Infrared Multiple Photon Dissociation Spectroscopy of Protonated Cyameluric Acid

WALTER E. OLMEDO; LILIANA B. JIMÉNEZ; ANDRÉS F. CRUZ ORTIZ; PHILIPPE MAÎTRE; GUSTAVO A. PINO; MAXIMILIANO ROSSA

JOURNAL OF PHYSICAL CHEMISTRY A

AMER CHEMICAL SOC

Lugar: Washington; Año: 2021 vol. 125 p. 607 - 607

1089-5639

he present study reports the first structural characterization of protonated cyameluric acid ([CA + H]+) in the gas phase, which paves the way for prospective bottom-up research on the condensed-phase chemistry of CA in the protonated form. A number of [CA + H]+ keto-enol isomers can a priori be produced as a result of protonation at available N and O positions of precursor neutral CA tautomers, yet ab initio computations predict different reduced [CA + H]+ isomer populations dominating the solution and gas phases that are involved in the ion generation process (i.e., electrospray ionization). Infrared multiple photon dissociation spectra were recorded in the 990−1900 and 3300−3650 cm−1 regions and compared with theoretical [B3LYP/6-311++G(d,p)] IR absorption spectra of several [CA + H]+ isomers, providing a satisfactory agreement for the most stable monohydroxy form in the gas phase, [1358a]+, yet the contribution of its nearly isoenergetic OH rotamer, [1358b]+, can