Photodissociation Studies of Mass-Selected Complex Cations Mg+(N,N-dimethylformamide)1,2

Abstract

Gas-phase complexes Mg+−[HCON(CH3)2]1,2 are mass-selected and studied by ultraviolet laser photodissociation in a time-of-flight mass spectrometer. Beside the dominant evaporation photofragments, some photoreaction products have also been detected from both complexes. Quantum mechanics calculations and deuterium-substitution experiments are employed to facilitate the structural, energetic, and mechanistic analysis of the photoreactions. For the most stable structures of the complexes, Mg+ is linked to the carbonyl oxygen atoms and situated trans to the −N(CH3)2 groups. Starting from these complex structures, photoproducts are generated through (1) H abstraction next to the carbonyl group by the photoexcited Mg+* (to form (CH3)2NCO+) and/or (2) the subsequent CO loss (to form CH3NH+CH2). For Mg+−[HCON(CH3)2]2, the further solvation tends to hold back the photoreactions because of the even more facile evaporation channels.