title: Solving the Tautomeric Equilibrium of Purine through Analysis of the Complex Hyperfine Structure of the Four (14)N Nuclei.
abstract: 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 (14)N 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.
authors.affiliation: Istituto per lo Studio dei Materiali Nanostrutturati (ISMN), Sezione di Bologna CNR, Via Gobetti 101, I-40129, Bologna, Italy.
authors.forename: Laura B
authors.initials: LB
authors.lastname: Favero
authors.affiliation: Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU) , Apartado 644, E-48080 Bilbao, Spain.
authors.forename: Iciar
authors.initials: I
authors.lastname: Uriarte
authors.affiliation: Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU) , Apartado 644, E-48080 Bilbao, Spain.|Dipartimento di Chimica, "G. Ciamician" dell'Università , Via Selmi 2, I-40126 Bologna, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Spada
authors.affiliation: Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU) , Apartado 644, E-48080 Bilbao, Spain.
authors.forename: Patricia
authors.initials: P
authors.lastname: Écija
authors.affiliation: Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU) , Apartado 644, E-48080 Bilbao, Spain.|Dipartimento di Chimica, "G. Ciamician" dell'Università , Via Selmi 2, I-40126 Bologna, Italy.
authors.forename: Camilla
authors.initials: C
authors.lastname: Calabrese
authors.affiliation: Dipartimento di Chimica, "G. Ciamician" dell'Università , Via Selmi 2, I-40126 Bologna, Italy.
authors.forename: Walther
authors.initials: W
authors.lastname: Caminati
authors.affiliation: Departamento de Química Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU) , Apartado 644, E-48080 Bilbao, Spain.
authors.forename: Emilio J
authors.initials: EJ
authors.lastname: Cocinero