?Gas Phase Structure and Fragmentation of [Cytosine-Guanine]Ag+ Complex Studied by Mass-Resolved IRMPD Spectroscopy?

A. CRUZ ORTIZ; R. A. JARA-TORO; M. BERDAKIN; E. LOIRE; G. A. PINO *

EUROPEAN PHYSICAL JOURNAL D

SPRINGER

Lugar: Berlin; Año: 2021 vol. 75

1434-6060

The silver-mediated cytosine-guanine [CGAg]+ pair was characterized by mass-resolved IRMPDspectroscopy and electronic structure calculations at the DFT level. Three fragments were observed:[GAg]+, [CAg]+ and [CH]+. From the mass-resolved IRMPD spectra recorded on the mass of each fragment,two isomers of the [CGAg]+ complex were identified. The most populated isomer is a Hoogsteenstructure [HooAg]+ between canonical cytosine (CKA(1)) and canonical guanine (GKA(9)), while thesecond isomer is an altered-Hoogsteen-like pair [*HooAg]+ in which guanine is in a non-canonical form(GKA(7)). The determined yields of each fragment are strongly dependent of the isomer of the precursorion because of the fragmentation energy of the different channels. Finally, the [CH]+ is suggested to beproduced by a metal-assisted proton transfer from guanine to cytosine preceded by an isomerization of the[HooAg]+ isomer.