Accessing [g]-Face π-Expanded Fluorescent Coumarins by Scholl Cyclization

Abstract

Face π-expanded coumarins are synthesized by employing the Scholl cyclization method. These new arene-annulated dipolar coumarins display interesting absorption and fluorescent properties. The large Stokes shifts, tuneable fluorescent quantum yields, and high photostability reveal promise in bioimaging application.

Synthesis and luminescence properties of functionalized V-shaped bis-coumarin derivatives

“…coumarin fused with arenes/heteroarenes) have attracted considerable attention due to their extended conjugation and possible utility in photonics, and are expected to provide several advantageous features over corresponding simple coumarins, such as larger Stokes shift, longer emission wavelength and higher quantum yield. [21][22][23][24][25] Nitisha and P. Venkatakrishnan 24 exploited the Scholl cyclization method to synthesize various [g]-face areneannulated dipolar coumarins; these arene-annulated dipolar coumarins exhibited better absorption and emission characteristics (large Stokes shifts, tunable fluorescent quantum yields and high photostability) compared to simple coumarins or benzocoumarins. Heterocycle-fused coumarin derivatives are another important emerging class of p-extended coumarins, in which various heterocycle units are fused to the coumarin skeleton to cause the resulting compounds to exhibit promising or even unprecedented properties.…”

Janus-Type AIE Fluorophores: Synthesis and Properties of π-Extended Coumarin-Bearing Triskelions

“…Their photophysical properties are promising for laser dyes [ 9 , 10 , 11 ], molecular sensors [ 12 , 13 , 14 ], and solar cells [ 15 ]. Furthermore, numerous extended coumarin dyes have been synthesized, and the photophysical properties based on their rigid and planar structures have been described [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. Conversely, unusual coumarin dyes with helical geometries have also been reported; these compounds represented a platform for the development of molecular chiral dopants [ 25 , 26 , 27 ].…”

AIEE-active V-shaped fused-biscoumarins: synthesis, photophysical and electroluminescence properties

“…[19][20][21][22][23] Heterocycle-fused coumarin derivatives with the p-extended conjugation systems possess promising photophysical properties in comparison with the simple coumarin derivatives. [24][25][26][27][28][29][30] Among the heterocycle-fused coumarins, V-shaped fused-biscoumarins have attracted significant attention due to their distinguished properties, such as bathochromic-shift in the emission and excitation wavelengths, colorimetric properties, and larger Stokes shift, [31][32][33][34][35] and the photophysical properties and applications of V-shaped fused-biscoumarins are strongly dependent on the fused coumarin ring systems. However, V-shaped fusedbiscoumarins have larger rigid conjugated planes in comparison with the simple coumarins, and they are more prone to forming strong intermolecular p-p stacking interactions in the aggregated state, resulting in aggregation-induced fluorescence quenching, which could limit their application in the field of organic optoelectronic devices.…”