- Preparation and deposition of stable monolayers of fullerene derivatives
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Two new fullerene derivatives have been synthesized, which tend to form Langmuir monolayers. Robust monomolecular layers are formed at the air/water interface, that can be transferred onto hydrophilic substrates by Langmuir-Blodgett or Langmuir-Schaefer techniques. The measured areas per molecule (105 A2 for 1a dropped from a deuteriochloroform solution at 20°C) reach those expected for a true monolayer of C60 at the air/water interface.
- Wang, Ping,Chen, Bo,Metzger, Robert M.,Da Ros, Tatiana,Prato, Maurizio
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- N-ALKYLATED AMINO ACIDS AND OLIGOPEPTIDES, USES THEREOF AND METHODS FOR PROVIDING THEM.
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The invention relates to the synthesis of amphiphilic amino acid derivatives, in particular to a method for the N-alkylation of an unprotected amino acid or the N-terminus of an oligopeptide substrate, comprising reacting said unprotected amino acid or oligopeptide substrate with an alcohol, e.g. a fatty alcohol, in the presence of a homogeneous transition metal catalyst.
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Page/Page column 17-19; 34-36; 47
(2018/10/25)
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- Pairing fullerenes and porphyrins: Supramolecular wires that exhibit charge transfer activity
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A concept is elaborated of pairing electron donors and electron acceptors that share a common trait, wire-like features, as a powerful means to realize a new and versatile class of electron donor-acceptor nanohybrids. Important variables are fine-tuning (i) the complexation strength, (ii) the electron/energy transfer behavior, and (iii) the solubilities of the resulting architectures. In particular, a series of supramolecular porphyrin/fullerene hybrids assembled by the hydrogen bonding of Hamilton receptor/cyanuric acid motif has been realized. Putting the aforementioned variables into action, the association constants (Kass), as they were determined from 1H NMR and steady-state fluorescence assays, were successfully tweaked with values in the range of 104-105 M -1. In fact, our detailed studies corroborate that the latter reveal a dependence on the nature of the spacer, that is, p-phenylene-ethynylene, p-phenylene-vinylene, p-ethynylene, and fluorene, as well as on the length of the spacer. Complementary performed transient absorption studies confirm that electron transfer is indeed the modus operandi in our novel class of electron donor-acceptor nanohybrids, while energy transfer plays, if any, only a minor role. The accordingly formed electron transfer products, that is, one-electron oxidized porphyrins and one-electron reduced fullerenes, are long-lived with lifetimes that reach well into the time domain of tens of nanoseconds. Finally, we have used the distance dependence on electron transfer, charge separation and charge recombination, to determine for the first time a ss value (0.11-1) for hydrogen-bonding-mediated electron transfer.
- Wessendorf, Florian,Grimm, Bruno,Guldi, Dirk M.,Hirsch, Andreas
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supporting information; experimental part
p. 10786 - 10795
(2010/09/17)
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