Mechanism of N/O Bond Scission of N₂O by an Unsaturated Rhodium Transient

The mechanism of formation of triplet (PNP)RhO and (PNP)Rh(N₂) (PNP = N(SiMe₂CH₂P^tBu₂)₂) from reaction of two molecules of (PNP)Rh with N₂O has been studied by DFT, evaluating mechanisms which (1) involve free N₂, and (2) which effect N/O bond scission in linearly coordinated (PNP)RhNNO. This work shows the variety of modes of binding N₂O to this reducing, unsaturated metal fragment and also evaluates why a mechanism avoiding free N₂ is preferred. Comparisons are made to isoelectronic CO₂ in its reaction with (PNP)Rh.