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Nanostrukturen und Grenzflächen Vortrag: Mi., 17:40–18:00 M-V21
Structural Aspects of Porphyrins as Biomimetic Antennas
Gernot Buth 1 , Myriam Linke-Schaetzel 2 , Christopher E. Anson 3 , Teodor
Silviu Balaban 2
1 Forschungszentrum Karlsruhe, Institut für Synchrotronstrahlung (ISS), Hermannvon-Helmholtz-Platz
1, D-76344 Eggenstein-Leopoldshafen – 2 Forschungszentrum
Karlsruhe, Institut für Nanotechnologie (INT) – 3 Universität Karlsruhe (TH), Institut
für Anorganische Chemie, Engesserstr. 15, D-76131 Karlsruhe
Light-harvesting occurs in some photosynthetic bacteria with great efficiency, sometimes
even at 100 m under the water surface. These photon sponges have organelles
called chlorosomes, which act as light-harvesters and which agglomerate bacteriochlorophyll
c as the main pigment molecule [1]. The advent of the ANKA Synchrotron source
[2] made possible collection of X-ray diffraction data on quite small crystals of several
self-assembling porphyrins which are equipped with the same recognition groups as
the natural bacteriochlorophyll. The solved crystal structures allow an unprecedented
insight into the supramolecular organization of such antenna systems [3]. Below is
shown a stack of a porphyrin which crystallizes into two different modifications and
which can pack in different ways [3]. In another example, a conformational switching
between energy and electron transfer will be presented [4]. X-ray crystallography allows
to understand the structural implications and thus programming of the self-assemblies
for a certain function, as for instance light-harvesting. It is hoped that this knowledge
will bear fruit in the construction of efficient biomimetic solar cells.
[1] T. S. Balaban, Acc. Chem. Res. 38 (2005) 612.
[2] H. O. Moser, Journal of Alloys and Compounds 328 (2001) 42.
[3] T. S. Balaban et al., Chem. Eur. J. 11 (2005) 2267.
[4] M. Linke Schaetzel et al., Chem Eur J. 12 (2006) 1931.