Photochemistry of 4,4′-Bipyridine. Nanosecond Absorption and Raman Study of the Hydrogen Atom Abstraction from Methanol and 2-Propanol.

The transients that are produced in the photolysis of 4,4'-bipyridine (44BPY) in methanol and in 2-propanol have been examined by use of transient absorption and time-resolved resonance Raman spectroscopies in the nanosecond time range. 4,4'-Bipyridine undergoes photoreduction by these alcohols, leading to the hydrogen adduct radical 44BPYH . . The reaction arises via quenching of the T 1 state of 44BPY by the abstraction by a nitrogen atom of a hydrogen atom from methanol (k Q =1.05'710 5 M -1 s -1 ) or 2-propanol (k Q =2.4'710 5 M -1 s -1 )