Excited-state dipole moments of some Coumarin dyes from a solvatochromic method using the solvent polarity parameter, E N T

Solvent effect on the spectral properties of dipolar laser dyes: Evaluation of ground and excited state dipole moments

“…The method based on the empirical polarity scale proposed by Reichardt [1] gave towering results with solvatochromic shift of dipolar molecules that correlate much better with microscopic solvent polarity N T E rather than the traditionally used bulk solvent polarity functions involving dielectric constant () and refractive index (n) as in the latter the error estimation of Onsager cavity radius 'a' has been minimized. The theoretical basis for the correlation as spectral shift with N T E has been developed by Ravi et al [27] and accordingly the excited state dipole moment is evaluated using the equation…”

“…SRB has been used to measure drug-induced cytotoxicity and cell proliferation for large-scale drug-screening applications [26]. Though, fluorescein dyes undergo very little nuclear reorganization, they are solvatochromic owing to the change in electronic distribution resulting in increased dipole moment in the excited state as compared to that of ground state [27]. The excited state dipole moment (e) of fluorescent dyes also establishes the tunability range of the emission energy as function of the medium.…”

Badania spektroskopowe efektów podwójnej fluorescencji w wybranym związku z grupy 1,3,4-tiadiazoli w rozpuszczalnikach organicznych oraz roztworach wodnych

“…Comparison with other compounds which demonstrate dual fluorescence leads to the conclusion that this phenomenon in FABT is not related to TICT, PICT or ESPIT and cannot be fully explained based on these theories [25][26][27][28][29][30][31][32][33][34]. The results obtained suggest that the dual fluorescence effect in FABT and similar thiadiazole derivatives is more likely resultant of both chromophore aggregation and molecular conformation.…”

“…Grabowski and remains one of the most popular theoretical models used in a large number of molecular spectroscopy studies. It has been reported that a significant change in the dipole moment of the excited molecule compared to that in the ground state is required for TICT to take place [29,30]. Molecules exhibiting effects associated with TICT states are also highly sensitive to solvent effects.…”

Spectral and quantum-mechanical characterizations of 7-amino-4-trifluoromethyl coumarin

“…Biological and chemical sensors, fluorescent probes and laser dyes, are some of their applications [8,9]. Coumarin dyes' solvatochromism is due to the change in electronic distribution resulting in an increase of dipole moments from ground state into excited state [10,11].…”