Low-temperature luminescence of purine derivatives: Salt effects
Xanthines (caffeine, theophylline and theobromine) and purine have very low quantum yields of fluorescence in ethanol and acetonitrile solutions at room temperature (Φf < 10-3; naphthalene as fluorescence reference). At 77 K xanthines show good fluorescence and phosphorescence spectra, while...
Guardado en:
| Autores principales: | , |
|---|---|
| Formato: | JOUR |
| Materias: | |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00222313_v85_n1-3_p129_Murgida |
| Aporte de: |
| Sumario: | Xanthines (caffeine, theophylline and theobromine) and purine have very low quantum yields of fluorescence in ethanol and acetonitrile solutions at room temperature (Φf < 10-3; naphthalene as fluorescence reference). At 77 K xanthines show good fluorescence and phosphorescence spectra, while purine only shows phosphorescence. Working at low temperature, the effect of the properties of the solid matrix (solvent composition and the presence of inorganic salts) on the emission spectra were studied. It was observed that the addition of inorganic salts changes the optical properties of the matrix (snowed matrix, cracked matrix, etc.) as well as produces heavy atom effect. These effects are opposite in the case of fluorescence, but are co-operative for phosphorescence. © 1999 Elsevier Science B.V. All rights reserved. |
|---|