Coordination Chemistry – Bonding
Chapter 10: pp 377-384
HW: 17b 27 28 29

Slides:  Nov_9_inked (I had to make these fresh, as the ol’ calculatin’ machine emitted smoke and crashed).

Goals:  predict HS/LS based on pi bonding; Predict d-orbital splittings in distorted geometries; (sigma-bonding in Td symmetry)

Ligand Field Theory:  Don’t freak out when making the MO diagrams for coordination compounds.   We’ve focused on Oh symmetry for simplicity, but the principles never change.  Where you CAN get in trouble is if you try to memorize your way through the MO process – very dangerous!  Although the MO diagrams for coordination compounds are very complex if all the pi-bonding symmetry types are included, I decided that teaching would be more effective if I focused on just showing you how the pi-bonding LGOs of T2g symmetry affected the MO correlation diagram.

Remember to first make the sigma-bonding MOs (sigma and sigma-star); THEN let the pi-bonding be a perturbation, if your ligands support pi-bonding.  You know what the CFZone should look like, so it’s really just a question of how much the metal-based T2g orbitals ‘move up’ (for pi-donating ligands) or ‘move down’ (for pi-accepting ligands).  Finally, verify your d-electron count,and put these into the CFZone.