The fluorescence quenching mechanism of coumarin 120 with CdS nanoparticles in aqueous suspension

Are the orientation and bond strength of the RCO2−⋯M link key factors for ultrafast electron transfers?

“…11,12 The K 11 (2) Previous X-ray data indicated a "straight up" geometry of the CF 3 CO 2 ‾•••M 3 unit with ionic Pd•••O distances of 2.57 to 3.06 Å with the CO 2 unit placed closer to one of the Pd-Pd bond. 10 In the absence of X-ray data, the optimized geometries of the assemblies were calculated using DFT and confirmed the expected geometry ( In order to verify whether the quenching is dominantly static, a mixed dynamic-static model was used, 14 ]. Because the V values are much larger than those for K D , the static quenching dominates the overall mechanism, and unsurprisingly, K 11 and K 12 are similar to V. In order to confirm this conclusion, this same analysis was performed on the assemblies' fluorescence at 77 K (i.e.…”

“…13 Values of n = 0.97 (MCP) and 1.83 (DCP) are obtained, which are consistent with the number of carboxylates on the dyes. In order to verify whether the quenching is dominantly static, a mixed dynamic-static model was used, 14 which is derived from a sphere of action quenching model:…”

Microwave assisted synthesis, characterization and investigation of antibacterial activity of 3-(5-(substituted-phenyl)-4,5-dihydro-1H-pyrazol-3-yl)-2H-chromen-2-one derivatives

“…Coumarin framework was reported as new protector of amyloid beta-induced neurotoxicity through the mitochondrial-dependent pathway (Song et al, 2013). In addition, they are widely used as food additives (Wei et al, 2018), chiroptical (Delcourt et al, 2019), perfumes, cosmetics, pharmaceuticals (Pereira et al, 2018), insecticides, optical brightening agents (Chatterjee & Seth, 2013), dispersed fluorescent and laser dyes (Acar et al, 2015). In a similar manner, the use of pyrazole as precursor for the synthesis of bioactive motifs (El Azab et al, 2019) and evaluation of their chemical behaviours have gained more importance in the recent decades for tumor cell growth inhibition (Cui et al, 2019) and agricultural (Venkateswarlu et al, 2018) applications.…”

Microwave-Assisted Synthesis and Biological Evaluation of Some Coumarin Hydrazides

“…Also, coumarins are used as food additive and cosmetics industry (15). The general commercial application of coumarins is the use of dispersed fluorescent brightening agents and as dyes for tuning lasers (16)(17)(18). A few coumarin-based derivatives acenocoumarol, dicoumarolum, and hymecromone which are approved for therapeutic purposes in the clinic are given below (Figure 1.)…”