Rational design and synthesis of 3-heteroaromatics coumarin molecules with unusual solution and solid dual efficient luminescence

Conjugating Coumarin with Tetraphenylethylene to Achieve Dual‐State Emission for Reversible Mechanofluorochromism and Live Cell Imaging

“…A slight modification of CT by introduction of N, N‐diethylamino unit at the 7‐position of coumarin results in NCT with significantly improved emission efficiency, showing a Φ FL of up to 0.22 (λ em,THF =478 nm). This can also be understood that the electron push‐pull structure between the diethylamino group and coumarin could further improve intramolecular charge transfer (ICT) processes to enhance their molar absorption coefficient [19] ( ϵ CT , THF =2.2×10 4 M −1 cm −1 , ϵ NCT , THF =3.6×10 4 M −1 cm −1 ) (Table S2) and the fluorescence performance [20] . In addition to the emission intensity, in comparison with CT , the enhanced electron transition within the molecules of NCT also leads to largely redshifted emission in both solution and the solid state (Table S2).…”

“…This can also be understood that the electron push-pull structure between the diethylamino group and coumarin could further improve intramolecular Chemistry-A European Journal charge transfer (ICT) processes to enhance their molar absorption coefficient [19] (ɛ CT, THF = 2.2 × 10 4 M À 1 cm À 1 , ɛ NCT, THF = 3.6 × 10 4 M À 1 cm À 1 ) (Table S2) and the fluorescence performance. [20] In addition to the emission intensity, in comparison with CT, the enhanced electron transition within the molecules of NCT also leads to largely redshifted emission in both solution and the solid state (Table S2). Further, the insertion of an additional phenyl linker between the 7-(diethylamino)coumarin and TPE units results in NCPT exhibiting stronger fluorescence (Φ THF = 0.44) as compared to NCT.…”

Synthesis and a TD-DFT study of a series of novel 3-imidazolyl-substituted coumarin molecules with large Stokes shifts

“…17,18 In general, the structure of 3-substituted coumarin is similar to that of trans -stilbene, with good molecular rigidity and π-conjugated electron delocalization, which further enhance its optical performance. 19–21 To date, the imidazolyl[1,2-α]pyridine moiety has been reported to show excellent photophysical properties, such as large Stokes shift and good photostability. 22–24 Furthermore, imidazopyridine has been found to be a basis for the development of new organic luminescent materials 25,26 and an ideal fluorescent group for the construction of fluorescent sensors.…”