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The water-soluble, bolaamphiphilic cyclopenta[hi]aceanthrylene-bis-phosphate has been synthesized. This compound exhibits absorption over the entire visible spectral range and a low-lying LUMO. In aqueous medium, cypac-bis-phosphate self-assembles into a spherical morphology and preserves the remarkable electronic properties of the monomer in the supramolecular assemblies.

Opposite to many chromophores that suffer from aggregation-caused quenching (ACQ), aggregation-induced emission (AIE) type chromophores exhibit intense fluorescence and efficient energy transfer in molecular assemblies. That is why aggregation-induced emitters have gained much attention in the fields of optoelectronic devices and the creation of artificial light-harvesting systems among others.[1] Previous work demonstrated light-harvesting in supramolecular vesicles assembled from phenanthrene-DNA conjugates.[2] In this work, the phenanthrenes have been replaced by either E-tetraphenylethylenes (TPEs) (Figure 1A) or Z-TPEs and resulted in the formation of AIE-active supramolecular assemblies. As evidenced by AFM, duplex 1 self-assembles in aqueous medium into spherical objects (Figure 1B). Similar results are also obtained for Z-TPE-modified DNA conjugates. Spectroscopic data as well as physicochemical properties of the supramolecular arrays will be presented and discussed on this poster.

The self-assembly of 3,6-disubstituted amine-linked phenanthrene trimers with a positively charged backbone leads to the formation of vesicles in aqueous medium. In contrast, it was shown that 1,6-disubstituted phosphodiester-linked pyrene trimers, with a negatively charged backbone, self-assemble into sheets. The preformed cationic and anionic objects can be layered on top of each other. Sandwich-type structures of differently charged supramolecular assemblies were analyzed by atomic-force microscopy.

A low optical bandgap and fullerene-like electron affinity of functionalized cyclopenta[hi]aceanthrylene (cypac) was reported and potential applications as electron acceptors in organic solar cells are suggested among others.[1] In this work, a water-soluble, bolaamphiphilic cypac derivative with a low-lying LUMO and intense absorption bands over an extended range of the UV-visible spectral region has been synthesized.[2] Self-assembly of cypac-bis-phosphate in aqueous medium leads to the formation of a supramolecular polymer with a vesicular morphology. The electronic properties of the monomer remain largely intact upon supramolecular polymer formation, as evidenced by UV-vis and cyclic voltammetry measurements.

An approach combining DNA nanoscaffolds [1,2] with supramolecular polymers [3] for the efficient and directional propagation of light-harvesting cascades has been developed. A series of photonic wires with different arrangements of fluorophores in DNA-organized nanostructures were linked to light-harvesting supramolecular phenanthrene polymers (SPs) in a self-assembled fashion. Among them, a light harvesting complex (LHC) composed of SPs and a photonic wire of phenanthrene, Cy3, Cy5 and Cy5.5 chromophores reveals a remarkable energy transfer efficiency of 59%. [1] K. Boeneman, D. E. Prasuhn, J. B. Blanco-Canosa, P. E. Dawson, J. S. Melinger, M. Ancona, M. H. Stewart, K. Susumu, A. Huston, I. L. Medintz, J. Am. Chem. Soc. 2010, 132, 18177-18190 [2] P. K. Dutta, R. Varghese, J. Nangreave, S. Lin, H. Yan, Y. Liu, J. Am. Chem. Soc. 2011, 133, 11985-11993 [3] C. B. Winiger, S. Li, G. R. Kumar, S. M. Langenegger, R. Häner, Angew. Chem. Int. Ed. 2014, 53, 13609-13613

We previously showed that 2,7-disubstituted phosphodiester-linked phenanthrene trimers self-assemble into tubular structures in aqueous medium.[1] Further it was shown that phenanthrene oligomers conjugated to DNA assemble into vesicles.[2] The DNA-phenanthrene conjugates presented here were also found to assemble into vesicular objects. Their morphology depends on the salt concentration and annealing conditions. The formed DNA-modified vesicles are investigated for functionalization by hybridization with Au nanoparticle-modified oligonucleotides. The vesicles were characterized by atomic force microscopy (AFM) and transmission electron microscopy (TEM).

An approach combining DNA nanoscaffolds [1,2] with supramolecular polymers [3] for the efficient and directional propagation of light-harvesting cascades has been developed. A series of photonic wires with different arrangements of fluorophores in DNA-organized nanostructures were linked to light-harvesting supramolecular phenanthrene polymers (SPs) in a self-assembled fashion. Among them, a light harvesting complex composed of SPs and a photonic wire of phenanthrene, Cy3, Cy5 and Cy5,5 chromophores reveals a remarkable efficiency of 66%. Stepwise transfer of the excitation energy collected by the light-harvesting SPs via the intermediate Cy3 and Cy5 chromophores to the final Cy5,5 acceptor proceeds by a Förster resonance energy transfer mechanism. In addition, the light-harvesting ability is documented by antenna effects ranging from 1.4 up to 16 for the different LHCs.

The self-assembly of 3,6-disubstituted amine-linked phenanthrene trimers, with a positive charged backbone in aqueous medium, form vesicles. In contrast, it was shown that 1,6-disubstituted phosphodiester-linked pyrene trimers, with a negative charged backbone, assemble to sheets. By preforming the supramolecular assemblies in its specific conditions, a buffer dependency can be avoided. Further it is possible to layer the cationic and anionic structures on top of each other. The different charged supramolecular assemblies were alternately layered on top of mica and analyzed by atomic-force microscopy.

