A series of novel conjugated homo (16a,b) and heterodimers (20) of pi-extended tetrathiafulvalenes with p-quinodimethane structures (exTTFs) linked by a conjugative vinyl spacer have been prepared by olefination Wittig-Horner reaction from the corresponding quinones (14, 19) and phosphonates (15a,b). The redox properties, determined by cyclic voltammetry, reveal a strong donor character and the presence of only one four-electron oxidation wave to form the tetracation species at oxidation potential values quite similar to those found for the related monomers. Theoretical calculations (PM3) show a planar central stilbene moiety and highly distorted exTTF units. The electronic spectra support as well as the electrochemical data and theoretical calculation the lack of significant communication between the exTTF units.
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http://dx.doi.org/10.1021/jo049741z | DOI Listing |
Chemistry
August 2020
LCC-CNRS, Université de Toulouse, CNRS, UPS, Toulouse, France.
carbo-Benzene is an aromatic molecule devised by inserting C units within each C-C bond of the benzene molecule. By integrating the corresponding carbo-quinoid core as bridging unit in a π-extended tetrathiafulvalene (exTTF), it is shown that a carbo-benzene ring can be reversibly formed by electrochemical reduction or oxidation. The so-called carbo-exTTF molecule was thus experimentally prepared and studied by UV-visible absorption spectroscopy and cyclic voltammetry, as well as by X-ray crystallography and by scanning tunneling microscopy (STM) on a surface of highly oriented pyrolytic graphite (HOPG).
View Article and Find Full Text PDFChemistry
March 2017
Institut de Química Computatcional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, Girona, 17003, Catalonia, Spain.
The reversible encapsulation of a tetrapyridyl extended-tetrathiafulvalene (exTTF)-based ligand (m-Py)exTTF by a tetragonal Zn-porphyrin-based prismatic nanocage (1) is described. The reversible uptake and release of the (m-Py)exTTF guest proceeds through drastic electronic and conformational changes occurring upon oxidation of the latter. This reversible system has been explored in a guest-exchange process, by addition of (m-Py)exTTF to the host-guest complex [C ⊂1], leading to fullerene C ejection from the host cavity.
View Article and Find Full Text PDFNanoscale
January 2015
Departamento de Química Orgánica I, Facultad de Química, Universidad Complutense, E-28040 Madrid, Spain.
The reactivity of several carbon nanoforms (CNFs), single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs) and graphene, has been investigated through a combination of arylation and click chemistry Cu(I)-mediated azide-alkyne cycloaddition (CuAAC) reactions. The approach is based on the incorporation of electroactive π-extended tetrathiafulvalene (exTTF) units into the triazole linkers to modulate the electronic properties of the obtained conjugates. The introduction of strain, by bending the planar graphene sheet into a 3D carbon framework, is responsible for the singular reactivity observed in carbon nanotubes.
View Article and Find Full Text PDFMacromol Rapid Commun
August 2014
Laboratory of Organic and Macromolecular Chemistry, Friedrich Schiller University Jena, Humboldtstr. 10, 07743, Jena, Germany; Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Philosophenweg 7, 07743, Jena, Germany.
The first polymer bearing exTTF units intended for the use in electrical charge storage is presented. The polymer undergoes a redox reaction involving two electrons at -0.20 V vs Fc/Fc(+) and is applied as active cathode material in a Li-organic battery.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
May 2014
Departamento de Química Orgánica, Fac. C.C. Químicas, Universidad Complutense de Madrid, Av. Complutense s/n, 28040 Madrid (Spain) http://www.ucm.es/info/fullerene/
Supramolecular polymers based on dispersion forces typically show lower molecular weights (MW) than those based on hydrogen bonding or metal-ligand coordination. We present the synthesis and self-assembling properties of a monomer featuring two complementary units, a C60 derivative and an exTTF-based macrocycle, that interact mainly through π-π, charge-transfer, and van der Waals interactions. Thanks to the preorganization in the host part, a remarkable log K(a)=5.
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