On the Ag+-Cytosine interaction: effect of microhydration probed by IR optical spectroscopy and density functional theory

M. BERDAKIN; V. STEINMETZ; P. MAITRE; G.A. PINO

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2015 vol. 17 p. 25915 - 25915

he gas-phase structures of cytosine?Ag+ [CAg]+ and cytosine?Ag+?H2O [CAg?H2O]+ complexes have been studied by mass-selected infrared multiphoton dissociation (IRMPD) spectroscopy in the 900?1800 cm−1 spectral region using the Free Electron Laser facility in Orsay (CLIO). The IRMPD experimental spectra have been compared with the calculated IR absorption spectra of the different low-lying isomers (computed at the DFT level using the B3LYP functional and the 6-311G++(d,p) basis set for C, H, N and O atoms and the Stuttgart effective core potential for Ag). For the [CAg]+ complex, only one isomer with cytosine in the keto-amino (KA) tautomeric form and Ag+ interacting simultaneously with the C(2)[double bond, length as m-dash]O(7) group and N(3) of cytosine was observed. However, the mono-hydration of the complex in the gas phase leads to the stabilization of a two quasi-isoenergetic structure of the [CAg?H2O]+ complex, in which Ag+ interacts with the O atom of the water molecule a