The torsional potential of 9,9'-bianthryl determined by laser-induced fluorescence in a free jet

Yamasaki, Katsuyoshi; Arita, Koji; Kajimoto, Okitsugu; Hara, Kimihiko

doi:10.1016/0009-2614(86)80072-0

Cited by 73 publications

(30 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, in the dyad, geometrical rearrangements, including rotation around the triple bond, can occur. This is analogous to the well-known twisted intramolecular CT (TICT) as in the classical example of 9,9′-bianthryl, in which CT is discussed in view of a twist of the former in-plane D/A pair. − For PDIPe, no twist is required to initiate CT and therefore we avoid this terminology. Nevertheless, this does not exclude a twist as the potential origin of the transient Stark shift.…”

Section: Resultsmentioning

confidence: 98%

Charge Localization after Ultrafast Photoexcitation of a Rigid Perylene Perylenediimide Dyad Visualized by Transient Stark Effect

et al. 2017

View full text Add to dashboard Cite

The intramolecular charge-transfer (CT) dynamics of a rigid and strongly conjugated perylenediimide-bridge-perylene dyad (PDIPe) has been investigated in dichloromethane using ultrafast transient electronic absorption spectroscopy and quantum chemical calculations. The strong electronic coupling between the dyad units gives rise to a CT band. Its photoexcitation forms a delocalized CT state with well-preserved ion bands despite the strong coupling. In the dyad, the electronic transition dipole moment of the electron donor perylene is aligned along the axis of the electric field vector with respect to the CT species. This alignment makes the donor sensitive to the Stark effect and thus charge density fluctuations in the CT state. Charge localization on the picosecond time scale manifests as a time-dependent Stark shift in the visible region. Quantum chemical calculations reveal a twist around the acetylene bridging unit to be the responsible mechanism generating a partial to an almost complete CT state. An estimate of the electric field strength in the CT state yields approximately 25 MV/cm, which increases to around 31 MV/cm during charge localization. Furthermore, the calculations illustrate the complexity of electronic structure in this strongly delocalized superchromophore and reflect the complications in the interpretation of transient absorption results when compared to steady-state approaches such as spectroelectrochemistry and model chromophore experiments such as photoinduced bimolecular charge transfer.

show abstract

Section: Resultsmentioning

confidence: 98%

Charge Localization after Ultrafast Photoexcitation of a Rigid Perylene Perylenediimide Dyad Visualized by Transient Stark Effect

et al. 2017

View full text Add to dashboard Cite

show abstract

“…All excited‐state ADC calculations were performed with a developmental version of the Q‐Chem 4.2 program package, and the methods implemented here are scheduled to be released within Q‐Chem 4.3. Post processing of the data was carried out using the TheoDORE 1.0 program …”

Section: Computational Detailsmentioning

confidence: 99%

Statistical analysis of electronic excitation processes: Spatial location, compactness, charge transfer, and electron-hole correlation

et al. 2015

View full text Add to dashboard Cite

We report the development of a set of excited-state analysis tools that are based on the construction of an effective exciton wavefunction and its statistical analysis in terms of spatial multipole moments. This construction does not only enable the quantification of the spatial location and compactness of the individual hole and electron densities but also correlation phenomena can be analyzed, which makes this procedure particularly useful when excitonic or charge-resonance effects are of interest. The methods are first applied to bianthryl with a focus on elucidating charge-resonance interactions. It is shown how these derive from anticorrelations between the electron and hole quasiparticles, and it is discussed how the resulting variations in state characters affect the excited-state absorption spectrum. As a second example, cytosine is chosen. It is illustrated how the various descriptors vary for valence, Rydberg, and core-excited states, and the possibility of using this information for an automatic characterization of state characters is discussed.

show abstract

“…This is also manifested in the heat of formation of the compound, its molecular polarizability, and its polarographic half-reduction potential. [21][22][23] In the vertical nonpolar singlet excited state, an optimum torsion angle of about 70°was deduced from the vibronic structure of laser-induced fluorescence spectra of BA in a free jet [24][25][26] and from a simulation of steady-state and timeresolved fluorescence spectra in nonpolar solvents. 27 The relaxed nonperpendicular configuration facilitates electron transfer from one subunit to the other if the charge-separated state is additionally stabilized in a polar environment.…”

Section: Introductionmentioning

confidence: 99%

Two-State Model for the Photophysics of 9,9‘-Bianthryl. Fluorescence, Transient-Absorption, and Semiempirical Studies

1998

View full text Add to dashboard Cite

The photophysics of 9,9‘-bianthryl (BA) were investigated by means of fluorescence spectroscopy, nanosecond transient-absorption spectroscopy, and semiempirical calculations. Fluorescence spectra and lifetimes were measured in more than 50 solvents in order to get a detailed picture of the solvent dependence. The results show that the fluorescence lifetime is constant in solvents of low polarity (D < 5) and increases with solvent polarity in more polar solvents. Departures from this trend can be traced to specific solute−solvent interactions. Excited-state singlet−singlet absorption spectra were measured in the ultraviolet range and show a marked solvent dependence. In polar solvents, the spectrum (λmax = 315 nm) is closely related to those of the radical ions of both BA and anthracene. The decay rate constant of this band is identical with that of the fluorescence emission in a range of solvents of varying polarity (D > 5), thus providing direct proof of the charge-separated character of the fluorescent state in polar solvents. The 315 nm band is absent in isooctane, indicating that the fluorescent state is not of charge-separated character in this case. Semiempirical calculations were carried out in order to rationalize the experimental data. Careful consideration of the symmetry character of the electronic states involved and of the solvent effect on these states indicates that two distinct transitions are responsible for the observed fluorescence emission; in nonpolar solvents, a nonpolar state with D 2 symmetry and a torsion angle that is markedly smaller than 90° is the fluorescent state, whereas in polar solvents fluorescence originates from a charge-separated perpendicular state of D 2 d symmetry. This latter state is responsible for the large solvent effects on fluorescence and singlet−singlet absorption. Triplet−triplet absorption and intersystem-crossing efficiency data were also measured in several solvents. They too are solvent-dependent but do not show characteristics of charge separation; they rather are influenced by specific solute−solvent interactions.

show abstract

The torsional potential of 9,9'-bianthryl determined by laser-induced fluorescence in a free jet

Cited by 73 publications

References 14 publications

Charge Localization after Ultrafast Photoexcitation of a Rigid Perylene Perylenediimide Dyad Visualized by Transient Stark Effect

Charge Localization after Ultrafast Photoexcitation of a Rigid Perylene Perylenediimide Dyad Visualized by Transient Stark Effect

Statistical analysis of electronic excitation processes: Spatial location, compactness, charge transfer, and electron-hole correlation

Two-State Model for the Photophysics of 9,9‘-Bianthryl. Fluorescence, Transient-Absorption, and Semiempirical Studies

Contact Info

Product

Resources

About