@article{6997,
  author = {P. B. Armentrout and M. T. Rodgers and J. Oomens and J. D. Steill},
  title = {Infrared multiphoton dissociation spectroscopy of cationized serine: Effects of alkali-metal cation size on gas-phase conformation},
  abstract = {The gas-phase structures of alkali-metal cation complexes of serine (Ser) are examined using infrared multiple photon dissociation (IRMPD) spectroscopy utilizing light generated by a free electron laser, in conjunction with ab initio calculations. Spectra of Li+(Ser) and Na+(Ser) are similar and relatively simple, whereas Cs+(Ser) includes distinctive new IR bands, and K+(Ser) and Rb+(Ser) exhibit intermediate behavior. Measured IRMPD spectra are compared to spectra calculated at a B3LYP/6-311+G(d,p) level to identify the structures present in the experimental studies. On the basis of these experiments and calculations, the only conformations accessed for the complexes to the smaller alkali-metal cations, Li+ and Na+, are charge-solvated structures involving tridentate coordination to the amine and carbonyl groups of the amino acid backbone and to the hydroxyl group of the side chain, M1[N,CO,OH]. For the cesiated complex, a band corresponding to a zwitterionic structure, ZW[CO2-], is clearly visible. K+(Ser) and Rb+(Ser) exhibit evidence of the charge-solvated analogue of the zwitterions, M3[COOH], in which the metal cation binds to the carboxylic acid group. Calculations indicate that the relative stability of the M3[COOH] structure is very strongly dependent on the size of the metal cation, consistent with the range of conformations observed experimentally.},
  year = {2008},
  journal = {Journal of Physical Chemistry A},
  volume = {112},
  number = {11},
  pages = {2248-2257},
  month = {Mar},
  isbn = {1089-5639},
  url = {<Go to ISI>://000253946100014 },
  note = {ISI Document Delivery No.: 273QFTimes Cited: 2Cited Reference Count: 39},
  language = {English},
}