A time-resolved diffuse reflectance study of the photo-reduction of 2,2′-bipyridine in faujasitic zeolites

Abstract

The siting location and conformation of 2,2′-bipyridine sorbed alone and co-sorbed with 1,4-diazabicyclo(2.2.2)octane (DABCO) in several faujasitic zeolites with different aluminium content were determined by a Raman spectroscopic study and Monte Carlo simulations. Theoretical and experimental results clearly indicate a trans → cis conformational change of the 2,2′-bpy molecule upon sorption into dehydrated Na n FAU ( n = 56, 85) whereas the trans conformation is retained in the purely siliceous zeolite FAU ( n = 0). The UV photolysis of 2,2′-bpy molecules sorbed alone generates a triplet excited state via singlet states, whereas in the case of co-sorbed DABCO, the photo-reduction of 2,2′-bpy by the amine leads to the radical anion.