Entropic effects in excited state CT reactions

Pigliucci, Anatolio; Vauthey, Eric; Rettig, Wolfgang

doi:10.1016/j.cplett.2008.12.091

Cited by 26 publications

(56 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These data show a substantial scatter, as reflected in the exceptionally large uncertainty reported for the activation energy E a of the LE ? ICT reaction rate constant k a (Scheme 1): 1.4 ± 1.9 kJ/mol [1]. An equally large scatter was found for DMABE: 2.0 ± 2.3 kJ/mol [1].…”

Section: Picosecond Decay Times Of Dmabn In Mecnmentioning

confidence: 84%

“…In a recent Letter [1], Rettig and coworkers presented decay times of five electron donor (D)/acceptor (A) molecules in acetonitrile (MeCN) undergoing a reaction from the locally excited (LE) state to the intramolecular charge transfer (ICT) state. These decay times were determined at 20°C by fluorescence upconversion, at a wavelength (350 nm) where only LE fluorescence occurs and also at a second wavelength (500 nm) at which predominantly ICT emission is detected [2].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Decay times of 4-(dimethylamino)benzonitrile in acetonitrile and conclusions on entropy of activation

Zachariasse

Druzhinin

Mayer

et al. 2009

Chemical Physics Letters

View full text Add to dashboard Cite

a b s t r a c tFrom picosecond decay times of 4-(dimethylamino)benzonitrile (DMABN) and 4-(dimethylamino)benzoic acid ethyl ester (DMABE) in acetonitrile (Ref.[1]), a conclusion on entropy effects cannot be made because of large uncertainties of the data. The planarized 1-tert-butyl-6-cyano-1,2,3,4-tetrahydroquinoline (NTC6) as a model for a planar intramolecular charge transfer (ICT) state and the influence of pretwist and size of the amino group is also discussed. For DMABE excited state absorption spectra show a decay of the locally excited (LE) and a rise of the ICT state of 1.0 ps, posing the question whether the lowest excited singlet state is of L b or L a character.

show abstract

Section: Picosecond Decay Times Of Dmabn In Mecnmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Decay times of 4-(dimethylamino)benzonitrile in acetonitrile and conclusions on entropy of activation

Zachariasse

Druzhinin

Mayer

et al. 2009

Chemical Physics Letters

View full text Add to dashboard Cite

show abstract

“…99,100 For example, if the transition state is more polar, the reaction rate increases with solvent polarity. This is probably the case for 1 and 3, for which the fluorescence time constants are clearly larger in nonpolar solvents, independently of their viscosity.…”

Section: Discussionmentioning

confidence: 99%

Tuning the Excited-State Dynamics of GFP-Inspired Imidazolone Derivatives

et al. 2009

View full text Add to dashboard Cite

The excited-state dynamics of five derivatives of the GFP-chromophore, which differ by the position and nature of their substituents, has been investigated in solvents of various viscosity and polarity and in rigid media using femtosecond-resolved spectroscopy. In polar solvents of low viscosity, like acetonitrile or methanol, the fluorescence decays of all compounds are multiexponential, with average lifetimes of the order of a few picoseconds, whereas in rigid matrices (polymer films and low temperature glasses), they are single exponential with lifetimes of the order of a few nanoseconds and fluorescence quantum yields close to unity. Global analysis of the fluorescence decays recorded at several wavelengths and of the transient absorption spectra reveals the presence of several excited-state populations with slightly different fluorescence and absorption spectra and with distinct lifetimes. These populations are attributed to the existence of multiple ground-state conformers. From the analysis of the dependence of the excited-state dynamics on the solvent and on the nature of the substituents, it follows that the nonradiative deactivation of all these excited chromophores involves an intramolecular coordinate with large amplitude motion. However, depending on the solvent and substituent, additional channels, namely, inter-and intramolecular hydrogen bond assisted nonradiative deactivation, are operative. This allows tuning of the excited-state lifetime of the chromophore. Finally, an ultrafast photoinduced intramolecular charge transfer is observed in polar solvents with one derivative bearing a dimethylaminophenyl substituent.

show abstract

“…A majority of both theoretical [13][14][15] and experimental 10,11,16 studies follow the ideas of Grabowski and co-workers, 6,17 who in their seminal work on the origin of the dual fluorescence on DMABN and related molecules proposed a model based on a twisted ICT state (TICT). In this model, the stabilisation of the ICT state is not only produced by the reorganisation of the polar solvent as in the model of Lippert et al, 1 but also by the geometrical rearrangement of the molecule with the dimethylamino group characterised by a twisting of about 901 with respect to the plane defined by the benzonitrile moiety.…”

Section: Introductionmentioning

confidence: 99%

A theoretical study of the intramolecular charge transfer in 4-(dimethylamino)benzethyne

Segarra‐Martí

Coto

2014

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

We have investigated the non-adiabatic relaxation processes occurring in the singlet manifold of 4-(dimethylamino)benzethyne (DMABE), a molecule isoelectronic with 4-(dimethylamino)benzonitrile (DMABN) but lacking its characteristic dual fluorescence, using multireference perturbation theory methods. The results obtained point out to the existence of a two-fold decay mechanism in which the population of the initially accessed L a state bifurcates towards a locally excited (LE) and a ps* state. Further relaxation to an emitting intramolecular charge transfer (ICT) state is impeded due to the presence of pronounced energy barriers along their associated potential energy surfaces. These results provide further evidence of the role of ps* states in the non-adiabatic relaxation processes of dialkylaminobenzonitriles.

show abstract

Entropic effects in excited state CT reactions

Cited by 26 publications

References 37 publications

Decay times of 4-(dimethylamino)benzonitrile in acetonitrile and conclusions on entropy of activation

Decay times of 4-(dimethylamino)benzonitrile in acetonitrile and conclusions on entropy of activation

Tuning the Excited-State Dynamics of GFP-Inspired Imidazolone Derivatives

A theoretical study of the intramolecular charge transfer in 4-(dimethylamino)benzethyne

Contact Info

Product

Resources

About