Steady-State and Time-Resolved Fluorescence Studies of Anthrylacrylic Ester

The photophysical properties of Anthrylacrylic ester were investigated in various solvents using steady-state and time-resolved fluorescence techniques. The dual fluorescence was observed in various solvents of different polarity functions. The emission bands observed are around 400 nm (band I) and 480 nm (band II) for 350 nm and 390 nm excitation at low concentrations (10–5 mol·dm–3) but at higher concentrations (10–3 mol·dm–3) only the emission (band II) at 480 nm alone was observed. The emission band observed around 400 nm shifts from 390 nm to 420 nm (shift 30 nm) when the excitation wavelength was varied from 300 nm to 380 nm and the emission band at 480 nm shifts from 430 nm to 510 nm (shift 80 nm) for the change of excitation wavelength from 380 nm to 400 nm. However, both emissions were observed for 380 nm excitation at lower concentrations. Solvatochromic shifts of electronic absorption and fluorescence emissions (band I & II) as a function of polarity functions were analyzed and the changes in dipole moment of the molecule was estimated (Δμ = 3.36 D & 5.98 D). Fluorescence decays monitored over each emission maxima showed bi-exponential behavior, and yielded two lifetime components respectively in the range 0.97 - 7.1 ns (at λem = 400 nm) and 0.34 - 7.23 ns (at λem = 480 nm). Based on the steady-state and time-resolved emission measurements emission band I (400 nm) and emission band II (480 nm) are respectively assigned as due to locally excited state (Trans-forms) and due to isomers (Cis-form).