An Examination of Linear Solvation Energy Relationships

Determination of the Formation of Dark State via Depleted Spontaneous Emission in a Complex Solvated Molecule

“…Compared to the absorption and emission spectra of LDS 751 in weak polar aprotic chloroform, the maxima of absorption shift to the blue and those of fluorescence shift to the red were observed when LDS 751 was dissolved in polar aprotic acetone and DMSO solvents, indicating the decreased solvent stabilization of S 1 relative to S 0 and increased charge separation in the excited state. 37 The large Stokes shift has been reported as the result of solvation and conformational relaxation correlated to the solvent polarity. To tentatively assign the dual fluorescence peaks around 680 and 730 nm, the potential energy surface calculations along C-C and C-N twisting coordinates of LDS 751 have been carried out for the ground state and excited states by using density functional theory (DFT) and timedependent DFT (TD-DFT) methods as implemented in the Gaussian 03 package.…”

“…The value of R obtained, about 0.60, by the fitting further indicates such a low-energy barrier during isomerization. 37 The barrier-crossing flux could be promoted by the faster solvation and SEP. The stimulated emission then become efficient when the wave packets move to the final relaxed dark TICT state surface after the faster decrease of the total available energy in the molecule above the central C-C twisting barrier, leading to the faster isomerization about 0.39 ps in low viscous acetone compared to the slower isomerization about 1.19 ps in high viscous DMSO.…”

Investigation of contrasting hydrogen bonding pattern of 3-(phenylamino)-cyclohexen-1-one with solvents in the ground and excited states

“…The absorption maxima and emission maxima of locally excited state (LE) of the probe in different solvents have been reported in Table 2. The Kamlet-Taft solvent parameters, viz, the polarizibilities (p ⁄ ), hydrogen bond donor abilities (a) and hydrogen bond acceptor abilities (b) of the solvents along with the Reichardt solvent parameters, E T (30) of the corresponding solvents have been taken from literature [28,29,35] and are reported in the same table. It has been observed that both the absorption and emission maxima of the probe change with changes in dielectric constant (e) of the solvents but no specific trend has been ob- Fig.…”

“…Section 3b deals with the result obtained in the steady state spectral studies. In Section 3c the linear free energy relationship (LFER) based Kamlet-Taft analysis [28,29] to model the absorption and emission maxima of the probe with solvent parameters has been described. In the section 4 the conclusions made from the present studies have been summarized.…”

“…The role of different solvent parameters, viz., the polarizibilities (p ⁄ ), hydrogen bond donor abilities (a) and hydrogen bond acceptor abilities (b) on the photophysics of PACO has been undertaken through Kamlet-Taft analysis [28,29]. Qualitative Lippert-Mataga analysis [4] has also been performed.…”