| Photo-induced reactions in metal ion-molecular complexes play animportant role in a wide range of biological, chemical, and physical processes.Ion-molecule complexes of Mg+(OCNC2H5)n and Mg+-cytosine wereproduced in a laser-ablation supersonic expansion source, followed byphotodissociation investigation in the reflection time-of-flight mass spectrometer(RTOFMS).Photodissociation action spectra of Mg+(OCNC2H5)1-3 were recorded in thespectral range of 230-440 nm. Except for minor reactive products Mg+OCN andC2H5 at short wavelengths from the photo-reaction of the singly solvatedcomplex Mg+(OCNC2H5), only evaporation products were observed from thephotodissociation of Mg+(OCNC2H5)n (n=1-3). Theoretical study was performedon the photodissociation of Mg+(OCNC2H5)1-3 at B3LYP/6-31+G** level. Thecalculated absorption spectra of Mg+(OCNC2H5)1-2 agree well with observedphotodissociation action spectra. An sp hybridization mechanism was proposedfor the complexation of Mg+ and C2H5NCO, which rationalizing the nearly linearbackbone of Mg+-O-C-N-C in the complex of Mg+(OCNC2H5).Photo-induced reactions in the magnesium cation-base molecule complex ofMg+-cytosine have been studied on both sides of the Mg+ (3 2P â†3 2S) atomictransition (～280 nm). The evaporation product, Mg+, as well as other four and fivereactive products were observed in the long and short wavelength regions,respectively. The tautomerism of neutral cytosine in gas phase was investigated byB3LYP/6-311+G** method. The ground-state geometries of the complexescomposed of magnesium cation and the low-lying tautomers of cytosine werefully optimized at the B3LYP/6-31+G** level. The bond dissociation energies(BDEs) of the complexes for the channels we observed were calculated at thesame theoretical level. Based on the calculations, the dissociation pathways of thecomplexes of Mg+-cytosine were given a reasonable interpretation.
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