Time-Resolved Resonance Raman Study of Biphenyl Occluded in the Supercages of Faujasitic Zeolites

The laser photolysis (248 nm, 20 ns) of biphenyl (BP, S0) occluded in the void space of faujasitic zeolites (NanFAU) , Nan(SiO2)192−n(AlO2)n with n=0, 56, 85 has been studied by time-resolved resonance Raman spectroscopy combined with time-resolved diffuse reflectance UV-visible absorption spectroscopy in the ns–μs time scale. The excitation (370 nm, 8 ns) of the RR scattering in the wavelength region of the UV electronic absorption of the transient species provides clear evidence of the radical cation (BP+) as major species for zeolites NanFAU (n=56, 85). The amount of triplet state (BP, T1) depends on the aluminum content and in a less extent on the fluence of the pump laser at the sample.