Photoinduced charge separation of methylphenothiazine in vanadium- and titanium-containing AlPO-5 and AlPO-11

The photoinduced charge separation of methylphenothiazine in aluminophosphate type 5 and 11 (AlPO-5 and AlPO-11) containing Ti(TAPO-5, 11) and V(VAPO-5,11) is studied with near UV irradiation at room temperature. Methylphenothiazine cation radicals (PC1+) are produced in MAPO-5, 11(M = Ti4+ and V5+) molecular sieves, and characterized by electron spin resonance and diffuse reflectance UV-vis spectroscopy. MAPO-5,11 molecular sieves are shown to be effective heterogeneous hosts to accomplish long-lived photoinduced electron transfer of methylphenothiazine (PC1) molecules at room temperature. A series of MRPO-5,11 samples are synthesized that increase the PC1 photoionization efficiency in comparison with AlPO-5,11, The photoionization efficiency increases in the order AlPO-11 < AlPO-5 < TAPO-11 < TAPO-5 < VAPO-11 < VAPO-5. it is found that the photochemistry in MAPO-5,11 molecular sieves depends on the type of transition metal ion and the AlPO pore size.