Structural identification of uric acid and its monohydrates by IR-UV double resonance spectroscopy

Abstract

We have employed IR-UV double resonance spectroscopy to identify the tautomeric and isomeric structures of uric acid and its monohydrated clusters which are produced by the techniques of laser-desorption and supersonic-jet cooling. The IR spectrum obtained for bare uric acid exhibits four distinct NH stretching transitions assignable to those of the most stable triketo form. We have also observed the two most stable monohydrated clusters, each with uric acid in the triketo form and water bonded to either the N3H or N9H site. It is demonstrated that the R2PI spectra of these monohydrates can be separated by using the IR-purified spectroscopic method.

Theoretical Study of Uric Acid and its Ions in Aqueous Solution

“…The vibrational frequencies and IR intensities of H 2 U vapor were calculated at the same B3LYP/6-311+(d,p) level of theory. However, as an approximate correction to the harmonic approximation used, the predicted wave numbers have been scaled by a factor of 0.958, following the work of Asami et al [15]. For the dipole moment and polarizabilty, as well as UV excitation spectrum, we preferred the exchange-correlation potential V xc known as statistical averaging of orbital potentials (SAOP) [16][17][18].…”

Hydrogen-bonding interactions of uric acid complexes with water/melamine by mid-infrared spectroscopy

“…In fact, the observed I on spectrum shown in Fig. 4 The UV spectra shown in Fig. 4(a) and is assigned predominantly to that of W89.…”

“…4,26 Computational methods All calculations were performed using the Gaussian 09 quantum code package. The resulting IR-depleted UV spectra enable us to examine if spectral features of other isomers are embedded in the UV spectra.…”

“…4 This enables us to acquire the IR spectra of the respective isomers. 4 This enables us to acquire the IR spectra of the respective isomers.…”

“…4,26 In this method, an IR laser with a high pulse energy (2 mJ per pulse) is tuned to a specific transition of a given isomer. 4,26 In this method, an IR laser with a high pulse energy (2 mJ per pulse) is tuned to a specific transition of a given isomer.…”