The Excited‐State Dynamics of Phycocyanobilin in Dependence on the Excitation Wavelength

Dietzek, Benjamin; Maksimenka, Raman; Hermann, Gudrun; Kiefer, W.; Popp, Jürgen; Schmitt, Michael

doi:10.1002/cphc.200400056

Cited by 20 publications

(27 citation statements)

References 28 publications

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“…[38][39][40] It results from a non-resonant scattering of the probe pulse from a grating that is formed by the two pump pulses. This scattering is independent of the presence of an optical resonance in the system under investigation and persists for delay times during which the three incoming laser pulses interact simultaneously with the sample.…”

Section: Resultsmentioning

confidence: 99%

“…Transient-grating spectroscopy was chosen for this study as it is well established that this coherent technique yields excellent signal-to-noise ratios and thus allows for a very precise fitting of the transient data. [38][39][40] In order to facilitate the interpretation of the transient curves gained by the transient-grating method, we measured transient absorption data first. These data were taken with a poor time resolution and were solely used to obtain spectral information about the excited states of the investigated complexes.…”

Section: Introductionmentioning

confidence: 99%

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Ultrafast Excited‐State Excitation Dynamics in a Quasi‐Two‐Dimensional Light‐Harvesting Antenna Based on Ruthenium(II) and Palladium(II) Chromophores

Dietzek

Kiefer

Blumhoff

et al. 2006

Chemistry A European J

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A detailed study on the excited-state-excitation migration taking place within the tetranuclear complex [{(tbbpy)(2)Ru(tmbi)}(2){Pd(allyl)}(2)](PF(6))(2) (tbbpy = 4,4'-di-tert-butyl-2,2'-bipyridine and tmbi = 5,6,5',6'-tetramethyl-2,2'-bibenzimidazolate) is presented. The charge transfer is initiated by the photoexcitation into the lowest metal-to-ligand charge-transfer (MLCT) band of one of the peripheral ruthenium(II) chromophores and terminates on the central structurally complex Pd(2) (II)(allyl)(2) subunit. Thus, the system under investigation can be thought of as a functional model for the photosynthesis reaction center in plants. The kinetic steps involved in the overall process are inferred from femtosecond time-resolved transient-grating kinetics recorded at spectral positions within the regions of ground-state bleach and transient absorption. The kinetics features a complex non-exponential time behavior and can be fitted to a bi-exponential rise (tau(1)> or =200 fs, tau(2) approximately 1.5 ps) and a mono- or bi-exponential decay, depending on the experimental situation. The data leads to the formulation of a model for the intramolecular excitation-hopping ascribing intersystem crossing and subsequent cooling as the two fastest observed processes. Following these initial steps, charge transfer from the ruthenium to the central complex Pd(2)(allyl)(2) moiety is observed with a characteristic time constant of 50 ps. A 220-ps component that is observed in the ground-state recovery only is attributed to excitation equilibration between the two identical Pd(allyl) chromophores.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ultrafast Excited‐State Excitation Dynamics in a Quasi‐Two‐Dimensional Light‐Harvesting Antenna Based on Ruthenium(II) and Palladium(II) Chromophores

Dietzek

Kiefer

Blumhoff

et al. 2006

Chemistry A European J

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“…The Nobel Prize to Ahmed H. Zewail stimulated even more this active research area. Even complex processes such as photosynthesis [13,14] or the initial ultrafast steps in vision [15], are well characterized and a quite detailed understanding of light-induced reactions on model systems now exists [13,[16][17][18][19][20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

“…In the present paper we review our recent work on femtosecond time-resolved spectroscopy to investigate the light-induced ultrafast excited-state processes of two very important biological photoreceptor chromophores, phycocyanobilin (PCB) [20] and protochlorophyllide a (PChla) [21][22][23][24]. The spectroscopic techniques employed to interrogate the light-induced processes in these systems are femtosecond time-resolved transient absorption and transient-grating spectroscopy, the latter being a special case of four-wave-mixing spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

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Femtosecond time‐resolved spectroscopy on biological photoreceptor chromophores

