Dissociation of Valine Cluster Cations

0533840 - ÚFCH JH 2021 RIV US eng J - Journal Article
Tiefenthaler, L. - Ončák, Milan - Kollotzek, S. - Kočišek, Jaroslav - Scheier, P.
Dissociation of Valine Cluster Cations.
Journal of Physical Chemistry A. Roč. 124, č. 41 (2020), s. 8439-8445. ISSN 1089-5639. E-ISSN 1520-5215
R&D Projects: GA MŠMT(CZ) EF16_027/0008355
Institutional support: RVO:61388955
Keywords : Action Spectrum * Vapor Phases * 1-Methylcytosine
OECD category: Physical chemistry
Impact factor: 2.781, year: 2020
Method of publishing: Open access

Independently of the preparation method, for cluster cations of aliphatic amino acids, the protonated form MnH+ is always the dominant species. This is a surprising fact considering that in the gas phase, they dissociate primarily by the loss of 45 Da, i.e., the loss of the carboxylic group. In the present study, we explore the dissociation dynamics of small valine cluster cations Mn+ and their protonated counterparts MnH+ via collision-induced dissociation experiments and ab initio calculations with the aim to elucidate the formation of MnH+-type cations from amino acid clusters. For the first time, we report the preparation of valine cluster cations Mn+ in laboratory conditions, using a technique of cluster ion assembly inside He droplets. We show that the Mn+ cations cooled down to He droplet temperature can dissociate to form both Mn-1H+ and [Mn-COOH]+ ions. With increasing internal energy, the Mn-1H+ formation channel becomes dominant. Mn-1H+ ions then fragment nearly exclusively by monomer loss, describing the high abundance of protonated clusters in the mass spectra of amino acid clusters.
Permanent Link: http://hdl.handle.net/11104/0312093