The invalidity of the photo-induced electron transfer mechanism for fluorescein derivatives

Abstract

The ground and excited state geometries, the excitation and emission energies for a series of fluorescein derivatives in aqueous solutions have been investigated using time-dependent density functional theory (TD-DFT) with B3LYP and a long-range corrected CAM-B3LYP functional. The RI-CC2 method was employed to confirm the CAM-B3LYP results. As far as we know, the excited state geometries for a series of fluorescein derivatives were optimized for the first time, and the conformational changes upon photoexcitation were discussed. Importantly, the previous proposed photo induced electron transfer (PeT) mechanism for dictating the fluorescence quantum yield (F fl ) of fluorescein derivatives was not fully supported by our calculations. Internal conversion may still be the most likely mechanism for dictating the F fl of fluorescein derivatives, which indicates a need for further experimental and theoretical studies on the excited state dynamics of fluorescein derivatives.

Time-Resolved Photodetachment Anisotropy: Gas-Phase Rotational and Vibrational Dynamics of the Fluorescein Anion

“…However, if this were the case, then one might also anticipate that the differential cross sections might change which would be reflected in r(t), which it is not. The charge-transfer nature of the S 1 excited state has been controversially discussed in the literature [41][42][43] and our indications suggest that a partial electron transfer does occur, at least in the gas-phase.…”

Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril

“…Furthermore, the strategy is similarly applicable to pH-sensitive fluoresceins, cyanines or rhodamines, in which protonation and deprotonation of suitably positioned amino groups can also modulate their fluorescence properties. It can also be used to design dyes which reduce their fluorescence upon binding, e.g., when electron-poor groups are generated by protonation which are quenched intramolecularly by donor-excited PET [70–74]. …”

Theoretical Study of the ESIPT Process for a New Natural Product Quercetin

“…The energy of corresponding molecular structurein S 0 state or S 1 state have been calculated with the hydroxyl group (O-H) bond lengths increased by the fixed step sizes. Although the TDDFT method is unlikely to accurately acquire the correct order of closely spaced excited states, a number of foregoingresearch work have manifested that the method was relatively reliable with respect to analyzing qualitatively the reaction pathways and the potential barrier of ESIPT processes39. The potential energy curves of six-membered ring proton transfer process shown in Fig.…”