Infrared Multiple Photon Dissociation Spectroscopy of Protonated Cyameluric Acid

OLMEDO, WALTER E.; JIMENEZ, LILIANA B.; CRUZ-ORTIZ, ANDRÉS F.; MAITRE, PHILIPPE; PINO, GUSTAVO A.; ROSSA, MAXIMILIANO

JOURNAL OF PHYSICAL CHEMISTRY A

AMER CHEMICAL SOC

Lugar: Washington; Año: 2021

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 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 absorptiom 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]+, cannot be neglected. This is indicative of the occurrence of [CA+ H]+ isomer interconversion reacti