Deep-red/NIR emitting coumarin derivatives - Synthesis, photophysical properties, and biological applications

Deep Red to NIR Emitting Xanthene Hybrids: Xanthene‐Hemicyanine Hybrids and Xanthene‐Coumarin Hybrids

“…Various deep red to NIR chromophores/fluorophores such as squaraine, [19][20][21] azo, [22][23][24] styryl, [25][26][27] perylene, [28][29][30] BODIPY, [31][32][33] aza-BODIPY, [32,34,35] cyanine, [36][37][38] coumarin, [39,40] and xanthene [41][42][43] are reported having either absorption or emission or both lying in the deep-red to NIR. A few such fluorophores are presented in Figure 1.…”

A promising small-sized near-infrared absorbing zwitterionic dye for DSSC and NLO applications: DFT and TD-DFT approaches

“…To improve DSSC (dye-sensitized solar cell) device performance, researchers have focused on producing panchromatic dyes with absorption spectra extending into the near-infrared (NIR) region by harnessing more solar energy. 1 In this context, various organic dye sensitizers have been studied and described in the literature, including coumarin, 2 porphyrin, 3–5 phthalocyanine, 6–8 diketopyrrolopyrrole, 9–11 phenoxazine, 12–14 squaraine, 15–17 BODIPY, 18–20 perylene, 21,22 and tetrahydroquinoline 23 units. Nevertheless, despite their overall photocurrent response, most studied NIR dyes have inappropriate highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) situated either above the electrolyte redox potential and/or below the conduction band of TiO 2 or both.…”

“…On the other hand, it is well known that a dye can be considered a good non-linear optical (NLO) material when it absorbs more and more in the red region. 2 Apart from absorption, greater dipole moments and thermal stabilities are the other crucial requirements that need to be fulfilled by the dyes to be used as an NLOphoric material as well as for DSSC sensitizers. 47,48 Hence we think that these dyes are potential candidates for use in DSSCs and NLO.…”

Exploring Structure–Activity Relationships in Photodynamic Therapy Anticancer Agents Based on Ir(III)-COUPY Conjugates

“…Examples of this strategy include the conjugation and/or integration of cyclometalated Ir­(III) complexes with organic fluorophores such as boron-dipyrromethene (BODIPY) − porphyrin, xanthene, and rhodamine derivatives . Coumarins, which are also well-known anticancer scaffolds − and the basis for the development of novel organic fluorophores, have also been covalently attached to Ir­(III) complexes and used as cyclometalating ligands. − In this context, we have been pioneers in describing a novel class of PDT agents based on the conjugation of a far red-emitting COUPY coumarin to a cyclometalated Ir­(III) complex (compounds 1a and 2a , respectively, in Figure ). , The resulting Ir­(III)-COUPY conjugate (compound 3a ) was found to be non-cytotoxic in the dark but highly photocytotoxic after irradiation with visible light, even under hypoxia, the latter being attributable to the selective generation of type I superoxide anion radicals .…”