Solving the Tautomeric Equilibrium of Purine through Analysis of the Complex Hyperfine Structure of the Four 14N Nuclei

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• 作者：Laura B. Favero ; Iciar Uriarte ; Lorenzo Spada ; Patricia Écija ; Camilla Calabrese ; Walther Caminati ; Emilio J. Cocinero
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2016
• 出版时间：April 7, 2016
• 年：2016
• 卷：7
• 期：7
• 页码：1187-1191
• 全文大小：309K
• ISSN：1948-7185

文摘

The rotational spectra of two tautomers of purine have been measured by pulsed jet Fourier transform microwave spectroscopy coupled to a UV ultrafast vaporization system. The population ratio of the two main tautomers [N(7)H]/[N(9)H] is about 1/40 in the gas phase. It contrasts with the solid state where only the N(7)H species is present, or in solution where a mixture of both tautomers is observed. For both species, a full quadrupolar hyperfine analysis has been performed. This has led to the determination of the full sets of diagonal quadrupole coupling constants of the four ¹⁴N atoms, which have provided crucial information for the unambiguous identification of both species. This work shows the great potential of microwave spectroscopy to study isolated biomolecules in the gas phase. All the work was supported by theoretical calculations.