Synthesis, Characterization, and Photophysical Investigation of a Dyad Comprising 8‐Methyl‐2‐phenylimidazo[1,2‐ <i>a</i> ]pyridine and <i>N</i> ‐methyl Maleimide for Photoinduced Electron Transfer

Abstract The focus of the present work is to develop a novel donor‐acceptor dyad consisting of 8‐methyl‐2‐phenylimidazo[1,2‐ a ]pyridine (IP) as electron donor and N ‐methyl maleimide (NMM) as electron acceptor. Keeping this in view, preliminary photophysical properties of IP and NMM are investigated in liquid medium by using steady‐state and time‐resolved spectroscopic techniques. The dyad IP‐NMM is synthesized and its material characterizations are carried out by using 1 H NMR, 13 C NMR, FT‐IR and mass spectrometry. Steady‐state and time‐resolved spectroscopic measurements are carried out to investigate the photophysical properties of the IP‐NMM dyad in liquid medium. A broad absorption band in the low‐energy region indicates the formation of ground state intramolecular charge transfer (ICT) complex in the IP‐NMM dyad. The photoexcited ICT complex of the IP‐NMM dyad gives rise to a broad fluorescence emission band at an even lower energy region. Interestingly, dual fluorescence emission is observed from the excited ICT complex of the IP‐NMM dyad due to conformational heterogeneity in the excited state. Our observations indicate the occurrence of photoinduced intramolecular electron transfer (ET) in the IP‐NMM dyad with a first‐order ET rate constant ∼ 10 10 s −1 in liquid medium.