The photochemical reaction of excited acetophenone and benzaldehyde in the gas phase

The photochemistry of acetophenone and benzaldehyde with hydrogen donors has been studied in the gas phase. The quenching rate constants of the triplet acetophenone and benzaldehyde can be well correlated with the ionization potentials of hydrogen donors. The results suggested that the charge-transfer interaction plays an important role in the gas-phase reaction as in the case of condensed phase reaction. The slopes of Rehm-Weller plot are more stiff in the gas-phase reaction than condensed phase reaction, which indicates higher degree of charge transfer. Secondary amines were consistently better quencher of carbonyl triplet than tertiary amines, and steric effects are probably to be of importance.