Bonding rearrangements in organometallic reactions: from orbitals to curly arrows

Reaction mechanisms include a description of both the nuclear and electronic rearrangements along the energetically most favourable pathway. Extracting the nuclear rearrangements from the outcome of quantum chemical calculations is straightforward, while it is more intricate for the electronic rearrangements. This is particularly true when changes in the bonding pattern are of interest, just as in the arrow-pushing formalism used in chemical schemes. Here, we report on our use of a simple and highly visual procedure to recover the bonding rearrangements along a reaction pathway from DFT calculations and to draw curly arrows. We show that the procedure allows us discern among mechanistic proposals in the context of organometallic reactions featuring the forming and breaking of bonds.