Quadrupolar Dyes Based on Highly Polarized Coumarins

Abstract

The fluorescence and other photophysical parameters of highly polarized, quadrupolar bis-coumarins possessing an electron-rich pyrrolo[3,2- b ]pyrrole bridging unit are highly dependent on the linking position between both chromophores. Delocalization of the LUMO on the entire π-system results in intense emission and strong two-photon absorption.

Synthesis of azafluoranthenes by iridium-catalyzed [2 + 2 + 2] cycloaddition and evaluation of their fluorescence properties

“…The characters of the S 1 state of azafluoranthenes were found to be HOMOs of 3bu, 3bv, 3bw, and 3au extended from the amino groups to the azafluoranthene skeleton, while the LUMOs were mainly located in the azafluoranthene skeleton. Thus, the S 1 states for azafluoranthenes bearing an amino group would have a large dipole moment because of the intramolecular charge transfer character, 23,25,[48][49][50] which is consistent with the result of the Lippert-Mataga plot (Fig. 5).…”

Polarized, V-Shaped, and Conjoined Biscoumarins: From Lack of Dipole Moment Alignment to High Brightness

“…Thus, in the differentiation of the properties of compound 7 and the regioisomeric V-shaped conjoined biscoumarin, we have an example of the wider problem of the strong differentiation of properties of coumarins with substituents in the 6 and 7 positions, which already has its own literature. 6 , 46 …”

“…It can also be seen that the adjacent LUMO + 1 orbital, responsible for the formation of the bright form of compound 7 , is a characteristic feature only of the 6-nitrocoumarin core, absent in the case of 7-nitrocoumarin. Thus, in the differentiation of the properties of compound 7 and the regioisomeric V-shaped conjoined biscoumarin, we have an example of the wider problem of the strong differentiation of properties of coumarins with substituents in the 6 and 7 positions, which already has its own literature. , …”

“…Thus, in the differentiation of the properties of compound 7 and the regioisomeric V-shaped conjoined biscoumarin, we have an example of the wider problem of the strong differentiation of properties of coumarins with substituents in the 6 and 7 positions, which already has its own literature. 6,46 The two V-shaped coumarins 18 and 19 differ by way of rigidification of the bridging nitrogen atom but the results of calculating the electronic structure in the ground state does not show any major differences between them. This is confirmed by the experimental absorption and emission energies.…”

Push–pull coumarin-based one-component iodonium photoinitiators for cationic nanocomposite 3D-VAT printing

“…Due to their properties, especially their polarized structure, 1 desirable spectral properties, 2 and high photoactivity, 3 coumarin derivatives have gained interest and application in numerous research areas such as dyes for solar cells (DSSCs) 4 and optoelectronics, 5,6 fluorescent probes in materials science [7][8][9][10][11][12] and biology, 13 components of photoresponsive polymers, 14 as well as quadrupole dyes. 15 The outstanding photoreactivity has allowed coumarin to find wide photopolymerization application. Coumarin derivatives are used as photosensitizers in cationic and radical polymerization, 16 for example, to polymerize epoxy-silicones.…”