Schmitt¹,

Dietzek

Hermann

et al. 2007

Laser & Photonics Reviews

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This paper reviews our results on femtosecond timeresolved spectroscopy (transient absorption, transient-grating and fluorescence spectroscopy) to study the photophysics and photochemistry of the two very important biological photoreceptor chromophores phycocyanobilin (PCB) and protochlorophyllide a (PChla). The compound PCB serves as a model chromophore for the photoreceptor phytochrome. By means of transient-grating spectroscopy where the excitation wavelength was varied over the spectral region of the S0 → S1-absorption the ultrafast processes were studied upon excitation with varying excess energy delivered to the system. On the basis of the results obtained, both the rate of the photoreaction in PCB and the rate of the decay of different excited-state species via different decay channels depend on the excitation wavelength. Furthermore, transient absorption experiments illuminating the excited-state dynamics of PChla, a porphyrin-like compound and, as substrate of the NADPH/protochlorophyllide oxidoreductase (POR), a precursor of the chlorophyll biosynthesis are presented. In addition to pump-energy-dependent measurements performed with PChla dissolved in methanol, the excited-state dynamics of PChla was interrogated in different solvents that were chosen to mimic different environmental conditions. In addition to the femtosecond time-resolved absorption experiments the picosecond time-resolved fluorescence of the system was studied. The transient absorption and time-resolved fluorescence data allow suggesting a detailed model for the excited-state relaxation of PChla describing the excited-state processes in terms of The model suggested to account for the excited-state relaxation processes in protochlorophyllide a upon photoexcitation is presented a branching of the initially excited state population into a reactive and nonreactive path. Thus, the excited-state potential energy surface exhibits two distinct S1 and Sx minima separated from the Franck-Condon region along two most likely orthogonal reaction coordinates. Finally, the model derived is related to models suggested to account for the reduction of PChla to chlorophyllide a within the natural enzymatic environment of POR.

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Reversible Phase Transformation and Mechanochromic Luminescence of Zn^II‐Dipyridylamide‐Based Coordination Frameworks

Tzeng

Chang

Wei

et al. 2012

Chemistry A European J

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A 1D double-zigzag framework, {[Zn(paps)(2)(H(2)O)(2)](ClO(4))(2)}(n) (1; paps = N,N'-bis(pyridylcarbonyl)-4,4'-diaminodiphenyl thioether), was synthesized by the reaction of Zn(ClO(4))(2) with paps. However, a similar reaction, except that dry solvents were used, led to the formation of a novel 2D polyrotaxane framework, [Zn(paps)(2)(ClO(4))(2)](n) (2). This difference relies on the fact that water coordinates to the Zn(II) ion in 1, but ClO(4)(-) ion coordination is found in 2. Notably, the structures can be interconverted by heating and grinding in the presence of moisture, and such a structural transformation can also be proven experimentally by powder and single-crystal X-ray diffraction studies. The related N,N'-bis- (pyridylcarbonyl)-4,4'-diaminodiphenyl ether (papo) and N,N'-(methylenedi-para-phenylene)bispyridine-4-carboxamide (papc) ligands were reacted with Zn(II) ions as well. When a similar reaction was performed with dry solvents, except that papo was used instead of paps, the product mixture contained mononuclear [Zn(papo)(CH(3)OH)(4)](ClO(4))(2) (5) and the polyrotaxane [Zn(papo)(2)(ClO(4))(2)](n) (4). From the powder XRD data, grinding this mixture in the presence of moisture resulted in total conversion to the pure double-zigzag {[Zn(papo)(2)(H(2)O)(2)](ClO(4))(2)}(n) (3) immediately. Upon heating 3, the polyrotaxane framework of 4 was recovered. The double-zigzag {[Zn(papc)(2)(H(2)O)(2)](ClO(4))(2)}(n) (6) and polyrotaxane [Zn(papc)(2)(ClO(4))(2)](n) (7) were synthesized in a similar reaction. Although upon heating the double-zigzag 6 undergoes structural transformation to give the polyrotaxane 7, grinding solid 7 in the presence of moisture does not lead to the formation of 6. Significantly, the bright emissions for double-zigzag frameworks of 1 and 3 and weak ones for polyrotaxane frameworks of 2 and 4 also show interesting mechanochromic luminescence.

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The Excited‐State Dynamics of Phycocyanobilin in Dependence on the Excitation Wavelength

Cited by 20 publications

References 28 publications

Ultrafast Excited‐State Excitation Dynamics in a Quasi‐Two‐Dimensional Light‐Harvesting Antenna Based on Ruthenium(II) and Palladium(II) Chromophores

Ultrafast Excited‐State Excitation Dynamics in a Quasi‐Two‐Dimensional Light‐Harvesting Antenna Based on Ruthenium(II) and Palladium(II) Chromophores

Femtosecond time‐resolved spectroscopy on biological photoreceptor chromophores

Reversible Phase Transformation and Mechanochromic Luminescence of Zn^II‐Dipyridylamide‐Based Coordination Frameworks

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The Excited‐State Dynamics of Phycocyanobilin in Dependence on the Excitation Wavelength

Cited by 20 publications

References 28 publications

Ultrafast Excited‐State Excitation Dynamics in a Quasi‐Two‐Dimensional Light‐Harvesting Antenna Based on Ruthenium(II) and Palladium(II) Chromophores

Ultrafast Excited‐State Excitation Dynamics in a Quasi‐Two‐Dimensional Light‐Harvesting Antenna Based on Ruthenium(II) and Palladium(II) Chromophores

Femtosecond time‐resolved spectroscopy on biological photoreceptor chromophores

Reversible Phase Transformation and Mechanochromic Luminescence of ZnII‐Dipyridylamide‐Based Coordination Frameworks

Contact Info

Product

Resources

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Reversible Phase Transformation and Mechanochromic Luminescence of Zn^II‐Dipyridylamide‐Based Coordination Frameworks