Photoinduced Electron Transfer in a Prototypical Mulliken Donor-Acceptor Complex: C2H4•••Br2

We report a new dual nozzle late mixing scheme for the trapping,and interrogation of prereactive donor-acceptor complexes that is used initially to examine photoinduced electron transfer in the prototypical Mulliken donor-acceptor (halogen bonded) pi-complex, C2H4 center dot center dot center dot Br-2. Excitation into the intense charge-transfer band of the complex leads exclusively to the anti conformer of the single reaction product, 1,2-dibromoethane, in agreement with the Mulliken theory of electron transfer.