TY - JOUR
AU - Fürstenberg, Alexandre
AU - Vauthey, Eric
TI - Ultrafast Excited-State Dynamics in Biological Environments
PY - 2007
JF - Chimia
JA - Chimia
SN - 0009-4293
VL - 61
IS - 10
SP - 617
EP - 620
L1 - http://www.ingentaconnect.com/search/download?pub=infobike%3a%2f%2fscs%2fchimia%2f2007%2f00000061%2f00000010%2fart00003&mimetype=application%2fpdf&exitTargetId=1193909833908
L3 - http://www.ingentaconnect.com/content/scs/chimia/2007/00000061/00000010/art00003
L4 - http://www.unige.ch/sciences/chifi/publis/pics/double/ref00904.png
M3 - 10.2533/chimia.2007.617
UR - http://dx.doi.org/10.2533/chimia.2007.617
N2 - We discuss and illustrate by several examples how the ultrafast excited-state dynamics of a chromophore can be altered when changing its environment from a homogenous solution to a biological molecule such as proteins or nucleic acids.
ID - 904
ER -

TY - JOUR
AU - Fürstenberg, Alexandre
AU - Vauthey, Eric
TI - Ultrafast Excited-State Dynamics of Oxazole Yellow DNA Intercalators
PY - 2007
JF - Journal of Physical Chemistry B
JA - J. Phys. Chem. B
SN - 1520-6106
VL - 111
IS - 43
SP - 12610
EP - 12620
L1 - http://pubs.acs.org/cgi-bin/article.cgi/jpcbfk/2007/111/i43/pdf/jp073182t.pdf
L2 - http://pubs.acs.org/cgi-bin/article.cgi/jpcbfk/2007/111/i43/html/jp073182t.html
L3 - http://pubs.acs.org/cgi-bin/abstract.cgi/jpcbfk/2007/111/i43/abs/jp073182t.html
L4 - http://www.unige.ch/sciences/chifi/publis/pics/double/ref00901.png
M3 - 10.1021/jp073182t
UR - http://dx.doi.org/10.1021/jp073182t
N2 - The excited-state dynamics of the DNA intercalator YO-PRO-1 and of three derivatives has been investigated in water and in DNA using ultrafast fluorescence spectroscopy. In the free form, the singly charged dyes exist both as monomers and as H-dimers, while the doubly charged dyes exist predominantly as monomers. Both forms are very weakly fluorescent: the monomers because of ultrafast nonradiative deactivation, with a time constant on the order of 3−4 ps, associated with large amplitude motion around the methine bridge, and the H-dimers because of excitonic interaction. Upon intercalation into DNA, large amplitude motion is inhibited, H-dimers are disrupted, and the molecules become highly fluorescent. The early fluorescence dynamics of these dyes in DNA exhibits substantial differences compared with that measured with their homodimeric YOYO analogues, which are ascribed to dissimilarities in their local environment. Finally, the decay of the fluorescence polarization anisotropy reveals ultrafast hopping of the excitation energy between the intercalated dyes. In one case, a marked change of the depolarization dynamics upon increasing the dye concentration is observed and explained in terms of a different binding mode.
ID - 901
ER -

TY - JOUR
AU - Duvanel, Guillaume
AU - Grilj, Jakob
AU - Schuwey, Anne
AU - Gossauer, Albert
AU - Vauthey, Eric
TI - Ultrafast excited-state dynamics of phenyleneethynylene oligomers in solution
PY - 2007
JF - Photochemical and Photobiological Sciences
JA - Photochem. Photobiol. Sci.
SN - 1474-905X
VL - 6
IS - 9
SP - 956
EP - 963
L1 - http://www.rsc.org/ej/PP/2007/b702647a.pdf
L2 - http://www.rsc.org/delivery/_ArticleLinking/ArticleLinking.cfm?JournalCode=PP&Year=2007&ManuscriptID=b702647a&Iss=9
L3 - http://www.rsc.org/publishing/journals/PP/article.asp?doi=b702647a
M3 - 10.1039/b702647a
UR - http://dx.doi.org/10.1039/b702647a
N2 - The excited-state dynamics of oligomeric phenyleneethynylenes (OPEs) of various length and substitution has been investigated by femtosecond time-resolved spectroscopy. The fluorescence lifetime of the OPEs decreases with the number of phenyleneethynylene units up to about 9. This effect is due to an increase of the oscillator strength for the S1–S0 transition. Dynamic features occurring within a few tens of picoseconds and ascribed to structural relaxation directly after population of the S1 state can be observed in non-viscous solvents. The effect of torsional disorder on the fluorescence intensity is shown to depend strongly on the nature of the substituent on the phenyl groups. All these effects are qualitatively discussed with a simple exciton model.
ID - 889
ER -