A low optical bandgap and fullerene-like electron affinity of functionalized cyclopenta[hi]aceanthrylene (cypac) was reported and potential applications as electron acceptors in organic solar cells are suggested among others.[1] In this work, a bolaamphiphilic cypac derivative was synthesized, which exhibits absorbance over the entire visible spectrum and self-assembles in aqueous medium into a vesicular morphology. The average size distribution of the vesicles can be controlled by the concentration of the monomeric building block cypac-bis-phosphate.

Supramolecular phenanthrene polymers with a negative charged phosphate backbone have been synthesized in our group. These assembled oligomers can act as light harvesting antennas. Herein we replaced the negative charged phosphate backbone by a positive charged amine one and analyzed the aggregation behavior and light harvesting properties. The self-assembly of 1,8-disubstituted amine-linked phenanthrene trimers in aqueous solution formed mono- and even multilayered vesicles based on atomic-force microscopy. The incorporation of pyrene into the vesicles allows aninvestigation of light harvesting properties.

2D supramolecular polymers may find application as functional platforms. Previously it was shown that the phosphodiester-linked trimers of 1,6-dialkynyl-substituted pyrene Py3 self-assembled into supramolecular nanosheets in aqueous medium [1]. Here we doped the supramolecular nanosheets with pyrene DNA conjugates to functionalize the nanosheets. Further the functionalized nanosheets were hybridized with Au nanoparticles modified with the complementary DNA strand. The two-dimensional supramolecular nanosheets were characterized by UV-vis spectroscopy and atomic-force microscopy (AFM).

Supramolecular phenanthrene polymers with a negative charged phosphate backbone have been synthesized in our group. These assembled oligomers can act as light harvesting antennas. Herein we replaced the negative charged phosphate backbone by a positive charged amine one and analyzed the aggregation behavior and light harvesting properties. The self-assembly of 1,8-disubstituted amine-linked phenanthrene trimers in aqueous solution formed mono- and even multilayered vesicles based on atomic-force microscopy. The incorporation of pyrene into the vesicles allows an investigation of light harvesting properties.

2D supramolecular polymers may find application as functional platforms. Previously it was shown that the phosphodiester-linked trimers of 1,6-dialkynyl-substituted pyrene Py3 self-assembled into supramolecular nanosheets in aqueous medium [1]. Here we doped the supramolecular nanosheets with pyrene DNA conjugates to functionalize the nanosheets. Further the functionalized nanosheets were hybridized with gold nanoparticles modified with the complementary DNA strand. The two-dimensional supramolecular nanosheets were characterized by UV-vis spectroscopy and atomic-force microscopy (AFM).

Photonic wires were constructed by sequentially arranging up to 3 fluorophores along a DNA scaffold with attached supramolecular phenanthrene polymers. This efficient light harvesting supramolecular polymers are formed through the assembly of short DNA and non-DNA amphiphilic oligomers in water. This yielded in creation of DNA-based photonic wires polymers with the capacity to harvest and transfer excitation energy. Förster resonance energy transfer (FRET) cascades conjugated to the phenanthrene harvesting antenna are presented as an efficient system for developing nanostructured photonic systems.

Efficient artificial light-harvesting antennas composed of multichromophoric array in a DNA scaffold are nowadays a key aspect in the supramolecular photochemistry [1]. Recently it was reported that the phenanthrene-pyrene supramolecular polymers can efficiently absorb photons which are transferred to the pyrene collection centre [2]. To expand this idea, 3,6-dialkynylphenanthrene trimer and new pyrene related oligomers were synthesized. As the DNA scaffolds are ideal platforms to organize chromophores the interesting point due to energy transfer is to introduce another acceptors in well-defined interchromophore distance from pyrene. This approach can be done by introducing complementary strand which contains appropriate chromophore in different position. Such a supramolecular complexes were investigated with different spectroscopic methods to prove efficient harvesting and transport of energy to the acceptor core through the intermediate donor-acceptor pyrene derivative.

Efficient artificial light-harvesting antennas composed of multichromophoric array in a DNA scaffold are nowadays a key aspect in the supramolecular photochemistry [1]. Recently it was reported that the phenanthrene-pyrene supramolecular polymers can efficiently absorb photons which are transferred to the pyrene collection centre [2]. To expand this idea, 3,6-dialkynylphenanthrene trimer and new pyrene related oligomers were synthesized. As the DNA scaffolds are ideal platforms to organize chromophores the interesting point due to energy transfer is to introduce another acceptors in well-defined interchromophore distance from pyrene. This approach can be done by introducing complementary strand which contains appropriate chromophore in different position. Such a supramolecular complexes were investigated with different spectroscopic methods to prove efficient harvesting and transport of energy to the acceptor core through the intermediate donor-acceptor pyrene derivative.

Supramolecular polymerization enables the construction of highly organized chromophore arrays and thus is a method to build up artificial light-harvesting antennae. In previous work we described the formation of a one-dimensional supramolecular polymer which absorbs light and effectively transfer the excitation energy to an acceptor. Assembly of a two-dimensional light-harvesting antenna would increase the number of ordered chromophores for energy collection. In this poster we will present results for a 2,7-disubstituted phenanthrene oligomer which forms tubular structures in aqueous medium. Those assemblies are only weakly fluorescent but the addition of minute amounts of acceptor results in a strong increase of fluorescence.