Unfolding of Hydrated Alkyl Diammonium Cations Revealed by Cryogenic Ion Mobility-Mass Spectrometry. Academic Article uri icon


  • Hydration of the ammonium ion plays a key role in determining the biomolecular structure as well as local structure of water in aqueous environments. Experimental data obtained by cryogenic ion mobility-mass spectrometry (cryo-IM-MS) show that dehydration of alkyl diammonium cations induces a distinct unfolding transition at a critical number of water molecules, n = 21 to 23, n = 24 to 26, and n = 27 to 29, for 1,7-diaminoheptane, 1,8-diaminooctane, and 1,10-diaminodecane, respectively. Results are also presented that reveal compelling evidence for unique structural transitions of hydrated ammonium ions associated with the development of the hydrogen-bond network around individual charged groups. The ability to track the evolution of structure upon stepwise dehydration provides direct insight into the intricate interplay between solvent-molecule interactions that are responsible for defining conformations. Such insights are potentially valuable in understanding how ammonium ion solvation influences conformation(s) of larger biomolecules.

published proceedings

  • J Am Chem Soc

author list (cited authors)

  • Servage, K. A., Fort, K. L., Silveira, J. A., Shi, L., Clemmer, D. E., & Russell, D. H.

citation count

  • 19

complete list of authors

  • Servage, Kelly A||Fort, Kyle L||Silveira, Joshua A||Shi, Liuqing||Clemmer, David E||Russell, David H

publication date

  • July 2015