Knowledge Bank

The construction of a custom fabricated photodissociation spectrometer permits the determination of thermodynamic properties (activation energies), reaction rates, and mechanistic details of bare metal cation mediated $\sigma $-bondactivationinthegasphase.Specifically,theproductsandratesresultingfromtheunimoleculardecompositionoftheNi$^+$Acetaldehydeadductaremonitoredafterabsorptionofaknownamountofenergy.ThetwodissociativeproductswhichareobservedinhighyieldareNi$^+$ and Ni$+$CO. The Ni$+$CO fragment ion could result from the activation of a C-C $\sigma$-bond or from the activation of a C-H $\sigma$-bond. The rate constant for the decarbonylation of Ni$+$Acetaldehyde was approximately 30 percent greater than that of the rate constant for the decarbonylation of Ni$+$Acetone. For the decarbonylation of Ni$+$Acetone, there needs to be a methide shift, whereas in the decarbonylation of Ni$+$Acetaldehyde one could have C-C insertion followed by an aldhyde H-shift. The rate-limiting step of the decarbonylation process will be discussed.