4th EucheMs chemistry congress

Poster Session 2
s1225
chem. Listy 106, s257–s1425 (2012)
Poster session 2 - Nanochemistry, Nanotechnology
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PhotoACtive ion exChAnGe PoLyStyrene
nAnofiBer textiLeS
P. henKe 1 , P. KuBAt 2 , J. MoSinGer 1
1 Charles University in Prague Faculty of Science, Department
of Inorganic Chemistry, Prague, Czech Republic
2 Academy of Sciences of the Czech Republic J. Heyrovsky
Institute of Physical Chemistry, Department of Spectroscopy,
Prague, Czech Republic
The nanofiber textiles prepared by electrospinning with an
encapsulated photosensitizer efficiently photogenerate singlet
oxygen, which is able to oxidize external chemical and biological
substrates/targets [1–3] . Herein we present sulfonated elektrospun
polystyrene (PS) nanofiber textiles with externally bound
cationic photosensitizers and/or encapsulated nonpolar
meso-tetraphenylporphyrin or aluminum phthalocyanine chloride.
We used two diferent types of cationic photosensitizers,
namely 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetra(p-
-toluenesulfonate) and methylene blue. The materials were studied
by microscopic methods, steady state and time-resolved
absorption and fluorescence spectroscopy. All nanofiber materials
exhibited photogeneration of singlet oxygen and singlet oxygen
mediated delayed fluorescence (SODF). Prompt and SODF was
used as a sensitive tool for estimation of an optimal amount of
externally bond photosensitizer for maximum generation of
singlet oxygen. Doped sulfonated PS nanofibers exhibit the
oxidation of an external substrate and antibacterial activity against
E. coli. when activated by visible light. Ever moderate sulfonation
strongly increase the wettability of hydrophobic PS nanofibers
yielding to increase of antibacterial activity of nanofibers with an
encapsulated photosensitizer. Extensive sulfonation of nanofibers
is associated with postpolymerization crosslinking effect
increasing the resistence of nanofiber material to nonpolar media
but decrease oxygen diffusion in polymer.
Acknowledgement: The research was supported by the Czech
Science Foundation (P207/10/1447 and P208/10/1678)
references:
1. Mosinger J.; Jirsak O.; Kubat P.; Lang K.; Mosinger B., Jr;
J. Mater. Chem., 2007, 17, 164.
2. Mosinger J.; Lang K.; Kubat P.; Sykora J.; Hof M.; Plistil L.;
Mosinger B., Jr.; J. Fluoresc. 2009, 19, 705.
3. Jesenska S.; Plistil L.; Kubat P.;Lang K.;Brozova L.;
Popelka S.; Szatmary L.; Mosinger J.; J. Biomed. Mater.
Res. Part A 2011, 99A, 676.
Keywords: Photochemistry; Photophysics; Singlet oxygen;
Porphyrinoids; Phthalocyanines;
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Photo-ACtive SPiroPyrAn-BASed
interLoCKed SySteMS
d. hernAndez MeLo 1 , J. tiBurCio 1
4 th EucheMs chemistry congress
1 Cinvestav, Chemistry, Mexico. D.F., Mexico
Interlocked molecules, such as catenanes and rotaxanes, are
considered models of artificial molecular machines since they can
transform an energy input (chemical, electrochemical or optical)
into a mechanical motion of their components without
dissociation. [1]
An important precursor for the synthesis of rotaxanes and
catenanes are pseudorotaxanes. In a previous work we have
shown that 1,2-bis(pyridinium)ethane axles and macrocyclic
ethers, like dibenzo-24-crown-8 ether [dB24C8] and
disulfonated-dibenzo-24-crown-8 ether [dSdB24C8] 2– , are
capable of assembling into [2]pseudorotaxanes, which then can
be transformed into [2]rotaxane type complexes. [2]
Now, we have developed a new [2]pseudorotaxane motif by
substitution of one pyridinium unit on the axle by a spyropiran
moiety (SP), which can be isomerized into a monocationic
merocyanine fragment (ME) by an optical or chemical stimulus. [3]
Isomerization of SP into ME changes the crown ether affinity
towards the axle. Here, we will discuss the behaviour of the axle
in presence of [dB24C8] or [dSdB24C8] 2– , in several different
solvents. Also, we will present our progress on the development
of [2]rotaxane systems where the motion can be controlled by
reversible structural changes on the axle.
In summary, we have designed a new spiropyran-based
interlocked molecule where the photo-isomerisation of the SP
fragment triggers the motion of the components.
references:
1. Coskun A., Banaszak M., Astumian R. D., Stoddart J. F.,
Grzybowski B. A. Chem. Soc. Rev. 2012, 41, 19-30.
2. Hoffart D. J., Tiburcio J., De la Torre A., Knight L. K.,
Loeb S. J. Angew. Chem. Int. Ed. 2008, 47, 97-101;
Mercer D. J., Vella S. J., Guertin L., Suhan N. D.,
Tiburcio J., Vukotic N., Wisner J. A., Loeb S. J. Eur. J.
Org. Chem. 2011, 1763-1770.
3. Raymo F. M., Giordani S. J., J. Am. Chem. Soc. 2001, 123,
451.
Keywords: Supramolecular chemistry; Rotaxanes;
Photochromism;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc