title: A photophysical study of purines and theophylline by using laser-induced optoacoustic spectroscopy.
abstract: The photophysics of purinic compounds (purine, 6-methylpurine, 6-aminopurine [adenine], 6-chloropurine, 6-methoxypurine) and theophylline in acetonitrile solution were studied by pulsed laser-induced optoacoustic spectroscopy (LIOAS) exciting at 266 nm. The effect of O2, Xe and MnCl2 on the photophysical behavior of these compounds was studied; as well, the formation quantum yield of purine and 6-methylpurine triplet states were determined, with phi T = 0.88 +/- 0.03 for both compounds. Multiphotonic and depletion processes were observed at high laser fluences. In order to explain this behavior, theoretical UV-visible absorption electronic spectra from both the S0 and S1 state have been calculated for purines and theophylline by using the semiempirical PM3 and ZINDO/S methods.
authors.affiliation: Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Agrentina. murgida@quimor.qo.fcen.uba.ar
authors.forename: D H
authors.initials: DH
authors.lastname: Murgida
authors.forename: G M
authors.initials: GM
authors.lastname: Bilmes
authors.forename: R
authors.initials: R
authors.lastname: Erra-Balsells
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D007834:Lasers; D010777:Photochemistry; D011687:Purines / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods; D013806:Theophylline / Q000737:chemistry*
chemical_list: D011687:Purines; D013806:Theophylline