analysis of η 2 vs. η 5 bonding of the pentazolato ligand to manganese monika wiedmann april 25,...
Post on 21-Dec-2015
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Calculations Calculations were done on Mn(N5)(CO)3 with the
pentazolato ligand in both the η5 and η2 orientations.
Geometry optimization and frequency calculations were performed at the RB3LYP 6-31+G(d) level.
Single point energy calculations were then run at the RB3LYP 6-311+G(3df) level.
NBO analysis was done to visualize the interactions between Mn and its ligands.
Natural Bond Orbital Analysis
Regular quantum mechanical calculations result in delocalized molecular orbitals.
NBO takes these and transforms them into localized orbitals familiar to chemists (s, p, d, σ, σ*, π, π*).
Interactions between specific orbitals can be visualized.
Nitrogen → Mn Electron Donation
Filled N-N σ bond donates electron density to unoccupied Mn 4s orbital.
Conclusions
Manganese η2–pentazolato tricarbonyl is more stable than manganese η5–pentazolato tricarbonyl by 12 kcal/mol (in the gas phase).
The NBO program is useful for visualizing the interactions of various orbitals.
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