TY - JOUR
AU - Sakai, Naomi
AU - Sisson, Adam L.
AU - Bhosale, Sheshanath
AU - Fürstenberg, Alexandre
AU - Banerji, Natalie
AU - Vauthey, Eric
AU - Matile, Stefan
TI - Rigid-rod push–pull naphthalenediimide photosystems
PY - 2007
JF - Organic and Biomolecular Chemistry
JA - Org. Biomol. Chem.
SN - 1477-0520
VL - 5
IS - 16
SP - 2560
EP - 2563
L1 - http://www.rsc.org/ej/OB/2007/b708449h.pdf
L2 - http://www.rsc.org/delivery/_ArticleLinking/ArticleLinking.cfm?JournalCode=OB&Year=2007&ManuscriptID=b708449h&Iss=16
L3 - http://www.rsc.org/publishing/journals/OB/article.asp?doi=b708449h
L4 - http://www.unige.ch/sciences/chifi/publis/pics/double/ref00888.png
M3 - 10.1039/b708449h
UR - http://dx.doi.org/10.1039/b708449h
N2 - Design, synthesis and evaluation of advanced rigid-rod π-stack photosystems with asymmetric scaffolds are reported. The influence of push–pull rods on self-organization, photoinduced charge separation and photosynthetic activity is investigated and turns out to be surprisingly small overall.
ID - 888
ER -

TY - JOUR
AU - Fürstenberg, Alexandre
AU - Deligeorgiev, Todor G.
AU - Gadjev, Nikolai I.
AU - Vasilev, Aleksey A.
AU - Vauthey, Eric
TI - Structure-Fluorescence Contrast Relationship in Cyanine DNA Intercalators: Toward Rational Dye Design
PY - 2007
JF - Chemistry - A European Journal
JA - Chem. - Eur. J.
SN - 0947-6539
VL - 13
IS - 30
SP - 8600
EP - 8609
L1 - http://www3.interscience.wiley.com/cgi-bin/fulltext/114294278/PDFSTART
L2 - http://www3.interscience.wiley.com/cgi-bin/fulltext/114294278/HTMLSTART
L3 - http://www3.interscience.wiley.com/cgi-bin/abstract/114294278/ABSTRACT?CRETRY=1&SRETRY=0
L4 - http://www.unige.ch/sciences/chifi/publis/pics/double/ref00887.png
M3 - 10.1002/chem.200700665
UR - http://dx.doi.org/10.1002/chem.200700665
N2 - The fluorescence enhancement mechanisms of a series of DNA stains of the oxazole yellow (YO) family have been investigated in detail using steady-state and ultrafast time-resolved fluorescence spectroscopy. The strong increase in the fluorescence quantum yield of these dyes upon DNA binding is shown to originate from the inhibition of two distinct processes: 1) isomerisation through large-amplitude motion that non-radiatively deactivates the excited state within a few picoseconds and 2) formation of weakly emitting H-dimers. As the H-dimers are not totally non-fluorescent, their formation is less efficient than isomerisation as a fluorescent contrast mechanism. The propensity of the dyes to form H-dimers and thus to reduce their fluorescence contrast upon DNA binding is shown to depend on several of their structural parameters, such as their monomeric (YO) or homodimeric (YOYO) nature, their substitution and their electric charge. Moreover, these parameters also have a substantial influence on the affinity of the dyes for DNA and on the ensuing sensitivity for DNA detection. The results give new insight into the development and optimisation of fluorescent DNA probes with the highest contrast.
ID - 887
ER -

