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Photochemistry resulting from excitation of a d–d transition at 575 nm between ligand-field states in the gas-phase [CuII(bpy)(serine–H)]+ · complex generated by electrospray ionization is reported. These results are discussed in terms of a reaction scheme proposed by Turecek and co-workers [C.L. Gatlin, F. Turecek, T. Vaisar, J. Mass Spectrom. 30 (1995) 1617] for collisionally activated dissociation of this complex at low center-of-mass collision energies under multiple-collision conditions. Three photofragment ions are observed, corresponding to elimination of formaldehyde, stepwise loss of formaldehyde followed by ·OC(OH)CHNH2, and transfer of a hydroxyl group to the CuII ion accompanied by loss of H2CCHNH2CO2. A fourth fragmentation channel reported by Turecek and co-workers corresponding to decarboxylation and associated dehydration is also observed at moderate center-of-mass collision energies under single-collision conditions but is absent in the laser photofragmentation difference mass spectrum resulting from excitation of [CuII(bpy)(serine–H)]+ · at 575 nm. |
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