Solvent polarity induces significant bathochromic shift on (4Z,4'Z)-4,4'- (((phenylazanediyl) bis (4,1-phenylene)) bis (methaneylylidene)) bis (2- phenyloxazol-5(4H)-one)

Abstract

Abstract A new environment-sensitive fluorescent probe (4Z, 4ʹZ)-4, 4ʹ-(((phenylazanediyl) bis (4, 1-phenylene)) bis (methanylylidene)) bis (2-phenyloxazol-5(4H)-one) (PPMP) is reported. PPMP emits light in the 508 to 644 nm region, making it a workable fluorescent probe. The molecule exhibits a substantial bathochromic shift with changing solvent polarity. The results are analyzed in terms of Onsager's reaction field theory. Bilot–Kawski, Lippert–Mataga, Bakhshiev, and Reichardt correlations are used to estimate the ground and excited state dipole moments. The results show that the predicted dipole moment of the excited state is significantly greater than that of the ground state. Gas phase quantum mechanical calculations based on density functional theory support the experimental results. This remarkable stability in a polar solvent, of the excited state, compared to the ground state, causes a significant bathochromic shift.