Direct Femtosecond Observation of Tight and Loose Ion Pairs upon Photoinduced Bimolecular Electron Transfer

Mohammed, Omar F.; Adamczyk, Katrin; Banerji, Natalie; Dreyer, J.; Lang, Bernhard Felix; Nibbering, Erik T. J.; Vauthey, Eric

doi:10.1007/978-3-540-95946-5_199

Cited by 21 publications

(36 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[45][46] As can be clearly seen in Figures 2 and 3 The two observed components suggest the occurrence of two types of donor-acceptor ion pairs with different associated couplings, in accordance with previous reports on other donor-acceptor systems. [47][48][49][50] The geometry and electronic coupling between donor and acceptor molecules can greatly affect both charge separation and charge recombination rates. 49 Hence, it is expected that the strong electronically coupled ion pairs will undergo fast charge recombination either to the neutral molecule or to the less coupled ion pairs.…”

Section: Acs Paragon Plus Environmentmentioning

confidence: 99%

“…[47][48][49][50] The geometry and electronic coupling between donor and acceptor molecules can greatly affect both charge separation and charge recombination rates. 49 Hence, it is expected that the strong electronically coupled ion pairs will undergo fast charge recombination either to the neutral molecule or to the less coupled ion pairs. On the other hand, the slowly formed ion pairs encountering lower degree of coupling will in turn undergoes charge recombination over a longer time window to the neutral molecule.…”

Section: Acs Paragon Plus Environmentmentioning

confidence: 99%

See 1 more Smart Citation

Bimolecular Excited-State Electron Transfer with Surprisingly Long-Lived Radical Ions

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Acs Paragon Plus Environmentmentioning

confidence: 99%

Section: Acs Paragon Plus Environmentmentioning

confidence: 99%

Bimolecular Excited-State Electron Transfer with Surprisingly Long-Lived Radical Ions

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…This indicates that PET from the excited DPP-Pt(acac) to TCNE is ultrafast (i.e., 3-4 ps), similar to that of DPP-Pt(acac) to the positively charged porphyrin 15 but much faster than the ISC of DPP-Pt(acac) or the PET processes in bimolecular systems without metal centers. 32,[42][43][44][45][46] Note that an ultrafast electron transfer that is much faster than ISC indicates that the PET reaction occurs from the singlet excited state rather than the triplet state. An ultrafast PET is evidence for a strong electronic coupling between DPP-Pt(acac) and TCNE.…”

Section: Exited-state Dynamics Of Dpp-pt(acac)mentioning

confidence: 99%

Ultrafast Excited-State Dynamics of Diketopyrrolopyrrole (DPP)-Based Materials: Static versus Diffusion-Controlled Electron Transfer Process

et al. 2015

Self Cite

View full text Add to dashboard Cite

Singlet-to-triplet intersystem crossing (ISC) and photoinduced electron transfer (PET) of platinum(II)-containing diketopyrrolopyrrole (DPP) oligomers in the presence and absence of tetracyanoethylene (TCNE), a strong electron-acceptor, were investigated using femtosecond and nanosecond transient absorption spectroscopy with broadband capabilities. The effect of incorporating platinum(II) in the photophysical properties of DPP molecule was evaluated by comparing the excited-state dynamics of DPP with and without Pt metal centers. Steady-state measurements reveal that platinum(II) incorporation greatly facilitates interactions between DPP-Pt(acac) and TCNE, resulting in the formation of charge transfer (CT) complexes. In the absence of TCNE, the transient absorption spectra revealed ultrafast ISC of DPP-Pt(acac) followed by a long-lived triplet state; however, in the presence of TCNE, PET from the excited DPP-Pt(acac) and from DPP to TCNE formed radical ion pairs. We measured an ultrafast PET from DPP-Pt(acac) to TCNE (i.e., a picosecond regime) that was much faster than that from DPP to TCNE (i.e., nanosecond time scale), which is a diffusion-controlled process. Our results provide clear evidence that the PET rate is eventually controlled by the platinum(II) incorporation.

show abstract

“…[8][9][10] Many fundamental photophysical and photochemical properties of organic molecules including charge transfer, charge separation and charge recombination are well understood in several chemical systems using time-resolved laser spectroscopy. 1,[11][12][13][14] On the other hand, most of those organic molecules exhibit very low photoluminescence quantum yields (PLQY) especially in liquid phase, depending on the active non-radiative deactivation channels present such as torsional/twisting motions, excited state structural changes and ultrafast internal conversion. [15][16][17][18][19] For instance, torsional motions are commonly known as a very efficient non-radiative deactivation mechanisms for organic molecules upon photon-excitation in a wide range of fields including biological and chemical systems as well as solid-state photovoltaic materials.…”

Section: Introductionmentioning

confidence: 99%

Tunable Twisting Motion of Organic Linkers via Concentration and Hydrogen-Bond Formation

et al. 2019

Self Cite

View full text Add to dashboard Cite

Benzothidiazole dibenzoic acid derivative (BTDB) is a well-known organic linker in various metal-organic framework structures as well as a fluorescent probe in biological systems. Here, we demonstrate that the radiative and non-radiative decay channels of BTDB can be interplayed and precisely controlled through concentration and hydrogen bond interactions as directly evidenced experimentally and theoretically. This leads to excited-state structural changes that significantly suppress the torsional motion around the Benzothidiazole moiety, leading to an enormous increase in the emission quantum yields from ~1% to 70%. These changes are associated with the existence of two equilibria where dimers and small-oligomers form in dimethylformamide (DMF), with high formation constants of 18,000 M-1 and 1.2 × 10 13 M-3 , respectively. These evolving species, i.e., the dimers and oligomers, are formed via hydrogen bonds between carboxylic acid groups present at the far-edge of the rod-like BTDB molecules. The estimated repeating number for this smalloligomer formation via bonded monomers is eight in DMF, as shown by emission spectra analysis. With deprotonation as a control experiment, these associated species can easily collapse to the initial monomer species, confirming the role of the hydrogen-bond formation on the observed phenomena. Theoretical studies and NMR experiments not only confirm the existence of the dimers, but also demonstrate the important role of the hydrogen bonds on the excited-state dynamics. These new findings provide a better understanding of the photophysical behaviors of organic linkers used in a wide range of chemical and biological applications.

show abstract

Direct Femtosecond Observation of Tight and Loose Ion Pairs upon Photoinduced Bimolecular Electron Transfer

Cited by 21 publications

References 11 publications

Bimolecular Excited-State Electron Transfer with Surprisingly Long-Lived Radical Ions

Bimolecular Excited-State Electron Transfer with Surprisingly Long-Lived Radical Ions

Ultrafast Excited-State Dynamics of Diketopyrrolopyrrole (DPP)-Based Materials: Static versus Diffusion-Controlled Electron Transfer Process

Tunable Twisting Motion of Organic Linkers via Concentration and Hydrogen-Bond Formation

Contact Info

Product

Resources

About