A Photophysical Study of Purines and Theophylline by Using Laser-Induced Optoacoustic Spectroscopy |
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| Authors: | Daniel H Murgida Gabriel M Bilmes Rosa Erra-Balsells |
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| Institution: | Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina;Centro de Investigaciones Opticas-ClOp (CONICET-CIC), La Plata, Argentina |
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| Abstract: | Abstract— The photophysics of purinic compounds (purine, 6-meth-ylpurine, 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 φT= 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. |
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