TY - JOUR
AU - Pigliucci, Anatolio
AU - Duvanel, Guillaume
AU - Lawson Daku, Latevi Max
AU - Vauthey, Eric
TI - Investigation of the Influence of Solute-Solvent Interactions on the Vibrational Energy Relaxation Dynamics of Large Molecules in Liquids
PY - 2007
JF - Journal of Physical Chemistry A
JA - J. Phys. Chem. A
SN - 1089-5639
VL - 111
IS - 28
SP - 6135
EP - 6145
L1 - http://pubs.acs.org/cgi-bin/article.cgi/jpcafh/2007/111/i28/pdf/jp069010y.pdf
L2 - http://pubs.acs.org/cgi-bin/article.cgi/jpcafh/2007/111/i28/html/jp069010y.html
L3 - http://pubs.acs.org/cgi-bin/abstract.cgi/jpcafh/2007/111/i28/abs/jp069010y.html
L4 - http://www.unige.ch/sciences/chifi/publis/pics/double/ref00886.png
M3 - 10.1021/jp069010y
UR - http://dx.doi.org/10.1021/jp069010y
N2 - The influence of solute−solvent interactions on the vibrational energy relaxation dynamics of perylene and substituted perylenes in the first singlet excited-state upon excitation with moderate (
ID - 886
ER -

TY - JOUR
AU - Duvanel, Guillaume
AU - Banerji, Natalie
AU - Vauthey, Eric
TI - Excited-State Dynamics of Donor-Acceptor Bridged Systems Containing a Boron-Dipyrromethene Chromophore: Interplay between Charge Separation and Reorientational Motion
PY - 2007
JF - Journal of Physical Chemistry A
JA - J. Phys. Chem. A
SN - 1089-5639
VL - 111
IS - 25
SP - 5361
EP - 5369
L1 - http://pubs.acs.org/cgi-bin/article.cgi/jpcafh/2007/111/i25/pdf/jp071560o.pdf
L2 - http://pubs.acs.org/cgi-bin/article.cgi/jpcafh/2007/111/i25/html/jp071560o.html
L3 - http://pubs.acs.org/cgi-bin/abstract.cgi/jpcafh/2007/111/i25/abs/jp071560o.html
L4 - http://www.unige.ch/sciences/chifi/publis/pics/double/ref00881.png
M3 - 10.1021/jp071560o
UR - http://dx.doi.org/10.1021/jp071560o
N2 - The excited-state dynamics of a series of electron donor−acceptor bridged systems (DABS) consisting of a boron−dipyrromethene chromophore covalently linked to a dinitro-substituted triptycene has been investigated using femtosecond time-resolved spectroscopy. The chromophores differ by the number of bromine atom substituents. The fluorescence lifetime of the DABS without any bromine atom is strongly reduced when going from toluene to polar solvents, this shortening being already present in chloroform. This effect is about 10 times weaker with a single bromine atom and negligible with two bromine atoms on the chromophore. The excited-state lifetime shortening is ascribed to a charge transfer from the excited chromophore to a nitrobenzene moiety, the driving force of this process depending on the number of bromine substituents. The occurrence of this process is further confirmed by the investigation of the excited-state dynamics of the chromophore alone in pure nitrobenzene. Surprisingly, no correlation between the charge separation time constant and the dielectric properties of the solvents could be observed. However, a good correlation between the charge separation time constant and the diffusional reorientation time of the chromophore alone, measured by fluorescence anisotropy, was found. Quantum chemistry calculations suggest that quasi-free rotation about the single bond linking the chromophore to the triptycene moiety permits a sufficient coupling of the donor and the acceptor to ensure efficient charge separation. The charge separation dynamics in these molecules is thus controlled by the reorientational motion of the donor relative to the acceptor.
ID - 881
ER -