Pyrrole as an NMR probe molecule to characterise zeolite basicity

The 1H NMR chemical shift of the N–H group of pyrrole adsorbed on alkali metal ion exchanged FAU-type zeolites depends on the zeolite intrinsic basicity, while, as shown for zeolite LiY, the NMR of alkali metal nuclei reflects the interaction of the aromatic cycle with the cations at sites SII.