A STUDY ON THE SPECTROSCOPY AND PHOTOPHYSICS OF N-PHENYL PYRROLE AND N-PHENYL PYRAZOLE

Comprehensive spectroscopic and photophysical studies of N-phenyl pyrr ole (PPr) and N-phenyl pyrazole (PPz) in different solvents show that a new emission band appears due to aggregation of PPr in water. The pr esence of beta-cyclodextrin (beta-CD) in aqueous solution of PPr cause s deaggregation but the twisted intramolecular charge transfer emissio n ceases due to the cavity effect. In PPz, aggregation and TICT emissi on are absent. Protonation in PPz is restricted to a single site only at very high acid concentration. Both the molecules are planar in the ground state.