clear Fe-Co anti-bonding character resulting in elongation of the Fe-Co bonds and the transformation of one of the terminal Co-CO groups to a bridging Co-CO-Fe group upon electron attachment. The thermochemical threshold PBE0 calculations are concordant with the observed appearance energies and structural parameters from single crystal X-ray diffraction for the neutral molecule are well reproduced at the BP86/def2-TZVP level of theory.