Simulation of luminescent of excited-state intramolecular proton-transfer dyes based on functionalized bipyridine derivatives

Four new [2,2ʹ-bipyridyl]-3,3ʹ-diol (BP(OH)2) derivative by –CN substituents is recommended as useful modifications of the parent structure. The excited state intramolecular- proton transfer process (ESIPT) has been characterized for BP(OH)2s with the use of computational methods. It has been determined that two tautomeric form of BP(OH)2 exists: in the ground and singlet excited states dienol (DE) and in the lowest excited triplet state diketo (DK). Their photophysical characteristics of new compound was studied. The S1-S0 and T1-S0 transition energies of BP(OH)2s from its DE and DK forms computed. In addition, the occurrence of ESIPT of BP(OH)2s is supported by the calculated T1-S0 transition energies. –CN substituent effect in BP(OH)2 on the ESIPT have investigates and demonstrates phosphorescence with a large Stokes shift.