| Autor: |
Folgado, José-Vicente, García, Hermenegildo, Martí, Vicente, Esplá, Mercedes |
| Zdroj: |
Tetrahedron; March 1997, Vol. 53 Issue: 13 p4947-4956, 10p |
| Abstrakt: |
Thianthrene (Eox= 1.47 V vsNHE) has been adsorbed into a series of zeolites beta (ß) and ZSM-5 in the NH4+or H+forms, having different particle size and Si/Al ratio. The resulting population of generated thianthrenium radical cation was determined by a combination of diffuse reflectance and ESR spectroscopies. From the results obtained it can be concluded: i) the process takes predominantly place in the interior of the voids (XPS measurements and lack of influence of the particle size); ii) ZSM-5 is more efficient than zeolite ß; iii) no strong acid sites are required (both NH4+and H+forms produced very similar spin concentrations); iv) the zeolite framework acts isolating the organic spins, thus avoiding diamagnetic coupling (zeolite samples do obey Curie law); and v) the population of oxidizing sites increases with the aluminum content of the zeolite. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
Full Text from ScienceDirect