Theoretical study on the excited-state photoinduced electron transfer facilitated by hydrogen bonding strengthening in the C337-AN/MAN complexes

► Hydrogen-bonded complexes C337-AN/MAN are studied by DFT and TD-DFT methods. ► Hydrogen bonds between C337 and AN (MAN) are strengthened in states S1 and S2. ► Infrared spectral redshift confirms hydrogen bonding strengthening in S1 and S2. ► Hydrogen bonding strengthening in S1 facilitates the PET from AN and MAN to C337.